Virginia Institute of Marine Science
MARINE AND COASTAL FISHERIES
Models that account for sex-specific behavior and population dynamics are becoming more common in the stock assessment of sexually dimorphic fishes. However, such models can be data intensive and require some knowledge or assumptions about the sex ratio of fishery landings. A recent stock assessment review of Summer Flounder Paralichthys dentatus identified the need to account for sex-specific fishing mortality in the assessment model; however, no data on the sex composition of the catch were available. Fishery-independent, sex-specific information for this species is collected annually by the National Marine Fisheries Service's Northeast Fisheries Science Center during their bottom trawl survey. Sex at age from the survey could be applied to the fishery landings if the probability of landing a given sex at a given age is equivalent for fish collected by the survey and those in the landings. To generate the first regionally comprehensive database on the sex ratio of Summer Flounder landings and to determine the efficacy of using survey sex-at-age keys to estimate the sex of landed fish, we recorded the sex composition of the commercial and recreational catches of Summer Flounder (n = 31,912) in 2010 and 2011. When (1) trawl survey length data were left-truncated to simulate the minimum retention sizes in the fisheries and (2) age-length keys generated from fishery-dependent data were applied to length frequency distributions from the survey to simulate the growth rates of landed fish, the sex-at-age pattern in the survey-derived data closely resembled the patterns in the catch. However, statistically significant differences in sex at age remained between the catch and the survey-derived data. We hypothesize that these differences are attributable to differences in the spatiotemporal distributions of the sexes and of the survey and fishing effort.
PLAICE HIPPOGLOSSOIDES-PLATESSOIDES; STRUCTURED ASSESSMENT METHOD; MARLIN MAKAIRA-NIGRICANS; NORTH PACIFIC-OCEAN; INDUCED EVOLUTION; AMERICAN PLAICE; STOCK ASSESSMENT; XIPHIAS-GLADIUS; SOUTHERN GULF; ST-LAWRENCE
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We would like to acknowledge all of the participating fishing docks, for-hire vessel captains, and mates that participated in this project. We thank the NMFS-NEFSC Aging Center, especially Eric Robillard; Integrated Statistics; Mark Luckenbach, Erin Reilly, Patti McGrath, and Roger Mann (Virginia Institute of Marine Science); Joe Cimino and Joe Grist (Virginia Marine Resources Commission), Chris Batsavage (North Carolina Division of Marine Fisheries); Jacqueline Wilson, Joe Costanzo, and Emerson G. Hasbrouck (Cornell Cooperative Marine Program); and the many technicians at the Haskin Shellfish Research Laboratory, Rutgers University. We are especially grateful to the Partnership for Marine Fisheries Science for providing 2 years of funding for this project through National Oceanic and Atmospheric Administration NMFS awards NA10NMF4720017 and NA10NMF4720402 and to the New Jersey Sea Grant College Program (Award NJSG-15-892).
Morson, Jason M.; Bochenek, Eleanor A.; Powell, Eric N.; Hasbrouck, Emerson C.; Gius, Jennifer E.; Cotton, Charles F.; Gerbino, Kristin; and Froehlich, Tara, Estimating the Sex Composition of the Summer Flounder Catch using Fishery-Independent Data (2015). MARINE AND COASTAL FISHERIES, 7(1), 393-408.