Saturday, April 18, 2009

How we've poisoned the killer whale

Many of us became familiar with the killer whale through various corny films, such as the Free Willy series, which often depict the whales being threatened by evil, oil-spilling businessmen or careless fishermen leaving their nets around. In reality, however, the status of the killer whale remains threatened due to a variety of factors which work in ways far more sinister than those of the aforementioned characters. A new study published in Environmental Toxicology and Chemistry has revealed that the declines in the northern and southern populations of killer whales found along B.C.'s coast can be attributed to environmental contaminants known as persistent organic pollutants (POPs). These contaminants accumulate in salmon during their time at sea, and subsequently become integrated into the systems of killer whales, which primarily consume salmon. Despite having been regulated, major POPS such as DDTs (pesticide) and PCBs (found in electrical capacitor and transformer fluid) are found in the highest concentrations within analyzed killer whale tissue. This is because any remaining residues of DDTs and PCBs continue to enter the ocean via terrestrial runoff, a process by which rain combines with and carries contaminants into the ocean. It is also important to note that while industrialized countries such as Canada and the USA have regulated the use of these POPs, with DDTs being banned 30 years ago, and PCBs being limited in their use, these practices have not been adopted universally. Many developing countries still continue to use these chemicals, which subsequently enter nearby bodies of water, eventually reaching the Pacific in less than five to eight days. Meanwhile, another threat looms on the horizon: another type of POP called PBDE (found in flame retardants) has been found to cause endocrine disruption as well as liver and thyroid complications in other marine organisms such as seals and is postulated to have similar effects on the killer whale. This POP has been found in moderate concentrations in the tissues of southern resident whales and will likely increase as this contaminant is not yet regulated. While a single salmon usually isn't chock full of POPs, and isn't in itself likely to poison a killer whale, because POPs characteristically remain within the fatty tissues of marine organisms over a lifetime of 50 to 70 years (as typical for a killer whale), the whale will eat enough salmon for significant levels of POPs to accumulate and effect its longevity. The effects of such elevated concentrations of contaminants include skeletal abnormalities, endocrine and immune system disruption, liver damage, as well as reproductive impairment. These effects are especially apparent in newborn calves and the southern resident killer whales. Calves have been found with particularly high concentrations of POPs in their systems, as these are passed on to them from their mothers at birth, and continue to accumulate as they are nursed with contaminated milk. As a consequence, about 43 percent of calves die within their first six months. Southern resident whales, whose range extends to the waters of California, are particularly prone to having high levels of POPs because of their feeding behaviors. Salmon in the southern waters carry higher amounts of POPs (southern waters being up to four times more contaminated than northern waters), and because these salmon have depleted fat stores, which they have used on their journey back to their streams, killer whales compensate for the lack of nutrition by consuming larger volumes. This has contributed to accelerated rates of decline for the southern residents which have decreased by 17 percent to 81 individuals since 1996 as compared to the northern residents which sit at 205 individuals, having declined 7 percent since 1997. It is estimated that it will take 30 years for the northern residents to recover from the effects of POPs, the southern residents closer to 60. So what is being done about the dire situation of the killer whales? Currently, a Recovery Strategy for B.C. resident killer whales has been developed by the Canadian government, and an American strategy for southern resident whales is expected to be released soon as well. However, this can always remain a case of all talk and no action. The government seems to be particularly prone to this; for example, this strategy was due to have come out in 2006, but only made its debut this past March after a threat of legal action by Ecojustice, a nonprofit environmental law organization. It has been stipulated that this delay has been due to Canadian military interference, which did not want the critical habitat of the killer whale identified in the strategy, seeing as it uses it for military sonar testing. Military sonar has been widely found to be damaging to marine organisms, its high frequency being found to harm the sensory organs and disrupt communication. Although the current strategy has identified critical habitat, the Department of Fisheries and Oceans has yet to formally declare protection of critical habitat of the killer whales under the Species at Risk Act. One can only wonder how long it will take for this strategy to even be implemented, and if, at that point, it will even be effective. As of today, the northern resident killer whales have a designated "threatened" status, while the smaller southern population has slipped to a more dire "endangered" status. What this illustrates is that there is never a "quick fix" for environmental damage. That is, we can't undo the effects of years of pesticide use and pollutant exposure overnight. In the meantime, the Earth and its wildlife continue to pay for our mistakes, or sometimes, more accurately, our carelessness. Due action has been, and continues to be, impeded by political and business interests—the unenforced Recovery Strategy and the nonexistence of any regulation to limit the serious threat of PBDEs illustrate that in many circumstances, the environment is not seen of high importance. It is quite disheartening to learn that this is still continuing, especially when we are just starting to feel the consequences of not caring for our planet. Aman Sundher is a biology student at Simon Fraser University.

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