Industrial fishing in the deep sea should be banned because it has depleted fish stocks that take longer to recover than other species, according to a paper to be released this week by an international team of marine scientists.
The article, published in the scientific journal Marine Policy, describes fishing operations that have in recent decades targeted the unregulated high seas after stocks near shore were overfished.
Describing the open ocean as “more akin to a watery desert,” the scientists argue that vessels have targeted patches of productive areas sequentially, depleting the fish there and destroying deep-sea corals before moving on to new areas.
Certain deep-sea species have gained widespread popularity — including orange roughy and Patagonian toothfish, otherwise known as Chilean sea bass — only to crash within a matter of years.
Elliott Norse, president of the Marine Conservation Institute and the paper’s lead author, said the world has turned to deep-sea fishing “out of desperation” without realizing fish stocks there take much longer to recover.
“We’re now fishing in the worst places to fish,” Norse said in an interview. “These things don’t come back.”
As vessels use Global Positioning System devices and trawlers, which scrape massive metal plates across the sea bottom, the catch of deep-water species has increased sevenfold between 1960 and 2004, according to the U.N. Food and Agriculture Organization.
“What they’re doing out there is more like mining than fishing,” said Kevin Hassett, director of economic policy studies at the American Enterprise Institute.
The estimated mean depth of fishing has more than tripled since the 1950s, from 492 feet to 1,706 feet in 2004, according to Telmo Morato, a marine biologist with the department of oceanography and fisheries at the University of the Azores in Portugal and one of the paper’s authors.
Fishing subsidies help sustain this practice, according to Rashid Sumaila, the paper’s other author, who directs the University of British Columbia Fisheries Centre. He said high-seas trawlers around the world receive roughly $162 million each year in government handouts, which amounts to a quarter of the value of the fleets’ catch.
“That is what is keeping most of them in business,” Sumaila said.
Bottom-trawling can crush deep-sea corals, which can live for as long as 4,000 years, the scientists noted. Some fish species of the deep live for more than a century, and while they can spawn many eggs, there can be several years in which juveniles fail to make it into adulthood.
Orange roughy, which Australia declared a threatened species in 2006, take 30 years to reach sexual maturity and live up to 149 years. The leafscale gulper shark, one of several deep-water sharks targeted for its liver oil, “matures late, has only 5-8 pups per year and lives to be 70 years old,” the authors write.
Ray Hilborn, a University of Washington professor of aquatic and fisheries science, questioned the paper on the grounds that several long-lived species off the Pacific Coast, such as geoduck clams, have been harvested sustainably at very low levels. In many cases, fishing operations take just 1 percent of the population, he said, and this keeps the stocks from collapsing.
“There’s no question [a ban] can be done,” Hilborn said in an interview, adding that the international regulatory regimes may not be up for the task. “The question is, is it worth it?”
Hilborn said that while deep-sea corals might be sacrificed in the pursuit of fishing, humans had accepted similar trade-offs when clearing old-growth forests for farmland. “Some of these habitats will probably be changed by fishing. Some of those corals will be gone,” he said. “From a conservation perspective, maybe we shouldn’t fish at all, and the ocean should be left pristine. Where is the food going to come from?”
But Daniel Pauly, a marine biologist at the University of British Columbia, said the costs of deep-sea fishing far outweigh the benefits.
“It’s a waste of resources, it’s a waste of biodiversity, it’s a waste of everything,” Pauly said. “In the end, there is nothing left.”
Maria Damanaki, the European Union’s commissioner for maritime affairs and fisheries, said in an interview that she would like to reduce fishing on the high seas and cut subsidies for deep-sea trawlers.
“I’ll try. I really agree there’s a danger there, so we have to be prudent,” said Damanaki, adding that nations such as France, Denmark, Portugal and Spain resist such efforts. “We have to try to persuade them to stop this.”