Want to see how widely humans are scouring the oceans for fish? Check out this striking map from the World Wildlife Fund’s 2012 “Living Planet Report.” The red areas are the most intensively fished (and, in some cases, overfished) parts of the ocean — and they’ve expanded dramatically since 1950:



To measure how intensively these areas are fished, Swartz et al., (2010) used the fish landed in each country to calculate the primary production rate (PPR) of each region of the ocean. PPR is a value that describes the total amount of food a fish needs to grow within a certain region. (WWF)

Between 1950 and 2006, the WWF report notes, the world’s annual fishing haul more than quadrupled, from 19 million tons to 87 million tons. New technology — from deep-sea trawling to long-lining — has helped the fishing industry harvest areas that were once inaccessible. But the growth of intensive fishing also means that larger swaths of the ocean are in danger of being depleted.

Daniel Pauly, a professor of fisheries at the University of British Columbia, has dubbed this situation “The End of Fish.” He points out that in the past 50 years, the populations of many large commercial fish such as bluefin tuna and cod have collapsed, in some cases shrinking more than 90 percent (see WWF’s chart to the right on Northern bluefin tuna).



(WWF, Living Planet Report 2012)

The full WWF report (PDF), meanwhile, is full of brightly colored graphs charting the decline of wildlife across the globe. All told, global vertebrate populations have declined by some 30 percent since 1970. But that number masks a lot of variation. Wildlife actually appears to be recovering in the temperate areas, while it’s disappearing at a rapid rate in the tropics. It seems there have been some modest conservation successes in the wealthier temperate regions — the European otter is staging an impressive comeback, for instance.

The major point the WWF paper emphasizes is that human consumption patterns are currently unsustainable. We’re essentially consuming the equivalent of one and a half Earths each year. This is possible because we borrow from the future, as is the case with fish — one day the world’s fish population may shrink, but there’s plenty for us now.

So is there any way to stop the slide? After all, it’s not like people can just stop eating fish altogether. Pauly, surprisingly, is fairly optimistic. He argues that strict government quotas on catches can help stop the slide. “There is no need for an end to fish,” he writes, “or to fishing for that matter.” (He’s not sold on aquaculture, or fish farming, since it often requires huge harvests of smaller fish to feed the big carnivorous ones in farms.)

The hitch is that when governments have tried to institute such quotas in the past — as they’ve recently attempted with Atlantic bluefin tuna — the rules can sometimes get watered down under lobbying pressure. Or occasionally shadowy black markets emerge to flout the rules. But no one said it was easy, halting the end of fish.