We’ve all marveled at the intrepid salmon swimming against the current, up waterfalls, and avoiding predators to return to its native spawning grounds, or at least we’ve all seen it on a nature show. This behavior is called philopatry, an animal’s tendency to return to its area of birth, and it’s not just for salmon. Many other big fish species in the Pacific have this instinct, and scientists suggest using it to save endangered fish populations.
Mapping migration patterns
Due to overexploitation, populations of large fish like marlin, tuna, and swordfish have decreased by at least 90 percent. Scientists strongly advocate protecting certain areas of the Pacific Ocean called the “blue corridors” with high traffic of fish migration to save these populations.
A recent study mapped the busiest fish migration superhighways in the Pacific Ocean, and experts want to use that information to point out where fishing should be limited or outright banned.
Using data on where fish are caught and where they’re known to spawn, researchers from the University of British Columbia (UBC) have mapped the migration routes of 11 species of fish. These are skipjack, yellowfin, bigeye tuna, albacore, pacific bluefin tuna, swordfish, common dolphinfish, striped marlin, black marlin, wahoo, and Indo-Pacific sailfish. While these findings need fine-tuning, as it is difficult to track with certainty the migration patterns of several wide-ranging fish species, the study has found areas in which experts recommend banning fishing altogether.
Plotting new protections
“Those high-traffic areas, two of which are in northeastern and central sections of the Pacific Ocean and two in the southwestern and central sections, should become parts of blue corridors, which are routes where strict fisheries management measures or partial bans of industrial fishing ought to be enforced to allow for increased connectivity of habitats and thus allow populations of marine species to maintain themselves,” says Daniel Pauly, the principal investigator at the UBC’s research institute.
Right now, there are very few marine sanctuaries in the open ocean, and identifying and regulating these migratory patterns could have an enormous benefit in rebuilding the diminished populations of big Pacific fish.
Source Study: Sustainability — Sustainability | Free Full-Text | Philopatry as a Tool to Define Tentative Closed Migration Cycles and Conservation Areas for Large Pelagic Fishes in the Pacific | HTML (mdpi.com)