The influence of temporal and spatial origin on size and early growth rates in captive Loggerhead Sea Turtles (Caretta caretta) in the United States

.—This study provides morphometric characteristics of early pelagic stage post-hatchling loggerheads in thenorthwestern Atlantic. We investigated whether differences in temporal and spatial nest origin influence initial size andgrowth potential in Loggerhead Sea Turtle (Caretta caretta) hatchlings from two genetically distinct subpopulations. Wesampled hatchlings from eight sites in the southeastern United States from North Carolina to Florida, representing twogenetically distinct subpopulations during three phases (“Early,” “Middle” and “Late”) of the 2002-nesting season. The largesthatchlings were produced at the northern-most nesting site. Initial hatchling size tended to decrease as latitude decreasedalong the eastern coast of the United States. Hatchlings from the Early phase of the nesting season grew faster than later phasehatchlings, reducing the time interval at the smallest sizes. The initial size differences and growth potential may affect earlystage survivorship by altering the risk of size-based predation and decreasing the transit time to the relative safety of GulfStream nursery habitats.