Marine mammals on the West Coast could now be consuming extra Chinook salmon than these being caught by industrial and leisure fisheries mixed, a brand new examine finds.

It reveals that recovering populations of killer whales, sea lions, and harbor seals have dramatically elevated their consumption of Chinook salmon within the final 40 years.

“We have been successful at restoring and improving the population status of protected marine mammals,” mentioned Brandon Chasco, a doctoral candidate at Oregon State University and lead writer of the examine. “But now we have the potential for protected seals and sea lions to be competing with protected killer whales, and all of which consume protected Chinook salmon.”

The badysis was a collaboration of federal, state and tribal scientists within the Pacific Northwest, together with Oregon State University and NOAA Fisheries. 

It could have critical implications for the restoration of each Southern Resident killer whales in addition to chinook salmon, each of that are protected by the Endangered Species Act. There are solely 76 Southern Resident killer whales alive right this moment, deeply regarding for scientists who imagine the orcas could disappear if critical motion shouldn’t be taken instantly.

Southern residents spend a lot of the 12 months in Puget Sound and the Salish Sea, and their main food regimen is Chinook. The examine discovered that the orcas eat about the identical quantity of salmon right this moment as they did 40 years in the past. It means that in right this moment’s ecosystem, competitors with different marine mammals could also be extra of an issue for southern residents than competitors with human fisheries.

The examine additionally reveals that a number of rising populations of resident killer whales in Canada and Southeast Alaska are estimated to eat the most important biombad of Chinook salmon, however harbor seals eat the most important variety of people, together with juveniles that are a primary goal for habitation restoration efforts round Puget Sound and the Columbia River.

The badysis discovered that salmon restoration applications up and down the West Coast have boosted numbers of untamed salmon, however elevated predation by recovering marine mammals presents a problem and will offset reductions in leisure and industrial harvests.

“The better we understand the different obstacles to salmon recovery, the better we can account for them as we plan and carry out recovery programs,” mentioned Isaac Kaplan, a badysis fishery biologist at NOAA Fisheries’ Northwest Fisheries Science Center and a co-author on the examine. “Recovery efforts must account for all of these challenges, and we’re providing more details about one important part of that picture.”
 

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