NOAA Fisheries Dr. Jim Berkson, Dr. Yan Jiao Paige Barlow, Bonnie Coggins, Christopher Hayes, Melissa Hedges, Eliza Heery, James Thorson Biased length frequencies in fisheries stock assessment Eliza Heery In many marine fisheries, length measurements are compiled from sub-samples of the total catch in order to provide information about the dynamics of the population. Often this data contains biases. Eliza is considering how bias in length frequency data can affect model estimates that are crucial for fisheries management by using a simulation approach to consider the effects of bias based on two different scenarios. Research at the RTR Unit focuses on providing critical information for the proper management of our nation's marine resources Life history and stock assessment of hammerhead sharks in the Gulf of Mexico and northwest Atlantic Ocean Christopher Hayes Chris is using catch data and abundance indices to estimate the change in population abundance of hammerhead sharks (Sphyrna spp.) in the western North Atlantic Ocean and Gulf of Mexico. He will estimate life-history parameters such as population growth rate and current population size, and simulate future population dynamics based on likely effects of a number of alternative fishing management policies. Chris with a neo-natal hammerhead Chris getting the length measurement of teleost bycatch Loggerhead sea turtle nesting beach survey and population model development Melissa Hedges Melissa is tagging nesting loggerhead sea turtles to estimate adult survival rate and female fecundity. Adult survival is an important component in understanding the dynamics of the population and how it will respond to conservation measures. Melissa excavates a nest to count the number of hatched eggs A baby loggerhead crawling to the ocean for the first time A female loggerhead lays her eggs Bonnie with a hatchling An adult loggerhead Shrimp bycatch in the Gulf of Mexico Bonnie Coggins The Gulf of Mexico shrimp fishery catches and discards large numbers of non-targeted fish species (bycatch). The NOAA Fisheries Service began an observer program on shrimp trawlers in 1992 to estimate shrimp and bycatch catch rates and the effectiveness of methods to reduce bycatch. Her project will analyze this dataset and estimate the bycatch of a number of important fish species. Bycatch examples: Lane Snapper and Triggerfish Shrimp trawl catch: more than just shrimp! Commercial shrimp trawler Analysis of Recreational Fishing Surveys and Data James Thorson Although recreational fishing has grown immensely in importance during the past thirty years, its national survey, MRFSS, has seen few revisions during this time. James plans to study the MRFSS survey, investigating (1) the sound interpretation of past data and (2) strategies for improving design in the future. Jim with a Grouper Fishing on a headboat Juvenile Gag grouper Eliza Warsaw Grouper Black Sea Bass Service RTR Unit Sea turtle interactions with the pelagic longline fishery: estimating number of bycatch events and post-interaction mortality Paige Barlow Leatherback and loggerhead sea turtles are caught incidentally in the longline fishery, which targets tuna and swordfish, and the NOAA Fisheries Service is responsible for estimating the number of threatened and endangered sea turtles caught. She will use simulation modeling to compare bycatch estimates using different mathematical models to test which methods work best under a range of scenarios. Results will be used to provide improved estimates of sea turtle mortality. Paige fishing onboard a headboat A loggerhead sea turtle caught as bycatch in the longline fishery Learning about loggerheads injured by the longline fishery