Wednesday, October 19, 2011

Grand Banks Cod are Finally Recovering

The world's richest fishery, the cod fishery on the Grand Banks off Newfoundland, was destroyed between 1960 and 1990. It started in the 1950s, when huge factory ships from Japan, Russia, and other countries descended on the Banks with giant nets. This trend accelerated in the 1960s, and the catch rose from its historical level of around 200,000 tons a year to 800,000 tons in 1968. Then it started to decline, falling 60% by 1975. At that point Canada banned foreign fisherman from within 200 miles of its shores, and the cod started to recover. But with the foreigners excluded the Canadian government decided to push for Canadian cod fishing in a big way, lending money for investments in boats and processing plants. For a while the catch was strong -- 688,000 tons in 1988 -- and the economy of Newfoundland boomed like never before in its history. In the late 1980s scientists started to warn that the level of fishing was unsustainable, and government scientists recommended a limit of 125,000 tons per year. The government thought this threatened too many jobs and arbitrarily doubled the limit. Starting in 1990 the catch began to crash, and in 1994 the government was forced to declare a complete moratorium on cod fishing on the banks. More than 30,000 jobs were lost.

Everyone thought the moratorium would last only a few years, but the cod stubbornly refused to come back. In fact, from 1994 to 2002, despite the fishing ban, the cod continued to decline. The once teeming waters of the Banks, where fishermen could catch cod just by dipping baskets into the water, were empty. The tiny, isolated "out towns" of the Newfoundland coast, founded to fish for cod and without any other economy, went into a despair from which they may never recover.

Nobody really knows why the cod could not recover, but a good guess is that the fishing was so intense, using heavy nets that were dragged across the ocean floor, that the ecosystem was damaged in ways we don't fully understand. Another problem is that fishing continued on the banks for other other species, including mackerel (which eat herring which eat young cod) and the small shrimp that feed many larger species, further messing up the ecosystem. Also, these fishermen often caught cod "accidentally", as "by-catch", sometimes so many that some environmentalists accused mackerel fishermen of taking cod on purpose. Whatever the reason, the cod did not come back, and it seemed like they might never come back. When I first learned about this, nearly ten years ago, I found it profoundly depressing.

Now, though, there is finally some good news. According to World Wildlife Fund-Canada, the number of cod on the Banks has grown by 69% since 2007. This is nothing to crow about, since the estimated population is only about 20% of what it was in 1980, but at least the collapse seems to have been stopped. Perhaps we will one day see the Banks teeming with fish again.

UPDATE

I just discovered another reason why the cod population was so slow to rebound: cod mature slowly:
Cod mature late — at 4 to 6 years old — and they can live as long as 25 years. Female cod do, in fact, produce astonishing numbers of eggs. But older cod lay two or three times as many eggs as younger cod. This means that a healthy cod population must include relatively large numbers of older fish.

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