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 headboatJuvenile 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