Saturday, June 15, 2013

Where have all the fishes gone?

Can we ever get our ecological act together?

Picking up on last week's theme of fighting against the declining baselines of what humans perceive as "normal" ecology, as they exploit their way down the food chain and wreak various other types of havoc on our world, a prime example is fishing. We have known forever that any body of water has only so many fish, and in lakes it is quite possible to "fish out" a species. But the ocean? Yes, we've known for at least a century or two that ocean fisheries can be fished out too.

An outstanding podcast from the CBC interviewed the author of a new book about this history, who makes the point that fishery depletion was a public and contentious issue in the 19th century, and fishermen where very resistent to the ├╝ber-exploitative methods like bottom-trawling that, several decades later, left much of the eastern seaboard such an ecological shambles. Time after time, our collective apparatus- the state- proved toothless and cowardly in the face of technological "advancement", private interests, and races to the bottom which wound up as tragedies of the commons.

But I'll turn to something more contemporary- an article about current fisheries management that has similarly depressing messages about the appalling lack regulation, even now, decades, indeed centuries, after all the issues have been crystal clear. If we can not manage our relations to fish in the face of short-term greed, how will we ever deal with CO2?

The paper is a global analysis of overfished stocks, and asks what the optimal policy would be, and how far we (or the relevant governing bodies) are from that policy and why. As is customary with contemporary fisheries "science", they take the most blinkered and mercenary attitude, asking not for ecological health in general, or restoration of fantastic yields seen in distant history, but only for the "Bmsy", or the maximum sustainable yield of fish biomass. The idea that other fisheries might depend in turn on the studied fishery, or that wild animals might rely on it, or that such fish populations might not have as their only end the servicing of human appetites ... that doesn't seem to enter their heads. Nor does the true historical scope of possible fish populations and yields.

At any rate, even on strictly Bmsy terms, which is to say the simplest dollar and cents approach, the fisheries they look at are grievously mismanaged. Species that could be restored in ten years are on trajectories to be restored in 100, if that. (Note that the halibut fishery is completely closed due to virtually none being left, which leads to the coincidence of the business as usual and other curves below.)

Projected recovery times for various collapsed fisheries of the northwestern Atlantic, under business as usual,  no fishing at all, and moderate fishing at the Bmsy (see text) levels.

The Bmsy is typically taken to be 0.3 times the current population of the fish, assuming a typical rate of reproduction, which largely goes into the maw of the fishing fleet. This is why the difference between no fishing and Bmsy fishing in the graph above is so small- that taking merely one third of the population each year is not such a big bite out of a rapidly reproducing species. For a slowly reproducing species, like sharks, the factor is going to be much smaller, but that is not discussed in the paper.

So it is apparent that under the current regulatory regimes, the hunters of these emblematic species and many others are not controlled, and can not control themselves from vacuuming up absurdly large proportions of the already depleted populations of these fish, directly in opposition to their own economic interests, in the long term.
"Regardless of their depletion level, at current fishing mortality rates, recovery to Bmsy remains a distant target for the majority of stocks that are now depleted (n=62 stocks in our analysis)."
The authors go on to make the additional point, which hardly needs making, that the length of time a species has been in a highly depleted state itself affects the time it will take (if ever) to recover. Whether this arises from permanent habitat destruction, (like from bottom trawling), or from ecological reconfiguration of their relation to other species, or gross genetic alterations like reductions in size in response to fishing pressure, or from loss of genetic diversity, or for other reasons, such species have a hard, hard road.

Fish are almost as invisible as CO2- out of sight, out of mind. And this problem also reflects the degradation of our public institutions and quality of public thinking, part of a long tradition of kow-towing to private business and individual "freedom", which authored such epic catastrophes as the dust bowl. We can do better.


  • The Fed talks about our conditions- the credit markets are still in bad shape. The Fed's money creation has little effect, as long as banks and other participants are not lending.
  • CO2 emissions at all-time high.
  • Nicaragua intends to build a canal, with Chinese and Russian help. How serious is it? Hard to tell.
  • Some economic history- breakup of the Ruble currency area.
  • B of A lied as a matter of course ... shocking! Disclosures about foreclosures.
  • Supply side theory ... oops!
  • Green tip- foam filler is a great way to weatherize, seal cracks, and insulate.
  • Economic image of the week- returns to capital vs labor. The talk turns out to be about inequality, looking into the void of our current public policy, in a TED-style way.



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