Apr 18 2012

How Well, and How Poorly, We Harvest Ocean Life

Written by Cornelia Dean | Science Writer
 
Overfishing: What Everyone Needs to Know. Ray Hilborn, with Ulrike Hilborn.
To hear some other people tell it, many depleted stocks are recovering nicely.

Ray Hilborn, a fisheries scientist at the University of Washington, wades into this disagreement in his new book and comes out with a lucid explication of a highly tangled issue.

Each argument, he concludes, has some truth on its side. “It depends on where you look,” he writes. “You can paint horror story after horror story if you want. You can paint success after success.”

He navigates the path between horror and success through scores of questions and answers, nearly all of which demonstrate how difficult it is to sort this issue out.

Take the most basic question: What is overfishing? There are several answers, the book tells us. There is “yield overfishing,” in which people take so many fish that they leave too few to spawn or catch too many fish before they are grown. Then there is “economic overfishing,” in which economic benefits are less than they could be. If too many boats chase too few fish, for example, the struggle to make a good catch leads to overspending on boats, fuel and so on.

(There is also “ecological overfishing,” but that is something we must live with as long as we want to eat fish, Dr. Hilborn says. Fishing by definition alters the marine environment.)

Dr. Hilborn tells us of fisheries that succeed — like the halibut industry in Alaska — and fish stocks managed into difficulty, and then out again, like the pollock of the Bering Sea.

And he gets into the issue of trawling, in which boats drop weighted nets to the bottom and drag them along, scraping up everything in their path. Critics liken trawling to harvesting timber by clear-cutting. For Dr. Hilborn, this analogy is not always apt, since in some areas the creatures rapidly repopulate the ocean floor.

Some countries do well by their fish, he writes, but with one exception they are relatively small: New Zealand, Iceland and Norway. The exception? The United States.

The true lesson of this book is that fisheries science is complicated; that the management of any given species must be considered in terms of its ecosystem; that fishing for one species alters the food web as a whole — and that sometimes there is not enough data to make good recommendations.

 
Read the full book review on The New York Times.
 

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