Sarah King
May 12, 2010
The coastal waters of BC serve as a hunting and traveling ground for many groups of orcas. Amazingly, one of these groups – the Northern Pacific Transient orcas, which consists of about 200-300 individuals – may soon be recognized as a separate and distinct species! Until recently, scientists were unable to solve the genetic puzzle that would allow them to reclassify these killer whales, which are actually from the dolphin family, as a stand alone species. But recent genetic evidence has revealed that the orcas in this group have mitochondrial DNA distinct enough to merit this reclassification. It has long been known that this small population has unique behavior and physiology. Most notably, these transients tend to hunt other marine mammals such as seals and sea lions whereas other orcas, like our resident populations, hunt salmon.
It was recently reported in The Province that if the greater scientific community supports this recent genetic finding, the tiny population of orcas would become Canada’s scarcest species, making them more rare than the endangered North Atlantic right whale or the whooping crane. Recognition of this group as a distinct species implies that the loss of these orcas would mean the extinction of an entire species – one that has been around for 700,000 years.
Northern Pacific Transient orcas are classified as Threatened under the Species at Risk Act (SARA). This is largely because orcas accumulate toxins (PCB’s, mercury etc.) within their bodies which are passed up through the food chain through their prey. Recent studies have found that transient killer whales have the highest concentrations of organochlorines of any marine mammal, and this toxic burden makes the orcas more susceptible to disease and reproductive difficulties. The rise in vessel traffic is also a concern for this species.
In addition to toxic contamination and impacts from vessel traffic, the three types of orcas that frequent BC’s waters- transient, offshore and residents- face various other threats including harassment, underwater noise, and dwindling prey supply. In 2008, Greenpeace and 8 other environmental organizations launched a lawsuit against the Department of Fisheries and Oceans (DFO) for their failure to protect the critical habitat of BC’s resident orca populations from such threats. Like the transient population, the northern resident population is designated under SARA as Threatened and the southern residents are designated Endangered, and as such, all the key components of their habitat must be legally protected.
This June, the hearing will begin in Vancouver and we are hoping to get some clarity on how DFO plans to protect the residents so they can recover and thrive. Over the next month, stay tuned for an in-depth look at the threats facing the resident orcas and how you can help push DFO to protect their future.