Migrating sea turtles need networked marine protected areas – study

Setting up protected areas just isn't enough: just like us, endangered wildlife need to network too.

 

A new study has highlighted the need to connect marine protected areas (MPAs) to ensure that they protect highly mobile endangered species. Scientists from Deakin University, Swansea University, and Pendoley Environmental consultancy used advanced satellite tracking systems to track the migration routes of 73 adult female flatback sea turtles (Natator depressus) from their nesting grounds to feeding areas along the northwest Australian coastline. 

 

The turtles were fitted with satellite transmitters programmed to send data every time the turtles surfaced and designed to fall off after 12 months. They determined that the turtles use a “core corridor”—a frequently-used underwater pathway—some 1,150 kilometers long and spanning 30,800 square kilometers. Fifty-two percent of this core corridor fell inside 11 marine reserves. 

 

Said Dr. Graeme Hays, "Our findings show that much of the flatback turtle's transit passage - between its breeding colonies and foraging grounds - falls within the newly established Commonwealth Marine Reserve network." The Commonwealth Marine Reserves network, established in 2012 to supplement State reserves, covers 36% of Australia's marine waters.

 

Scientists also found that flatback turtles share the corridor with humpback whales (Megaptera novaeangliae). Scientists compared the flatback turtles' tracking data with tracking data for humpback whales as well as blue whales (Balaenoptera musculus), olive ridley sea turtles (Lepidochelys olivacea), and whale sharks (Rhincodon typus) that also migrate in the same general area. 

They discovered that the migratory track of humpback whales showed a 96% overlap with the core flatback turtle corridor. Blue whale, olive ridley sea turtle, and whale shark tracks overlapped with the flatback corridor by 5-10%. The general distribution ranges of at least 20 species of marine mammals (dugongs, whales, dolphins), marine reptiles (sea turtles, saltwater crocodiles, sea snakes), and sharks also overlapped with the corridor.

 

Networks of MPAs offer greater benefits compared to standalone MPAs because of the ecological linkages between the different sites. These linkages include the migration of adults, the dispersal of larvae, and the shifting needs of species as they grow and mature from juveniles to adults. Data from tracking studies such as this reveal how different species use different environments, allowing conservation planners to design MPA networks that maximize the benefits for the ecosystems and all stakeholders involved. — TJD, GMA News