Shark Bycatch

Commercial shrimpers from Georgia are collaborating with regional partners to determine the most effective way to reduce bycatch mortality from shrimp trawls and collect more accurate data on bycatch of highly migratory shark species.

Blacknose sharks, Carcharhinus acronotus

One phase of the project specifically studies the interaction between blacknose sharks and shrimp trawlers in the South Atlantic, and addresses the need for more current, reliable shark population and bycatch data. Blacknose sharks are considered a ‘species of concern’, which means NOAA’S National Marine Fisheries Service has concerns regarding their status, but there is not enough information to list them under the Endangered Species Act.

The University of Georgia Marine Extension (MAREX) and their partners are working to provide more information about threats to migratory shark species off the Georgia coast.

NOAA considers the blacknose to be overfished, and estimates that 86, 381 blacknose die in the South Atlantic and Gulf of Mexico each year, and 4,856 of those mortalities are attributed to shrimp bycatch in the South Atlantic. However, very little data exists from shrimp trawlers about how many blacknose sharks they are hauling aboard. In a collaboration involving local commercial shrimpers and scientists, this project aims to provide more information to address those concerns through outreach and education.

Observers will be placed on shrimp trawlers off the Georgia Coast as part of the project to record the number of migratory shark species caught and what condition they are in when returned to the water. Workers from MAREX, DNR and local shrimpers will also collect fishery-independent data on board the R/V Georgia Bulldog, a 72’ shrimp trawler that has been converted for research and education.

Comparing Turtle Excluder Devices (TEDs)
Two different types of Turtle Excluder Devices, or TEDs, will be tested for their ability to reduce bycatch and improve shrimp retention. The industry standard TED uses a 4” bar spacing compared to a new design called the Georgia Jumper Big Boy that uses a 2” bar spacing. The project will encourage the use of TEDs with 2” bar spacing and distribute Big Boy TEDs to cooperating vessels free of charge.

The project also aims to provide economic incentives to reduce bycatch and assess the effectiveness of bycatch reduction devices (BRDs) in preventing shark mortality. A heavy load of non-target species causes the boat to drag and waste fuel. A slow moving net may also allow shrimp to escape.

Comparisons show that the Big Boy TED greatly reduces total bycatch, including jellyfish, sharks and finfish, and catches the same amount of shrimp.

The UGA MAREX project is funded by the National Oceanic and Atmospheric Administration (NOAA) Cooperative Research Program with support from Georgia Sea Grant and the Department of Natural Resources (DNR).

For more information, contact Lisa Liguori, Associate Director, University of Georgia Marine Extension Service, at 912-264-7269 or liguori@uga.edu.