Somatic growth of juvenile green turtle (Chelonia mydas) morphotypes in the Colombian Pacific

Abstract

Somatic growth rates of green turtles (Cheloniamydas) are affected by foraging success and influence their survival and reproduction. Gorgona National Park (GNP) in the Colombian Pacific (2°58′03″N, 78°10′49″W) is an insular foraging site that offers a unique opportunity to study the black (occurring only in the eastern Pacific) and yellow (with western Pacific nesting beach origins) morphotypes of green turtles during their juvenile phase. A total of 995 turtles were captured and marked between October 2003 and December 2012. Recapture rates were low (20 black morphotype and 13 yellow morphotype turtles) but suggested that at least some turtles remain in the area for extended periods (>5 years). Mean growth rate was slightly higher for black morphotype (mean 0.92 ± 0.24 cm y−1) than yellow morphotype turtles (mean 0.74 ± 0.26 cm y−1), and both morphotypes displayed a non-monotonic growth pattern. Black morphotype turtles grew faster at intermediate sizes, similar to black turtles at other locations in the eastern Pacific, whereas yellow morphotype turtles had slowest growth at intermediate sizes. Our data underscore the importance of GNP as a foraging habitat for C. mydas individuals from distinct nesting populations and indicate that these morphotypes have different growth patterns while residing at the same foraging site.