Spatial and temporal patterns of harvesting of the Vulnerable pig-nosed turtle Carettochelys insculpta in the Kikori region, Papua New Guinea

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.

Salinity of the coastal nesting environment and its association with body size in the estuarine pig‐nosed turtle

“…Opposite to the Daly River, population that do not perform extensive migrations to nest (Doody et al ., 2003 a ), female Kikoris migrate from their foraging aggregations in the delta to the coastal and riverine nesting areas (Georges et al ., 2008 a ; Eisemberg et al ., in press). Larger size is often associated with a greater tolerance to saline exposure (Dunson, ; Dunson & Seidel, ) and migration (Moll & Moll, ).…”

Local harvest of pig-nosed turtle (Carettochelys insculpta) in the Kao River, Boven Digoel District, Southern Papua, Indonesia

“…To obtain information on the extent of harvesting areas, we followed the pig-snouted turtle egg collectors during their activities for a total of 20 days following the study of Eisemberg et al (2015) in the Kikori region, PNG. We visited 5 villages around nesting grounds and hunting lodges of the Kao River: Asikie, Sesnukt, Amboran, Anggamburan, and Geten Tiri, to record information on the harvest and number of eggs collected and other types of natural resources utilized.…”

“…One of the widely distributed turtles from the southern part of Papua is the pig-nosed turtle (Carettochelys insculpta Ramsay, 1886), also found in Papua New Guinea and northern Australia (Eisemberg et al 2018). The turtle has been used as a source of animal protein (both eggs and meat) for generations in some locations of Indonesian Papua and Papua New Guinea (Eisemberg et al 2015(Eisemberg et al , 2018Triantoro and Tuharea 2017). Additionally, residents around Vriendschap River, Asmat District in South Papua Province, used pig-nosed turtles as dowry (Triantoro and Rumawak 2010).…”

“…Additionally, residents around Vriendschap River, Asmat District in South Papua Province, used pig-nosed turtles as dowry (Triantoro and Rumawak 2010). Pressure on the pig-nosed turtle population has increased in recent years, particularly in Indonesian parts of Papua and Papua New Guinea, mainly due to human population growth and the high utilization of these animals (Burgess and Lilley 2014;Eisemberg et al 2015). In northern Australia, agricultural activities and drainage of watersheds have the potential to seriously impact its populations (Eisemberg et al 2018).…”

Boosting female hatchling production in endangered, male‐biased turtle populations

“…Disproportionate production of one sex in temperature‐dependent sex determination species may lead to an adult population with a biased sex ratio, decreasing effective population size and genetic diversity (Vogt , Vogt and Bull , Servan et al , Godley et al ). The sex ratio of adult turtles can also be influenced by humans because females are preferentially harvested (Mrosovsky , Souza and Vogt , Aresco , Gibbs and Steen , Eisemberg et al ). A primary sex ratio skewed toward males could be particularly problematic (Vogt , Vogt and Bull , Servan et al ).…”