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Blame CO2, not sea otters, for SE Alaska shellfish decline

  • Author: Greg Brown
  • Updated: September 29, 2016
  • Published March 25, 2013

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 carbon dioxide 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 harms 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 have 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 kelp to absorb CO2, reducing the rate of ocean acidification and prolonging the shellfish industry in Southeast Alaska.

No one alive has 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 been living in an artificially elevated market since that time.

The proposal by Sen. Bert Stedman, R-Ketchikan, to initiate predator control on sea otters via a bounty will only speed the demise of the shellfish industry. And while a bounty may result in 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, an environmental investment business. Less than 2 percent of its assets are in a local whale-watching business. This commentary first appeared in the Homer Tribune and published here with permission.

The views expressed here are the writer's own and are not necessarily endorsed by Alaska Dispatch, which welcomes a broad range of viewpoints. To submit a piece for consideration, e-mail commentary(at)

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