By LAINE WELCH
August 31, 2009
Sea otters in Southeast Alaska were hunted almost to extinction by Russian fur traders in the 18th and 19th centuries, and estimates peg the population at just 2,000 in 1911. Sea otters were re-introduced to the region by ADF&G in the 1960s; within a decade their numbers reached 160,000 animals, and otter counts have grown exponentially ever since.
Sea otters can grow larger than four feet and weigh up to 90 pounds. They are voracious feeders and eat 25% of their body weight each day. Sea otters are blamed in part for the collapse of the lucrative abalone fishery, which ended in 1995.
"It is clear that abalone cannot co-exist in commercial quantities with sea otters," said a 1999 fishery report to the state Board of Fisheries.
Now, their appetites are starting to take a bite out of other commercially important species.
"We've closed many fisheries now - sea cucumbers, urchins, and just this last year we closed the first geoduck fishery due to presumed sea otter predation," said Zac Hoyt, a diver and research biologist at ADF&G in Petersburg.
"When you're under water in a geoduck bed, it's pretty amazing how efficient otters are at getting these big clams that burrow two or three feet under the substrate," he added. "It's literally like a back hoe has been on the bottom in those sandy areas."
No one knows how many sea otters have set up housekeeping in Southeast or how much shellfish they're feasting upon. Hoyt and Sunny Rice, the local Sea Grant marine advisor, aim to start finding out.
"The first step of our proposed project is to get an estimate of how many otters are in southern Southeast before we can move forward with anything else," Rice said, adding that concerns by fishermen and subsistence users prompted the study.
More fishermen, especially Dungeness crabbers, are telling her they are being forced out of traditional areas by sea otters, Rice said. Should they be holding on to their dungie permits?
"The reason we're tackling this whole thing is due to a lack of scientific information," Rice said. "It would be nice to verify what we're hearing from commercial fishermen - they'll go into a bay and see evidence of otter predation all along the shore, and at the same time, they're not catching any crab in their pots."
"We want to try and estimate the take of four commercially important species by sea otters - Dungeness crab, geoduck clams, urchins and sea cucumbers," Hoyt added.
The project also aims to learn how far the otters are foraging.
"Is there some reason
why they haven't come all the way into the far inside waters
of Southeast Alaska, or have they just not gotten here yet? That's
an important question for fishing fleets," Rice said.
Pollock does acid
Chemistry proves Alaska's oceans are more acidic, and it is affecting the ability of tiny sea creatures to grow shells. But what about direct impacts of ocean acidification on the state's largest fishery?
"We know there is going to be some impact on the calcifying organisms which make up a lot of the diet of the commercially valuable species. But we don't yet understand what the direct physiological impact is going to be on pollock," said Jeremy Mathis, a chemical oceanographer at the University of Alaska School of Fisheries and Ocean Sciences at Fairbanks.
With funding from the Pollock Conservation Research Cooperative, Mathis and colleagues this week will begin an experiment on one year old pollock, hatched and reared at the NOAA Alaska Fisheries Science Center in Oregon. Over three months the fish will be tested at acidity levels that are predicted to occur over the next 100 years. A second phase next spring will focus on newly hatched larval pollock.
"We will have a control tank of pollock growing under current levels, and compare growth rate - all of the indicators of health, metabolism and physiology," Mathis said. "I believe increased acidity levels will boost stress hormones in the fish. But we won't be able to tell that until we do some of these comprehensive studies."
Alaska pollock accounts for one-third of total U.S. fish landings. The pollock study will serve as a base line for other commercial fish species, such as cod. Mathis said results will be published next summer.
An algae bio-refinery is getting underway on Cape Cod in Massachusetts aimed at soon producing 5 percent of the state's diesel and home heating oil. The project is a partnership with a Wellfleet start-up called Plankton Power, Woods Hole Oceanographic Institute, the Regional Technology Development Corp. and the National Guard.
Cape Cod is among the world's most productive fishing grounds.
"When you have a world-class resource and world-class marine scientists in the same location, that's really a dream come true," said Plankton Power CEO Curt Felix.
The Guard is providing five acres on its base in Falmouth to begin the venture. The project will grow algae in fully contained re-circulating seawater systems to produce oil, and tap wastewater from the military base for nutrients. Carbon dioxide will be added from several sources, including industries. The mix will initially generate up to 1 million gallons of biodiesel a year, enough to meet the needs of Cape Cod. Expansion to 100 acres and 100 million gallons of biodiesel a year will meet 5 percent of the state's demand.
Algae biodiesel has a composition that is almost identical to petroleum diesel, but is more efficient and produces lower emissions, said Plankton Power CEO Curt Felix. Most algae fuels have been tested and grown in warmer climes, but the Cape Cod strain thrives in cold saltwater in low light. Because cold tends to prompt more fat storage, the cold water algae produces and stores more oil. Algae can be turned into biofuel in just three weeks, compared to six months for vegetable oils.Exxon Mobil has reportedly invested $600 million in algae biofuel testing. www.planktonpower.net
Fish high five
Laws for the SEA won third
place in the 2009 Capitolbeat awards in the "beat reporting"
category. Capitolbeat is a national association of state capitol
reporters and editors. Laws for the SEA, written by Bob Tkacz,
has covered the fish beat in Alaska's state capitol since 1994.