Study sheds new light on data-poor fisheries and how recovery can boost seafood supply. Data-poor stocks are doing worse than stocks with robust data.
A study published in Science magazine contains new population assessments for thousands of fisheries around the globe, providing insight on the health of data-poor fisheries that account for more than 80 percent of the world’s catch. The research confirms suspicions that these fisheries are in decline, but it also highlights hope for the future: most of these fisheries have not yet collapsed.
“Until now, our sense of how fisheries are doing has been based on a minute fraction of the world’s fisheries – the large, valuable stocks for which we have lots of data,” says UCSB scientist Steve Gaines. “This represents only a few hundred of over 10,000 fish stocks. It’s a tiny slice that can give us a skewed view.”
“For most fisheries, we simply didn’t know how many fish were out there and whether their populations were trending up or down,” says lead author and economist Christopher Costello. “Without good information on fish populations, managing sustainably can be a hard thing to do. It’s like trying to decide how far you can drive your car without knowing how much gas is in the tank.”
New method shows: over half the world’s fisheries are in decline
The scientists examined fisheries lacking formal assessment and developed a method using species’ life history, catch, and fishery development data to estimate the status of thousands of unassessed fisheries worldwide. The results show that over half the world’s fisheries are in decline. Across the globe, stocks with robust data are doing better than those less-studied, regardless of the country that manages them.
The authors say that if we act quickly to prevent overfishing and allow depleted stocks to recover to sustainable levels, they could provide more seafood over the long-term. This could increase the amount of fish brought to shore by 8-40 percent on average – and more than double it in some areas – compared to yields predicted if we continue current fishing trends.
The scientists caution that the new method cannot take the place of formal assessment programs for individual fisheries, but their approach provides accurate global and regional information that they hope will inform fisheries management decisions. “At a regional scale, we can gain up to 80 percent of the insights of traditional assessment approaches with just 1 percent of the cost,” says Gaines.
The longer we wait, the more costly it will be
“Strong management could increase the number of fish in the ocean by over 50 percent,” says Gaines. “When fish populations are healthy they produce more young. It may seem paradoxical, but we can get more fish on our plates by leaving more in the water.”
The gains expected from recovery are most pronounced for small scale fisheries, many of which are in countries that face rapid population growth and depend on fish for local food security. Even in North America and Europe, recovery would bring both economic and environmental benefits.
“The good news here is that it’s not too late,” explains Costello. “These fisheries can rebound. But the longer we wait, the harder and more costly it will be to bring these fisheries back. In another ten years, the window of opportunity may have closed.”
Costello et al., Status and Solutions for the World’s Unassessed Fisheries. Science, Published online 27 September 2012.
Note: This text was largely based on a press release by Bren School at UCSB, University of Washington and California Environmental Associates. There is also a press release from the University of California – Santa Barbara.