Science Facts

The Southern Resident Killer Whales are spiraling toward extinction

“Restoring Columbia River Chinook salmon is perhaps the single most important thing we can do to ensure the future survival of the Southern Resident Community of killer whales.  We cannot hope to restore the killer whale population without also restoring the salmon upon which these whales have depended for thousands of years.  Their futures are intricately linked.” — Dr. Rich Osborne, research associate with The Whale Museum in Friday Harbor, Washington (2015).

Compiled by Sharon Grace

Facts

• The Southern Resident Killer Whales (Orcinus orca) are critically endangered.

• After nearly a decade on the endangered species list, these killer whales are not recovering.  There were 88 whales when listed in 2005; today there are just 80.

• Since being listed as endangered, 37 Southern Resident Killer Whales (Orcinus orca) have died, while only 21 have been born and survived.  This is nearly a two to one death ratio.

• There is insufficient year round Chinook salmon to sustain the Southern Resident orcas.  The whales are dying due to cumulative pressures tied to lack of prey.

• In 2013-2014, eight Southern Residents died, a number of late-term calves were miscarried by females, and calves that survived birth, did not make it through their first year.

• Approximately 75% – 80% of the whales’ diet is Chinook salmon (Oncorhynchus tshawytscha).

• The whales need more Chinook salmon to survive and recover, as shown in multiple studies by both government1 and non-government2 researchers.

• The Columbia-Snake River basin once produced more salmon than any other river system in the world.  Historically, the Snake River watershed produced about half of all salmon in the basin.  Today, only about 1% of the historic number of fish returns to the watershed to spawn.

• According to NOAA Fisheries “[p]erhaps the single greatest change in food availability for resident killer whales since the late 1800s has been the decline of salmon in the Columbia River basin,”into which the Snake River flows.

• The past ability of the Snake/Columbia watershed to produce enormous salmon runs gives these rivers the most potential for again producing great chinook runs, which would enable the Southern Resident orcas to survive.

• The dams on the Columbia-Snake River are a major factor in the decimation of the salmon runs.4

• The Southern Resident Killer Whales need an estimated 800,0005 quality Chinook salmon annually to survive.  They need a two-fold increase in order to recover to a self-sustaining population of between 150-160 whales.

• The Southern Residents spend more than half their time in coastal waters.6  Their visits to the coastal waters off Westport, Washington and the mouth of the Columbia River coincide with high concentrations of spring Chinook salmon. 7

• The best available science indicates that the whales are likely to be especially reliant on the Columbia/Snake River watershed’s early spring, nutrient-rich Chinook salmon runs.8

• The SRKW population must increase by an average 2.3 percent per year for 28 years in order to be removed from the Endangered Species list.9

• Wilderness acreage creates the most perfect in-stream spawning habitat.  Breaching the four lower Snake River dams would open the gateway to a vast, 5500-mile expanse of intact spawning and rearing streams that run through more than 15 million acres of wilderness.  These are the highest elevation streams, and, therefore, the most global warming resistant salmon streams in the entire lower 48.  Breaching these dams would greatly increase a critical food source for the Southern Resident orcas, particularly in the winter months.

• Breaching the four lower Snake River dams is the single measure most likely to recover abundant salmon and steelhead in time to permit the Southern Resident orcas to survive.

References

1. Ford, JKB, et al., Linking Killer Whale Survival and Prey Abundance: Food Limitation in the Ocean’s Apex Predator?, 6 BIOLOGY LETTERS 141 (2010), p. *3, http://rsbl.royalsocietypublishing.org/content/early/2009/09/14/rsbl.2009.0468.  See also NOAA Fisheries, SRKW Recovery Planning and Implementation (2011), p. 2.

2. Ayres KL, et al. (2012) Distinguishing the Impacts of Inadequate Prey and Vessel Traffic on an Endangered Killer Whale (Orcinus orca) Population.  PLoS One 7: e36842, http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036842.

3. NMFS (2008) Recovery Plan for Southern Resident Killer Whales (Orcinus orca), p. II-82. National Marine Fisheries Service, Northwest Region, Seattle, WA, available at http://www.nwr.noaa.gov/Marine-Mammals/Whales-Dolphins-Porpoise/Killer-Whales/ESA-Status/Orca-Recovery-Plan.cfm.

4. See e.g., Nat’l Wildlife Fed’n v. Nat’l Marine Fisheries Serv., 839 F. Supp. 2d 1117, 1131 (D. Or. 2011) (“[T]here is ample evidence in the record that indicates that the operation of the FCRPS causes substantial harm to listed salmonids.  . . . NOAA Fisheries acknowledges that the existence and operation of the dams accounts for most of the mortality of juveniles migrating through the FCRPS.”)

5. Krahn, M.M., Wade, P.R., Kalinowski, S.T., Dahlheim, M.E., Taylor, B.L., Hanson, M.B., Ylitalo, G.M., Angliss, R.P., Stein, J.E., Waples, R.S., 2002. Status Review of Southern Resident Killer Whales (Orcinus orca) under the Endangered Species Act, US Dept. Commer., NOAA Tech. Memo. NMFS-NWFSC-54, Seattle, WA, p. 19.

6. J. Acoust. Soc. Am., Vol. 134, No. 5, November 2013, Hanson et al.: Killer Whale Acoustic Recorder Occurrence, 3486, http://oceanwidescience.org/cms/wp-content/uploads/2014/12/Hanson-et-al-2013.pdf.  2013 Southern Resident Killer Whale Satellite Tagging, http://www.nwfsc.noaa.gov/research/divisions/cb/ecosystem/marinemammal/satellite_tagging/blog.cfm.

7. Hanson et al.: Killer Whale Acoustic Recorder Occurrence, supra.

8. Ayres KL, et al. (2012), id., at pp. 7-9.

9. NMFS (2008) Recovery Plan for Southern Resident Killer Whales (Orcinus orca), p. v.