
Reduce Fish Catch Now for Bigger Net Profits Later
A new and compelling argument for reducing fish harvests – the profit motive – could persuade world fishers to endure the short-term pain of lower catches for the long-term gain of higher returns for their labor, according to authors of a ground-breaking study on fisheries over-exploitation.
They say their findings, published in the journal Science Dec. 7, will help overcome a key cause of over-fishing – industry opposition to lower catches – by demonstrating that when stocks are allowed to recover, profits take a sharp turn upward.
“It has always been assumed that maximizing fishing profits will lead to stock depletion and possibly even extinction of some commercial species,” says co-author Quentin Grafton, research director at the Crawford School of Economics and Government at the Australian National University (ANU) and one of the co-authors of the paper “Economics of Over-exploitation Revisited.”
“But our results prove that the highest profits are made when fish numbers are allowed to rise beyond levels traditionally considered optimal. In other words, bigger stocks mean bigger bucks.”
The simple reason is “the stock effect”: when fish are more plentiful and thus easier to catch, fishers don’t have to spend as much on fuel and other costs to fill their nets – profits are higher.
The U.N. Food and Agriculture Organization (FAO) deems an estimated 25 percent of world fish stocks depleted – stocks with strength below levels that produce “maximum sustainable yield.” (Akin to pruning a bush, the “maximum sustainable yield” of a healthy fish stock is achieved after some harvesting; when there are too many fish, the stock suffers from disease and predation.)
According to Grafton and co-authors Tom Kompas and Ray Hilborn, if stocks were assessed against the levels that maximize profit, many more fisheries would be considered over-exploited. Their work also shows that higher costs (such as fuel), lower output prices for fish and smaller discount rates all increase the optimal economic stock size relative to the stock size that maximizes the sustainable yield.
“Conservation promotes both larger fish stocks and higher profits,” says Tom Kompas, director of the International and Development Economics Program in ANU’s Crawford School of Economics and Government. “This is a win-win for the world’s fisheries and for the global marine environment.
“The debate is no longer whether it is economically advantageous to reduce current harvests – it is – but how fast stocks should be rebuilt.”



















