CANBERRA, Jan. 14 (Xinhua) -- Ghost nets, the fishing nets that have been left or lost in the ocean by fishermen, are threatening the wildlife in the sea of Australia, especially for sea turtles, scientists from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) said in a statement on Monday.
According to the figures in the statement, around 640,000 tonnes of fishing gear is lost or discarded each year. These ghost nets, originating mainly from fisheries in Asia and Australia, are a particular problem in Australia's Gulf of Carpentaria, where they can reach densities of up to three tonnes/km, among the highest recorded worldwide.
It is also a global problem, capturing seabirds, marine mammals and sea turtles worldwide. Lost or abandoned fishing gear makes up only 20 percent of marine debris but has a disproportionate effect because it is designed to capture wildlife.
Australia is home to six of the world's seven threatened species of marine turtle. During a recent cleanup of ghost nets on beaches in the Gulf, 80 percent of animals recorded in nets were marine turtles, including Olive Ridley, Hawksbill, Green and Flatback turtles.
CSIRO's research on ghost nets is focusing on this problem. " Our research goes beyond discovering where ghost net fishing is taking place, to actually estimating its impact on biodiversity, in particular on threatened marine turtles," Dr Denise Hardesty of CSIRO said.
"Using a model of ocean currents and data collected by Indigenous rangers on the number of ghost nets found during beach cleanups, we simulated the likely paths ghost nets take to get to their landing spots on beaches in the Gulf of Carpentaria," she said.
"Our research shows that combining models of marine debris with species occurrence data could identify global hot spots for impact, helping pinpoint where prevention and clean-ups could really make a difference to biodiversity," Dr Hardesty said.