No abstract

Extant estuarine and freshwater animals show a variety of adaptations to marine life, which could reflect transitional stages in a gradual evolution from freshwater to the sea. Our aim was to identify the temporal and spatial environment associated with pig‐nosed turtles Carettochelys insculpta coastal nesting in the Kikori Region, Papua New Guinea (PNG). We also related the use of coastal areas with size within and among different populations of C. insculpta and species of the superfamily Trionychoidea. Throughout its range, C. insculpta nests during the drier months when suitable sandbanks are exposed. In PNG, rainfall in the drier season dilutes salinities and C. insculpta nests in coastal sandbanks. In Australia, high salinities prevail in the river mouths during the nesting season and no coastal use is observed. Trends toward a larger body size in coastal areas suggest that size is an important factor to explore coastal environments. It is unlikely that female C. insculpta with less than 50 cm (curve carapace length) would be able to cope with the Kikori coastal environment. Expanding this trend to its superfamily Trionychoidea, only species larger than 37 cm (leathery carapace length) explore coastal environments. As the Australian coast is not suitable for nesting, the selection for larger body sizes was probably relieved. Of course, the reverse could be true, but our study provides an example of the caution required when placing evolutionary interpretations on life‐history traits whose manifestation is studied only within a restricted portion of a species range.

No abstract

Management of wildlife use by communities living a partially traditional lifestyle is usually more successful when the interactions between those communities and the environment are well understood. We mapped the harvest areas for the Vulnerable pig-nosed turtle Carettochelys insculpta for six language-groups in the Kikori region of Papua New Guinea and compared harvest parameters between different areas and language-groups and, when possible, between 1980–1982 and 2007–2009. Spatially, the main influence on harvest method was a tribe's location relative to the turtle's distribution. No small juveniles (< 20 cm straight-line carapace length) were found outside the Kikori delta, which is probably the species’ feeding grounds. In contrast, nesting females were captured only in upstream and coastal sandbank areas. Temporally there were distinct differences in harvesting parameters between tribes, which may be explained by differential employment opportunities. To halt the decline of pig-nosed turtles in the Kikori region we recommend the establishment of beach and feeding-ground protection initiatives, together with monitoring of the turtle population and harvest. Concomitantly, trips specifically targeted at harvesting the turtles, which account for 81% of the animals captured, need to be restricted. These initiatives should include all six language-groups and take into account their specific harvesting patterns.