chapter  6
Impacts on marine turtles
Pages 23

Of the seven extant species of marine turtle, six occur in Queensland waters: green (Chelonia mydas), hawksbill (Eretmochelys imbricata), loggerhead (Caretta caretta), flatback (Natator depressus), olive ridley (Lepidochelys olivacea) and leatherback (Dermochelys coriacea) turtles. Most are defined by the IUCN (2013) as critically endangered, endangered or vulnerable (Table 6.1). As a result of many natural and anthropogenic pressures – including predation of nests by feral foxes and pigs, incidental catches in fishing and shark control nets, ingestion of litter, boat strikes, Indigenous hunting, habitat destruction and tourism – declines in many marine turtle populations have been documented. Marine turtles are vulnerable to those impacts as a result of their life histories, which involve very high natural mortality of hatchlings and of small juvenile turtles, the use of a limited number of nesting beaches, high fidelity to nesting sites and feeding grounds, limited interaction between genetic stocks and long maturation periods. Mature female turtles come ashore at nesting sites on specific beaches to lay several large clutches of eggs in a single nesting season – a life history that requires high survivorship of adults. Yet many human impacts on turtles – including those described in this chapter – have affected female turtles disproportionately at that critical life stage.