The Impact of Turtle Excluder Devices and Fisheries Closures on Loggerhead and Kemp's Ridley Strandings in the Western Gulf of Mexico

The Sea Turtle Stranding and Salvage Network has been monitoring turtle strandings for more than 20 years in the United States. High numbers of strandings in the early to mid-1980s prompted regulations to require turtle excluder devices (TEDs) on shrimping vessels (trawlers). Following year-round TED implementation in 1991, however, stranding levels in the Gulf of Mexico increased. We evaluated the efficacy of TEDs and other management actions (e.g., fisheries closures) on loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtle populations by analyzing a long-term, stranding data set from the western Gulf of Mexico. Our analyses suggest that both sea turtle population growth and shrimping activity have contributed to the observed increase in strandings. Compliance with regulations requiring turtle excluder devices was a significant factor in accounting for annual stranding variability: low compliance was correlated with high levels of strandings. Our projections suggest that improved compliance with TED regulations will reduce strandings to levels that, in conjunction with other protective measures, should promote population recoveries for loggerhead and Kemp's ridley turtles. Local, seasonal fisheries closures, concurrent with TED enforcement, could reduce strandings to even lower levels. A seasonal closure adjacent to a recently established Kemp's ridley nesting beach may also reduce mortality of nesting adults and thus promote long-term population persistence by fostering the establishment of a robust secondary nesting site.