Southern Resident Killer Whales

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Northwest Fisheries Science Center staff observe an orca at close range

The Southern Resident Killer Whales (SRKW) ( English for southern local killer whales ) are a killer whale population in the northeastern Pacific . An alternative name is Orcas of the Salish Sea .

Basics

Killer whales have an individually different drawing, which means that individuals can be differentiated. By carefully observing the animals in the Northeast Pacific, off the coast of Canada and the USA for decades, it has been possible to identify groups of animals that exhibit different behavioral patterns and whose social associations normally have no contact with one another. Genetic studies have shown that there is hardly any gene flow between the groups ; whether morphological differences can also be determined is controversial. The populations are therefore possibly in the process of developing into different species ( sympatric speciation ). After the observations, it was possible to distinguish groups of whales that remained in a restricted marine area (“resident”) or that passed through and were therefore only observed occasionally (“transient”). In addition, there are inhabitants of the open ocean (“offshore”) who only occur in exceptional cases near the coast. The local, resident, populations feed mainly on fish, while for the migratory, transient, marine mammals are more important as prey.

In all categories it was possible to differentiate between large groups (“communities”). The local animals form two such groups, a northern and a southern one. The large groups themselves are divided into schools that stay together permanently (“pods”), within which subgroups (“subpods”, “intra-pod groups”) had to be distinguished. The Southern Resident Group is one of the large groups (communities).

Animal welfare

It is the only killer whale population listed as endangered by the United States Fish and Wildlife Service . It is protected by the Endangered Species Act .

J clan

Unlike other populations, the Southern Resident Killer Whales only consist of one group with 73 animals, the J-Clan , which consists of three subgroups, the J-Pod with 22 animals, K-Pod with 17 animals and L-Pod with 34 Animals with four to eleven matrilineal lineages in each pod. In 2012 two calves were born, one in the J-Pod and one in the L-Pod. A calf born in 2013 did not survive. After several years without surviving calves, a calf was born in the J-Pod in 2019. The oldest known killer whale, Granny , at 105 years of age , belonged to the J-Pod of this population. She died in late 2016.

food

The Southern Resident Killer Whales eat fish and probably prefer the king salmon (Chinook) over other species. The following preferences were determined on the basis of observation, autopsy and fecal analysis:

Well-known members of the Southern Resident Killer Whales

Individual evidence

  1. ↑ Orcas of the Salish Sea . Retrieved June 30, 2014.
  2. ^ AR Hoelzel, M. Dahlheim, SJ Stern (1998): Low Genetic Variation Among Killer Whales (Orcinus orca) in the Eastern North Pacific and Genetic Differentiation Between Foraging Specialists. Journal of Heredity 89: 121-128. doi : 10.1093 / jhered / 89.2.121 (open access)
  3. ↑ MA Bigg, PF Olesiuk, GM Ellis Social Organization and Genealogy of Resident Killer Whales (Orcinus orca) in the Coastal Waters of British Columbia and Washington State. In: Philip S. Hammond, Sally A. Mizroch, Gregory P. Donovan (editors): Individual Recognition of Cetaceans: Use of Photo-Identification and Other Techniques to Estimate Population Parameters. Report of the International Whaling Commission Special Issue 12. Cambridge, 1990: 383-406.
  4. ↑ As of 2005. The Endangered Species Act - Protecting Marine Resources . Retrieved June 30, 2014.
  5. ↑ a b Recovery Plan for Southern Resident Killer Whales (Orcinus orca) .
  6. ^ Granny, World's Oldest Orca, Returns to Home Waters at 103 Years Old.