By California Porpoises Rebound in a Big Way Following Ban on Indiscriminate Fishing Nets
After decades of use, gillnets and the fishing strategies that employ them have been banned by California law, providing a sanctuary blessing for seabirds, sharks and the secret porpoise.
The years between 1987 and 2002 saw many gillnet bans in California coastal counties, where previously dead marine animals were found on beaches entangled in nets, causing outrage among locals.
Used literally for thousands of years, the gillnet is an efficient way to fish. The fibers hook onto the gills of fish, but they can also trap other animals such as sharks, otters, seabirds, and harbor porpoises.
The latter, one of the smallest toothed whales on Earth, is a highly secretive animal and as such represents a challenge for marine biologists tracking its populations. Karin Forney, a marine biologist with the National Oceanic and Atmospheric Administration, has been studying them for three decades.
“Harbor porpoises show that if you stop killing them… they can come back. That they are capable of bouncing back, “Forney told the LA Times. “They have a resilience and they will recover if we just let them.”
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The rebound could almost be considered an understatement. In the capture areas of Monterey Bay, Morro Bay along the coast north of Santa Barbara, and the San Francisco and Russian river systems, porpoise studies have shown that since the bans, populations have added approximately 8,230 new members.
It’s a significant triumph for the hidden marine mammal, which in Morro Bay alone grew from 570 individuals in 1990 to more than 4,000 in 2012.
Another species that will have benefited from the ban on gillnets are the great white sharks, which used to get caught by all kinds of networks. Since the Marine Resources Protection Act of 1990, which was implemented in 1994 and which prohibited drifting and gillnets, very few great white sharks have been caught bycatch.
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As species protected from international trade and relatively unknown to science, the fewer members of the species are accidentally killed, the better, as population levels are difficult to determine correctly.
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