The Southern Resident Killer Whales (SRKW) are often said to be the most researched orcas in the world, inhabiting a distinct territory that is well studied by biologists. This group of whales is actually a large, extended family and is comprised of three separate pods: J, K and L. Given the pods’ ease of accessibility to scientists, much is known about fluctuations in their population numbers over the last few decades.
Historical estimates for the SRKWs during the late 1800s place the population at roughly 200 individuals. However, during the period between 1965 and 1975, the demand for orcas in the marine aquarium business decimated their numbers. A total of 45 orcas were captured and sent to aquariums around the world while at least 13 additional orcas died during the capture process.
Even though the J, K and L pods today are decades removed from the captures that broke up families and destroyed valuable genetic lines, their numbers have struggled to rebound and the population is still nowhere near where it was a century ago. In 1995, the SRKW population hit a high at 98 animals. The most recent count of SRKW numbers was published on July 1, 2015 by the Center for Whale Research. They found the current population to be at 81 whales, boosted by the births of four new calves born since last winter.
Now, four new whales may not sound like a lot, especially given that the population of these animals used to number in the hundreds. However, this is very welcome news given the odds that have been stacking up against the orcas over the recent years, literally endangering their existence.
An Endangered Whale Tale
The aquarium captures of the 60s and 70s did the whales no favors as far as their wild populations go, but a number of other factors have been actively working against the animals’ attempts to rebound. And the impact of these issues has actually been so extreme, that the SRKWs were labeled as “endangered” in 2001 in Canada under the federal Species At Risk Act (SARA). They also gained recognition in the United States when they were listed as “endangered” in 2005 under the Endangered Species Act. So, what’s causing the SRKW population numbers to plummet?
Unfortunately, there is not just one thing that is bringing harm to these orcas- it’s actually a variety of issues that are all coming together to make life very difficult for the whales.
For one, pollution is causing major problems for the orcas’ health and sadly, it’s all coming from their food. The SRKW’s meal of choice is Chinook salmon which are abundant in the orcas’ territory. Unfortunately, the waters where both the Southern Residents and Chinook reside are very close to several urban areas in the United States and Canada. This means more pollution, especially for the orcas which sit atop the food web and accumulate higher levels of some nasty chemicals. This includes things like DDT, mercury and PCB’s which get stored in the orcas’ fat reserves, making them more susceptible to reproduction problems and illness.
Another issue endangering the SRKW population is food shortage. Without enough food and, mainly Chinook salmon, the whale population obviously cannot be sustained. Fishing, pollution, and dams are currently driving Chinook numbers down and the impacts on whales are showing. Activists are now petitioning the government to remove the dams on the lower Snake River in an attempt to boost Chinook populations and help the whales. Efforts are ongoing and it remains to be seen whether activists will get their wish and if it will have a positive impact on the whales.
A final major threat to the SRKW numbers is conflict with vessels. The orcas reside in a very busy shipping highway and are often trailed by whale watching boats in the summer months. Commuters in the area utilize ferries for transportation, and personal and commercial fishing boats are abundant in the area as well. Below the surface of the water, all of these running engines can result in a deafening noise for the whales who depend on sound for communication, navigation, and location of prey. The ships also present a hazard should they collide with a whale. As the human population in the area grows, the trouble presented by vessels to animals like orcas will only increase.
Where Do (Whale) Babies Come From?
Well, whale babies come from the same place that all other babies come from. But it is important for scientists to understand where these babies came from- specifically what factors may have recently helped improve reproduction rates in the Southern Residents. Of course, researchers can only make educated guesses to explain the recent baby boom for the SRKW pods, but it is a worthwhile topic to ponder because it helps conservationists understand what environment these animals require in order to continue to recover.
Dr. Eric Ward of NOAA Fisheries noted an increase in Chinook numbers last year (2014) which may have helped usher in the newest batch of baby whales. Considering that food shortage is seen as one reason for the whales’ decline, this is a very significant observation. It shows the importance of helping Chinook populations recover in order to offer enough healthy food sources for the declining SRKW populations.
Reason to Hope
Four new whales is certainly nothing to scoff at, but it also doesn’t mean the population is safe just yet. After all, scientists remind us that baby orcas only have a 50 percent chance for survival into adulthood. But things do look promising so far.
The four new whales born to the SRKW pods this year relieve a drought that has haunted the population for nearly three years: no live births have occurred in that time period. The news is also welcome in light of the recent discovery of a dead, pregnant member of the J-pod last October. These births have brought an end to a series of failures and letdowns in recent years.
Another especially encouraging aspect of the recent baby boom in the SRKW pods is the fact there is a female in the mix. Females of reproductive age have become harder to come by in these pods, and yet they are obviously essential in mothering the calves that will become the next generation.
The orcas still have a ways to go until they can be removed from the Endangered Species list with a wild population of 120 individuals, but so far in 2015, their population has done nothing but trend in the positive direction and that should be reason for hope.
Lead Image Source: Adam Rifkin/Flickr