Sea otters not to blame for shellfish decline

By Greg Brown

The fate of the shellfish industry in Southeast Alaska appears to be sealed. This fate has comparatively little to do with overfishing or the return of sea otters. It has to do with CO2 and the fact that about 25 percent of CO2, which comes mostly from coal-fired power generation and fossil fueled powered vehicles, gets absorbed by the ocean, resulting in an increase in ocean acidity. This increase negatively affects the calcification process used by shellfish to make shells.
Since there has been no real effort to address this issue by only a few governments in the world, it is probably already too late to save the shellfish industry. The question is when we will lose shellfish, and that is something over which we do have some limited control.
The rate of ocean acidification can be slowed down by creating a greater opportunity for more kelp to grow. Kelp is a plant that absorbs CO2 in the ocean, just as trees do on land. Kelp growth can be increased by reducing the number of sea urchins that consume kelp, effectively turning kelp forests into deserts.
The best way to control sea urchins is to restore the ecosystem by allowing sea otters to re-establish themselves and eat sea urchins, thus returning the kelp forests to their natural levels. This will allow the kelp to absorb CO2, thus reducing the rate of ocean acidification – and thereby prolonging the shellfish industry in Southeast Alaska.
No one alive has ever known what the nearshore marine ecosystem in Southeast Alaska looked like before the sea otter was driven almost to extinction by the Russian fur trade, and, in fact, the shellfish industry has actually been living in an artificially elevated market since that time.
Senator Stedman’s proposal to initiate predator control on sea otters via a bounty will only speed up the demise of the shellfish industry, and while the implementation of a bounty may result in some short-term gains for some user groups, the shellfish industry will just go away more quickly with predator control than without it.
There is also reliable scientific information suggesting that herring production — and therefore salmon production — will increase as the kelp forests return.
Returning our nearshore marine ecosystem to its natural state is a win for all of us.

Greg Brown is the owner of Weather Permitting Alaska LLC, which is an environmental investment business. Less than two percent of its assets are in a local whale-watching business.

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Posted by on Mar 20th, 2013 and filed under Point of View. You can follow any responses to this entry through the RSS 2.0. Both comments and pings are currently closed.

3 Responses for “Sea otters not to blame for shellfish decline”

  1. Carbon pollution makes the oceans more acidic. That’s bad for coral reefs, fish, and humans.

  2. Mike Kinville says:

    Having never met Mr. Brown I would love to give him the benefit of doubt regarding his motivations, but without a doubt he has presented declarative information that reduces chaotic and complex issue to the point of meaninglessness. Captain Gregg takes on the science of Ocean Acidification, swings mightily…and misses.

    He exposes his bias when he damns the world’s shellfish industries. Studies such as “Is Ocean Acidification an Open-Ocean Syndrome? Understanding Anthropomorphic Impacts on Seawater pH” (Duarte et al) address the complexities involved; (natural) “changes in watersheds…yield high-magnitude decadal changes of up to 0.5 units in coastal pH”. This natural variance in pH overlies the .1 unit of decrease in pH attributed to human C02 emissions, a decrease reached over the entirety of the industrial revolution.

    The effect of decreased pH and the concurrent decrease in carbonate ions varies greatly between shell building species. Without long term studies of the shellfish in question it is baseless conjecture to attribute entire population declines to anthropogenic C02 emissions.

    I also find it counterintuitive that in an area such as SE Alaska, which is subject to the vigorous Japanese Current and huge tidal action, that local C02 absorption by kelp would have any significant impact on local pH levels.

    Perhaps a wise way forward would be to initiate a controlled study, starting with a count of shellfish in a controlled area, followed by the culling of the sea otters that enter the study site. At specified intervals the shellfish population could be reassessed. This would be a great time to assess kelp impact on C02 absorption and pH levels as well.

  3. BillyH says:

    Kind of funny that an “environmental investment” company would have any credibility to anyone except for Greenpeace and the Sierra Club. So Mr. Investor, tell me why they King and Dungenous crab never returned after being overfished in the 70’s. It definitely couldn’t have been the increase in marine mammals and predatory fish such as halibut and cod. You greenies are just wanting to blame that nasty coal. You’d blame gun violence on coal if you could. And one last thing to steam on….Why are the oyster farms across the bay thriving? Maybe they are super shellfish that can live in battery acid. Get real folks.

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