Resident Orca Population
Orcas of the San Juan Islands were highly prized captures - sought after for aquariums around the world. Today this practice is finally illegal but the impacts are long lasting.
Orca capture in the San Juan Islands is one of the main reasons that the orca population in the Salish Sea — the population of Southern Resident Killer Whales (SRKW) — has experienced a major decrease over the past several decades. It is estimated that the resident orca population in this area once numbered 200 individual orcas. For a number of reasons, among which has been the extensive practice of capture for marine parks and aquariums in the 1960s and 1970s, the resident orca population has now fallen to 84 individuals.
Apart from the direct influence that holding orcas in captivity has had on decreasing the population of orcas, a number of other factors have exacerbated this downward trend. Overall degradation of the environment resulting from unsustainable fishing practices and habitat destruction, for instance, has made a considerable impact on the availability of salmon in the area. Research has shown that when the availability of prey like salmon is low, there is a corresponding decrease in the rates of birth and survival of SRKW.
The Impact of Orca Capture on the Orca Population
Thanks to the establishment of a cataloging system for orcas through the efforts of researcher Ken Balcomb and his team, the so-called annual Orca Survey was established. This has allowed scientists to chart trends in the SRKW orca population and establish some of the effects that orca capture has had on the SRKW population through the years. For instance, one of the major observations has been that no orcas in the current population were born between 1960 and 1970 — the period of time when orca capture was the most extensive.
Throughout the 1960s and 1970s, it is estimated that nearly 50 killer whales were removed from the Salish Sea. In 1972, a federal government law was passed — the Marine Mammal Protection Act — preventing further capture, feeding or harassment of marine mammals. In spite of this law, it is believed that capture in Washington state ended as late as 1976. Even though many years have passed since then, the effects of orca capture can still be observed in the Salish Sea until this day.
Orca Capture and the Effect of Toxins on the SRKW Population
Aside from the destructive impact of orca capture, toxins have been another major reason for the declining population of SRKW in the Salish Sea. Unfortunately, toxins are very high in urban areas, so resident orcas are very likely to be exposed to toxins through the food they consume. In particular, some of the most problematic toxins are DDTs and PCBs — pesticides that were historically contained in lubricants and coolants. Even though these pesticides were banned several decades ago because of their high toxicity and extremely damaging effect on our environment, remnants are still present in our environment and food chain.
Unfortunately, orcas frequently end up consuming these toxins via their food and storing them in their fat or their blubber. Apart from causing immune system failures in the individual orcas, these toxins are also damaging to subsequent generations of killer whales. For instance, when mothers give birth to calves, many of the toxins that they have stored in their blubber get passed on to their calves through their milk. As a result of the higher level of toxins in their bodies, baby orcas are then much more susceptible to disease and premature death.
If you are interested in ways that you can help SRKW, one of the best ways to do so is by supporting sustainable fishing practices and only purchasing sustainably caught salmon. In addition, many organizations are concerned about SRKW recovery promotion. If you are looking for an organization to donate to, feel free to contact us for more information. Without the proactive help of regular citizens, the population size of this endangered species will experience a further decline, seriously threatening the region’s marine biodiversity.
For more information about orcas in the Salish Sea, feel free to contact San Juan Kayak Expeditions. We would be happy to provide you with information regarding this fascinating population of marine animals. In addition, we offer a number of guided whale watching tours, kayak tours and multi-day kayak trips. If you are interested, feel free to contact us today at 360-378-4436!