Scientists have known since the late-1990s that Earth's oceans appeared to be running out of fish. Global marine catch peaked in 1996, and fishermen around the world have reeled in fewer and fewer fish every year since. While a new estimate of yearly fishing numbers suggests that official reports have drastically underestimated catch amounts—which indicates the Earth's oceans may have been an even better source of food than previously thought—the study also found that, since their peak, catch numbers have been declining at a much higher rate than we thought.
Vanishing fish stocks are a familiar story for Pacific Standard readers. In our May/June 2015 issue, Bonnie Tsui chronicled one man's efforts to draw attention to overfishing in Japan. Toshio Katsukawa, a marine scientist at Mie University, persuaded the country's government to place restrictions on fishing of Pacific bluefin tuna—the most highly prized sushi fish in the seafood-loving nation, Tsui noted. Such restrictions help to prevent populations from totally collapsing, but the new study, published this week in Nature Communications, suggests that such restrictions have yet to slow the world's declining fish stocks.
Every year, member countries submit catch data to the United Nations' Food and Agriculture Organization. While those official records capture most numbers from industrial fishing, they are incomplete.
In 2010 alone, as much as 32 million metric tons of captured fish were not reported.
"We always knew that the FAO data had problems, but we thought this was a minor problem that could be ignored because only a few countries had problems," says Daniel Pauly, a professor at the University of British Columbia and lead author on the study. "It was only gradually that we realized that the mistakes were systematic, and really strong, and that they were biasing the catch of lots of countries downward."
Pauly and his colleagues realized that the FAO was drastically underestimating catch by overlooking data from fisheries that supplied only local markets, subsistence fisheries that only supported families, illegal fishing, and other sources such as recreational or tourist fishing; if a nation didn't have an estimate for any of those categories, the catch amount was recorded as zero.
To get a more accurate view of global catch, an international team of hundreds of researchers, including roughly 100 from the University of British Columbia itself, reconstructed annual catch between 1950 and 2010 by combining FAO data with estimates from a variety of regional sources. For over a decade, the team collected data from every country around the world, combing through records from other international and regional organizations, publications from various governments' departments of fisheries, colonial archives, and even household and nutritional surveys.
If there was no data for a region's artisanal, recreational, or subsistence fisheries, the team would create an estimate based on the "shadow" cast by fisheries on the societies they serve—the amount of fish sold at markets or consumed by residents, or the amount of fuel sold to fishing vessels. ("It's not possible to fish without having an effect on the society around you," Pauly points out.)
"What came out of that is that 50 percent more fish are caught than is reported," Pauly says. In developed countries, the reconstructed average was usually between 20 and 30 percent higher than reported catches, but in the developing world, "it can be 100, 200, 300 percent," he says. In 2010 alone, as much as 32 million metric tons of captured fish were not reported.
The new numbers underscore a problem that many scientists have known about for some time. As Tsui reported last year, Katsukawa spent years trying to raise awareness of overfishing in Japan, but ran into many obstacles. For one, "[c]riticism of Japanese fishing practices has often been interpreted as an attack on Japanese culture," Tsui wrote. But Katsukawa's cause started gaining momentum around 2009, after Japan's small-scale fisherman watched their catch numbers—and incomes—plummet. Katsukawa knew enacting quotas limiting the number of fish allowed to be caught and encouraging fishermen to only keep adult catch could help save both the fish and the fisherman. As Tsui explained:
A three-kilogram juvenile bluefin sells for 500 yen per kilo; if you wait six years, the fish grows into a 100-kilo fish that sells for 5,000 yen per kilo, Katsukawa says. That's a tenfold increase in price per kilogram, and a nearly 100-fold gain in total profit, on a single fish. And because the fish will have had a chance to reproduce, the population can sustain itself. Everybody wins.
To be sure, Japan's restrictions are a step in the right direction for a nation that consumes more fish per capita than almost any other, but regional restrictions alone are not enough to reverse global trends.
"We have two results that are almost contradictory: One is that the world's oceans are very productive—they produce more fish for us than we knew were available. The second is that these resources are going down the tube very rapidly," Pauly says. "Since 1996, the decline is very marked in the reconstructed data." And that decline is visible even when numbers from the Unites States, Northwestern Europe, Australia, and New Zealand—all of which have stringent quota policies—are excluded. This indicates, Pauly argues, "[the] decline is not because countries are very prudent and fish less. This is a decline because they fish too much."
If fisheries are to become sustainable, the intensity of fishing around the globe will have to be reduced. Developed countries around the world have more demand for seafood than they can supply from their own waters. As a result, rich countries meet their excessive demands by pumping fish out of the developing world, Pauly claims.
"Recently, the British government has went on a publicity campaign recommending people to double the consumption of fish," he says. "Where the hell is Britain going to get this fish?"
Since We Last Spoke examines the latest policy and research updates to past Pacific Standard news coverage.