Sex Ratio of Summer Flounder Commercial and Recreational Landings

The summer flounder stock has been in a rebuilding stage since a management plan was adopted in the late 1980s when the abundance was at an all time low.  In the mid-2000s, despite continuing expansion of the stock, summer flounder biomass still lagged behind rebuilding goals and this resulted in increased quota restrictions.  In 2008, the Southern Demersal Working Group (SDWG) addressed this issue during the stock assessment by identifying gaps in available data that limited assessment of the stock.  One consequence of this was the formation of the Partnership for Mid-Atlantic Fisheries Science (PMAFS).  PMAFS obtained funds to support research initiatives designed to address many of the outstanding concerns and data limitations identified by the SDWG.  A top priority was the collection of sex data from the commercial and recreational landings as the absence of these data prevented independent modeling of male and female summer flounder population dynamics and life history. 

In March of 2010, PMAFS therefore initiated a data collection program designed to obtain information on sex and age for commercial and recreational landings of summer flounder for states from Massachusetts to North Carolina.  Pursuant to this objective, in 2010 sex and length data were collected from over 14,000 fish landed in the commercial and recreational summer flounder fisheries in 35 ports across these states and scales and/or otoliths from a subset of these fish have been sent to the National Marine Fisheries Service (NMFS) for aging.  Preliminary data on sex-at-length from 2010 show interesting geographic and fishery-dependent trends.  Coast-wide and at all length categories, fish sampled in the recreational fishery were almost exclusively female (% female = 95%; n = 6,250).  Rhode Island and Connecticut were the only states that landed males in significant numbers (% female = 75%; n = 698).  Overall, males were much more common in the commercial fishery (% female = 65%; n = 7011), where regional differences in sex-at-length were less evident.  Finally, coast-wide, more males were landed at a given size in the commercial fishery than were landed at the same size in the recreational fishery.  For example, at 45 cm, the fraction female sampled in the commercial fishery was just 66%, while in the recreational fishery it was 93%.  Regional and fishery-specific sex-at-age keys may be required to confidently apply sex ratio to commercial and recreational landings.