Determining Incidental Discard Mortality of Atlantic Sea Scallops in the Scallop Dredge Fishery in the Mid-Atlantic Bight

Incidental mortality of small scallops passing through the 4-inch rings of the 12′  turtle excluder dredge was assessed off of New Jersey.  A twine mesh bag (17/8′′) was sewn into the top of the dredge apron to collect the scallops and other organisms passing through the dredge rings.  Twenty tows were conducted with the experimental dredge.  A sub-sample of scallops collected in the mesh bag was then categorized into three categories based upon shell damage, namely not injured, sub-lethal, and lethal.  The percentage breakdown of scallops was 70% not injured, 28% sub-lethal and 2% lethal.  Scallops from each category were returned to the seafloor in cages and monitored to assess mortality at one and two-week intervals.  Preliminary results indicate that 7% of the sublethal scallops died and 37% of lethal category scallops died after being returned to the sea in cages for two weeks. The surviving scallops with lethal damage may not have died because of limited scavenger/predator access. Incidental mortality was estimated to be 3% of all scallops that passed through the four-inch rings and 4% if all lethally damaged scallops are assumed to have died.