Assessment of the probability of loggerhead sea turtle ( Caretta caretta) recovery in the Northwest Atlantic Ocean within 50 years of federal and state protection in the U.S.

摘要

Systematic implementation of sea turtle conservation measures have occurred in the U.S. since the 1970's. As such, this dissertation assessed the probability that loggerhead sea turtles (Caretta caretta) in the NW Atlantic will meet or exceed recovery criteria in the minimum timeframe (i.e., 50 years) specified by the Recovery Plan. Mathematical modeling (Chapter 1) of a theoretical population resembling an important nesting assemblage in a stochastic environment for 200 years revealed broad (106k) fluctuation in annual nest counts without extinction, as well as strong contemporary environmental influence on annual nest counts. Modeling also substantiated the importance of monitoring the relative abundance of juvenile females as the most reliable forecasting metric for nest count trajectories up to two decades into the future. In-water monitoring of loggerhead sea turtle demographic structure at a coastal foraging ground between South Carolina and north Florida suggests a shift away from a stable size distribution during 2000--2015, but which may eventually be tempered by the relative abundance of cohorts hatched near the turn of the last century (Chapter 2). The high relative abundance of juvenile females captured in this coastal trawl survey bodes well for sustained annual nest counts in the coming decade (Chapter 3). Slightly elevated female frequency among the smallest loggerhead sea turtles captured is consistent with a warming climate, but a 100-year association with the Atlantic Multi-decadal Oscillation suggests that reduced female production should begin to occur in the coming decade.