Mapping The Pacific's Busiest 'Blue Corridors' Could Help Us Save Fish Populations

Overexploitation has led to the decline of large fish in the open sea.

Scientists argue we need to protect the blue corridors to pull fish like tuna, swordfish, and marlin back from the brink.

A recent study on the Pacific Ocean has mapped the busiest underwater traffic lanes using a fish's tendency to return to its birthplace.

This behavior is not just an impulse for salmon.

Other fish species return to their birth location to reproduce, and experts want to use that information to reveal where we need to limit or ban fishing.

Tracking large fish as they swim across vast swathes of ocean is incredibly difficult, which means scientists don't know much about migratory routes in the high seas.

If some fish return to their spawning grounds, they should create an annual loop through some parts of the ocean.

The migration loops of 11 fish species in the Pacific Ocean have been inferred by researchers at the University of British Columbia.

The 11 species considered were skipjack, yellowfin, bigeye tuna, albacore, pacific bluefin tuna, swordfish, common dolphinfish, striped marlin, black marlin, and Indo-Pacific sailfish.

The results are only tentative and are based on several assumptions, but they provide important clues about where fish might be swimming at certain times of the year.

When all the migration pathways are superimposed on a map, the overlap shows several high priority areas for preservation.

The red and orange spots are the ocean regions that should be protected first.

Relano and Pauly are related.

Habitat use maps for large pelagic species in the Pacific are generated by superposing the habitat use maps of the different stocks.

In the busiest blue corridors, the authors recommend banning or reducing industrial fishing of large pelagic species.

The northeastern and central sections of the Pacific Ocean should become part of blue corridors, which are routes where strict fisheries management measures or partial bans of industrial fishing should be enforced to allow for.

There are very few marine reserves in the open ocean. Blue corridors could help protect the coast from large fish and whale migration routes.

Blue corridors are important for large pelagic species. The bigger the better.

The best-case scenario for conserving and rebuilding stocks would be an even larger and continuous blue corridor stretching from 30 to 160.

A blue belt of that size could help rebuild fish stocks.

The study was published in a journal.