Pink Salmon Is Another Potential Threat To Orcas, Scientists Agree

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Besides dams, pollution and vessel noise, already identified as threats to the Northwest Pacific killer whales, scientists determined that pink salmon is also endangering the orcas. Four salmon researchers made this finding after they analyzed the data about orcas gathered on the Center for Whale Research.

The scientists noticed the killer whales have died in have died in even-numbered years more than in odd-numbered years over the last 20 years. The finding shocked them, as it suggests that such a pattern has to be linked to pink salmon which returns in considerable numbers to the waters between Washington State and Canad once every other year.

However, the four researchers are not yet sure that the pink salmon interfere in the orcas’ habitat, but they believe that it’s plausible. Pink salmon, therefore, might negatively impact killer whales’ ability to hunt chinook salmon, their favorite prey.

Pink Salmon Is Another Potential Threat To Orcas, Scientists Agree

“The main point was getting out to the public word about this biennial pattern so people can start thinking about this important, completely unexpected factor in the decline of these whales. It’s important to understand better what’s occurring here because that could help facilitate recovery actions,” said Greg Ruggerone, one of the four salmon researchers.

“We know that some are good years for the whales and some are bad years, but we hadn’t put it together that it was a biennial trend,” added Ken Balcomb, the founder of the Center for Whale Research.

Pink salmon is thriving in the oceans thanks to conservation policies and ocean changes. Therefore, pink salmon populations are on the rise. According to the researchers, the stress caused by the pink salmon in odd years reflects in higher mortality rates in orcas during the next year, that’s why death tolls in killer whales were higher in even-numbered years.


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