Tunas, sharks and ships at sea — ScienceDaily

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A map showing the roaming of sharks and tuna in the Eastern Pacific, as well as maps of fishing boats traveling in this vast area, can help marine managers identify areas of the high seas where vulnerable species may be at risk.

Stanford University researchers created such a map by analyzing the habitats of more than 800 sharks and tuna and 900 industrial fishing boats. Focusing on the international waters of the Northeast Pacific, they found that ships from Taiwan, China, Japan, the United States and Mexico accounted for more than 90% of the main habitats of seven shark and tuna species.

"The high seas are the global commons of the oceans," said Stanford University's graduate student in biology, the first author of the paper, Timothy White, published on March 13th at Science Advances . “This analysis opens the door to whether we believe that the current mode of operation of the high seas is the fairest, most effective and desirable dialogue.”

The researchers hope that their findings will help UN member states to develop the world's first legally binding treaty to protect international waters known as the high seas.

"We can protect species near the North American coastline, but the same species may be exposed to high levels of international fishing on the high seas. By increasing the transparency of where fish and fleets meet, we can identify hotspots that may require international protection. "Barbara Block, Professor of Marine Science Prosolo, Stanford University, said.

The place where fish are caught in fish

The team's work is based on the 2018 study led by Global Fisheries Watch, Block Labs and other researchers, published in the journal Science. In that study, the researchers obtained four years of data from the Automatic Identification System (AIS) – tracking ship movements via satellite – and developed a machine learning algorithm that maps the footprints of 70,000 fishing vessels around the world until Details about the fishing method of each ship. In this article, the researchers focused on the activities of more than 900 vessels from 12 countries in the Northeast Pacific to better understand the overlap of fishing fleets, sharks and tuna in these waters.

A meaningful solution for overfishing of some shark and tuna populations is hampered by two major mysteries: where fishing is taking place and where fish are. To help solve these mysteries, the researchers combined the ship's position with the preferences of the marine habitat, which came from a decade-long tracking program, the Pacific Predator Mark (TOPP). The plan includes Pacific bluefin tuna, yellowfin tuna, albacore tuna, white shark, short-winged shark shark, squid shark and blue shark. In addition to salmon sharks, all of these species are currently listed as threatened or near-risk species in the IUCN Red List of Endangered Species, although some species are sustainably harvested in the Northeast Pacific.

In the 10 years of the TOPP program, 876 electronic tags were deployed on individual sharks and tuna. Hundreds of separate trips – each spanning hundreds to thousands of kilometers – show the researchers that the marine area is the preferred habitat for each species.

By integrating animal, ship and environmental data, the researchers predicted the highest overlap between marine areas and commercial fishing fleets.

"The biggest challenge is to combine these very different data sets," White said. “By adding the latest ship tracking and machine learning techniques to the marine scientist's toolbox, we are able to more clearly describe how fish and fisheries interact, and this information can tell how our management strategy should reflect this.”

High Seas Protection

The ongoing discussion of the United Nations High Seas Treaty by 2020 is very much concerned with the ideas of these researchers. As a window of interaction between humans and animals on the high seas, they believe that their work can help guide which parts of the Northeast Pacific deserve special consideration, and which fishing activities should be addressed and which countries play an important role in conservation.

"These analyses give us a chance to get a deeper understanding of the dynamics of this ocean and see that managers and stakeholders should focus," said Francisco Farati, a researcher at Stanford University's Hopkins Marine Station. paper. “We need to work harder to protect the corners of this planet, because these are the best marine environments in the world.”

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Material provided by Stanford University . Original text by Taylor Kubota. Note: Content can be edited for style and length.


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