A study published on 3 September in Nature Ecology & Evolution used one of the most extensive datasets available on the movement of large marine animals ― part of the Census of Marine Life’s Tagging of Pacific Predators (TOPP) project ― to track the migratory behaviour of 14 species across geopolitical boundaries. This included leatherback turtles, Pacific bluefin tunas, white sharks, sooty shearwaters, and California sea lions, among others. The researchers found that the species cumulatively visited 37 jurisdictions while some, such as the near-threatened Laysan albatross, spent more than 75 per cent of their time in the high seas.
The high seas are often referred to as the “Wild West” of the ocean since the UN’s Convention on the Law of the Sea of 1982 left the high seas free of restrictions, declaring that resources found on or under the seabed are the “common heritage of mankind.” Under international law, every coastal nation has exclusive rights to utilize resources and regulate fisheries within their exclusive economic zone (EEZ), which can extend up to 200 nautical miles from shore. However, the high seas outside EEZs are still considered global commons and are among the least protected areas on the planet.
Under the Nagoya Protocol, another UN pact, 105 countries have agreed on rules to prevent “biopiracy,” the removal of biological resources such as plant or animal DNA from a nation’s habitats without proper permission or compensation. But the rules do not apply in international waters. Moreover, some argue the pact also hinders studies aimed at protecting biodiversity.
All species were found to spend some time in the high seas where they are under threat from plastic pollution, illegal fishing, overfishing, and incidental catching of non-target species. According to the authors, the critically endangered leatherback turtle travels through more than 30 countries as well as the high seas. Many large predators are declining or threatened, in part owing to their migratory behaviour, which exposes them to an increasingly vast array of dangers. For example, white sharks are protected in US and Mexican waters but spend around 60 per cent of their time unprotected in the high seas, according to TOPP data. These new findings effectively highlight the need for multilateral, cooperative, and international agreements to manage marine species.
The study is set to boost the successful establishment of a global treaty for conservation and management of the high seas, for which discussions have been underway at the UN since 2016. Publication of the paper coincides with the latest set of UN talks to begin on 4 September to discuss management of the high seas beyond national jurisdiction, including the proposed 2020 treaty. Four sessions of two-week-long talks are planned over two years.
The latest series of talks will focus on creating protected areas within the high seas to safeguard vulnerable marine species, establish shared maritime resources and technology, and support further research on environmental impacts. The goal is to protect marine biodiversity and avoid further plundering of the high seas, which cover half the planet yet lack adequate environmental protection. The talks will also open up opportunities for countries to collaborate on the successful protection of species that migrate through these distant and currently uncontrolled waters.
Lead author of the paper, Autumn-Lynn Harrison, a research ecologist at the Smithsonian Migratory Bird Center, suggests, “The first step to protecting them [marine species] is knowing where they are over their annual cycle and promoting international agreements to manage the threats they may face across several countries.”
(1) Harrison, A-L et al. The political biogeography of migratory marine predators. Nature Ecology & Evolution (2018). DOI: 10.1038/s41559-018-0646-8