Slide background

Protecting Orca by Restoring Salmon

Save Our wild Salmon works closely with orca advocates, orca-based businesses and scientists regionally and nationally to protect and restore the main prey base – chinook salmon – that Southern Resident Killer Whales (SRKWs) depend upon for their survival and recovery.

SOS first began this work in 2006, when NOAA-Fisheries listed the SRKWs as ‘endangered’ under the Endangered Species Act. In 2015, after a series of devastating orca deaths during the previous year, SOS joined forces with several other advocacy organizations to found the Orca Salmon Alliance (OSA) in order to better advocate for these two iconic Northwest species – Chinook salmon and Southern Resident orcas – whose fates are inextricably linked.

Orca and salmon: an ancient relationship

Highly social, highly intelligent Southern Resident Killer Whales have roamed the coastal waters of the Pacific Northwest for hundreds of thousands of years – relying primarily on an abundance of large, fatty chinook salmon for their diet. In recent decades, however, their numbers have declined precipitously; steep declines of chinook salmon populations across the Pacific Northwest is a leading cause of this decline.

Orcas’ reliance on chinook salmon that originate in the Columbia-Snake River Basin during key times of the year has long been accepted in the scientific community. Though behavioral patterns can vary greatly year to year, SRKWs typically spend approximately half of the year roaming the West Coast - from British Columbia to northern California – hunting for salmon. In its 2008 SRKW Recovery Plan, NOAA-Fisheries acknowledges orcas’ historic reliance on Columbia Basin chinook and describes its population declines as “[p]erhaps the single greatest change in food availability for resident killer whales since the late 1800s...”. But it has only been more recently that this Southern Resident Orca – Columbia Basin Chinook salmon nexus has explicitly documented and detailed with acoustic data, satellite tagging data, fecal sample analysis, and visual confirmation.

Scientists have identified three main causes of decline for SRKWs today: lack of sufficient prey, toxins, and vessel noise. It is the lack of an adequate prey base throughout the year, however, that is broadly recognized as the most important factor and one that must be urgently addressed in order to protect this apex predator from extinction. Numerous SRKW hormone analyses based on fecal sample collections in the last few years confirm the tight connection between chinook salmon abundance in Northwest marine waters and the survival and reproductive success of SRKWs.

Restoring Columbia-Snake salmon is key to orca survival

New science also confirms that SRKWs spend large amounts of time hunting at and near the mouth of the Columbia River, especially during the months from January – April. This is the same time when spring chinook are schooling up near the river’s mouth before they return to river in search of their natal spawning gravels. Spring chinook are especially valuable to these orca due to their relatively large size and their high fat content. In the last several years, many orcas have spent more time on the coast, as some key inland Chinook populations in the Fraser and other rivers have declined. These declines elevate even further the importance of protecting and restoring Chinook populations in the Columbia Basin and other coastal river systems.

Restoring healthy, robust populations of chinook salmon in the Columbia and Snake Rivers must be a critical SRKW conservation priority. Since orca don’t have refrigerators, their survival and recovery depends on an adequate prey base throughout the year. With its large size, historic productivity, significant restoration potential, large pockets of pristine, high elevation habitat and low human population, the Columbia-Snake River Basin is an essential current and potential source for the large numbers of chinook salmon that orca need.

Protecting and restoring these critical populations depends on substantially improving the health of this ecosystem. A modernized Columbia River Treaty that includes a new third purpose – ecosystem-based function - and a legally valid, science-based Federal Salmon Plan (BiOp) that includes the removal of the lower Snake River dams, expanded spill at dams that remain, and other key measures are essential to the fate and future of the Southern Resident Orcas.

Share This