Evaluation of Summer Flounder Discard Mortality Part II

Project Description 2009-2010

This study is an extension of the previous project and is designed to collect data relative to the discard mortality of summer flounder during the winter, offshore fishery.  The driving force behind the research is the presumptive use of an 80% discard mortality rate by the present Summer Flounder (fluke) Fishery Management Plan.  Discard mortality is defined as the  percentage of fish discarded after capture that do not survive.  The two major reasons for being discarded are minimum size regulations and quota or trip limits.  Discard mortality is one of the most important issues related to marine fisheries management today.  The use of an 80% discard mortality rate creates concern to both those involved in fisheries management and the fishermen themselves.  Cornell Cooperative Extension's (CCE) Marine Program, with the cooperation of local fishermen, is conducting scientific trawl surveys in an effort to collect data.  This data can then be used in combination with information from the inshore study to determine an accurate  discard mortality rate for fluke that is based on scientific evidence. CCE staff will conduct research aboard commercial draggers that are engaged in the offshore mixed trawl fishery as well as specifically directed fluke trips.

The procedure is similar to that of the inshore study with only the shore-side maintenance of the live fish being different.  Each trip consists of three tows; one, two and three hours each.  After each tow, CCE staff conducts an immediate and a delayed (30 minute) cull of both legal and sub-legal sized fluke.  Sampled fish are evaluated for condition, weighed, measured and tagged using different color tags to correspond to a specific tow and cull.  The offshore study has an additional component that targets large fish in order to compare their discard mortality relative to other fluke. The fish selected are maintained alive in on-board, temperature controlled holding tanks.  The remainder of the catch is sorted by species and weighed.

The live fish, along with trap caught control fish, are held for 14 days at an established finfish aquaculture facility.  The fish are monitored during captivity for mortality.  Tag information from the dead fish is recorded.  Scale samples and otoliths are collected for additional age data.  Sex is also determined and documented for all dead fish.

CCE staff collects blood samples from a representative number of the captive fish as well as from non-sample fish onboard the boat.  The blood is analyzed for cortisol levels which provide information on the health and stress condition of the fish.

Upon conclusion of the 14 days of monitoring for mortality, the remaining fish are evaluated for physical condition and released.  We continue to seek any information from tagged fish that have been released.  There is a reward for each tag reported with the tag number, tag color, location, water depth, size and weight of the fish at capture.  Please report all tags!



NMFS RSA Program


Cornell Cooperative Extension of Suffolk County—

Marine Program (CCE)


Rutgers University—Haskin Shellfish Research Laboratory


The Long Island Commercial Fishing Association (LICFA) 


Mid-Atlantic Fishery Management Council (MAFMC)


Montauk Inlet Seafood, Inc.—Montauk, NY