Updating size- and age-at-maturity schedules for southern flounder in North Carolina

Southern flounder Paralichthys lethostigma are consistently among the most valuable finfish resources in North Carolina. However, elevated harvest rates during the past two decades have contributed to a ‘depleted' status for the stock. Although recently completed studies have improved our understanding of southern flounder biology and harvest patterns within the state, they have also generated evidence questioning the validity of the current estimates of size- and age-at-maturity being used to assess the stock. Accurate maturity schedules are essential to rebuild stock biomass and promote population recovery. We have collected southern flounder throughout the 2009 spawning season from multiple North Carolina locations to update the size- and age-at-maturity estimates. We are currently investigating macroscopic stages of gonadal tissue and identifying correlates with a suite of other morphological characteristics, such as length, weight, and the gonadosomatic index (GSI). We are also working to validate the present macroscopic staging methods currently used by state resource biologists by examining histological samples in an effort to improve the accuracy and precision of macroscopic techniques. Otolith microchemistry will also be analyzed to help describe patterns of habitat use as they relate to reproductive events.