The Orca, or killer whale. In Roman mythology Orcinus means ‘of the kingdom of the dead’, or belonging to Orcus, ruler of the dead. Killer whale came from the Spanish whaler’s term of whale killer – so named because they would see them hunt in packs to take down larger baleen whales. At some point in our crazy language history that got swapped and now they are killer whales. But the Latin Orca is less ominous, it means shape of a barrel or cask – an apt description of their body type. These whales are fierce and intelligent predators, so perhaps it isn’t surprising they would become associated with such deathly names, but there is so much more to this species.
The SRKW are one of 10 different ecotypes (a distinct form of a species that lives in a particular habitat) of killer whales. In the 1970s when they were first observed they were found mainly off the southern end of Vancouver Island, in the Salish Sea, and thus named the Southern Resident Killer Whales. The other group found in the same area is the Northern Resident Killer Whales (NRKW), and they were mainly found in the Northern Vancouver Island region. The SRKW usually come to the Salish Sea in the spring, summer and fall, and are found in south and central California and up to SE Alaska during the winter. They can travel an average of 75 miles a day, so they can cover some distance pretty quickly!
SRKW are sexually dimorphic – if you see a large whale with a 6ft tall, straight dorsal fin, that is a mature male (15-25 years old). Males are 20-26ft and 12,000lbs or more. Females are 18-22ft, 8-11,000lbs with a smaller curved dorsal fin (mature at about 15 years, and reproductively active until about 40 years). SRKW can live as long as 100+ years (the famous Granny (see pic) was estimated to be 106 when she passed), but females average about 50 years and males only about 29 years (max 50-60 years). Each individual is identified by the shape, size, nicks/scars present in the dorsal fin, along with the white saddle patch just behind the dorsal fin. Each pod (group of related individuals) can also be identified by their calls, as they each have a distinctive dialect, with some calls shared between pods. It is very cool because you can tell what pod is present just by listening!
The SRKW are perhaps one of the most well-known killer whale ecotypes, especially in North America, because they are the only endangered population of killer whales in the world. This is because in 1965-1975 many animals were taken from the three pods: J, K and L, to supply whales for marine parks. By 1974 they were down to 71 animals. They peaked to 79-80 in 2001, but now have been decreasing again, and as of December 31, 2019 there were only 73 animals left (K pod: 17; L pod: 34, J pod: 22).
Why this recent decline? There is debate about which reason is the most pressing or most influential on the health of the population, but the big issues are reduced quantity and quality of prey (salmon), pollution (persistent organic pollutants) that can affect reproduction, and noise and disturbance from vessels. Food is probably the biggest, most immediate issue for these whales. They are fish eaters and mainly eat salmon, and in particular, Chinook salmon. This makes sense because Chinook are higher quality prey compared to other salmon species, so you get more bang for your buck (or the energy you expend to catch it). But that also means that if the Chinook aren’t doing well (which they are not), then neither are the whales. And it has been shown that the ups and downs in the whale’s population numbers closely follow the ups and downs in Chinook numbers. It should also be noted that noise and vessel disturbance can affect this as well. Noise can mask the whale’s echolocation making it harder for them to find their prey, and the whales may have less time to forage due to vessel disturbance. Thus finding enough food can be difficult for many reasons.
Finding food is a family affair with the SRKW, as is most everything they do. These whales have a rather unique social structure. They live in matrilines, where the grandmothers and mothers lead. This is not too uncommon in the animal world, but the fact that both the male and female offspring remain with their mothers for their ENTIRE lives is. Most of the time one of the sexes (usually the male) leaves the family group. The older non-reproductively active females (this is called senescence) are extremely important because they hold the knowledge- hunting methods, parenting techniques, expertise in mediating conflict to name a few. They hunt together and share their prey – often taking a salmon and ripping it apart to share with members of the pod. In particular, mothers will share more with their sons than their daughters. This is likely because males can pass on more of their genes (and thus their mom’s genes) because they can father lots of babies, whereas females have a limited number of babies they can have in a lifetime. Interestingly this comes with a downside, if the mother dies, the son (even if he is an adult) has an increased risk of dying: 8x higher risk over the next two years.
These are highly social, strong bonded animals and these social networks are affected by prey abundance. They are less interconnected when salmon is less abundant, smaller groups means less mouths to feed, but also means less social interaction, connectedness and knowledge transfer. Sometimes all 3 pods get together in what is called a super pod – where they can mate, bond and share information. Puget sound may be a culturally important meeting place for the SRKW. If events like these happen less, it could have large impacts on long-term survivability of each pod and the population as a whole.
Unfortunately, reproduction is down in the SRKW pods. There has only been 1 viable calf in the last 9-10 years. Females have a 15-18 month gestation. The first year of life is tough for any mammal – the mortality rate is about 25% for most species. But for the SRKW this number is a devastating 37-50%. This is likely due to the stress of not getting enough food, along with the issues that pollution can cause with toxicity in their bodies that is transferred into the calves through the milk, causing the calves to be less healthy and reduce survivability. The pain this is causing to these highly social and intelligent species was put on display when J35 carried her newborn dead calf for 17 days straight and for 1,000 miles. This was intense grieving, and it was painful to watch. All we can hope is that this image will remain in people’s minds, reminding them of the plight of this population and urge them to find ways to help and protect these magnificent animals.
The SRKW face many challenges, most of them human related. But the good news about that is that we can do something about that. We can change our behavior and that can help these magnificent, social, intelligent, culturally unique animals. Check out groups like the Center for Whale Research, The Whale Museum and Wild Orca to learn what you can do to help the SRKW.