Salmon restoration and the recovery of the Southern Residents

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Killer whales (Orcinus orca) are the largest members of the oceanic dolphin family and can be found in waters across the globe. They are incredibly social animals, travelling, hunting and playing in groups known as pods. Often times these pods are family-based, where the mother leads her offspring and their young, sharing hunting techniques and specific vocalizations.

When it comes to feeding, killer whales as a species are generalists, eating anything from fish to pinnipeds (seals) to other cetaceans (whales). Depending on the geographical location of certain populations of these whales we tend to see specialization in their diets. Known as “ecotypes,” some killer whale populations specialize in marine mammals, some on sharks, and most commonly in our area, salmon.

Killer whales are an iconic species in Washington State. Three pods known as the Southern Residents frequent the Puget Sound and people from around the world travel to the area to catch a glimpse of these whales from land and at sea. These Southern Resident whales however are listed as endangered under the Endangered Species Act. They face many threats daily from polluted waters, boating traffic and a diminishing food supply. The majority of the Southern Residents’ diet consists of salmon, with Chinook salmon being the primary choice due to them being large fish with a high lipid (fat) content and can be found in Puget Sound year-round. These salmon however are also listed under the Endangered Species Act, making their availability a limiting factor in the recovery of the Southern Resident killer whales.

Young orca feeding on salmon ( (c) NOAA, Lynne Barre)

Young orca feeding on salmon
( (c) NOAA, Lynne Barre)

Southern Resident killer whales travel between British Columbia and California each year, spending the summer months feeding on salmon in Puget Sound. Chinook salmon make up about 70% of the Southern Residents’ salmonid diet and of that 70%, approximately 3-7% originates from the Skagit River.

The Skagit River is the largest river system that flows into the Puget Sound, stretching 150 miles and draining 1.7 million acres in British Columbia and Washington State. The Skagit is the only large river system in Washington that contains healthy populations of all five native salmon species and two species of trout. Restoring habitat and flow conditions within the Skagit watershed is important for increasing wild fish stocks critical to the recovery of Puget Sound’s endangered whale population.

Skagit Fisheries Enhancement Group works to improve and restore habitat to support salmon populations. By helping to restore salmon populations, we also help restore killer whale populations. Help us help them by getting involved!

 

By WSC Education Associate KayLani Siplin

 

 

Sources:

http://www.orcanetwork.org/Main/PDF/preyselectionFord.pdf

http://www.orcanetwork.org/Main/PDF/preystudy2010.pdf

http://www.orcanetwork.org/Main/PDF/Biol.%20Lett.-2010-Ford-139-42.pdf

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