Shellfish Dredge Survey

a dredge sitting on deck of boat — The dredge used in the survey

Dredge used int he survey being set — The dredge being deployed from the new vessel, *R/V Reliance*

fishing boat on open water — Towing the dredge

small fishing boat underway on open water — Hauling dredge back

Background

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

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