Abstract
See Project ID 1151 for tracking of courting greens from Sandy Cape: http://www.seaturtle.org/tracking/?project_id=1151
The traditional owners of K'gari (Fraser Island), the Butchulla people, gained Native Title over much of K'gari in 2014, and we acknowledge their long heritage on and nurturing of this beautiful land, and wish them well with their new opportunities.
The idea of monitoring nesting turtles in the Sandy Cape rookery on K'gari-Fraser Island was initiated in the 1992-3 season by Rowan Foley, a Butchulla man, who was then employed as a Ranger by Queensland (National) Parks and Wildlife Service, (QNPWS, now QPWS) and as a result some nest and track-count monitoring was undertaken by long-time annual campers Karl & Sue Klein, and the Lighthouse Keepers, Dudley & Sue Fulton, & Aubrey Strydom & Lainie Rowe.
Rowan's report recommending that a turtle census be undertaken was accepted by QPWS and in the 1993-4 season Steve Price - QPWS 2IC Ranger at Waddy Point, with the support of his RIC Bart Klekar, came to the top end of K'gari-Fraser Island with the two Michaels - volunteers from the Mon Repos Turtle Rookery.
A number of Park Rangers and the Lighthouse Keepers were inducted into turtle species I.D., flipper tagging, and data sheet entry and so began an 18 year monitoring program, with a 17 night mid-season nesting census and flipper tagging of all turtles coming ashore during the census across the 44km of beach from Rooney Point to Ngkala Rocks.
In that first season the first nest relocations to near the Lighthouse gate by vehicle was trialed, using three doomed clutches laid below the king tide level.
This was successful and since then 5 nest relocation cages with a total capacity of 120 clutches have been developed at strategic locations along the rookery, and recently also at Orchid Beach, to enable protection of doomed loggerhead and green clutches, and to provide protection for a percentage of loggerhead clutches from vehicle and camping impacts, and dingo and goanna (monitor lizard) depredation.
In the first few years in the 1990's between 50 to 100 greens, but only 5 to 7 loggerheads were nesting annually, and drowned adult loggerhead turtles were being found washed up on the beach.
Nesting numbers increased to twelve to fifteen loggerheads a year from 1997 when a seasonal 3 to 5 km wide trawl exclusion zone was established along the NW beach between Rooney Point and Sandy Cape, and then climbed to near 50 nesting each year after the introduction of TEDs, (Turtle Exclusion Devices) in the Queensland trawl fishery nets in 2001.
Currently annually about 40 to 50 loggerheads nest along the 44 kilometers of the Rooney Point to Sandy Cape to Ngkala Rocks rookery, and between 50 and 100 loggerhead nests are protected by relocation each season, by the Sandy Cape Lighthouse Volunteer Caretakers, in a program supported by QPWS.
Green nests are not generally relocated, as the Southern Barrier Reef green turtle population is still slowly increasing since turtle protection in Queensland began in the early 1950s, and these eggs support the Wongari (Dingo) population as part of their natural diet.
While sometimes up to 600 greens nest in a season, and as few as 3 the next season, most commonly between 50 and 100 green turtles come in to nest each year. This variability provides some protection to the greens clutches by sometimes alternatively flooding the predators' diet one season with a mass nesting and starving them the next.
A study of dingo impacts on the nests saw nest depredation vary between 15% in a season when there was a mass nesting of over 250 greens and 85% when there were only about 30 greens nesting.
A potential new threat to the rookery is the advance of feral foxes and pigs up K'gari-Fraser Island. They are in large numbers on the adjacent mainland and are good swimmers.
In recent years foxes have been sighted at Awinya Creek, only 30 to 40 kilometers from either end of the Sandy Cape rookery, and in December 2018 a feral pig was seen on the beach in the rookery only 5km south of Sandy Cape.
Monitoring of nests for any pig and fox impacts will guide management plans to provide further protection.
Over the years since 1993 over 500 male green turtles were tagged courting in the shallows or basking on the beach, and a correlation between their numbers and the size of the concurrent green nesting season was observed. Some were found to be carrying flipper tags from the Shoalwater Bay turtle rodeo program, and K'gari-Fraser Island tagged males were being found at Shoalwater Bay, and in the Whitsundays.
It was found that female green turtles tagged on the Island in the September/October courting season were being seen that season nesting further north at other rookeries in the Southern Great Barrier Reef, and at the Wongarra Coast and Wreck Rock mainland rookeries.
In 2014 two males were tagged while courting at Sandy Cape and one returned home to Shoalwater Bay Qld, and one to the outer Barrier Reef near Olympic Reef.
The green female April O'Moreton, who had been tagged as a juvenile in 1992 in Moreton Bay was found courting at Sandy Cape in 2015 and given a satellite tracker, and she moved on to nest at North West Island in the Capricorn Bunker group.
In the 2015-16 season the project also tracked 5 green males and in 2016-17 a further 6 green males, to expand the knowledge of where they come from to court at Fraser Island, what connectivity they have to other known courting areas, and to examine the areas in the Great Sandy Marine Park they use during their courting sojourn.
Three females were tracked in the 2016-17 season - one with a history of nesting at K'gari-Fraser Island, one known to forage in the Whitsundays, and one known to nest at Wreck Island in 1998 in the Capricorn Bunker group.
In November 2017, 3 nesting loggerhead females and 8 nesting green females, and in December 2018, 5 nesting loggerhead females were given trackers, to enable comparison of the female's inter-nesting habitat use with that of the males courting habitat, and help inform an assessment of the adequacy of the seasonal go-slow and no-trawl zones in the Great Sandy Marine Park.
|
