It has been almost a decade since the southern variant of orca, or killer whales, was placed on the endangered species list in 2005, but they are still in trouble. Back in the 1960s the killer whales found in the Puget Sound and surrounding area numbered up to 140 by best estimates, but that numbered quickly decreased as people began hunting them down to display in marine wildlife parks. Now there are only 82 of the great predators left.
The National Oceanic and Atmospheric Administration (NOAA) recently released a study on the mammals that discussed three primary causes for their population decline. The first was the pollution that has built up in their bodies. The endangered southern orca species are at the top of their food chain, so they inevitably consume all the harmful chemicals that seep into other animals’ diets. These primarily include dichlorodiphenyltrichloroethane or DDT, which was banned back in the 1970s and polychlorinated biphenyl, or PCB, which is used primarily as a coolant in electrical apparatuses. The chemicals may not immediately affect the Orcas either, because they are often stored away in fat cells and not released until there is some kind of food shortage.
The second reason scientists from NOAA found regarding why southern orcas are still in trouble, and possibly in decline, is that the endangered species’ primary food source, Chinook salmon, is also in decline. The killer whales can tell the difference between a sockeye salmon and a Chinook salmon by detecting small differences in the fish’s swim bladder using sonar. This leads them to be very picky in what kind of dish that they eat. The fish are in decline because they are also ingesting the harmful pollutants listed above from rivers along the west coast. Those in the north, in more industrialized areas like Vancouver and Seattle, have more PCBs, and those in the more agricultural south, have more DDT, which was used as an insecticide.
That means that some orca pods have more of one type of pollutant than others because of the locations that they commonly live in. There are three main orca pods that scientists know of, J, K and J. The L and K pods are associated with DDT because they go south to feed much more often than the K pods, which stay in the northern waters of the Pacific Ocean. There is a species of northern orca whales that primarily lives in Alaska and the north coast of the United States, which some scientists think get the better portion of fish, because when a salmon exits a river they usually turn north. This species is doing much better than their southern cousins, with over 300 known whales in existence.
The third problem is boat noise. Noise from ocean vehicles makes the behaviors of the endangered species change. Laws are in place to help keep boats away from the Orcas, but they are very hard to enforce. It used to be that you had to stay at least 100 yards away from the animals, but recently that numbered has increased to 200 yards. Until recently, researchers did not know where orcas went in the colder months of the year, but using special satellite tags and acoustic monitoring systems, they have been able to track the endangered species movements as they go south down the coast. This means that laws requiring boaters to stay away from the animals have to be in place in multiple states along a coastline that stretches thousands of miles.
There are other problems that the whales face as well, such as a lack of young females to continue reproducing for future generations. Also orcas rarely wash up to shore after they have died, so scientists do not get a chance to do extensive research on how and why they may have died in the first place. Many activists hope the trend of decline can be reversed, but for now the troubled southern orca is still an endangered species.
By B. Taylor Rash
Q13 Fox Seattle