Natal origins of juvenile green turtles (Chelonia mydas) in the Bahamas:
a comparison of recent and historical rookery contributions
Abstract
Green sea turtle conservation benefits from knowledge of population
connectivity across different life stages. Green turtles are usually
managed at the level of genetically discrete rookeries, yet individuals
from different rookeries mix at foraging grounds. Rookeries may be
impacted by processes at foraging grounds, hence rookery contributions
to mixed foraging assemblages must be considered. Bimini, Bahamas, is an
important foraging ground for juvenile green turtles, but rookery
contributions to this assemblage have never been resolved. We generated
mitochondrial DNA (mtDNA) sequences for 96 green turtles from Bimini and
used Mixed Stock Analysis (MSA) to determine rookery contributions to
this foraging assemblage using high-resolution (~817
base pair) and low-resolution (~490 base pair) rookery
baseline data. The high-resolution data indicated that Quintana Roo,
Mexico and Central Eastern Florida contributed most to Bimini. The
low-resolution data indicated that Southwest Cuba and Central Eastern
Florida contributed the most to Bimini. The results of the
low-resolution MSA differ from a previous study conducted in Great
Inagua, Bahamas which may reflect rookery size, rookery proximity to
foraging grounds, the influence of currents, or a combination of these
factors. While the presence of large credible intervals in our results
does not permit explicit interpretation of individual MU contributions
identified in MSAs, our results reveal substantial relative differences
in rookery contributions to Bahamian foraging assemblages. Our study
highlights the importance of regularly monitoring rookery contributions,
resolving regional recruitment patterns to inform conservation, and the
importance of using high resolution data in future MSA’s to improve
rookery contribution accuracy.