Healthy killer whale populations are dependent on adequate prey levels. Reductions in prey availability may force whales to spend more time foraging and might lead to reduced reproductive rates and higher mortality rates. The Southern Residents have experienced significant changes in food availability during the past 150 years because of human impacts on prey species.

Widespread reductions in salmon abundance from British Columbia to California during this period have likely had the greatest effects on the whales. Wild salmon have declined primarily because of degradation of aquatic ecosystems resulting from modern land use changes, overharvesting, and hatchery production. The recovery plan calls for support of ongoing restoration efforts for depleted salmon populations:

1.1 Rebuild depleted populations of salmon and other prey to ensure an adequate food base for recovery of the Southern Residents.

Northwest Region Puget Sound salmon recovery

Puget Sound Partnership

1.1.1 Support salmon restoration efforts in the region.

1.1.2 Support regional restoration efforts for other prey species.

1.1.3 Use NMFS authorities under the ESA and the MSFCMA to protect prey habitat, regulate harvest, and operate hatcheries.