Decline Of the NW Orcas
Published in Ocean Realms Magasine, Winter 2000/2001 Issue
Editor’s note: since this article was published, 6 more orcas from the southern residents have mysteriously disappeared. The population is plummeting and now sits at 78 whales.
Breaching skyward in an explosion of foam, J-1 sends a two-foot Chinook salmon tumbling, before it lands, stunned and motionless on the sea’s surface. J-1, a 50-year old bull orca better known locally as ‘Ruffles’, quickly captures and consumes the fish, then deftly arches below the surface to begin the maneuver anew.
But for Ruffles, and the other members of his extended clan in the northwest, prey isn’t always readily available. In fact, a regional salmon shortage is contributing to the alarming, fast-paced decline of J clan, commonly known as the ‘southern resident’ orca community.
Northwest researchers and environmentalists are concerned. This past summer, the southern resident orca community, comprised of J, K and L-pods, has dropped in number to only 82 remaining whales. This decline represents a decrease of 14% since January 1999, and a 17% overall decline since the middle 1990s. This drop is also in stark contrast to growth dynamics of other Pacific orca stocks in British Columbia and Prince William Sound, which appear to be increasing at a rate of 3% per year.
Lower Survival Rates
“We’ve recently compared survival rates on the southern resident population from 1974; comparatively these last few years, rates are at the lowest they’ve ever been,” observes researcher Paul Wade, who with colleagues Ken Balcomb and David Bain, produced a draft population report at a National Marine Mammal Laboratory (NMML) workshop in Seattle this past April. Recent whale mortalities, including that of Ruffle’s nephew J-18, a young, relatively healthy bull (and his mother J-10 a month later), have prompted biologists to gather and discuss that matter, and possibly seek to obtain an ‘endangered species’ listing for the southern resident population.
“The main factors which seem to be contributing to this decline are toxic chemical contamination, scarcity of prey, and the growing impact of marine vessel traffic present around orcas during their peak feeding and breeding periods,” says researcher David Bain from the Whale Museum on Washington’s San Juan Island. These three specific factors were also identified as prime concerns in the report published after the NMML workshop in April.
Toxic contamination, particularly the accumulation of polychlorinated biphenyls (PCB) in fatty tissues, have given these orcas the distinction of being the most chemically contaminated marine mammals in the world. “These animals are literally considered ‘toxic waste’ when they wash up on shore,” adds Robert McLaughlin, SeaWolf boardmember. “In fact, concentration levels in this orca population run almost twice as high as in the St. Lawrence beluga whales controversy,” adds McLaughlin, “While PCBs have been outlawed in the US for some time, these orca have accumulated a ‘legacy’ of contamination that they continue to pass on, from mother to calf, generation to generation.” PCB accumulations are known to weaken mammalian immune systems, and make injured of sick whales more susceptible to infections and other illnesses.
Combined with the added stress associated with prey scarcity, some whales, like J-18, seem destined to die in what would otherwise be their prime breeding years. While PCBs have been outlawed in the United States for more than two decades, the toxin persists in ocean sediments and continues to enter the food chain through prey species and, ultimately, into top level predators such as orcas.
Chemical contamination from other sources, such as industry and consumer-based toxins dumped into stormwater drains, rivers and streams leading to the ocean have also impacted survival and spawning habitat for salmon and other prey fish. “Certainly, the recent listing of Chinook salmon as an endangered species in the northwest is also a factor,” says Ken Balcomb, a whale researcher who heads the Center for Whale Research on San Juan Island. “To make matters even more complex, Puget Sound’s herring stock – the prey that the salmon themselves feed upon – may be the next candidate species to win a federal ‘endangered’ status listing,” adds Balcomb.
The decline in available prey cause orcas to range further afield to forage, and may have an additional impact on time needed for crucial resting, socialization and mating activities. “The solution to this problem is fish restoration,” Comments Balcomb, “Not just with salmon, but also herring, groundfish and all other declining fish in the orcas’ ecosystem – unless we do something about that, the southern residents may be gone in as few as three generations (25 years).”
Stress From Eco-Tourism
Ironically, the growing eco-tourism industry itself is now considered a cause contributing to the decline. Ken Balcomb’s colleague David Bain recently concluded a study that suggests the growing marine traffic around these whales might be adding to the impacts, and threatening their long-term survival. “While the southern residents don’t appear to be leaving their foraging area altogether, we do have periodic disappearances – and we have observed that their daily activities have changed as a result of vessel intrusion,” says Bain.
Changes in behavior could be caused by the impact of increased stress and energy output resulting from boat avoidance maneuvers, deep-lung inhalation of poly-aeromatic hydrocarbons (gasoline fumes) from surrounding boats, and the interruption of necessary socialization behaviors such as breeding, bonding and instructing younger whales to forage for prey. “Boating restrictions around these whales is an issue that we can control,” adds Bain, “Perhaps it’s time to implement some access or proximity limitations and encourage the public to switch toward shore-based whale watching.”
Live Captures Contibuted to Decreased Birth Rates
One other significant factor suspected of contributing to the current decline involves the historical live capture operations of the 1970s, that removed many breeding age orcas from this population for exploitation by the marine parks entertainment industry. Today, all but one of these captured whales are dead, but the sole survivor – a perfectly healthy and contaminant-free breeding age female from L-pod named “Lolita’ – could become a mother to any entire generation of healthy offspring. Unfortunately Lolita is a performing orca in a Florida theme park, and her owner has no intention of releasing her to the researchers who would rehabilitate and return her to her wild family in the northwest.
Yet this last option might be one way to stall the decline. Today, only seven sexually mature male orcas remain in the southern resident clans, two of these (including J1) are approaching the maximum life span estimated for males. And since orcas do not breed outside of their clans, there is validity to the observation that mortality will continue to exceed the current birth rate. Even if the southern resident orcas where to adapt and be capable of dealing with the immediate factors of prey shortage, pollution and vessel traffic, there are not enough new whales being born to reverse the overall decline.
Loss of Biodiversity
Ultimately, the issue at hand appears to be whether the southern residents are headed toward extirpation. While there are an unknown number of killer whales roaming the world’s oceans, each population, or stock, is thought to be genetically distinct. “The southern residents harbor unique genetic, social and linguistic characteristics,” concludes SeaWolf’s McLaughlin, “If these orcas were to disappear completely, we won’t simply be losing a cultural and ecological cornerstone of Pacific Northwest identity – we would also be losing irreplaceable biodiversity from our seas.”
The loss of a pinnacle predator species in any ecosystem is a dramatic signal that the world’s ocean are not well. While the Canadian government listed the southern resident orcas as a “threatened species” last spring, the United States is still awaiting the data necessary to consider a similar listing for the stock in 2001. Currently, the decline continues; what is evident is that new, proactive and immediate actions must be implemented to prevent the extirpation of the southern residents altogether.
In the Haro Strait, ‘Ruffles’ and his sub-pod continue to forage freely, leaving the inland sea periodically when the seasons change, or a migration of prey draws them to the outer coasts. For generations, his clan has endured climatic and ecological changes in their home waters, returning each spring to grace the Haro Strait with their breath-taking acrobatics and haunting underwater vocalizations.
There is still uncertainly of the fate that ultimately awaits the southern resident orca community; perhaps they will recover and replenish their ranks, or perhaps some turn of the tide will change the health of the northwest ecosystem so that their clans can flourish and begin a new cycle of ecological prosperity. Yet it may also come, one spring, that the inland seas will remain, simply, silent.
What lies ahead is unknown, but one fact does remain clear – without the songs of Ruffles and others of his clan, who have roamed these coastal waters for so many centuries, the northwest will be a far emptier place.
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