Bay Water Quality Report

2023

Weekly Water Quality Report 10/1/23-10/6/23:

Narragansett Bay surface water temperatures increased slightly with the warm weather this week  (66-68°F).  All stations are currently reporting oxygen levels above 4 mg/L. Water clarity has improved throughout the bay.  Chlorophyll levels stayed about the same this week (5-25 ug/L). All conditions are normal for this time of year.

Weekly Water Quality Report 9/23/23-9/30/23:

Water temperatures continued to cool this week for Narragansett Bay (63-65°F).  All stations are currently reporting oxygen levels above 3 mg/L.   Chlorophyll levels have also declined this week (5-25 ug/L).  The bay remains slightly stratified with all the rain this summer.

Weekly Water Quality Report 9/16/23-9/22/23:

Water temperatures continued to cool this week for Narragansett Bay (68-71°F).  Hurricane Lee passing offshore caused partial mixing over the weekend.  As a result, oxygen levels rebounded as of 9/16/23 at all stations.  All stations are currently reporting oxygen levels above 3 mg/L.  The bay became more stratified as the week progressed with the rain event during the week.  In addition, chlorophyll levels are elevated (10-35 ug/L chlorophyll). 
 

Weekly Water Quality Report 9/9/23-9/15/23:

Water temperatures cooled slightly this week for Narragansett Bay (69-74°F). The bay remains highly stratified from all the rain this past week. In addition,chlorophyll levels are slightly elevated (5-35 ug/L chlorophyll).

With the stratification, several stations are reporting intermittent hypoxic conditions (DO < 3 mg/L for more than 6hr a day). As of 9/10/23, the real-time data is showing intermittent hypoxia in the Providence River, Upper Mt Hope Bay, Upper Narragansett Bay, including Greenwich Bay, and Upper West Passage area. The most extreme conditions are found in western Greenwich Bay with readings between 1-2 mg/L. This upper bay wide hypoxic event will be monitored closely.

Weekly Water Quality Report 9/2/23-9/8/23:

Water temperatures increased this week for Narragansett Bay with the heat wave (71-77°F).  The oxygen readings at most stations remain above 3 mg/L although oxygen levels have declined.   As of 9/6/23, Greenwich Bay is experiencing intermittent low oxygen throughout the day (4-8hr with DO<3mg/L). Chlorophyll levels have increased slightly within the Providence River, Greenwich Bay, and Upper Mt Hope Bay (CHL>20 ug/L).  These events will be monitored closely.

Monitoring completed by RI DEM and RI DOH indicated that abundance of HAB phytoplankton species was low (far-below below action levels) during late August and the first week of September 2023:

Alexandrium (paralytic shellfish poisoning): Alexandrium species were absent in all samples analyzed during August and thus far in 3. September 2023.

Dinophysis (diarrhetic shellfish poisoning): Dinophysis species abundance was low during August 2023 and thus far in September 2023, with all observations well-below the action level of 30,000 cells per liter.

Pseudo-nitzschia (amnesiac shellfish poisoning): Pseudo-nitzschia abundance was low during early August 2023 and thus far in September 2023, with all observations well-below the action level of 20,000 cells per liter.

Margalefidinium (‘rust tide’): Water discoloring blooms of Margalefidinium were not observed in any areas during late August and early September 2023.

Weekly Water Quality Report 8/26/23-9/1/23:

Water temperatures stayed about the same this week for Narragansett Bay (71-74°F). The oxygen readings from all stations are normal for this time of year (DO>3 mg/L). In addition, chlorophyll levels are not elevated (5-20 ug/L chlorophyll).

Weekly Water Quality Report 8/19/23-8/25/23:

Water temperatures cooled slightly this week for Narragansett Bay (71-74°F).  As of 8/22/2023,the oxygen levels in the Upper Bay improved to normal conditions (Do>3 mg/L). In addition, chlorophyll levels declined at all stations (5-20 ug/L chlorophyll).
 

Weekly Water Quality Report 8/12/23-8/18/23:

Water temperatures remain about the same this week for Narragansett Bay (72-75°F). The bay is highly stratified from all the rain throughout the week. In addition, chlorophyll levels are elevated levels at all stations (10-30 ug/L chlorophyll).
As of 8/14/2023, with further development of the stratification and phytoplankton bloom, hypoxic conditions were reported, in the Providence River, Upper Bay, Upper East Passage and in the West Passage to the Quonset Point area. Oxygen levels are below 3 mg/L in these areas (2-3  mg/L). This upper bay wide hypoxic event will be monitored closely. 

As a result of all the fresh water and phytoplankton bloom, the bay waters have a brownish tint that does not appear to be the result of any HABs.  RI DEM and RI DOH indicated low abundance of HAB phytoplankton species for the first half of August 2023:

Alexandrium (paralytic shellfish poisoning):

Alexandrium species were absent in all samples analyzed thus far during August 2023. 

Dinophysis (diarrhetic shellfish poisoning):

Dinophysis species abundance was low during early August 2023, with all observations well-below the action level of 30,000 cells per liter.

Pseudo-nitzschia (amnesiac shellfish poisoning):

Pseudo-nitzschia abundance was low during early August 2023, with all observations well-below the action level of 20,000 cells per liter.

Margalefidinium (‘rust tide’):

Water discoloring blooms of Margalefidinium were not observed in any areas during this time period.

Weekly Water Quality Report 8/4/23-8/11/23:

Water temperatures stayed about the same this week for Narragansett Bay (72-76°F). All stations are reporting DO levels >3 mg/L.  Chlorophyll levels have declined bay-wide and only remain slightly elevated in the embayments (5-30 ug/L).

Weekly Water Quality Report 7/29/23-8/4/23:

Water temperatures cooled this week for Narragansett Bay (72-75°F). As a result, the bay became less stratified (more mixed).  The vertical mixing resulted in improved dissolved oxygen conditions.  As of 8/2/23, most stations are reporting DO levels >3 mg/L.  Chlorophyll levels have declined bay-wide and only remain slightly elevated in the embayments (5-30ug/L).

Monitoring completed by RI DEM and RI DOH indicated that abundance of HAB phytoplankton species was below action levels during late July 2023:

Alexandrium (paralytic shellfish poisoning): Alexandrium species were absent in all samples analyzed during July 2023. 

Dinophysis (diarrhetic shellfish poisoning): Dinophysis species abundance was low during July 2023, with all observations well-below the action level of 30,000 cells per liter.

Pseudo-nitzschia (amnesiac shellfish poisoning): Pseudo-nitzschia abundance increased to above the action level of 20,000 cells per liter on 7/13/2023 in the Mt. Hope Bay and northern East Passage area.  Follow-up sampling demonstrated absence of the biotoxin domoic acid in shellfish tissue samples.  Monitoring during late-July (7/17 through 7/27) has shown reduced Pseudo-nitzschia abundance in Upper Narragansett Bay, the East Passage, the Sakonnet River and in the coastal salt ponds. 

Margalefidinium (‘rust tide’): Water discoloration blooms of Margalefidinium were not observed in any areas during this time period.

Weekly Water Quality Report 7/22/23-7/28/23:

Water temperatures warmed slightly this week for Narragansett Bay (80-82°F). The bay remains highly stratified from all the rain this past week. In addition, the phytoplankton bloom in the upper bay persists at elevated levels at all stations (10-80 ug/L chlorophyll). 

With the stratification and phytoplankton bloom, several stations are reporting hypoxic conditions (DO < 3 mg/L). As of 7/19/23, the real-time data continues to show hypoxic conditions in the  Providence River, Upper Bay, and Upper East Passage and West Passage to the Quonset Point area. Oxygen declined further this week in these areas (0.5-2 mg/L). There is a risk for fish kills based on the data.  This upper bay wide hypoxic event will be monitored closely.

Weekly Water Quality Report 7/15/23-7/21/23:

Water temperatures warmed slightly this week for Narragansett Bay (77-80°F). The bay remains highly stratified from all the rain this past week. In addition, the phytoplankton bloom in the upper bay persists at elevated levels at all stations (10-80 ug/L chlorophyll). 

With the stratification and phytoplankton bloom, several stations are reporting hypoxic conditions (DO < 3 mg/L). As of 7/19/23, the real-time data is showing the hypoxic conditions in the  Providence River, Upper Bay, and Upper East Passage and West Passage to the Quonset Point area. The most extreme conditions are found in the Upper Providence River, western Greenwich Bay, and Upper Mt Hope Bay (0.5-2 mg/L). In western Greenwich Bay, intermittent hypoxia has been recorded since 7/16/23. This upper bay wide hypoxic event will be monitored closely.

Weekly Water Quality Report 7/8/23-7/13/23:

Water temperatures stayed about the same this week for Narragansett Bay are 74-80°F. Chlorophyll levels are slightly elevated at all stations throughout the Upper Bay (5-30 ug/L). Dissolved oxygen readings improved slightly this week in Greenwich Bay and Upper Mt Hope Bay.  All other stations remain above the 3 mg/L threshold for hypoxia.  

Weekly Water Quality Report 7/1/23-7/7/23:

Water temperatures continue to warm this week for Narragansett Bay are 74-80°F. Chlorophyll levels remain elevated at all stations throughout the Upper Bay (10-50 ug/L). Dissolved oxygen readings have continued to decline this week in Greenwich Bay and Upper Mt Hope Bay. As of 7/4/23, Greenwich Bay is experiencing hypoxic conditions  (DO< 3 mg/L). Oxygen levels remain below 2 mg/L for about 4-6 hours a day.  All other stations remain above the 3 mg/L threshold for hypoxia.  A spatial survey will be conducted next week to monitor this event more closely. 

Weekly Water Quality Report 6/24/23-6/30/23:

Water temperatures continue to warm this week for Narragansett Bay are 70-74°F. Chlorophyll levels are slightly elevated (5-30 ug/L). Dissolved oxygen readings have declined this week. As of 6/26/23, Greenwich Bay, Providence River, and Upper Bay areas are experiencing lower than normal oxygen levels (3-4 mg/L).  All stations remain above the 3 mg/L threshold for hypoxia.

Weekly Water Quality Report 6/17/23-6/23/23:

Water temperatures warmed slightly this week for Narragansett Bay are 66-70°F. Chlorophyll levels remain low (<15 ug/L). Dissolved oxygen readings are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 6/10/23-6/16/23:

Water temperatures warmed slightly this week for Narragansett Bay are 65-69°F. Chlorophyll conditions are no longer elevated (<15 ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 6/03/23-6/09/23:

All water quality parameters are reading within the normal range for this time of year. With all the smoke hase this week, water temperatures cooled this week for Narragansett Bay are 60-68°F. Chlorophyll conditions are slightly elevated within the Providence River, Upper Mt Hope Bay, and Greenwich Bay (>15 ug/L). Dissolved oxygen levels are above 5 mg/L at all stations.

Weekly Water Quality Report 5/29/23-6/02/23:

All water quality parameters are reading within the normal range for this time of year. Water temperatures warmed this week for Narragansett Bay are 64-71°F. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations.

Weekly Water Quality Report 5/20/23-5/26/23:

All NBFSMN stations were deployed over the past two weeks. Water temperatures this week for Narragansett Bay are 60-63°F. This is similar to this time last year. Chlorophyll conditions are currently slightly elevated at any of the NBFSMN stations (<20ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

HAB phytoplankton monitoring completed by RIDEM and RIDOH indicated that abundance of HAB phytoplankton species (Alexandrium spp., Pseudo-nitzschia spp., Dinophysis spp.) have been well-below levels of concern during April and May 2023.

Weekly Water Quality Report 10/1/22-10/07/22:



Water temperatures continued to cool this week throughout Narragansett Bay (60-62°F).  The bay is well mixed. Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels are normal for this time of year at all stations this week (DO>4 mg/L).

Weekly Water Quality Report 9/24/22-9/30/22:

Water temperatures continued to cool this week throughout Narragansett Bay (64-67°F).  The bay is well mixed. Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels are normal for this time of year at all stations this week (DO>4 mg/L).

Weekly Water Quality Report 9/17/22-9/23/22:

Water temperatures cooled this week throughout Narragansett Bay (67-70°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels are normal for this time of year at all stations this week (DO>4 mg/L).

Weekly Water Quality Report 9/10/22-9/16/22:

Narragansett Bay becomes well mixed this week, and water quality conditions remain normal for this time of year.  Water temperatures cooled slightly throughout Narragansett Bay (72-73°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels remain above the hypoxia threshold at all stations this week. (DO>3 mg/L).

On 9/13/22, a sewage leak of 450,000 gals of raw sewage was reported in the Warwick Pond area by RIDEM.  The rupture of the Warwick sewer line caused RIDEM to extend the Upper Bay shellfish closures and issue a no-contact advisory for Warwick Pond, Buckeye Brook, Mill Creek, and Mill Cove. This event continues to be monitored closely by RIDEM. Please see RIDEM press releases for more information.

Weekly Water Quality Report 9/3/22-9/9/22:

With the large rainfall event on 9/5-9/6/22 (10+ inches), Narragansett Bay surface salinities decreased 2 ppt this week. As a result, RIDEM closed several conditional areas to shellfishing due to this rain event. Please see RIDEM press releases for more information.

Water temperatures cooled slightly throughout Narragansett Bay (72-74°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels remain above the hypoxia threshold at all stations this week. (DO>3 mg/L). These water quality conditions are normal for this time of year.

HAB phytoplankton monitoring conducted by RIDEM shows harmful algal bloom species (Alexandrium spp, Dinophysis spp, and Pseudo-nitchia) counts remain low throughout the summer.  In addition, 'rust tides' (large blooms of Cochlodinium spp) have not been observed so far this summer.  HAB monitoring will continue through the Autumn of 2022.

Weekly Water Quality Report 8/28/22-9/2/22:

Water temperatures cooled this week throughout Narragansett Bay (73-76°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels recovered to normal levels at all stations (DO>3 mg/L). All water quality conditions are normal for this time of year.

Weekly Water Quality Report 8/20/22-8/27/22:

Water temperatures stayed about the same this week throughout Narragansett Bay (75-78°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels recovered to normal levels at all stations (DO>3 mg/L). All water quality conditions are normal for this time of year.

MassDEP reported a fish kill in the Swansea area.  The dead fish consisted mainly of juvenile menhaden.  This was reported on 8/23/22.

Weekly Water Quality Report 8/13/22-8/19/22:

Water temperatures cooled this week throughout Narragansett Bay (75-78°F). Chlorophyll conditions are no longer elevated (0-20 ug/L).  Dissolved oxygen levels recovered to normal levels at all stations (DO>3 mg/L). All water quality conditions are normal for this time of year.

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during the first three weeks of August 5 -19, 2022.

HAB phytoplankton remained either absent or present in low abundance levels in Narragansett Bay, coastal waters south of Newport, and the coastal salt ponds during mid-August 2022.   

During the first week of August 2022 there was a modest increase in Pseudo-nitzschia abundance to levels of 4,000 to 10,000 cells per liter in the coastal salt ponds and the West Passage of Narragansett Bay.  These levels were below the action level of 20,000 cells per liter.  More recent samples collected during 8/11 to 8/17/2022 showed that Pseudo-nitzschia had declined to levels of several thousand cells per liter or less.  RI DEM and RI DOH will continue to monitor HAB phytoplankton abundance in shellfishing areas.

Weekly Water Quality Report 7/30/22-8/05/22:

Water temperatures stayed about the same again this week throughout Narragansett Bay (75-83°F). Chlorophyll conditions remain elevated throughout the bay (5-30 ug/L).  As of 8/7, Dissolved oxygen levels recovered to normal levels at most stations (DO>3 mg/L). Greenwich Bay is still experiencing occasional low oxygen conditions for about 6hr each day (DO< 3mg/L; min DO of 1.9 mg/L). 

Weekly Water Quality Report 7/30/22-8/05/22:

Water temperatures stayed about the same this week throughout Narragansett Bay (75-83°F). Chlorophyll conditions have increased throughout the bay (5-30 ug/L). Dissolved oxygen conditions declined at several stations. The Upper Bay area is experiencing slightly low oxygen levels as of 8/2, with a minimum DO value of 2.5 mg/L . During the same time period (8/2-present), Greenwich Bay is experiencing low oxygen conditions for about 6hr each day (DO< 3mg/L; min DO of 2 mg/L). A spatial survey is scheduled for next week to examine the extent of this event.

RI DEM & RI DOH Harmful Phytoplankton (HAB) Summary 8/5/2022

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during the last two weeks of July and early August 2022.

HAB phytoplankton remained either absent or present in very low abundance levels in Narragansett Bay, coastal waters south of Newport, and the coastal salt ponds during the first last two weeks of July 2022.

During the first week of August 2022 there was a modest increase in Pseudo-nitzschia abundance to levels of 4,000 to 10,000 cells per liter in the coastal salt ponds. These levels are still below the action level of 20,000 cells per liter. Pseudo-nitzschia abundance remained low in Upper Narragansett Bay, the Sakonnet River, and Greenwich Bay (0 to 1,000 cells per liter). RI DEM and RI DOH will continue to monitor HAB phytoplankton abundance in shellfishing areas.

Weekly Water Quality Report 7/23/22-7/29/22:

Water temperatures cooled slightly this week throughout Narragansett Bay (75-83°F). Chlorophyll conditions have decreased slightly throughout the bay (5-20 ug/L). Dissolved oxygen conditions declined at several stations. The Upper Bay area experienced slightly low oxygen levels from 7/23-7/26, with a minimum DO value of 2.5 mg/L . During the same time period (7/23-7/26/22), Greenwich Bay was experiencing low oxygen conditions for about 6hr each day (DO< 3mg/L; min DO of 1.8mg/L). As of 7/29/22, oxygen levels are above 3.5 mg/L at all stations.

Weekly Water Quality Report 7/16/22-7/22/22:

Water temperatures continued to increase with the heat wave this week throughout Narragansett Bay (75-83°F). Chlorophyll conditions have increased slightly throughout the bay (5-30 ug/L). Dissolved oxygen levels remain over 3.5 mg/L at most stations. All stations are reporting normal conditions for this time of year.

Weekly Water Quality Report 7/9/22-7/15/22:

Water temperatures continued to increase this week throughout Narragansett Bay (71-78°F). Chlorophyll conditions have decreased slightly throughout the bay (5-20 ug/L). Dissolved oxygen levels remain over 4 mg/L at most stations. All stations are reporting normal conditions for this time of year.

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during the first two weeks of July 2022.

HAB phytoplankton remained either absent or present in very low abundance levels in Narragansett Bay, coastal waters south of Newport, and the coastal salt ponds during the first two weeks of July 2022. Abundance of Alexandrium spp., Dinophysis spp. and Pseudo-nitzschia spp. were well-below levels of concern. RI DEM and RI DOH will continue to monitor HAB phytoplankton abundance in shellfishing areas.

Weekly Water Quality Report 7/2/22-7/8/22:

Water temperatures continued to increase this week throughout Narragansett Bay (70-75°F). Chlorophyll conditions are elevated at many of the NBFSMN stations (5-30 ug/L). Dissolved oxygen levels remain over 4 mg/L at most stations. Conditions have improved in Greenwich Bay with only experiencing a couple hours a day with oxygen levels below 3 mg/L.

Weekly Water Quality Report 6/25/22-7/1/22

All water quality parameters are reading within the normal range for this time of year. Water temperatures increased slightly this week throughout Narragansett Bay(68-74°F). Chlorophyll conditions are elevated at many of the NBFSMN stations (5-30 ug/L). Dissolved oxygen levels have declined at most stations with the rise in temperatures, but all stations remain over 4 mg/L except for Greenwich Bay. As of 6/30/22, Greenwich Bay is experiencing intermittent low oxygen (<2 mg/L) for about 8 hours a day. This event will be further investigated next week with a spatial survey of the Bay. RIDEM has also been conducting HAB surveys.

RI DEM & RI DOH Harmful Phytoplankton (HAB) Summary 7/1/2022

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during the last two weeks of June 2022.

HAB phytoplankton remained either absent or present in very low abundance levels in Narragansett Bay, Sakonnet River and the coastal salt ponds during the second half of June 2022. Abundance of Alexandrium spp., Dinophysis spp. and Pseudo-nitzschia spp. were well-below levels of concern. RI DEM and RI DOH will continue to monitor HAB phytoplankton abundance in shellfishing areas.

Weekly Water Quality Report 6/18/22-6/24/22:

All water quality parameters are reading within the normal range for this time of year. Water temperatures increased slightly this week throughout Narragansett Bay( 66-73°F). Chlorophyll conditions are slightly elevated at any of the NBFSMN stations (<20 ug/L). Dissolved oxygen levels are above 4 mg/L at all stations.

Weekly Water Quality Report 6/11/22-6/17/22:

All water quality parameters are reading within the normal range for this time of year. Water temperatures continued to increase this week throughout Narragansett Bay( 65-72°F). Chlorophyll conditions are slightly elevated at any of the NBFSMN stations (<20ug/L). Dissolved oxygen levels are above 4 mg/L at all stations.

Weekly Water Quality Report 6/04/22-6/10/22:

All water quality parameters are reading within the normal range for this time of year. Water temperatures this week for Narragansett Bay are 63-68°F. This is a slight increase from last week. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations.

Weekly Water Quality Report 5/28/22-6/03/22:

All water quality parameters are reading within the normal range for this time of year. Water temperatures this week for Narragansett Bay are 62-65°F. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations.

Weekly Water Quality Report 5/23/22-5/27/22:

All NBFSMN stations were deployed this week. Water temperatures this week for Narragansett Bay are 60-65°F. This is similar to this time last year. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during April and May 2022.

Alexandrium spp. were absent in most samples analyzed during April and May 2022. Alexandrium was detected at several stations at levels of up to low hundreds of cells per liter on one sample date (4/21/22). This appeared to be a short-lived Alexandrium increase as Alexandrium was not detected in samples collected since 4/21/22.

Dinophysis spp. were absent in nearly all samples analyzed during April and May 2022. When present, Dinophysis was at levels of only tens of cells per liter.

Pseudo-nitzschia spp. have been present in lower Narragansett Bay at elevated levels for most of April and May 2022. Elevated Pseudo-nitzschia counts of near or greater than the 20,000 cells per liter have persisted in the lower Bay from 4/19/22 through 5/17/22. Counts on 5/17/22 showed increased Pseudo-nitzschia abundance in the Upper Bay also. Shellfish meat testing (LC MSMS) completed by RI DOH has indicated that there is an absence of domoic acid in shellfish meats collected in both the West Passage (samples from 4/20 and 5/19/22) and in the Upper Bay (samples from 5/19/2022). A summary of recent Pseudo-nitzschia counts and shellfish meat domoic acid test results is below. RI DEM and RI DOH will continue to monitor this Pseudo-nitzschia bloom with phytoplankton cell counts and shellfish meat toxin testing.

Weekly Water Quality Report 9/25/21-10/1/21:

Surface temperatures cooled this week throughout Narragansett Bay (65-67°F). The bay is well mixed. All stations are reporting oxygen levels above 4 mg/L. Chlorophyll readings have remained low this week (<15 ug/L). All water quality conditions are normal for this time of year.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 9/18/21-9/24/21:

Surface temperatures stayed about the same again this week throughout Narragansett Bay (69-71°F). The bay is well mixed. All stations are reporting oxygen levels above 4 mg/L. Chlorophyll readings have remained low this week (<15 ug/L). All water quality conditions are normal for this time of year.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 9/11/21-9/17/21:

Surface temperatures stayed about the same this week throughout Narragansett Bay (69-72°F). Oxygen levels are also about the same throughout the Upper Bay. All stations are reporting oxygen levels above 3 mg/L. Chlorophyll readings have remained low this week (< 20 ug/L). All water quality conditions are normal for this time of year.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 9/4/21-9/10/21:

Surface temperatures stayed about the same this week throughout Narragansett Bay (69-72°F). Oxygen levels are about the same throughout the Upper Bay. All stations are reporting oxygen levels above 3 mg/L. Chlorophyll readings have remained low this week (< 20 ug/L). With more rain this week, the salinity levels surface to bottom remain with a difference of 2-8ppt causing some stratification in the headwaters.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 8/28/21-9/3/21:

This week's water quality was from the rain from the remnants of Hurricane Ida. Prior to the storm from 8/28-9/1, the Upper Bay, Upper West Passage, and most of Greenwich Bay were experiencing low oxygen conditions ( DO< 3 mg/L). Chlorophyll levels were also elevated throughout the bay during this time period (10-60 ug/L).

During the storm on Weds-Thurs, the bay became slightly mixed. Surface temperatures decreased and have become more uniform throughout Narragansett Bay (69-71°F). Oxygen levels are about the same throughout the Upper Bay. All stations are reporting oxygen levels above 3 mg/L. Chlorophyll readings have decreased after the storm. The salinity levels surface to bottom remain with a difference of 2-8ppt causing some stratification in the headwaters.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 8/21/21-8/27/21:

Tropical Storm Henri affected water quality measurements this week. The data showed the tropical storm caused the bay to become well mixed right after the storm. However, with the warm conditions this week, surface temperatures increased throughout Narragansett Bay (75-80°F). The bay is now highly stratified with increased surface temperatures and surface to bottom salinity differences being about 2-5ppt. Oxygen levels are about the same throughout the Upper Bay. All stations are reporting oxygen levels above 3 mg/L. Chlorophyll readings have increased this week. As of 8/26/21, all stations are reporting elevated chlorophyll levels (10-60 ug/L). This is expected with increased nutrient loadings from the tropical storm earlier in the week. As a result, we expect oxygen levels to decrease in the coming week.

Harmful algae monitoring in the Bay and coastal salt ponds showed that HAB phytoplankton continued to be below levels of concern.

Weekly Water Quality Report 8/14/21-8/20/21:

Water temperatures and water quality conditions remain about the same this week for Narragansett Bay (70-77°F). Oxygen levels are about the same throughout the Upper Bay. Most locations were reporting oxygen conditions throughout the upper bay above 3 mg/L. Hypoxic conditions persist in a few areas, such as the Providence River, western Greenwich Bay, and Upper Mt Hope Bay (DO< 3 mg/L). Chlorophyll levels remain stable at most stations (5-30 ug/L).

Weekly Water Quality Report 8/7/21-8/13/21:

Water temperatures increased this week for Narragansett Bay (70-77°F). Oxygen levels improved at all stations this week. As of 8/10/21, most locations were reporting oxygen conditions throughout the upper bay above 3 mg/L. Hypoxic conditions persist in a few areas, such as the Providence River, western Greenwich Bay, and Upper Mt Hope Bay (DO< 3 mg/L). Chlorophyll levels remain stable at most stations (5-30 ug/L).

Harmful algae bloom (HAB) monitoring in the Bay and coastal salt ponds showed HAB phytoplankton abundance to be at low abundance in most locations. Several observations of Pseudo-nitzschia spp. made in the West Passage of Narragansett Bay approached the action level of 20,000 cells per liter. Precautionary analysis of sentinel shellfish from the area demonstrated that this elevated Pseudo-nitzschia abundance had not impacted shellfish (shellfish had biotoxin levels below detection).

Weekly Water Quality Report 7/31/21-8/6/21:

Water temperatures cooled slightly this week for Narragansett Bay (69-73°F). Oxygen levels declined at all stations this week. As of 8/1/21, most locations were reporting hypoxic conditions throughout the upper bay (2-3 mg/L). A spatial survey, led by Brown University, revealed low oxygen from the Providence River to the Quonset Pt area (1-3 mg/L). Upper Providence River, western Greenwich Bay, and Upper Mt Hope Bay are reporting the lowest readings for about 6-8 hrs a day (DO< 2 mg/L). Water clarity is reduced from a predominant skeletonema bloom. It is known to give the water a brown tint. Chlorophyll levels remain stable at most stations(5-30 ug/L). This event will be monitored closely.

Weekly Water Quality Report 7/24/21-7/30/21:

Water temperatures stayed about the same this week for Narragansett Bay (70-75°F). With the cool fronts over the weekend, stratification decreased at most stations. In addition, chlorophyll levels have decreased at most stations (5-30 ug/L).

With the decrease in stratification and phytoplankton bloom, dissolved oxygen levels have increased at most stations. The low oxygen event ended on 7/25/21 at most locations throughout the upper bay. Presently, oxygen levels are above 3 mg/L from Conimicut Pt to the lower bay, with exceptions in cove areas. Upper Providence River, western Greenwich Bay, and Upper Mt Hope Bay are reporting intermittent hypoxia for about 6-8 hrs a day (DO< 3mg/L).

Weekly Water Quality Report 7/17/21-7/23/21:

Water temperatures stayed about the same this week for Narragansett Bay (70-77°F). The bay remains highly stratified from all the rain this month. In addition, the phytoplankton bloom in the upper bay persists at elevated levels at all stations (10-80 ugl/L chlorophyll). This bloom gives bay surface waters a brown tint. The phytoplankton bloom consists mainly of Skeletonema spp. – a type of diatom that does not produce biotoxins.

With the stratification and phytoplankton bloom, several stations are reporting hypoxic conditions (DO < 3 mg/L). Spatial surveys, led by Brown University this week, revealed these hypoxic conditions are found throughout the Providence River, Upper Bay, and Upper West Passage to the Quonset Point area. This event has been documented since 7/19/21 with the most extreme conditions being found in the Upper Providence River, western Greenwich Bay, and Upper Mt Hope Bay (0.5-2 mg/L). This hypoxic event will be monitored closely.

Weekly Water Quality Report 7/11/21-7/16/21:

Water temperatures increased this week for Narragansett Bay (70-77°F). After the passing of tropical storm Elsa, the bay received a large volume of freshwater. As a result, the upper bay is highly stratified. In addition, the upper bay is experiencing a phytoplankton bloom (10-80 ugl/L chlorophyll). This bloom gives bay surface waters a brown tint. The phytoplankton bloom consists mainly of Skeletonema spp. – a type of diatom that does not produce biotoxins.

With the stratification and phytoplankton bloom, stations from the Providence River to the Mt View area of the upper bay are experiencing hypoxic conditions (DO< 3 mg/L). Upper Providence River, western Greenwich Bay, and Upper Mt Hope Bay are reporting very low oxygen for several hours a day (0.5-2 mg/L). Spatial surveys will be conducted next week to determine the full extent of this event. This hypoxic event will be monitored closely.

RI DEM and RI DOH monitoring has shown that levels of potentially harmful algae Alexandrium spp., Dinophysis spp. and Pseudo-nitzschia spp. remain below levels of concern in the Bay and coastal salt ponds.

Weekly Water Quality Report 7/3/21-7/10/21:

Water temperatures cooled this week for Narragansett Bay (70-73)°F. Dissolved oxygen conditions are good (DO >3.5 mg/L) at most stations. Stations in the upper reaches of the bay are experiencing intermittent low oxygen (western Greenwich Bay, Upper Providence River, and Upper Mt Hope Bay). Oxygen levels are at hypoxic levels (1.5-3mg/L) for about 4-12 hrs per day at these locations. The rest of Narragansett Bay is reading normal water quality conditions for this time of year.

Weekly Water Quality Report 6/26/21-7/2/21:

Water temperatures this week for Narragansett Bay are 60-77°F. This is about a 4 degree increase from last week. Dissolved oxygen conditions are good (DO >3.5 mg/L) at all stations. All water quality parameters, throughout the rest of the bay, are reading within the normal range for this time of year.

RIDEM-OWR shellfishing program monitors for harmful algal blooms throughout the year. Early summer results show Pseudo-nitzschia was at low abundance (0 to 3,000 cells/L) from late February through early June 2021. In mid-June 2021 Pseudo-nitzschia abundance increased to a maximum of 15,000 to 16,000 cells per liter in the lower West Passage of Narragansett Bay. This June Pseudo-nitzschia increase was not observed in other regions, such as the coastal salt ponds and Greenwich Bay. Pseudo-nitzschia abundance appeared to be declining by late June 2021. HAB monitoring of RI shellfish waters will continue through the summer.

Weekly Water Quality Report 6/19/21-6/25/21:

Water temperatures this week for Narragansett Bay are 66-73°F. This is about a 2 degree increase from last week. Dissolved oxygen conditions are good (DO > 3.5 mg/L) at all stations. All water quality parameters, throughout the rest of the bay, are reading within the normal range for this time of year.

Weekly Water Quality Report 6/12/21-6/18/21:

Water temperatures this week for Narragansett Bay are 64-70°F. This is about the same as last week. Chlorophyll conditions remain slightly elevated throughout the upper reaches of Narragansett Bay (Providence River, Greenwich Bay and Upper Mt Hope Bay) (10-30 ug/L). Dissolved oxygen levels are above 4 mg/L at all stations, with the exception of Upper Mt Hope Bay. Upper Mt Hope Bay is experiencing periods of low oxygen on a diel cycle for about 4-6 hr per day (DO<3 mg/L). All other water quality parameters, throughout the rest of the bay, are reading within the normal range for this time of year.

Weekly Water Quality Report 6/05/21-6/11/21:

Water temperatures this week for Narragansett Bay are 64-70°F. This is about a 4 degree increase from last week. Chlorophyll conditions are slightly elevated at the upper NBFSMN stations (Providence River, Greenwich Bay and Upper Mt Hope Bay) (10-30 ug/L). Dissolved oxygen levels are above 4 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 5/29/21-6/04/21:

Water temperatures this week for Narragansett Bay are 60-63°F. This is about the same as last week. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<20 ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 5/23/21-5/28/21:

All NBFSMN stations were deployed the week of 5/23/20. Water temperatures this week for Narragansett Bay are 60-66°F. This is slightly warmer than this time last year. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 10/3/20-10/9/20:

Water temperatures cooled slightly this week throughout Narragansett Bay (66-64°F). The bay is well mixed this week. As a result, oxygen levels are above 5 mg/L at all stations. Chlorophyll readings are below 25 ug/L at all stations. In the Upper West Passage, "rust bloom patches" were observed on 10/9/20. All NBFSMN stations are reporting normal conditions for this time of year.

Weekly Water Quality Report 9/26/20-10/2/20:

Water temperatures stayed about the same this week throughout Narragansett Bay (68-64°F). The bay remains well mixed this week. As a result, oxygen levels are above 5 mg/L at all stations. Chlorophyll readings are below 25 ug/L. All NBFSMN stations are reporting normal conditions for this time of year.

Weekly Water Quality Report 9/19/20-9/25/20:

Water temperatures continued to cool this week throughout Narragansett Bay (68-64°F). The bay is well mixed this week. As a result, oxygen levels are above 4 mg/L at all stations. Chlorophyll readings are below 25 ug/L. All NBFSMN stations are reporting normal conditions for this time of year. Mt Hope Bay Buoy was lost from its original location.

Weekly Water Quality Report 9/12/20-9/18/20:

Water temperatures cooled this week throughout Narragansett Bay (68-70°F). The bay is well mixed this week. As a result, oxygen levels are above 4 mg/L at all stations. Chlorophyll readings are below 25 ug/L. As of 9/15/20, there have been no observations of "rust tides" throughout Narragansett Bay. All NBFSMN stations are reporting normal conditions for this time of year.

Weekly Water Quality Report 9/5/20-9/11/20:

Water temperatures stayed about the same this week throughout Narragansett Bay (71-73°F). Oxygen levels remain at normal conditions for this time of year at the NBFSMN stations located in the bay proper areas (DO> 3 mg/L). A spatial survey on 9/7/20, led by Brown University, revealed hypoxic condition in bottom waters of the Providence River from the Hurricane Barrier down to Gaspee Point (DO< 2.5 mg/L). As of 9/10/20, Upper Mt Hope Bay in the Taunton River area, is also observing low oxygen conditions (DO<3 mg/L). Cochlodinium ("rust tide") blooms are still present in patchy areas throughout the bay. In these bloom areas chlorophyll levels are >40 ug/L based on NBFSMN data. These events will be monitored closely in the coming week.

Weekly Water Quality Report 8/29/20-9/4/20:

Water temperatures cooled this week throughout Narragansett Bay (71-73°F). Bay waters are relatively well mixed. As a result, oxygen levels remain at normal conditions for this time of year at all stations (DO> 3 mg/L). Cochlodinium ("rust tide") blooms are still present in patchy areas throughout the bay. In these bloom areas chlorophyll levels are <40 ug/L based on NBFSMN data.

Weekly Water Quality Report 8/22/20-8/28/20:

Water temperatures have stayed about the same this week throughout Narragansett Bay (73-77°F). Bay waters are relatively well mixed. As a result, oxygen levels remain at normal conditions for this time of year at almost all stations (DO> 3 mg/L). Greenwich Bay still has intermittent hypoxia with oxygen levels below 3 mg/L for 10-15 hours per day throughout this week. Cochlodinium ("rust tide") blooms are still present in patchy areas throughout the bay. In these bloom areas chlorophyll levels are >40 ug/L based on NBFSMN data.

RIDEM conducted surveys on the bloom patches over the past week. Patches of the 'rust tide' dinoflagellate Cochlodinium polykrikoides (now Margolefidinium polykrikoides) continue to be present in Narragansett Bay and some coastal salt ponds. Surveys conducted 8/17 to 8/20 showed abundances of 0.5 to 1.5 million cells per liter in the Upper Bay (north of Prudence Island). The East Passage had Cochlodinium abundance of 0.5 to 5 million cells per liter, with extensive rust tide patches visible from Prudence Island south to Gould Island and in the waters near the Newport Bridge from Jamestown east to outer Newport Harbor and Brenton Reef. The southern portion of Mt Hope Bay had 0.5 to 1.0 million Cochlodinium cells per liter while the Sakonnet River had no visible rust tide patches on 8/19/2020.

Samples collected 8/24 to 8/27 showed rust tide was present at low levels or absent at the breachways of the salt ponds (Pt. Judith, Potter, Ninigret, Quonochontaug and Winnapaug Ponds). No rust tide patches were observed in Bristol Harbor and east of Prudence Island on 8/24. Similarly, rust tide was not detected in samples collected in Block Island’s Great Salt Pond this week. Recent cooler weather may help to terminate the August 2020 rust tide bloom.

In addition, RIDEM & RIDOH monitoring indicated that abundance of the HAB phytoplankton Alexandrium spp., Pseudo-nitzschia spp. and Dinophysis spp. remained below levels of concern in all RI shellfish growing areas during August 2020.

The RI DEM Division of Marine Fisheries responded to two fish kills at Fogland Point in Tiverton this week. In both cases, the only species affected was Atlantic Menhaden. Upon investigation, staff observed schools of live Menhaden being chased by predators (possibly blue fish or striped bass). DMF staff believe the Menhaden were chased into shallow water or onto the beach where they were trapped and stressed, causing the DO to be depleted in that localized area. No evidence of other water quality problems was observed.

Weekly Water Quality Report 8/15/20-8/21/20:

Water temperatures cooled this week in Narragansett Bay with cool fronts passing the area (74-77°F). As a result, as of 8/17/20, oxygen levels have improved at almost all stations to normal conditions for this time of year (DO> 3 mg/L). Greenwich Bay still has intermittent hypoxia with oxygen levels below 3 mg/L for 10-15 hours per day throughout this week. Cochlodinium ("rust tide") blooms are still present in patchy areas throughout the bay. In these bloom areas chlorophyll levels are >40 ug/L. RIDEM will continue to monitor these Cochlodinium blooms in the coming week.



Over the weekend of 8/14/20-8/16/20, RIDEM Division of Marine Fisheries investigated multiple fish kills within Narragansett Bay. The areas affected by the fish kills were: Apponaug Cove, Bullock Cove, Allin’s Cove, and Rumstick Point. Multiple species were observed including: Atlantic menhaden, mummichogs, striped killifish, American eel, Atlantic silversides, northern kingfish, blue crabs, summer flounder, and blue mussels. Blue mussels have an upper temperature threshold of ~80-85F, and water temperatures have been consistently high lately. It is likely that these kills are linked to hypoxic conditions due to the recent heat wave and algal blooms. Suspected Cochlodinium polykrikoides blooms were observed at the fish kill sites (known as "rust tide", distinguishable by the murky brown water it creates). In addition, low oxygen (< 2 mg/L) was recorded at the NBFSMN stations near the fish kill locations during this time period. Given these conditions, it is most likely that these die-off events were caused by these hypoxic conditions.

Weekly Water Quality Report 8/08/20-8/14/20:

Water temperatures continue to warm slightly this week in Narragansett Bay (77-81°F). Chlorophyll conditions have increased throughout the bay (>40 ug/L, in some areas). As of 8/7/20, there have been several observations of Cochlodinium bloom patches ("rust tide") throughout Narragansett Bay and the coastal ponds in Rhode Island. The chlorophyll levels have been above 50 ug/L within these patches. As a result, low oxygen has been observed at the NBFSMN stations north of the Mt View area, including Mt Hope Bay. The Seekonk River and Greenwich Bay stations are observing the worst conditions (DO< 1 mg/L). These areas, along with Ninigret Pond, are observing severe hypoxia (DO < 3 mg/L for 24 hours or more) throughout this week. These areas will be monitored closely over the next week due to a threat of a potential fish kill when oxygen levels are persistently below 3 mg/L. Other areas within the Upper Bay (north Prudence Island including the Providence River) and Mt Hope Bay are experiencing intermittent low oxygen with levels between 1-3 mg/L for about 10-12 hours a day.

As of 8/14/20, RIDEM Marine Fisheries is investigating two fish kills in the northern portions of the bay.

RIDEM & RIDOH monitoring indicated HAB phytoplankton abundance were low and well-below levels of concern in all shellfish growing areas during the early summer of 2020.

Weekly Water Quality Report 8/01/20-8/7/20:

Water temperatures warmed slightly this week for Narragansett Bay (77-80°F). Chlorophyll conditions have increased throughout the bay (<40 ug/L). With the high winds from Hurricane Isaias passing by Rhode Island early this week, the bay is partially mixed and oxygen levels have recovered at all stations (DO>3 mg/L).



RIDEM & RIDOH monitoring indicated HAB phytoplankton abundance were low and well-below levels of concern in all shellfish growing areas during the early summer of 2020.

Weekly Water Quality Report 7/25/20-7/31/20:

Water temperatures stayed about the same this week for Narragansett Bay (75-79°F). Chlorophyll conditions have increased throughout the bay (<30 ug/L). As of 7/28/20,the Upper Bay and Providence River oxygen levels declined below 3 mg/L. Hypoxia still persists in most of western Greenwich Bay with conditions below 3 mg/L for several hours (6-8hr) per day throughout the week. Oxygen levels in the rest of Narragansett Bay proper remain above 3 mg/L. These events will be monitored closely.

RIDEM & RIDOH monitoring indicated HAB phytoplankton abundance were low and well-below levels of concern in all shellfish growing areas during the early summer of 2020.

Weekly Water Quality Report 7/18/20-7/24/20:

Water temperatures increased slightly this week for Narragansett Bay (74-79°F). Chlorophyll conditions have decreased throughout the bay (<20 ug/L). Oxygen levels have improved in most areas of the bay this week. As of 7/21/20,the Upper Bay and Providence River were reading above 3 mg/L. Hypoxia still persists in most of western Greenwich Bay with conditions below 3 mg/L for several hours (6-8hr) per day throughout the week. Oxygen levels in the rest of Narragansett Bay proper remain above 3 mg/L.

RIDEM & RIDOH monitoring indicated HAB phytoplankton abundance were low and well-below levels of concern in all shellfish growing areas during the early summer of 2020.

Weekly Water Quality Report 7/11/20-7/17/20:

Water temperatures increased slightly this week for Narragansett Bay (73-77°F). Chlorophyll conditions have increased throughout the bay (<40 ug/L). Chlorophyll levels are highest in the Providence River and Greenwich Bay areas (20-40 ug/L). Based on a spatial survey this week, several areas in Narragansett Bay have been identified as hypoxic. Low oxygen was documented throughout the Providence River to Conimicut Point (DO< 3 mg/L). In addition, most of western Greenwich Bay has experienced dissolved oxygen conditions below 3 mg/L for the majority of this week. Hypoxic conditions have been intermittent (about 6-8 hrs per day with DO between 1-3 mg/L) in upper Mt. Hope Bay in the later part of the week. Oxygen levels in the rest of Narragansett Bay proper remain above 3 mg/L. These events will be monitored closely in the coming week.

RIDEM & RIDOH monitoring indicated HAB phytoplankton abundance were low and well-below levels of concern in all shellfish growing areas during the early summer of 2020. Alexandrium spp. were absent in most (94%, or 48 of 51) samples analyzed during early summer 2020. Alexandrium abundance ranged from 0 to 400 cells per liter which is below levels of concern. No follow-up biotoxin testing for PSP was required.

Dinophysis spp. began its seasonal summer increase, but Dinophysis levels also remained well below levels of concern during early summer 2020. Dinophysis was present in 47% of the 51 samples examined. Dinophysis spp. were present at a maximum level of 1,000 cells per liter which is below the level of concern and no DSP biotoxin follow-up testing was required.

Pseudo-nitzschia spp. were present in 47% (24 of 51) of samples examined during early summer 2020. There was a moderate increase in abundance during early June 2020, with greater than 10,000 cells per liter observed at several stations on June 9, 2020. Maximum Pseudo-nitzschia spp. abundance during early summer was 18,500 cells per liter (station 6P-3 at the entrance to Potters Pond on 6/9/2020) which is below the action threshold of 20,000 cells per liter .Pseudo-nitzschia abundance declined and was low (less than 750 cells per liter) in all shellfish growing areas from mid-June 2020 to mid-July 2020. No follow-up ASP biotoxin testing was required during early summer 2020.

Weekly Water Quality Report 7/4/20-7/10/20:

Water temperatures stayed about the same this week for Narragansett Bay (70-77°F). Chlorophyll conditions are stable throughout the bay (<20 ug/L). Dissolved oxygen levels are above 4 mg/L at most of the NBFSMN stations. Dissolved oxygen levels have declined at the Conimicut Point station;however, levels remained about 3 mg/L throughout the week. Greenwich Bay is still observing about 6 hours a day with dissolved oxygen conditions below 3 mg/L. These events will be monitored closely in the coming week. All other water quality parameters are reading within the normal range for this time of year. RIDEM & RIDOH monitoring indicated that abundance of harmful algae bloom (HAB) phytoplankton species remained below levels of concern.

Weekly Water Quality Report 6/27/20-7/3/20:

Water temperatures warmed about 3 degrees this week for Narragansett Bay (67-77°F). Chlorophyll conditions are stable throughout the bay (<20 ug/L). Dissolved oxygen levels are above 4 mg/L at most of the NBFSMN stations. Dissolved oxygen levels have declined at the Greenwich Bay station this week. Greenwich Bay is observing about 6 hours a day with dissolved oxygen conditions below 3 mg/L. This event will be monitored closely in the coming week. All other water quality parameters are reading within the normal range for this time of year. RIDEM & RIDOH monitoring indicated that abundance of harmful algae bloom (HAB) phytoplankton species remained below levels of concern.

Weekly Water Quality Report 6/20/20-6/26/20:

Water temperatures warmed about 5 degrees this week for Narragansett Bay(67-73°F). Chlorophyll conditions have stayed about the same this week (<20 ug/L). Dissolved oxygen levels are above 4 mg/L at most of the NBFSMN stations. Dissolved oxygen levels have declined at Greenwich Bay. They remain slightly about 3 mg/L throughout this week. As temperatures rise, we expect to see further decline at this station. Conditions in Greenwich bay will be monitored closely in the coming week. All other water quality parameters are reading within the normal range for this time of year. RIDEM & RIDOH monitoring indicated that abundance of harmful algae bloom (HAB) phytoplankton species remained below levels of concern.

This month, DEM has received reports of clinging jellyfish in Point Judith and Potter Ponds. Additionally, Division of Marine Fisheries staff observed a clinging jellyfish while conducting their June seine survey in Narrow River. These jellyfish attach to submerged vegetation (particularly eel grass) in calm waters, and have the potential for a powerful sting in sensitive individuals. DEM recommends that anyone wading in the coastal ponds in areas of eel grass use precautions such as wearing waders, a wetsuit, or rash guard or remain in sandy or surfy areas outside of the clinging jellyfish habitat. These jellyfish will likely be present in these areas throughout the summer until their life cycle ends in the early fall. Division of Marine Fisheries biologists will continue to monitor their presence in the coastal ponds throughout the summer.

Weekly Water Quality Report 6/13/20-6/19/20:

Water temperatures warmed slightly this week for Narragansett Bay(64-64°F). Chlorophyll conditions have stayed about the same this week (<20 ug/L). Dissolved oxygen levels are above 4 mg/L at all NBFSMN stations. All water quality parameters are reading within the normal range for this time of year. RIDEM & RIDOH monitoring indicated that abundance of harmful algae bloom (HAB) phytoplankton species remained below levels of concern.

Weekly Water Quality Report 6/6/20-6/12/20:

Water temperatures warmed another 3 degrees this week for Narragansett Bay(63-67°F). Chlorophyll conditions have elevated slightly this week at many of the NBFSMN stations (<20 ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 5/22/20-5/29/20:

Water temperatures warmed about 3 degrees this week for Narragansett Bay are 60-64°F. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during April through early June 2020.

HAB phytoplankton abundance was generally low through the spring of 2020, with a brief increase in Pseudo-nitzschia spp. abundance observed during late May 2020.

Alexandrium spp. were present in only 23% of the samples examined during spring 2020. There was a brief and modest increase in Alexandrium abundance during April (April 7 to April 23, 2020) at multiple monitoring stations. During this period Alexandrium was observed at low abundance levels of 10 to 200 cells per liter. These levels are below levels of concern and no follow-up PSP testing was required.

Dinophysis spp. were also relatively scarce during spring 2020. Dinophysis was present in 35% of the 60 samples examined. Dinophysis abundance tended to increase moderately during late May as the waters warmed. Dinophysis spp. were present at a maximum level of 500 cells per liter which is below the level of concern and no DSP follow-up testing was required.

Pseudo-nitzschia spp. were present in 52% (31 of 60) of samples examined during spring 2020. Pseudo-nitzschia spp. abundance was relatively low during April and early May 2020. From mid-May through late May, Pseudo-nitzschia abundance increased at coastal areas such as Sakonnet Point, the southern Sakonnet River, the southern West Passage off Newport and Jamestown and the southern West Passage near Whale Rock and Bonnet Cove. Pseudo-nitzschia abundance remained low in Upper Narragansett Bay and the coastal Salt Ponds. Maximum Pseudo-nitzschia abundance observed during late May was 52,000 cells/L (at South Sakonnet on 5/27/2020). Two samples collected on 5/27/2020 in the Sakonnet Point area exceeded the 20,000 cell/L action level. However, follow-up biotoxin testing indicated that there was no domoic acid present in these plankton samples (Scotia rapid tests). In addition, follow-up sampling in the area indicated that Pseudo-nitzschia abundance had declined to low levels of 0 to 6,400 cells/L during June 1 to June 3, 2020.

HAB monitoring will continue through the summer of 2020.

Weekly Water Quality Report 5/22/20-5/29/20:

All NBFSMN stations were deployed the week of 5/22/20. Water temperatures this week for Narragansett Bay are 57-61°F. Chlorophyll conditions are not currently elevated at any of the NBFSMN stations (<10ug/L). Dissolved oxygen levels are above 5 mg/L at all stations. All water quality parameters are reading within the normal range for this time of year.

Weekly Water Quality Report 10/5/19-10/11/19:

Water temperatures have cooled several degrees this week (60-62°F). The bay is well mixed and all bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L)./p>

Weekly Water Quality Report 9/28/19-10/4/19:

Water temperatures have cooled several degrees this week (64-65°F). The bay is well mixed and all bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L).

Weekly Water Quality Report 9/21/19-9/27/19:

Water temperatures stayed about the same this week (67-70°F). All bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L).

Weekly Water Quality Report 9/14/19-9/20/19:

Water temperatures cooled slightly this week (67-70°F). Narragansett Bay remains well mixed. All bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L).

Weekly Water Quality Report 9/7/19-9/13/19:

Water temperatures cooled slightly this week (68-70°F). Narragansett Bay is well mixed. All bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L). As of 9/11/19, Seekonk River was reporting dissolved oxygen conditions above 3 mg/L.

Weekly Water Quality Report 8/31/19-9/6/19:

Water temperatures stayed about the same this week (69-72°F). Narragansett Bay is well mixed. All bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L). The Seekonk River is still experiencing intermittent hypoxia (DO< 3 mg/L).

Weekly Water Quality Report 8/24/19-8/30/19:

Water temperatures cooled about 2 degrees this week (69-72°F). Narragansett Bay is well mixed. All bay stations are reporting normal conditions for this time of year (DO>3 mg/L and CHL<20 ug/L). The Seekonk river is still experiencing intermittent hypoxia (DO< 3 mg/L).



RI DEM received three reports of dead menhaden in the Seekonk River area from 8/24 – 8/26. RI DMF investigated two sites (Blackstone Park Conservatory near the Narragansett Boat Club and Bold Pt Park south of the I-195 bridge). A few dozen to a few hundred adult menhaden were observed along the shoreline and floating in the water. It is likely that these fish are from the same mortality event and are floating downriver. Dissolved oxygen was measured at both sites and was still low (3.9 mg/L at surface and 1.9-2.1 mg/L at bottom). These mortality events are consistent with what we observed last week and likely the result of ongoing intermittent hypoxia.



HAB UPDATE AUGUST 2019: RI DEM and RI DOH harmful phytoplankton monitoring indicated that abundance of HAB phytoplankton species remained low at most locations in Narragansett Bay, RI coastal waters and the salt ponds during August 2019. Alexandrium spp. (PSP potential) were absent in all samples (n=42) collected during August, 2019. Dinophysis spp. (DSP potential) were present at low abundance levels of less than 300 cells per liter which is far below the level of concern.



An increase in Pseudo-nitzschia spp. (ASP potential) to levels of 20,000 to 34,000 cells/L was noted in the southern East Passage and southern West Passage during early August (8/5 – 8/6/2019). Pseudo-nitzschia was present in 85% of samples and 4 samples exceeded the 20,000 cell/L action level during early August 2019. Follow-up analysis indicated that domoic acid was detected in one of the four elevated Pseudo-nitzschia samples. However, testing of nearby sentinel shellfish (blue mussels) in the Ft Wetherill (Jamestown) and GSO dock (Narragansett) area demonstrated that domoic acid was not accumulating in the shellfish. Continued sampling showed that Pseudo-nitzschia levels declined to low levels by August 20th and have remained low through August 29th. RI DEM and RI DOH will continue to monitor HAB phytoplankton in RI shellfish growing waters.

Weekly Water Quality Report 8/17/19-8/23/19:

Water temperatures stayed about the same this week (71-75°F). Narragansett Bay is mostly stratified from the rain earlier in the week. Spatial surveys this week revealed the western portion of Greenwich Bay, areas in the Seekonk and Providence Rivers are experiencing intermittent hypoxia (about 8hr per day with conditions less than 3 mg/L).



On 8/19, RI DEM received a report of dead Atlantic menhaden in the Seekonk River. RI DMF responded to the scene and found dead menhaden in the hundreds, and schools of live menhaden numbering in the thousands. Bluefish were also seen preying on live menhaden. With the high temperatures as of late, as well as such a high concentration of menhaden, dissolved oxygen levels are likely being depleted in localized areas at night or during low tide, resulting in mortality events. This is likely exacerbated by predators chasing the fish into warmer, fresher, low DO water. We may see more fish kill events such as this until water temperatures cool. With cooler marine water mixing into the estuary during each high tide, we hope these mortality events will be kept to a minimum.

Weekly Water Quality Report 8/10/19-8/16/19:

Water temperatures cooled this week 71-75°F. Narragansett Bay is mostly stratified from the rain earlier in the week. Spatial surveys this week revealed most of Greenwich Bay, Upper East and West Passages dissolved oxygen levels remain above 3 mg/L.

Weekly Water Quality Report 8/3/19-8/9/19:

Water temperatures stayed about the same this week (74-80° F). All stations are now reporting oxygen levels above 3 mg/L. Chlorophyll levels remain low throughout the bay (<20 ug/L).

Weekly Water Quality Report 7/27/19-8/02/19:

Water temperatures warmed slightly this week (74-80° F). Narragansett Bay remains slightly stratified this week. Western Greenwich Bay is experiencing several hours per day at hypoxic levels (<3 mg/L). This is a slight improvement over last week, where dissolved oxygen levels were less than 2 mg/L. The Providence River to Conimicut Point are experiencing similar conditions with dissolved oxygen levels between 2-3 mg/L for up to 8 hours per day. These areas of hypoxia will be monitored closely over the next week. Another spatial survey will be conducted next week.



Below is the HAB report for the month of July:

RI DEM and RI DOH harmful phytoplankton monitoring indicated that abundance of HAB phytoplankton species remained low in Narragansett Bay, RI coastal waters and the salt ponds during July 2019. Alexandrium spp. (causative organism for PSP – paralytic shellfish poisoning) was absent in all areas during July 2019. Dinophysis spp. (causative organism for DSP – diarrhetic shellfish poisoning) was present in low abundance (maximum of 3,100 cells per liter) in some upper Narragansett Bay and salt pond locations. Dinophysis abundance (maximum of 3,100 per liter) was far below the level of concern (30,000 per liter) during July 2019. Pseudo-nitzschia abundance (causative organism for ASP – amnesic shellfish poisoning) was also low during July 2019, with a maximum abundance of 2,800 cells per liter which is far below the 20,000 cell/L level of concern. HAB monitoring of RI will continue, with the next report in mid-August.

Weekly Water Quality Report 7/20/19-7/26/19:

Water temperatures stayed about the same this week 73-78°F. Narragansett Bay is mostly stratified from the rain earlier in the week. Spatial surveys this week revealed most of the Providence River had a mid water hypoxia with DO levels between 1-3 mg/L. Western Greenwich Bay reported severe hypoxia in the coves (DO > 1 mg/L) and hypoxic conditions west of Sally Rock (<3 mg/L). Mt Hope Bay also reported hypoxic conditions near the mouth of the Kickamuit River. The Upper East and West Passages showed declines in dissolved oxygen this week, but remain above 3 mg/L. These areas of hypoxia will be monitored closely over the next week.

Weekly Water Quality Report 7/13/19-7/19/19:

Water temperatures warmed slightly this week 73-78°F. The Upper Providence River, Greenwich Bay and Upper Mt Hope Bay continue to experience intermittent low oxygen for about 4-12 hours a day ( > 3 mg/L). Chlorophyll levels are slightly less this week in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>25 ug/L). All other areas are reporting normal oxygen levels (<4 mg/L).



Below is a summary of HAB phytoplankton monitoring of RI shellfish waters completed by RI DEM and RI DOH during late May through early July 2019.



Alexandrium spp. were relatively uncommon, being present in only 11 of 54 samples analyzed. Maximum abundance was 225 cells/L which is far below the action level of 1,000 cells/L.



Dinophysis spp. were also relatively uncommon in the monitoring samples, with Dinophysis present in 22 of 54 samples analyzed. Maximum abundance was 3,150 cells/L which is far below the action level of 30,000 cells/L.



Pseudo-nitzschia spp. were present in 24 of 54 samples analyzed and abundance ranged from 0 to 39,390 cells/L . Pseudo-nitzschia had an increase in abundance during late May and early June 2019. Elevated Pseudo-nitzschia abundance was confined to the coastal region and the lower Bay, with no elevated counts in the upper Bay or in the coastal salt ponds. Samples collected near Sakonnet Light (station 14-E12 on 5/30/19), just north of Sakonnet Harbor (station 5C-3 on 5/30/19) and near the northern end of Jamestown (station 3W-9 on 6/4/19) all exceeded the 20,000 cell/L threshold. Follow-up toxin testing (Scotia ASP test) detected no domoic acid in these plankton samples. Out of an abundance of caution, mussel samples were collected and analyzed from four sentinel sites (Sakonnet Harbor, Fort Wetherill, Conanicut Point, GSO dock; collected 6/5/19). Mussels from these four sites had no evidence of domoic acid (results less than detection limit). The brief pulse of elevated Pseudo-nitzschia declined by the second week of June 2019 and its abundance has remained low through early July 2019. This is the third year in a row in which a brief increase in Pseudo-nitzschia abundance has been detected near the coast and lower Bay during June.

Weekly Water Quality Report 7/6/19-7/12/19:

Water temperatures warmed slightly this week 73-75°F. The Upper Providence River, Greenwich Bay and Upper Mt Hope Bay continue to experiencing intermittent low oxygen for about 4-12 hours a day this week ( < 3 mg/L). Chlorophyll levels are elevated in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>15 ug/L). All other areas are reporting normal oxygen levels (>4mg/L).

Weekly Water Quality Report 6/29/19-7/05/19:

Water temperatures warmed another 2 degrees this week 70-74°F. Greenwich Bay and Upper Mt Hope Bay are experiencing intermittent low oxygen for about 4-8 hours a day this week ( < 3 mg/L) Chlorophyll levels are elevated in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>15 ug/L).

Weekly Water Quality Report 6/22/19-6/28/19:

Water temperatures warmed another 2 degrees this week 68-71°F. Greenwich Bay and Upper Mt Hope Bay are experiencing intermittent low oxygen for about 4-8 hours a day this week ( < 3 mg/L) Chlorophyll levels are elevated in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>15 ug/L).

Weekly Water Quality Report 6/15/19-6/21/19:

Water temperatures warmed another 2 degrees this week 64-68°F. With the heavy rains this week, the bay is stratified. All other bay conditions are normal for this time of year. Chlorophyll levels are elevated in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>15 ug/L).

Weekly Water Quality Report 6/8/19-6/14/19:

Water temperatures warmed another 2 degrees this week 62-66°F. With the heavy rains this week, the bay is stratified. All other bay conditions are normal for this time of year. Chlorophyll levels are slightly elevated in the Upper Bay, Upper Mt Hope Bay and Greenwich Bay (>10 ug/L).

Weekly Water Quality Report 6/1/19-6/7/19:

Water temperatures warmed about 4 degrees this week 60-64°F. Overall, the bay remains stratified. All other bay conditions are normal for this time of year.

Weekly Water Quality Report 5/25/19-5/31/19:

Water temperatures warmed a little this week 56-61°F. Surface salinity is below average bay wide (24-28 ppt) from the above average rain fall for the month of May. As a result, most of the bay is stratified. All other bay conditions are normal for this time of year.

Weekly Water Quality Report 5/18/19-5/24/19:

Monitoring stations were installed throughout the bay over the past week. Data is reporting normal conditions for this time of year. Water temperatures are about 55-59°F.



RIDEM & RIDOH harmful phytoplankton summary - May 2019

Phytoplankton monitoring of RI shellfish growing waters indicated that abundance of potentially harmful phytoplankton remained far below levels of concern during late winter and spring of 2019 (this summary is for February 21 to May 23, 2019).



Alexandrium spp. were observed in 16 of 74 samples with a maximum abundance of 1,040 cells per liter. Alexandrium abundance increased in late April 2019, with a single sample collected off the northern end of Jamestown (station 3W-9 on 5/2/2019, 1,040 Alexandrium cells/L) exceeding the action level of 1,000 cells/L. This plankton sample tested negative for the presence of PSP toxins (Scotia test) and follow-up samples in the area showed Alexandrium abundance had declined below the action level. Alexandrium continued to be present at low levels of tens to hundreds per liter at several locations through late May 2019.



Pseudo-nitzschia spp. were either absent or present at low abundance during late winter and spring of 2019. Pseudo-nitzschia was observed in 5 of 74 samples analyzed and maximum abundance was 275 cells per liter, far below levels of concern.



Dinophysis spp. were present in 18 of 74 samples analyzed. Dinophysis abundance was on the increase in late May 2019, with a maximum of 3,200 Dinophysis cells/L observed in Mt Hope Bay on 5/23/19. This abundance level is below action levels and is likely part of the typically observed summer Dinophysis increase.



HAB monitoring and water quality will continue through the summer season.

BART Water Quality Report:9/29/18-10/5/18:

Water temperatures have stayed about the same this week (67-68° F). Chlorophyll levels have remained low this week (< 15 ug/L). All bay stations are reporting normal oxygen levels for this time of year (>3 mg/L).



DEM and DOH HAB monitoring indicated that abundance of Alexandrium spp. and Dinophysis spp. remained low (0 to <50 cells per liter) in all areas monitored. Pseudo-nitzschia spp. abundance was also low (0 to <50 cells per liter) in most areas, but a modest increase in Pseudo-nitzschia spp. abundance to levels of 2,000 to 5,000 cells per liter (compared to a precautionary threshold of 20,000 cells per liter) was noted in the lower West Passage, Little Narragansett Bay and some salt ponds during late September.

BART Water Quality Report: 9/22/18-9/28/18:

Water temperatures have cooled in the bay again this week (67-68° F). Chlorophyll levels have remained low this week (< 20 ug/L). All bay stations are reporting normal oxygen levels for this time of cc year (>3 mg/L).

BART Water Quality Report: 9/15/18-9/21/18:

Water temperatures have cooled in the bay again this week (70-73° F). Chlorophyll levels have remained low this week (< 20 ug/L). All bay stations are reporting normal oxygen levels for this time of cc year (>3 mg/L).

BART Water Quality Report: 9/8/18-9/14/18:

With the storms and cool weather this week, water temperatures have cooled about 3 degrees (71-77° F). Chlorophyll levels have declined throughout the bay with the rain and clouds that persisted for most of the week. All stations are reporting chlorophyll levels less than 10 ug/L. As of 9/9/18, all stations throughout the NBFSMN are reporting normal oxygen levels for this time of year (>3 mg/L). This is an improvement from last week.

BART Water Quality Report: 9/1/18-9/7/18:

With the heat wave this week, water temperatures continued to increased slightly (77-81° F). The Providence and Seekonk River stations are reporting low oxygen conditions this week (< 2 mg/L). A spatial survey this week showed oxygen levels as low as 0.12 mg/L in the Upper Providence River. Western Greenwich Bay also continues to report about 8 hours a day with oxygen levels between 1-3 mg/L for the whole water column. Western Greenwich Bay embayment is still showing elevated chlorophyll levels (>25 ug/L). Chlorophyll levels have declined throughout the rest of Narragansett Bay (< 10 ug/L). Most bay stations are reporting normal oxygen levels for this time of year (DO > 3 mg/L). The rust tide appears to have declined during early September in most parts of the Bay.

On Wednesday 9/5, thousands of small silver baitfish (suspected to be juvenile Menhaden), as well as some invertebrates were reported dead on the shores near Goose Point and floating in the water of the Seekonk River. On Tuesday 9/4, a spatial survey conducted with Brown University found bottom DO in nearby Phillipsdale was low (1.5 mg/L). Hypoxic values at the bottom were observed in the Providence River Channel down to Bullocks reach, with values from 1.5 mg/L near the Hurricane Barrier increasing to 3.0 mg/L near Bullocks Cove. This fish kill is likely due to hypoxic conditions.

BART Water Quality Report: 8/25/18-8/31/18:

With the heat wave this week, water temperatures have increased slightly (76-79° F). Most stations are reporting normal oxygen levels for this time of year (DO > 3 mg/L). However, the water quality station in western Greenwich Bay continues to report about 8 hours a day with oxygen levels between 2-3 mg/L for the whole water column. The Mt. View station, in the upper West Passage, is also reporting similar condition in the bottom waters only. These stations are also recording sporadic chlorophyll levels over 100 ug/L. These levels can be attributed to these bloom patches Cochlodinium polykrikoides in these areas.



Abundance of HAB phytoplankton (Alexandrium spp., Dinophysis spp. and Pseudo-nitzschia spp.) remained low throughout all areas of the Bay and salt ponds during late August 2018. However, water-discoloring patches of the ‘rust tide’ organism Cochlodinium polykrikoides remain present in areas of the upper Bay, Greenwich Bay, the West Passage and some salt ponds. Sampling has indicated that Cochlodinium abundance in the most-dense patches is in the 300,000 to 1 million cells per liter range, a decline from the levels observed in early August. It is expected that rust tide patches will persist and continue to move around the Bay, dependent on wind, tide and currents until the water cools. Cochlodinium does not produce a toxin that is harmful to humans, so it is safe to swim, fish and shellfish while the rust tide is present. RIDEM will continue to monitor the rust tide during summer and early autumn 2018

BART Water Quality Report 8/18/18-8/24/18:

The cool fronts this week have helped to improve conditions throughout the bay. Bay water temperatures have cooled about 2 degrees (76-78° F). Northerly winds have helped to mix the water column and improve oxygen conditions. As of 8/19/18, most of the bay stations are recording normal oxygen levels for this time of year (DO> 3 mg/L).



A spatial survey conducted this week, revealed low oxygen levels persist in the northwestern portions of Greenwich Bay. The water quality station in this area is reporting about 8 hours a day with oxygen levels between 2-3 mg/L. This is an improvement from last week.



RIDEM is still monitoring patches of ‘rust tide’ caused by an abundance or bloom of a naturally occurring type of phytoplankton called Cochlodinium polykrikoides. While these single celled organisms are small, they can reach abundance levels. Some stations are recording chlorophyll levels over 100 ug/L. These levels can be attributed to these bloom patches. These events will continue to be monitored closely.

BART Water Quality Report 8/11/18-8/17/18:

On 8/10/18, RIDEM Division of Marine Fisheries responded to two fish kill reports in western Greenwich Bay. About 1,000 fish (juvenile menhaden, river herring, juvenile weakfish, eels) were dead near the mouth of Apponaug Cove. Oxygen levels were measured along the docks with a surface DO between 3.3 and 3.6 mg/L. Bottom DO was between 0.09 and 2.40mg/L. Dead shrimp in Greenwich Cove near Chepiwanoxet Point were also reported. In the early morning hours of 8/10/18, oxygen levels were less than 1 mg/L surface to bottom. Low oxygen is the probable cause for these fish kill events.



This week, the western Greenwich Bay station continues to record several hours per day (10-12 hrs) with oxygen concentrations below 2 mg/L. Additional surveys, conducted on 8/15/18, show a large portion of western Greenwich Bay and its coves are still experiencing hypoxic to anoxic conditions. Chlorophyll levels also remain high in the Greenwich Bay area (>30 ug/L). The potential threat of additional fish kills remain high in Greenwich Bay based on the water quality information this week.



In other areas of the bay, bay waters cooled slightly this week (78-81° F). The Providence River and Upper Bay continue to experience intermittent hypoxic conditions in the bottom waters (DO> 3 mg/L). Chlorophyll levels are also elevated in Providence River, Upper Bay and portion of Mt Hope Bay, consisting of primarily Cocholdinium spp. (>25 ug/L). All of these events will continue to be monitored closely.



RIDEM has been monitoring patches of ‘rust tide’ caused by an abundance or bloom of a naturally occurring type of phytoplankton called Cochlodinium polykrikoides. While these single celled organisms are small, they can reach abundance levels of millions of cells in one liter of water. This elevated abundance can cause noticeable water discoloration or rust tide. During July and August 2018 RIDEM has observed Cochlodinium levels of 3 to 8 million cells per liter in rust tide patches in Greenwich Bay, upper Narragansett Bay, Wickford and Bullocks Cove. Cochlodinium does not produce a toxin that is harmful to humans, so it is safe to swim, fish and shellfish while the rust tide is present. RIDEM will continue to monitor the rust tide during summer 2018. For more information, please see the DEM rust tide fact sheet or call RI DEM at (401) 222-4700.

BART Report 8/4/18-8/10/18:

Bay waters warmed a few degrees with the heat wave this week (78-83° F). The western Greenwich Bay station continues to record several hours per day with oxygen concentrations below 2 mg/L. A spatial survey conducted this week showed that most of Greenwich Bay and all its coves are experiencing periods of severe hypoxia to anoxia most of the day (< 1mg/L for more than 6 hours a day). Oxygen levels in the Providence River and Upper Bay have declined further this week. Several areas throughout the Providence River and the Upper Bay are experiencing hypoxic conditions in the bottom waters (DO> 3 mg/L). This is a decline from last week bay wide. Chlorophyll levels remain high in the Greenwich Bay area (>25 ug/L). There is a large bloom in Greenwich Bay consisting of primarily Cocholdinium spp. Chlorophyll levels are also elevated in Providence River, Upper Bay and portion of Mt Hope Bay (>20 ug/L). These large events will continue to be monitored closely.

BART Weekly Report 07/28/18-08/3/18:

Bay waters stayed about the same this week (73-81° F). The western Greenwich Bay station continues to record several hours per day with oxygen concentrations below 2 mg/L. This is a decline from last week. Chlorophyll levels remain high in the Greenwich Bay area (>20 ug/L). Chlorophyll levels have also increased in the Providence River (>20 ug/L). For species information see the harmful algal bloom report (HAB) below. Oxygen levels in the Providence River and Upper Bay have declines slightly, but remain above 3 mg/L. These events will be monitored closely.



July HAB report: Abundance of HAB phytoplankton species (Alexandrium spp., Pseudo-nitzschia spp., Dinophysis spp.) remained low at all locations sampled during July 2018. A single sample collected at Block Island had slightly elevated Alexandrium spp. abundance; a follow-up sample at that location is planned for early August. While not routinely monitored, abundance of Cochlodinium spp. (the dinoflagellate that has the potential to form ‘rust tides’) is on the increase in Greenwich Bay. Several rust-red patches of water, with levels of ~3 million Cochlodinium cells per liter, were observed at the mouth of Apponaug Cove and in Greenwich Cove on 7/30/2018. HAB phytoplankton monitoring will continue, with the next report expected in early September.

BART Weekly Report 07/7/18-07/13/18:

Bay waters warmed slightly this week (71-81° F).Dissolved oxygen concentration in the Providence River have improved this week. As of 7/12/18, all stations reporting dissolved oxygen above 3 mg/L, except Greenwich Bay. The western Greenwich Bay station continues to record several hours per day with oxygen concentrations below 2.5 mg/L. This is an improvement from last week. Chlorophyll levels have declined, but remain slightly elevated in the Providence River, Greenwich Bay, and Upper Mt. Hope Bay (>20 µ/L). These events will be monitored closely.

BART Weekly Report 07/14/18-07/20/18:

Bay water temperatures stayed about the same this week (72-79° F). The coves, such as Greenwich Bay, are reporting the highest temperatures. Western Greenwich Bay station continues to record several hours per day with oxygen concentrations below 3 mg/L. All stations throughout the Upper Bay are recording oxygen concentrations above 3 mg/L.Chlorophyll levels are not elevated at any station this week (<20 µ/L). This is an improvement from last week.

BART Weekly Report 06/30/18-07/6/18:

With the warm air this week, bay water temperatures have warmed about 3-8 degrees (69-80° F). The coves, such as Greenwich Bay, are reporting the highest temperatures. A spatial survey conducted this week by Brown University revealed several cove areas with hypoxic conditions (DO< 3 mg/L). Greenwich Bay, Bristol Harbor and the Providence River documented dissolved oxygen concentrations between 1-3 mg/L. As of 6/20/18, the western Greenwich Bay station continues to record several hours per day with oxygen concentrations below 2.5 mg/L. Stations within the Upper Bay are recording oxygen concentrations above 3 mg/L. This is a decline from last week. Chlorophyll levels remain elevated in the Providence River, Greenwich Bay, and Upper Mt. Hope Bay (>20 ug/L). These events will be monitored closely.

BART Weekly Report 06/23/18-06/29/18:

Water temperatures stayed about the same this week (66-73° F). Chlorophyll levels remain elevated in the Providence River, Greenwich Bay, and Upper Mt. Hope Bay (>20 ug/L). As of 6/20/18, the western Greenwich Bay station is reporting low oxygen condition for about 6 hours per day (2< bottom DO >3 mg/L). All other stations are reporting normal oxygen concentrations for this time of year (DO> 4 mg/L).

BART Weekly Report 06/16/18-06/22/18:

Water temperatures increased about 5 degrees this week (66-73° F). Chlorophyll levels have increased in the Providence River, Greenwich Bay, and Upper Mt. Hope Bay (>20 ug/L). Dissolved oxygen levels have declined in Greenwich Bay. As of 6/20/18, the western Greenwich Bay station is reporting low oxygen condition for about 6 hours per day (2< bottom DO >3 mg/L).

Below is the harmful algal bloom (HAB) report from RIDEM's shell fishing program for the month of June.

HAB Report for June 2018: HAB phytoplankton monitoring completed by RI DEM and RI DOH during June 2018 indicated that there was an increase in Pseudo-nitzschia spp. in early through mid-June. Pseudo-nitzschia abundance increased to greater than 50,000 cells per liter (more than twice the 20,000 cells per liter Pseudo-nitzschia HAB monitoring action level) at multiple location in the East and West Passages south of Prudence Island during early June (samples collected on 6/4/18 and 6/6/18). Follow-up sampling on 6/11/18 and 6/12/18 in the lower Bay and lab analysis indicated that domoic acid was being produces at low levels in the plankton in the lower Bay. Shellfish (mussels) collected at sentinel sites in the lower Bay were analyzed and, fortunately, were found to have either no domoic acid present or extremely low (1/500th the FDA standard) levels of domoic acid present. By the third week of June (samples collected 6/18/18 and 6/19/18), Pseudo-nitzschia abundance had declined to ~10,000 cells per liter or less as the bloom appears to have declined throughout the Bay. Pseudo-nitzschia abundance in the coastal salt ponds (samples collected in Pt. Judith, Potter, Ninigret, Quonochontaug and Winnapaug Ponds and Little Narragansett Bay) remained low during June 2018. Abundance of other HAB species (Alexandrium spp. and Dinophysis spp.) remained low and far below levels of concern in all areas monitored during June 2018.

BART Weekly Report 06/09/18-06/15/18:

Water temperatures stayed about the same this week (61-67° F). All stations are reporting normal oxygen conditions (>4 mg/L).

BART Weekly Report 06/03/18-06/08/18:

Water temperatures increased slightly this week (61-66° F). Chlorophyll levels are slightly elevated in Mt Hope Bay and Greenwich Bay (<15 ug/L). All stations are reporting normal oxygen conditions (<4 mg/L).



RI DEM/DOH HAB phytoplankton monitoring report for May 2018

HAB phytoplankton monitoring completed by RI DEM and RI DOH during May 2018 indicated that Pseudo-nitzschia spp. abundance declined from thousands of cells per liter in early May to much lower levels from mid-May through the end of the month. Alexandrium abundance increased during mid-May (15-23 May) at multiple locations throughout the Bay. Four samples from the various areas (Upper Bay, West Passage, Little Narragansett Bay) exceeded the 1,000 cell/L Alexandrium action level. All four of these samples tested negative for saxitoxin in the plankton by Scotia tests. Samples collected in late May suggest that Alexandrium abundance has declined following the brief mid-May 2018 increase. Dinophysis abundance has begun its summer increase, but remained far below actions levels during May 2018.

BART Weekly Report: 5/27/18-6/2/18

The water quality monitoring stations were established this week. Water temperatures are normal for this time of year (60-65° F). Chlorophyll levels are slightly elevated in Mt Hope Bay and Greenwich Bay (>15 ug/L). All stations are reporting normal oxygen conditions (>4 mg/L).

DEM/DOH HAB phytoplankton monitoring report for 9/15/2017 to 10/20/17:

HAB Phytoplankton monitoring during the second half of September and October 2017 indicated that Alexandrium spp. (responsible for PSP) and Dinophysis spp. (responsible for DSP) were either absent or present at very low levels throughout all areas sampled in Narragansett Bay, coastal salt ponds and Block Island.

Abundance of Pseudo-nitzschia spp. (responsible for ASP) had been elevated (near 20,000 cells per liter) in lower Narragansett Bay and along the coast during early September 2017. However, Pseudo-nitzschia abundance in those areas declined dramatically to 0 to 1,000 cells per liter following the sustained northeast winds of Tropical storm Maria. During October 2017, Pseudo-nitzschia was largely absent or at low abundance throughout Narragansett Bay. Modest levels of Pseudo-nitzschia (1,000 to 7,000 cells per liter, well below the threshold of concern) remained in the coastal waters near the breach-ways of the coastal salt ponds during late October 2017. HAB phytoplankton monitoring by RI DEM and RI Department of Health will continue through the winter months.

BART Weekly Report: 9/9/17-9/15/17

Water temperatures stayed about the same this week throughout the Bay (69-71° F). As of 9/7/17, all stations were reporting normal conditions for this time of year (DO> 3 mg/L; CHL< 20ug/L).

DEM/DOH HAB phytoplankton monitoring report for 9/1/2017 to 9/15/2017:

Phytoplankton monitoring carried out by RI DEM and RI Department of Health indicated that abundance of Pseudo-nitzschia spp. has increased in offshore waters along the RI coast during the first two weeks of September 2017. Samples collected at the entrance to the East Passage (Brenton Reef), West Passage (Whale Rock) and at the entrance to Pt. Judith Pond all had Pseudo-nitzschia abundance of near or slightly above 20,000 cells per liter. Follow-up sampling of shellfish in these areas showed no evidence of domoic acid accumulation in the shellfish. Abundance of Pseudo-nitzschia spp. remained far below the threshold of concern in Upper Narragansett Bay, Greenwich Bay, Mt. Hope Bay and the Sakonnet River. Other HAB phytoplankton species (Alexandrium spp. and Dinophysis spp.) were either absent or remained at low abundance levels throughout all areas. We will continue to track Pseudo-nitzschia abundance in the lower Bay and along the south coast of RI over the next several weeks.

BART Weekly Report: 9/2/17-9/8/17

Water temperatures continued to cool this week throughout the Bay (69-71° F). As of 9/7/17, all stations were reporting normal conditions for this time of year (DO> 3 mg/L; CHL< 20ug/L. Water clarity has also improved this week bay wide.

BART Weekly Report: 8/27/17-9/1/17

Water temperatures cooled this week throughout the Bay (69-73° F). The bay proper remains well mixed this week with normal conditions (DO > 3 mg/L). In Greenwich Bay and Providence River areas chlorophyll levels (CHL) remain elevated (CHL> 20 ug/L). The elevated chlorophyll levels in Greenwich Bay are related to a persistent patchy bloom event. This bloom event is associated with small patches of ‘rust tide’ Cochlodinium polykrikoides, which is not harmful to human health. These patches were noted in Greenwich Bay and its coves for the past few weeks. For more information on the Cochlodium bloom, see HAB report below.

As of 8/27/17, oxygen levels in the bottom waters have remained low intermittently (several hours per day) in Greenwich Bay and its coves only. Dissolved oxygen readings are between DO 1-3 mg/L at the stations in these areas. A spatial survey conducted this week, led by Brown University, revealed hypoxic to anoxic levels throughout the day in western Greenwich Bay and its coves (DO between 0-3 mg/L). These low oxygen and bloom events will continue to be monitored closely.

HAB phytoplankton monitoring report for 8/18/17 to 8/31/17:Phytoplankton monitoring has indicated an absence of Alexandrium spp. in all areas sampled during the second week of August 2017. Similarly, Dinophysis spp. were either absent or present at only low concentrations of less than 100 cells per liter in all areas sampled. However, an increase in abundance of Pseudo-nitzschia spp. was noted in some areas during the second half of August. Pseudo-nitzschia spp. increased to levels of hundreds to low thousands of cells per liter in the lower West Passage, Lower East Passage and at the entrances to some coastal salt ponds. Pseudo-nitzschia spp. were either absent or present at low levels of less than 100 cells per liter in Upper Narragansett Bay, Greenwich Bay, Mt. Hope Bay and the Sakonnet River. Patches of Cochlodinium polykrikoides (‘rust tide’) were noted in Greenwich Bay during late August 2017. Cochlodinium patches in the Bay during August 2017 have been less extensive than those observed during 2016. The RI DEM and RI Department of Health will continue to monitor for potentially harmful algae, with the next report in mid-September 2017.

BART Weekly Report: 8/20/17-8/26/17

Water temperatures stayed about the same again this week throughout the Bay (72-78° F). The bay proper remains well mixed this week with normal conditions (DO > 3 mg/L). In Greenwich Bay and Providence River areas chlorophyll levels (CHL) are elevated and surface waters are super saturated (CHL> 20 ug/L; DO> 125%). The elevated chlorophyll levels in Greenwich Bay are related to a bloom event that is occurring in this area. The bloom event is associated with small patches of ‘rust tide’ Cochlodinium polykrikoides, which is not harmful to human health. These patches were noted in Greenwich Bay for the past few weeks.

Since 8/14/17, oxygen levels in the bottom waters have remained low intermittently (several hours per day) in the Seekonk and Providence Rivers, Greenwich Bay and western Mt Hope Bay. Dissolved oxygen readings are between DO 1-3 mg/L at the stations in these areas. A spatial survey conducted this week, led by Brown University, revealed hypoxic to anoxic levels throughout the day in western Greenwich Bay and its coves (DO between 0-3 mg/L). These low oxygen and bloom events will continue to be monitored closely.

BART Weekly Report: 8/12/17-8/19/17

Water temperatures stayed about the same again this week throughout the Bay (72-78° F). The bay proper remains well mixed this week with normal conditions (DO > 3 mg/L). In Greenwich Bay and Providence River areas chlorophyll levels (CHL) are elevated and surface waters are super saturated (CHL> 20 ug/L; DO> 125%). The elevated chlorophyll levels in Greenwich Bay are related to a bloom event that is occurring in this area (see below).

As of 8/14/17, oxygen levels in the bottom waters have declined in the Seekonk and Providence Rivers, Greenwich Bay and western Mt Hope Bay. Dissolved oxygen readings are between DO 1-3 mg/L at the stations in these areas. A spatial survey conducted this week, led by Brown University, revealed hypoxic to anoxic levels throughout the day in western Greenwich Bay and its coves (DO between 0-3 mg/L). These low oxygen and bloom events will continue to be monitored closely.

Abundance of potentially harmful algae remained low during the first two weeks of August 2017. HAB (Harmful Algal Bloom) species were either absent or at low abundance levels of less than 1,000 cells per liter in twenty one (21) samples collected at sites in Upper Narragansett Bay, Greenwich Bay, Mt. Hope Bay, the coastal salt ponds and at Block Island. Alexandrium spp. was absent in all samples, Dinophysis was absent or at less than 100 cells/L in all samples and Pseudo-nitzschia spp. was absent in 19 of 21 samples collected during the first two weeks of August 2017. Pseudo-nitzschia spp. was detected at low levels (~1,000 cells per liter) at only one offshore site and at the breachway entrance to one of the salt ponds. Small patches of ‘rust tide’ Cochlodinium polykrikoides, which is not harmful to human health, were noted in Greenwich Bay. DEM and RI will continue to monitor for potentially harmful algae, with the next report in late August 2017.

BART Weekly Report: 8/5/17-8/11/17

Water temperatures stayed about the same this week throughout the Bay (72-78° F). The bay proper remains well mixed this week. All stations are reporting normal oxygen conditions (DO > 3 mg/L). As of 8/4/17, surface chlorophyll levels declined throughout the bay (CHL < 20 µg/L).

Larval crabs (Polyonyx spp) have been observed throughout the bay this week.

BART Weekly Report: 7/29/17-8/4/17

Water temperatures warmed this week throughout the Bay (72-78° F). The bay proper remains well mixed this week with normal conditions (DO > 3 mg/L). In the Mt Hope Bay, Greenwich Bay, and Providence River areas chlorophyll levels (CHL) are elevated and surface waters are super saturated (CHL> 20 ug/L; DO> 125%). The elevated chlorophyll levels in Greenwich Bay are related to a bloom event that is occurring in this area.

Harmful algae bloom monitoring by RI DEM and the RI Department of Health showed that abundance of potentially harmful species of phytoplankton remained low during the first week of August 2017. Alexandrium spp. was absent in all samples and Dinophysis spp. remained at low levels of 0-100 cells per liter. Pseudo-nitzschia spp. was absent or at low levels in the Upper Bay and remained at low levels of approximately 2,000 cells per liter in the lower Sakonnet River. Abundance of the non-toxic ‘rust tide’ forming dinoflagellate Cochlodinium polykrikoides has started to increase. Small rust red patches of Cochlodinium at levels of 1 – 2 million cells per liter were observed in Greenwich Bay at the mouth of Greenwich Cove and Apponaug Cove.

As of 7/31/17, oxygen levels in the bottom waters have declined in these areas. Dissolved oxygen levels are low in the Providence River, Upper Bay area, Greenwich Bay and Upper Mt Hope Bay (DO 1-3 mg/L). A spatial survey conducted this week, led by Brown University, revealed hypoxic to anoxic levels throughout the day in western Greenwich Bay and its coves (DO between 0-3 mg/L). These low oxygen and bloom events will continue to be monitored closely.

BART Weekly Report: 7/22/17-7/28/17

With the cool front early in the week, Bay water temperatures have cooled a few degrees this week (69-75° F). With cool conditions and high winds this week, the bay water column is well mixed. As a result, oxygen levels at all station have recovered to normal conditions (DO > 3 mg/L). Chlorophyll levels are low at all stations (<10 µg/L). Another spatial survey is scheduled for next week.

Abundance of potentially harmful phytoplankton remained below levels of concern during the second half of July 2017. Samples collected between July 17thand July 27th indicated that Alexandrium spp were absent in most samples, with a maximum abundance of 80 cells per liter. Similarly, Pseudo-nitzschia spp. were absent in 20 of 22 samples and were present at a maximum of only 130 cells per liter. Dinophysis spp. were present at low abundance levels of 40 to 120 cells per liter. RI DEM and the RI Department of Health will continue to monitor potentially harmful algae through the year.

BART Weekly Report: 7/15/17-7/21/17

Water temperatures warmed this week throughout the Bay (73-78° F). Chlorophyll levels remain elevated in Mt Hope Bay, Greenwich Bay.and the Providence River (>20 µg/L). As of 7/18/17, oxygen levels have declined bay wide. Dissolved oxygen levels are low in the Providence River, Upper Bay area, Greenwich Bay and Upper Mt Hope Bay (DO 1-3 mg/L). Western Greenwich Bay continues to report hypoxic to anoxic levels in the early morning hours (DO between 0-3 mg/L for 6-8 hours per day). Stations in the Upper West Passage are reporting normal oxygen conditions (>3 mg/L). These low oxygen events will continue to be monitored closely.

Larval crabs (Polyonyx spp)are continuing to be observed in the Upper West Passage of Narragansett Bay.

BART Weekly Report: 7/8/17-7/14/17

Water temperatures stayed about the same this week throughout the Bay (71-77° F). As of Chlorophyll levels remain elevated in Mt Hope Bay and the Providence River (>20 µg/L). As of 7/8/17, oxygen levels have rebounded bay wide. Dissolved oxygen levels remain low Upper Mt Hope Bay (DO < 2 mg/L). Greenwich Bay continues to report low oxygen levels in the early morning hours (DO between 2-3 mg/L for 6-8 hours per day). All other NBFSMN stations are reporting normal oxygen conditions (>3 mg/L). This low oxygen event will be monitored closely.

Routine harmful algae bloom (HAB) monitoring by RI DEM and RI Department of Health indicated that abundance of potentially harmful phytoplankton is currently below thresholds of concern. Abundance of harmful algae remained low during the last week of June and the first two weeks of July 2017. Water samples (n = 39) collected in the coastal salt ponds, off Block Island, along the coast south of Newport and Jamestown, in the Sakonnet River, in Upper Narragansett Bay and in the East and West Passages of the Bay showed a consistent pattern of low abundance of potentially harmful phytoplankton at all locations. Abundance of Alexandrium spp. was low (0 to 75 cells per liter), Dinophysis spp. abundance was also low (0 to 4,000 cells per liter) and Pseudo-nitzschia spp. abundance remained low (0 to 4,000 cells per liter).



Larval crabs have been observed in Mt Hope Bay (Polyonyx spp) and the Warwick Neck areas of Narragansett Bay.

BART Weekly Report: 7/1/17-7/7/17

Water temperatures increased this week throughout the Bay (71-77° F). As of 7/2/17, chlorophyll levels have been elevated in Mt Hope Bay and the Providence River (>25 µg/L). Since 7/3/17, oxygen levels have declined bay wide. A spatial survey lead by Brown University this week revealed patches of low oxygen in the Providence River, Mt Hope Bay, and Upper Bay(DO < 3 mg/L, in some areas). Dissolved oxygen levels are lowest in Upper Mt Hope Bay (DO < 2 mg/L). Greenwich Bay continues to report low oxygen levels in the early morning hours (DO between 2-3 mg/L for 6-8 hours per day). All other NBFSMN stations are reporting normal oxygen conditions (>3 mg/L). This low oxygen event will be monitored closely.

BART Weekly Report: 6/24/17-6/30/17

Water temperatures stayed about the same this week throughout the Bay (69-73° F). Chlorophyll levels are no longer elevated in the Upper Bay, Mount Hope Bay, and Greenwich Bay (<20 µg/L). Since 6/23/17, Greenwich Bay is reporting low oxygen levels in the early morning hours (DO between 2-3 mg/L for 6-8 hours per day). All other NBFSMN stations are reporting normal oxygen conditions (>3 mg/L).

BART Weekly Report: 6/17/17-6/23/17

Water temperatures continued to increase this week throughout the Bay (65-73° F). Chlorophyll levels are elevated in the Upper Bay, Mount Hope Bay, and Greenwich Bay (>20 µg/L). Earlier in the week (6/19/17-6/20/17), low oxygen was reported at a few locations in the Upper Bay (DO <3 mg/L). As of 6/21/17, all NBFSMN stations are reporting normal oxygen conditions (>4 mg/L).

Harmful algae bloom (HAB) monitoring by RI DEM and RI Department of Health showed an increase in abundance of Pseudo-nitzschia spp. during the second week of June 2017. Pseudo-nitzschia spp. abundance of greater than 100,000 cells/L was detected at several stations in the lower Bay and in Block Island Sound. Follow-up sampling during the third week of June indicated that Pseudo-nitzschia abundance was declining in these areas. Pseudo-nitzschia abundance remained low (0 to 3,500 cells/L) at all stations sampled in Greenwich Bay and Upper Narragansett Bay during the first three weeks of June. Abundance of other HAB phytoplankton species remained low during June, with no Alexandrium spp. detected and low abundance of Dinophysis spp. (0 to 1,000 cells/L).

BART Weekly Report: 6/10/17-6/16/17

Water temperatures increased this week throughout the Bay (63-70° F). Chlorophyll levels are elevated in the Providence River and Greenwich Bay (>20 µg/L). A spatial survey, through Brown University, was conducted this week throughout the Upper Bay. This survey revealed low oxygen in the coves of Greenwich Bay (2-3mg/L). All NBFSMN stations are reporting normal oxygen conditions (>4 mg/L).

BART Weekly Report: 6/3/17-6/9/17

The water quality monitoring stations were established this week. Water temperatures are normal for this time of year (60-63° F). Chlorophyll levels are elevated in the Providence River and Greenwich Bay (>20 µg/L). All stations are reporting normal oxygen conditions (>4 mg/L).

The RIDEM and Department of Health conducted synoptic harmful algae bloom (HAB) phytoplankton monitoring on Tuesday May 30, 2017. Samples were collected at 24 locations in RI marine waters spanning from Upper Narragansett Bay to the nearshore waters south of Jamestown, Newport and Sakonnet, five salt ponds and Block Island. Results showed that HAB phytoplankton species were either absent or, if present, were present at low levels. Alexandrium spp. were present from 0 to 100 cells/L, Pseudo-nitzschia spp. were present from 0 to 500 cells/L and Dinophysis spp. were present from 0 to 250 cells/L.

BART Weekly Report: 5/28/17-6/2/17

The water quality monitoring stations were established this week. Water temperatures are normal for this time of year (60-62° F). All stations are reporting normal oxygen conditions (>4 mg/L).

Here is an update on RI DEM and RI DOH harmful algae bloom (HAB) sampling results for May 2017: Low numbers of HAB species were detected, but HAB species abundance remains below levels of concern. RI DEM will continue routine monitoring of HAB phytoplankton species in RI shellfish growing waters during the summer 2017 season.

BART Weekly Report: 9/24/16-9/30/16

Water temperatures continued to cool this week (69-72° F). There is a uniform water column with high winds this week. All stations are reporting normal oxygen conditions for this time of year (>4 mg/L). The Cochlodinium has become more sporadic; earlier this week, the only patches were observed in Mount Hope Bay. It is expected to see the bloom event decline with the cooling temperatures. For more information about Cochlodinium, please see this downloadable fact sheet.

BART Weekly Report: 9/18/16-9/23/16

Water temperatures cooled only slightly this week (72-74° F). The water column is more uniform, with no evidence of stratification. All stations are reporting normal oxygen conditions for this time of year (>3 mg/L). Greenwich Bay is reporting the lowest oxygen readings this week at 3.2 mg/L on average. The NBFSMN stations are still recording the Cochlodinium event as elevated chlorophyll in patches around Narragansett Bay. However, the bloom patches have become more sporadic this week. Chlorophyll levels range between 5-55 µg/L at most stations in Narragansett Bay. Elevated chlorophyll levels were recorded at Mount Hope Bay and Greenwich Bay (>30 µg/L). All other parameters are reporting normal for this time of year. Schools of menhaden have been spotted throughout Greenwich Bay.

BART Weekly Report: 9/11/16-9/17/16

The NBFSMN stations are still recording the Cochlodinium event as elevated chlorophyll in patches around Narragansett Bay. Chlorophyll levels range between 5-55 µg/L at most stations in Narragansett Bay. Elevated chlorophyll was recorded at Mount Hope Bay, Poppasquash Point and Greenwich Bay (>30 µg/L). All other parameters are reporting normal for this time of year. Temperatures continue to cool this week (72-77° F). Also, all stations are reporting normal oxygen conditions for this time of year (>4 mg/L), except Greenwich Cove. In Greenwich Cove, oxygen readings are below 2 mg/L. Schools of menhaden have been spotted in Greenwich Bay.

BART Weekly Report: 9/3/16-9/10/16

RI DEM's Office of Water Resources has been observing and receiving reports of patches of rust-red water visible at the surface in portions of Narragansett Bay, Mount Hope Bay and some RI coastal salt ponds over the past several weeks. RI DEM staff have sampled these red water patches during late August and early September 2016 and identified the causative organism. The red water is caused by a bloom of large numbers of naturally occurring microscopic phytoplankton. More specifically, the rust-tide, as it is commonly referred, observed in RI waters is caused by a dinoflagellate called Cochlodinium polykrikoides. Red water patches sampled in RI waters during the 2016 bloom have contained 1 million to 6 million Cochlodinium cells per liter. Cochlodinium has red photosynthetic pigments which cause the rust-red color visible on the water surface. This "rust tide" should not be confused with "red tide" that has led to shellfish closures in other New England states.

The rust-tide dinoflagellate is non-toxic to humans, even if ingested. However, Cochlodinium produces a hydrogen-peroxide like compound that may damage delicate gill tissue of finfish and shellfish exposed to a concentrated population of the dinoflagellate. Accumulations or blooms of Cochlodinium appear to be a regional phenomenon this summer, with water-discoloring 'rust tides' of Cochlodinium observed in Peconic Bay off the eastern end of Long Island (NY), and in Buzzards Bay (MA) and off Martha's Vineyard (MA). Persistence of this non-toxic bloom in RI waters is highly dependent on weather, but this species generally blooms in warm water and the population is anticipated to decline as water temperature cools to 60° F or less. RI DEM staff will continue to monitor the bloom over the next several weeks.

The NBFSMN stations have been recording this event as elevated chlorophyll. Chlorophyll levels range between 5-45 µg/L at most stations in Narragansett Bay. Elevated chlorophyll were recorded at Conimicut Point, Mount Hope Bay, Poppasquash Point and Greenwich Bay (>30 µg/L). All other parameter are reporting normal for this time of year. Temperatures continue to cool this week (73-78° F). Also, all stations are reporting normal oxygen conditions for this time of year (>4 mg/L).

As of September 10, two new stations were established in Mount Hope Bay, near Cole and Taunton Rivers in Massachusetts. These buoys are funded through MA DEP.

BART Weekly Report: 8/27/16-9/2/16

Temperatures cooled slightly this week (75-79° F). Chlorophyll levels range between 5-35 µg/L at most stations in Narragansett Bay. Elevated chlorophyll was only recorded at Poppasquash Point and Greenwich Bay (>20 µg/L). Overall, conditions at all stations are reporting normal oxygen conditions for this time of year (>4 mg/L).

BART Weekly Report: 8/20/16-8/26/16

Temperatures stayed about the same this week (75-81° F). Chlorophyll levels range between 5-25 µg/L at most stations in Narragansett Bay. A spatial survey led by Brown University this week revealed low dissolved oxygen at surface and at depth in the Seekonk and Providence Rivers (<3mg/L). Hypoxic conditions were observed at the bottom from Phillipsdale to the area off Sabin Point. Low oxygen was also reported in Greenwich Cove. Overall, water south of Conimicut Point were clear, well mixed and normal oxygen conditions for this time of year (>4 mg/L). Water clarity was relatively high throughout the Bay, with overall secchi disk readings about 2 m. Large numbers of comb jellies (phylum Ctenophora) have been observed throughout the Bay.

BART Weekly Report: 8/13/16-8/19/16

With the heat wave, surface temperatures have continued to warm this week (75-81° F). Chlorophyll levels range between 5-25 µg/L throughout Narragansett Bay. As of August 17, most stations are reporting oxygen levels above 4 mg/L. The water column is well mixed and all parameters are normal for this time of year.

BART Weekly Report: 8/6/16-8/12/16

With the heat wave this week, surface temperatures have increase about 2 degrees (73-81° F). Chlorophyll levels range between 5-25 µg/L at most stations in Narragansett Bay. A spatial survey led by Brown University this week revealed low oxygen in the Seekonk and Providence Rivers from Phillipsdale to the southern tip of Fields Point (<3 mg/L). Values near the bottom ranged from 1.06 to 2.2 mg/L and the lowest DO of 0.35 mg/L was measured near the bottom off of Save the Bay on the Edgewood Flats. Greenwich Bay has also been reporting low oxygen (<3mg/L) since August 10. This low oxygen event will be monitored closely. Large numbers of larval crabs (including Genus Portunus and Polyonyx) have been observed throughout the Bay.

BART Weekly Report: 7/30/16-8/5/16

Surface temperatures decreased slightly this week (73-79° F). Chlorophyll levels range between 5-20 µg/L. The Bay is well mixed and most stations are reporting normal conditions for this time of year.

BART Weekly Report: 7/23/16-7/29/16

Surface temperatures continued to increase slightly this week (74-81° F). Chlorophyll levels range between 5-25 µg/L. As of July 27, oxygen levels have increased to concentrations over 3 mg/L in western Greenwich Bay. Most stations are reporting normal conditions for this time of year.

BART Weekly Report: 7/16/16-7/22/16

Surface temperatures continued to increase slightly this week (73-78° F). Chlorophyll levels have declined throughout the week in most areas with levels ranging between 5-25 µg/L. Periods of low oxygen appear to only be persisting in western Greenwich Bay this week. This area is reporting oxygen concentrations below 3 mg/L for about 4-8 hrs per day. This event will be monitored closely. A spatial survey of the Upper Bay area led by Brown University is scheduled for July 28.

BART Weekly Report: 7/9/16-7/15/16

Surface temperatures stayed within the same range as last week (72-77° F). A persistent chlorophyll bloom that began on June 30 in western Greenwich Bay, areas in the Providence River, and areas within Mount Hope Bay has continued (>20 µg/L). These areas are also documenting periods of low oxygen (<3 mg/L) about 4 to 8 hours per day. Greenwich Cove is reporting near anoxic conditions (<1 mg/L). These events will continue to be monitored closely.

BART Weekly Report: 7/2/16-7/8/16

Surface temperatures continued to increase this week (72-77° F). As of June 30, a chlorophyll bloom has been observed in western Greenwich Bay, areas in the Providence River, and areas within Mount Hope Bay (>20 µg/L). As a result, water clarity has declined this week. These areas are also documenting periods of low oxygen (<3mg/L) about 4 to 8 hours per day. These events will be monitored closely. A spatial survey, led by Brown University, is scheduled for next week. Other observations this week include large numbers of larval crabs (Genus: Portunus and Polyonyx) throughout the Bay.

BART Weekly Report: 6/25/16-7/1/16

Surface temperatures continue to increase this week (68-75° F). As of June 28, a chlorophyll bloom has been documented in western Greenwich Bay and Greenwich Cove (>20 µg/L). Western Greenwich Bay is also presently experiencing periods (4-6 hours per day) of low oxygen (<3 mg/L). All other stations are reporting normal conditions for this time of year.

BART Weekly Report: 6/18/16-6/24/16

Surface temperatures continue to increase this week (67-74° F). As of June 19, oxygen levels in the Upper Bay have begun to decline; however, they do remain above 3 mg/L at all stations. All other parameters are normal for this time of year.

BART Weekly Report: 6/11/16-6/17/16

Surface temperatures have increased slightly this week (67-71° F). The water column throughout the Upper Bay is fairly uniform due to strong winds earlier in the week. As a result, all parameters are normal for this time of year. A spatial survey led by Brown University, conducted on 6/16/16, showed only one location in the Providence River with low oxygen (<3 mg/L). The rest of sample area of the Upper Bay, including Greenwich Bay, reported dissolved oxygen readings all above 3 mg/L.

BART Weekly Report: 6/4/16-6/10/16

Surface temperatures have increased slightly this week (67-69° F). The water column throughout the Upper Bay is fairly uniform due to the strong winds throughout most of the week. As a result, all parameters are normal for this time of year. Dissolved oxygen readings are above 3 mg/L. A spatial survey led by Brown University will be conducted this coming week.

BART Weekly Report: 5/29/16-6/3/16

The buoys were deployed throughout Narragansett Bay this week. The first reports show all parameters are normal for this time of year. Dissolved oxygen readings are above 3 mg/L. Surface bay temperatures are 66-68° F on average. Schools of menhaden have been observed in the Upper Bay.

Rhode Island contacts for sightings of the crab:



Kevin R. Cute, Marine Resources Specialist

Coastal Resources Management Council

Stedman Government Center

4808 Tower Hill Road

Wakefield, Rhode Island 02879

Phone: 401-783-3370

Fax: 401-783-3767

Email: kcute@crmc.ri.gov



Chris Deacutis, Chief Scientist

Narragansett Bay Estuary Program

URI Bay Campus 02882

Phone: 401-874-6217

Fax: 401-874-6869

Email: deacutis@gso.uri.edu



David Gregg, Executive Director

RI Natural History Survey

PO Box 1858

Kingston, Rhode Island 02881

Phone: 401-874-5800

Fax: 401-874-5868

Email: dgregg@rinhs.org