Tracking marine migrations across geopolitical boundaries aids conservation

Date:  September 3, 2018

Source:  University of California - Santa Cruz

Summary:

A new study uses tracking data for 14 species of migratory marine predators, from leatherback turtles to blue whales and white sharks, to show how their movements relate to the geopolitical boundaries of the Pacific Ocean. The results provide critical information for designing international cooperative agreements needed to manage these species.

The leatherback sea turtle is the largest living turtle and a critically endangered species. Saving leatherback turtles from extinction in the Pacific Ocean will require a lot of international cooperation, however, because the massive turtles may visit more than 30 different countries during their migrations.

A new study uses tracking data for 14 species of migratory marine predators, from leatherback turtles to blue whales and white sharks, to show how their movements relate to the geopolitical boundaries of the Pacific Ocean. The results provide critical information for designing international cooperative agreements needed to manage these species.

"If a species spends most of its time in the jurisdiction of one or two countries, conservation and management is a much easier issue than it is for species that migrate through many different countries," said Daniel Costa, professor of ecology and evolutionary biology at UC Santa Cruz and a coauthor of the study, published September 3 in Nature Ecology & Evolution.

"For these highly migratory species, we wanted to know how many jurisdictional regions they go through and how much time they spend in the open ocean beyond the jurisdiction of any one country," Costa said.

Under international law, every coastal nation can establish an exclusive economic zone (EEZ) extending up to 200 nautical miles from shore, giving it exclusive rights to exploit resources and regulate fisheries within that zone. The high seas beyond the EEZs are a global commons and are among the least protected areas on Earth. Discussions have been under way at the United Nations since 2016 to negotiate a global treaty for conservation and management of the high seas.

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