Shellfish Dredge Survey

The RI shellfish dredge survey began in 1993. The purpose is to monitor the relative abundance and distribution of quahog clams within Narragansett Bay. The data collected is used in stock assessments, development of Fishery Management Plans, and to characterize and map essential quahog habitat within the bay.

Survey Design
The survey encompasses the upper Narragansett Bay. The region is split into stratums and each stratum is sampled biannually. The exception being Greenwich Bay which is sampled annually.

Survey Gear
The survey uses a hydraulic dredge with an 18-inch width which is towed from a vessel. The dredge is equipped with a 1-inch mesh to ensure all legal sized quahogs are retained.

Sampling Methods
The dredge is towed behind the vessel for a length of 100 feet within each station. All quahogs are counted and measured (hinge width in mm). Bycatch species are identified and enumerated. Details regaring the trip are recorded, such as date, sediment type, and position (latitude and longitude).

Sampling Frequency
Every station within a stratum are sampled biannually, except for Greenwich Bay which is sampled annually..

Sampling Locations: Dredge Survey Stations

For more information about the survey please contact Pat Barrett