Fuel subsidies that allow deep-sea trawling fleets to destroy fish stocks must be banned to prevent permanent damage to fragile marine ecosystems, scientists said yesterday.

Industrial fishing operations are devastating marine species and reef habitats that have taken centuries to grow and cannot easily recover because they mature and reproduce so slowly, the American Association for the Advancement of Science conference was told.

Deep-sea fisheries that lie in international waters more than 200 nautical miles from land are largely unregulated.

The fishermen are searching for species such as the pelagic armourhead, black cod, which is unrelated to regular cod, grenadier and orange roughy. The trawlers lay waste to the sea floor in the process.

The deep-sea fishing industry receives subsidies worth more than $152 million (£78 million) a year, according to research. Most of the subsidies and fleets come from Japan, Russia, South Korea and Spain. New Zealand catches about 15,000 tonnes of orange roughy each year, down from a peak of 54,000 in 1988-89.

Without the subsidies, the global industry would operate at an annual loss of $50 million because it uses huge quantities of fuel to drag the 15 tonne nets.

Oceanographers, economists and marine biologists said that an international ban on fuel subsidies would prevent much of the damage at a stroke.

“Eliminating global subsidies would render these fleets economically unviable,” said Rashid Sumaila, of the University of British Columbia in Canada, an economist who led the analysis of fishing subsidies. “From an ecological perspective we cannot afford to destroy the deep sea. From an economic perspective, deep-sea fisheries cannot occur without subsidies. The bottom line is that current deep fisheries are not sustainable.”

Industrial-scale fishing away from coastal waters is particularly damaging because deep-sea fish grow very slowly and live for many decades. Stocks cannot bounce back from even a single episode of overfishing.

Selina Heppell, of Oregon State University, said: “One of the adaptations to living in a cold dark place is to slow way down. The orange roughy grows so slowly that it may not reach sexual maturity until it is 34 years old, and may live to be 150 years old.

“If you go to the market and pick up your orange roughy fillet, it’s possible that fish was born when Lincoln was President of the United States. Perhaps we need a consumer guideline that says we shouldn’t eat fish that are older than our grandmothers.” The slow growth rates of most deep-sea fish mean that the fisheries cannot be managed sustainably. The only economical way to catch them is using supertrawlers more than 600 feet (183m) long, which take everything in a section of sea before moving on.

“While it may be a good short-term business practice to fish out stocks and move on, we now see global declines of targeted species,” said Robert Steneck, of the University of Maine. “The harvest of deep-sea fishes is a lot like the harvest of old-growth timber, except we don’t ‘replant’ the fish.”

An attempt to ban unregulated deep-sea fishing at the UN failed in December.

Fish and ships

— Orange roughy are thought to live for 150 years

— Japan subsidises deep-sea fishing by $35 million (£18 million) a year. The industry also receives subsidies from: Russia ($30m), South Korea ($27m), Spain ($20m), Faroe Islands ($15m), Australia ($10m), Ukraine ($7m), Estonia ($5m) and Iceland ($2m). France, Lithuania and Latvia each give less than $1m a year.

Source: University of British Columbia

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