ESR 22:73-84 (2013)  -  DOI: https://doi.org/10.3354/esr00535

Genetic stock composition of loggerhead turtles Caretta caretta bycaught in the pelagic waters of the North Atlantic

Erin L. LaCasella1,*, Sheryan P. Epperly2, Michael P. Jensen1, Lesley Stokes2, Peter H. Dutton

1Marine Mammal & Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 8901 La Jolla Shores Drive, La Jolla, California 92037, USA
2Southeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 75 Virginia Beach Drive, Miami, Florida 33149, USA

ABSTRACT: Sea turtle populations disperse widely across oceans and migrate between terrestrial nesting habitat and distant feeding and developmental habitats. Understanding population stock structure is important for accurately assessing threats such as mortality from fishery bycatch and for defining specific demographic units of conservation concern. We compared 775 bp mtDNA control region haplotypes from 389 juvenile loggerhead turtles sampled as bycatch in the US pelagic longline fishery in the western North Atlantic Northeast Distant (NED) region to haplotype frequencies observed in 23 genetically distinct nesting stocks representing the 4 distinct population segments (DPSs) that have been identified throughout the Atlantic Ocean and Mediterranean Sea. We used Bayesian mixed-stock analysis to produce stock composition estimates for juvenile loggerhead turtles that use pelagic habitat in the central North Atlantic. We found that nearly all of the loggerheads caught in NED waters belonged to the Northwest Atlantic DPS (mean = 99.2%), with the majority coming from the large eastern Florida rookeries (mean = 84.0%). We also detected contributions from the western Florida rookeries (mean = 11.7%) and Mexico (mean = 3.5%) but found little evidence of contributions from the rookeries of the South Atlantic, Northeast Atlantic, or Mediterranean DPSs. These results will help improve specific threat assessments and are relevant to ongoing development of conservation plans that are aligned to the recent DPS listings for loggerheads.


KEY WORDS: Mitochondrial DNA · Mixed stock analysis · Fisheries · Bycatch · Northeast Distant Longline Fishery


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Cite this article as: LaCasella EL, Epperly SP, Jensen MP, Stokes L, Dutton PH (2013) Genetic stock composition of loggerhead turtles Caretta caretta bycaught in the pelagic waters of the North Atlantic. Endang Species Res 22:73-84. https://doi.org/10.3354/esr00535

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