Biology in the News Explained

Your high-fish diet will soon be a thing of the past

Time to start getting your omega-3′s from plants. We are long past the golden age of fish production and quickly approaching a complete crash of most fisheries, in case you had not noticed. Probably it was inevitable, but over a decade ago, a couple of biologists figured it was worth a shot to point out that policy changes actually taking the future into account, rather than simply pretending to, needed to be made. (Roughgarden J, Smith F, 1996. Why fisheries collapse and what to do about it. Proceedings of the National Academy of Science U S A. 93(10):5078-83 [open access].)

Apparently no one making the regulations even tried to implement their idea, which admittedly would probably not go over well in the real world, because it involved taxing, rather than subsidizing, fishermen.

To make their point, the authors first list some of the various rationalizations for the collapse of the Newfoundland cod industry:

Many causes have been cited for this collapse, including a lack of political will to impose adequate quotas, overoptimistic stock assessments by fishery scientists, poaching from foreign fleets, exceptional mortality from natural predators, climate change, subsidies to fishers, and overcapitalization…

Do any of these sound familiar to those reading a recent NY Times article about chinook salmon?

Of course this problem with the salmon fishery is not an isolated crisis in which we cannot possibly imagine the causes, despite such mind bogglingly out-of-touch utterances as this: “It’s unprecedented that this fishery is in this kind of shape,” said Donald McIsaac, executive director of the [Pacific Fisheries Management] council, which is organized under the auspices of the Commerce Department.

Perhaps it is unprecedented for that particular fishery, but why would anyone expect an outcome different from nearly every other heavily exploited fish species? For example, consider the crashed Newfoundland cod – historically it was one of the most abundant fisheries. No one could imagine the possibility of depleting it. There are now also warnings about tuna, another historically abundant species.

Ultiimately the issues cropping up are probably the tip of an iceberg that has repercussions not just for mere fisheries, but for the health of the entire planet, which remember is mostly ocean. This leads some to pin the blame on climate change for crashing fisheries. But they are missing the point. The problem specific to fisheries remains one of overexploitation – it just has not been correctly defined.

We now must face up to admitting that fishing limits, even those that have been faithfully adhered to, have been based at best on significant lack of ecological information, and at worst, on mostly short-term economic criteria.

As Roughgarden and Smith point out:

May et al. (May, R. M., J. R. Beddington, J. W. Horwood, and J. G. Shepherd. 1978. Exploiting natural populations in an uncertain world. Mathematical Biosciences 42:219-252) concluded that “What seems really needed is not further mathematical refinement, but rather robustly self-correcting strategies that can operate with only fuzzy knowledge about stock levels and recruitment curves.”

For thirty years at least, it has been clear that fishery management has needed to focus on how to incorporate ecological complexity (compounded by complexity introduced by detrimental environmental impacts by all sorts of human activity), rather than crunch numbers based on the last available year of data for catch. Is there truly anyone in this business who can possibly be surprised that any fishery is collapsing now?

Of course, Roughgarden and Smith’s analysis is naive in its economic assumptions such as this, when they state that after a crash “…the industry must contract anyway, and by managing for ecological stability the prospects of subsequent collapses are minimized.” Unfortunately, for most natural resources, long-term gain is completely overshadowed by short-term profit, to an irrational degree, which will not emerge out of traditional economic models.

Still, the authors have a proposal that makes a little more sense for helping fisheries last a little longer:

(i) Establish a target stock at 3/4 of the average unharvested abundance [i.e., harvest much less than what appears to be ecologically sustainable].
(ii) Tax the revenues from any fish caught when the stock is below target.

As they discuss it, condition (1) essentially builds in insurance for fisheries, which only makes sense given our deep and continuing lack of understanding of the complex interactions of habitat loss and climate change, combined with only vague estimates for rates of increase, habitat carrying capacity, amount of predation, etc. And yet current practice ignores the environmental factors, and pretends that our numbers for the rest are accurate.

Condition (2) makes sense too, but seems unlikely to be successfully implemented. The point of it is to make it more costly, rather than more profitable, to fish when stocks are depleted below a sustainable level. Unfortunately, the current situation is that the harder it becomes to catch a certain species of fish, i.e. as it becomes depleted, the more rare it becomes, and thus more expensive. A tax would have to be severe indeed to cut into the profits of fishers catching the rarest fish, and thus politically probably impossible. If implemented it would surely increase poaching and the black market even beyond what it already is.

The damage is done. Fishing limits have been set historically (when they were set at all, usually belatedly) based on faulty ecological assumptions influenced by strong economic pressures, while ignoring the continuing fluctuations (many with unknown cause, such as in the case of the chinook salmon) that change the sustainable catch – and thus can crash a seemingly healthy fishery quickly after a series of below-normal population years. The mistake is similar to that made by authorities making Western water allocations during an unusually wet period there, and steadfastedly sticking by them even when a fraction of that water is now available. Perhaps moratoriums on fishing some populations such as the Newfoundland cod will give us a second chance to make saner policy. But it would be a foolish bet to make.


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