UBC study says sea otter comeback worth millions, but not beneficial to all
The return of playful, popular sea otters to the Pacific shores of British Columbia is adding nearly $50 million a year to the province’s economy despite its impact on valuable fisheries, says a study.
University of British Columbia researchers say their conclusions may apply anywhere top predators have been returned to ecosystems from which they had been eliminated. But they warn the benefits must be evenly shared.
“When people invest in restoring ecosystems, including top predators, it can have large, positive benefits for people,” said Russ Markel, one of the authors of the paper published Thursday in the journal Science. “(But) First Nations and coastal communities were not consulted when sea otters were reintroduced 50 years ago and many of the benefits are not reaching or remaining in them.”
Sea otters were nearly wiped out along the B.C. coast by 19th-century fur traders. In the otters’ absence, prey species such as clams, sea urchins and crabs thrived.
Those booms gave rise to lucrative fisheries that sustained small towns and First Nations along the coast for decades.
Between 1972 and 1979, 89 sea otters were reintroduced to their former habitat and protected under the Species At Risk Act. There are now thousands of them.
The scientists attempted to measure the environmental, economic and social impacts of the population increase and weigh them against each other in dollars.
“This study takes this complex tangle of predator-induced interactions and it places them in a social and economic context,” said co-author Jane Watson.
With fewer urchins grazing on them, underwater kelp forests have grown twentyfold, providing new habitat for a range of fish from rockfish to salmon. Stocks of ling cod have tripled and the overall amount of life in the water has increased by 37 per cent, which has created new fisheries worth nearly $10 million.
More carbon has been stored, worth about $2 million at current carbon prices. Tourists have spent a total of about $42 million for the privilege of seeing the otters cavort.
But otters eat up to a quarter of their body weight every day, so various clam fisheries have lost about one-quarter of their value. Fewer crabs and sea urchins have been landed.
The paper estimates the total loss at just over $7 million.
That leaves a net benefit of about $46 million, although the scientists acknowledge a wide margin of error.
Much of that net benefit has escaped local people, the paper says.
The authors urge reorienting fisheries policy toward local benefits and food security.
They suggest returning to some traditional practices such as clam gardens, which use rock walls at low-tide lines to increase the amount of productive shellfish habitat on a beach.