Abstract

Foraging grounds are critical to the survival of marine turtles, yet studies of these areas lag behind those of nesting sites. Our study represents the first data and discussion on marine turtle distribution, abundance, and health at a marine turtle foraging ground in the central Pacific, Palmyra Atoll National Wildlife Refuge, which constitutes a regionally important mixed-size-class foraging ground for green turtles (Chelonia mydas) and, to a lesser extent, for hawksbill turtles (Eretmochelys imbricata). Surveys and anecdotal reports suggest that nesting activity is rare, and we have confirmed the presence of limited suitable nesting habitat. During in-water activities from 2008 to 2011, we caught 211 green turtles ranging from postpelagic juveniles to adults (weight: mean  =  44.6 kg, range  =  7.2–146.3 kg; curved carapace length (CCL): mean  =  69.7 cm, range  =  41.0–113.6 cm) and 2 juvenile hawksbills (weight2009  =  16.3 kg, CCL2009  =  57.0; weight2011  =  11.2 kg, CCL2011  =  50.5 cm). Body condition indices did not significantly differ by year of capture. These indices, along with the absence of observed fibropapilloma tumors, indicated that turtles at Palmyra Atoll were on average in very good condition. We also conducted 11 relative abundance surveys from 2005 to 2011, a subset of which revealed an uneven distribution of turtles around Palmyra Atoll with 3 hot spots of turtle abundance off the flats to the north, south, and east. By linking several aspects of our research program with similar efforts at foraging grounds throughout the Pacific Basin, we can further our understanding of poorly known regional migratory connectivity.

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