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There are fewer fish in the sea than ever. Complexity theory, argues mathematician George Sugihara, provides a counterintuitive way to revitalize the world's fisheries
Part of a 12-step program for fisheries ecologists? “Yes,” Sugihara says. “It feels a little bit like that.”
Note: This article was originally printed with the title, "Chaos and the Catch of the Day".
Paul Raeburn is a freelance science writer based in New York City.
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8 Comments
Add CommentI wonder what fishing technology could be used to ensure catches are only of youger fish? Sidney Holt
Reply | Report Abuse | Link to thisPerhaps the answer is to put randomness back into fishing : If we banned fish shoal detection technology, fishermen would go back to trawling around at random. So this would ensure that some shoals of both young and old fish would survive to maintain populations. As captains would certainly object that this would waste engine fuel, an alternative answer would be to enforce no-go zones to reintroduce a little chaos into the system?
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Could be possible with a bit of thought. Doing hook & line baitboating near floating aggregation devices in the eastern tropical pacific would tend to take the smaller yellowfin, and without bycatch. It would also tend to be more labor-intensive and less fuel-intensive, important since fuel will now get scarcer forever. Mexico's Cantarell oilfield is crashing and Mexico won't be a petroleum exporter 5 years from now.
Reply | Report Abuse | Link to thisAdmittedly, this is based on the peculiarities of one species, but perhaps learning and taking advantage of such behavioral quirks is what it will take.
Instead of banning areas to fish or making more laws or complicated bycatch rules ... why not tell fishermen to only keep fish of certain relative sizes - those around the 50 - 75 percentile range (maybe - don't know if this is a good number to capture a proper fish maturity). Then, spend the money to educate everyone as to why this needs to be so. The result is at the markets, public opinion would keep marketers and the public from trading in certain sizes.
Reply | Report Abuse | Link to thisIn the ocean, the small fry will be left to grow and the largest will be left to give stability - and enough numbers in the "catchable" range will slip by to become big fish.
Now, this is sustained with public opinion and not with tax dollars to patrol and check up on fishers. And it doesn't rely on fishers only since they can only sell certain sizes.
Will there still be a "black market"? Sure, but it will not be illegal, so if a few of the "wrong" sizes are sold, that will satisfy that small demand (at a higher price - but most wont deal in those fish due to the greater uncertainty over the ability to sell.
Restricting catches of small fish has one major drawback. Fishermen throw the small fish overboard, where they simply die because they have suffered from lack of oxygen for so long. Using bigger net meshes is better, as the small fish can theoretically escape. But as fish have no fear of nets, do they try to escape through the mesh from the accustomed safety of the shoal?
Reply | Report Abuse | Link to thisEnforcing quotas is unpopular worldwide, but it does work in Norway...
The article by Paul Raeburn in your February issue explains how mathematician George Sugihara discovered that fishing big as opposed to small fish is bad. Ive been advocating that perspective in publications for decades*, based on my former experience as Chief of Marine Resources for FAO, especially for Mediterranean fisheries which since the second WW have been dominated by targeted harvesting of juvenile bottom fish. Few of these survive to maturity, but then these are/were apparently protected by refugia, which for the Mediterranean are rocky, untrawlable areas along the narrow shelf edge. The EC is now getting the Mediterranean message, and considering closure of areas in the NE Atlantic where large cod congregate (I mean mature cod I doubt that any large cod are left in the North Sea). This strategy has worked (up to a point) in the Mediterranean. Until the last decade, fisheries for juveniles despite a lack of quota control, mostly seemed sustainable. That they are apparently no longer so, is probably less because of targeting juveniles, but due to the combined influence of relentless fishing, land runoff and habitat destruction; all described in the Mediterranean fisheries literature.
Reply | Report Abuse | Link to thisSincerely,
John F. Caddy, Aprilia, Italy.
The article by Paul Raeburn in your February issue explains how mathematician George Sugihara ‘discovered’ that fishing big as opposed to small fish is bad. I’ve been advocating that perspective in publications for decades*, based on my former experience as Chief of Marine Resources for FAO, especially for Mediterranean fisheries which since the second WW have been dominated by targeted harvesting of juvenile bottom fish. Few of these survive to maturity, but then these are/were apparently protected by ‘refugia’, which for the Mediterranean are rocky, untrawlable areas along the narrow shelf edge. The EC is now getting the Mediterranean message, and considering closure of areas in the NE Atlantic where ‘large’ cod congregate (I mean mature cod – I doubt that any large cod are left in the North Sea). This strategy has worked (up to a point) in the Mediterranean - until the last decade, fisheries for juveniles despite a lack of quota control, mostly seemed sustainable. That they are apparently no longer so, is probably less because of targeting juveniles, but due to the combined influence of relentless fishing, land runoff and habitat destruction; all described in the Mediterranean fisheries literature.
Reply | Report Abuse | Link to thisSincerely,
John F. Caddy, Aprilia, Italy.