Can Alaska's biggest fisheries withstand climate change?

Thomas C. Royer

Are we witnessing the collapse of Alaska's great fisheries?

The sharp decreases of Bering Sea pollock stocks (Daily News, Nov. 14, 2008) raise the question of whether Alaska's sustainable fisheries are a myth.

Fisheries are generally classified as a sustainable resource on the assumption that they can be maintained for future generations. However, studies have demonstrated man's ability to deplete major fisheries since the Middle Ages.

A recent book, "The Unnatural History of the Sea" by Callum Roberts, traces the destruction of fish populations from the estuaries of England after 1000 AD to the most recent demise of orange roughy off New Zealand. It has been estimated that 90 percent of large fish have now been depleted.

Will the Bering Sea pollock fishery continue to decline? Is it already too late?

This commercial fishery emerged in the mid-1970s, coincident with a rapid warming of the northern North Pacific and Bering Sea. That warm period has finally reversed in the last several years with the arrival of cooler waters.

History is not on the side of this fishery. For example, cooler water temperatures also preceded the demise of the northern cod in the Northwest Atlantic in the 1990s. This led to overfishing of the less productive stock. That cod fishery has not yet recovered, even though commercial fishing has been halted for nearly a decade.

What steps are necessary to assure sustainable fisheries for future generations of Alaskans?

First we must measure our current fish populations accurately. We cannot effectively manage the fisheries if we do not know their numbers.

Second we must improve our measurements of the changes in the ocean climate that are taking place in Alaska waters. This will help determine how those changes influence our fish stocks.

Ocean measurements in the Gulf of Alaska and Bering Sea help us understand how the fisheries respond to changing climate conditions. These measurements are part of "an invisible federal infrastructure" that maintains "eyes on the ocean."

Funding of the two ongoing, long-term, ocean measurements in Alaska's waters are in jeopardy. These data will assist in the proper management necessary to harvest fish. As we better understand how the fishery responds to climate change, fish stock models will become more accurate. The costs of these management and observation programs are small compared to the more than $1 billion dollars that is generated annually by Alaska's fisheries.

This month the National Marine Fisheries Service proposed an 18 percent cut in the allowable pollock catch for the Bering Sea. That might be too little too late since it does not adequately compensate for ocean climate changes. The agency has already reduced the 2009 Gulf of Alaska pollock catch limit by 36 percent. We could be witnessing a final struggle for survival of the Bering Sea pollock fishery, similar to that of the northern cod.

Ensuring sustainability of Alaska's fisheries is priceless and is our obligation to Alaska's future. No one wants the collapse of the Newfoundland and Northwest Atlantic northern cod to be repeated here in Alaska.

Thomas C. Royer is professor emeritus University of Alaska Fairbanks. He now lives in Virginia.