Fish stock abundance increases when intensely managed, study shows

Published: Jan. 15, 2020 at 6:37 PM AKST
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Studies on global fisheries rarely make national news, but University of Washington professor of Fisheries and Aquatic Sciences Ray Hilborn says that the public perception of fisheries is still recovering from one eye-catching study in 2006.

"A paper come out that said if current trends continue, all fish stocks will be collapsed by 2048, and that got front page New York Times, front page Washington Post, and it was totally wrong," Hilborn said. "It was so contrary to my experience and lots of people, you can imagine almost everyone working on fisheries in Alaska. Ultimately I got together with the first author of the paper and we figured we could actually try to understand why we had such different perspectives."

The result of the collaboration was a paper published in 2009 which showed that on average, stock abundance appeared to be stable.

"What they had assumed is that if that catch goes down, the catch is declining, and that simply wasn't true. Most of the stocks they called collapsed, the catch had declined for other reason. Many times regulation, some times international 200 mile zones," Hilborn said.

Hilborn worked to build a data set on the abundance of fish stocks, rather than just the reported catch.

More than a decade later, Hilborn's research shows how intensely managing fisheries has resulted in increased abundance of fish stocks.

"The public and a very high proportion of the scientific world believe this narrative that fish stocks are declining around the world, and it's simply not true. In much of the world, fish stocks are increasing, not declining," Hilborn said.

The study only looked marine fish, so anadromous fish including salmon were not included.

"But that would be true for Alaska salmon as well. There is more salmon in the North Pacific now than any time in history. Yes, Chinook are generally not doing very well, but overall for the last 20 years, pink, chum, sockeye have been at record abundance," Hilborn said.

The study looks at global fisheries from the global perspective. At a local level, the low stock of Pacific cod in the Gulf of Alaska is forcing fishermen to adapt this season even though.

"The Gulf of Alaska cod fishery is totally in the toilet, but the management system has responded. It basically closed the fishery, almost completely, and that's exactly what you need to do," Hilborn said. "All the belief is this decline of cod had nothing to do with fishing. It had to do probably with climate change, but it could be something else."

While the outlook is positive for fisheries in the developed world, Hilborn's study points out that about half of the world's fisheries lag behind in establishing and enforcing sustainable fishery management. Although many Alaskans catch the fish they eat, the global fish market is highly interconnected, and products from loosely regulated regions make it onto American grocery store freezer chests.

The study found that compared to regions with intense management, regions with less developed fishery management had on average 3-times greater harvest rates and half the abundance of assessed stocks. About half of the world's fishery

"There's more interest in places like China, Thailand, Indonesia and India in doing fisheries management. They have very primitive management systems at the moment. Often almost no enforcement," Hilborn said.

Hilborn argues that the value of sustainable fishery management extends beyond economic benefits because many fish stocks are particularly important some of the poorest people in the world. Over fishing and poor management could lead to food insecurity for the people who depend on fish.

"In that part of the world fish is often the dominant form of protein. So just from the humanitarian perspective, we want to see these fisheries sustainably managed," Hilborn said.

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