Particle physics research

New research highlights ‘blue corridors’ for highly migratory fish

New research has identified four high-traffic areas in the Pacific Ocean that should be considered high priority if conservation efforts focused on large pelagic fish such as tuna, blue marlin and swordfish are to be successful .

By studying the tendency of fish to return to their birthplace to reproduce – a concept known as philopatry, which is often mistakenly thought to apply only to salmon species – and by combining this knowledge with catch distribution maps and genetic tagging and sequencing studies, researchers at UBC The sea around us identified the tentative migration routes of 11 tuna and other large pelagic fish in the Pacific Ocean and determined that certain areas should be considered “high” and “very high” priorities when it comes to maintaining their populations.

“We applied the concept of philopatry to movements gleaned from tagging studies of species such as near-threatened Pacific bluefin tuna and heavily fished yellowfin tuna, and we also combined this information with population linkages inferred from studies. genetics. This allowed us to identify tentative annual migration cycles,” said Veronica Relano, PhD student at The sea around us and lead author of study that presents these results.

“What’s interesting is that when we compared our proposed migration routes and the mapped capture data from 1950 to 2016 available on the The sea around us website, we found many coincidences. Obviously, the accuracy of these routes is enhanced by taking philopatry into account, although they are still tentative,” she said.

After analyzing the seasonal migration routes of each of the 11 fish species individually, the researchers overlaid them and found that several species and populations of these large pelagic fish use the same migration routes.

“These high-traffic areas, two of which are in the northeast and central sections of the Pacific Ocean and two in the southwest and central sections, should be part of the blue corridors, which are routes where strict measures fisheries management plans or partial industrial fishing bans should be enforced to allow for increased habitat connectivity and thus allow marine species populations to sustain themselves,” said co-author Dr Daniel Pauly. study and The sea around us principal researcher.

“But before creating a protected area to support the recovery of declining fish populations, it is important to consider all the knowledge available on the migrations and movements of different species. This is what we set out to do with this study. Our results suggest in which areas such efforts would be more effective, but as noted in our title, the closed migration cycles we propose are tentative, and so it would be good if other researchers set out to test their validity.” he declared.

The article “Philopatry as a tool to define provisional closed migration cycles and conservation areas for large pelagic fishes in the Pacific” was published in Sustainability.


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More information:

Veronica Relano et al, Philopatry as a Tool to Define Tentative Closed Migration Cycles and Conservation Areas for Large Pelagic Fishes in the Pacific, Sustainability (2022). DOI: 10.3390/su14095577

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