Sea Turtle Ecology in the Gold Coast Region, Australia: Habitat Use, Nesting Behaviour and Movement Patterns

Abstract

Habitat destruction and human exploitation has caused major declines in global sea turtle populations, resulting in six out of the seven species of sea turtles being classified as endangered or critically endangered by the International Union for the Conservation of Nature (IUCN). Extensive research has been undertaken on sea turtle nesting, breeding structure and abundance, migration and threats. However, little detailed information is available within the literature on sea turtle nesting behaviour, movement patterns and habitat usage within southern peripheral habitat limits of eastern Australia. This study investigates sea turtle ecology within the southern peripheral habitat limits on the east coast of Australia, Gold Coast region. The study focuses on the green, Chelonia mydas and loggerhead, Caretta caretta turtles, two species known to utilise the marine habitats of the Gold Coast Broadwater, South Stradbroke Island (SSI) and Cook Island (NSW) complex. The research quantified aspects of the nesting behaviour, movement patterns, habitat availability and usage, with a specific focus on the extensive seagrass meadows of the Gold Coast Broadwater. Seagrass habitats within the Broadwater were mapped in 2008 using aerial photography revealing that meadows cover 1208 ha within the Gold Coast Broadwater, an increase of 347 ha since 1987. Overall, 166 seagrass patches were mapped ranging in size from 0.25 ha to 124.4 ha with a mean size of 7.3 ± 15.9 ha. Despite the increase in the total seagrass extent, there was a significant decline in the mean patch size of seagrass meadows between 1987 and 2005. Despite the importance of seagrass meadows for turtles as foraging areas, the meadows in the Broadwater appeared to be poorly utilised by turtles.