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Pollution Could Kill Half of the World’s Wild Orca Populations

PCB chemicals have been banned since the 1970s, but it’s still harming animals worldwide, including orcas.

By Jenna DeedyPublished 6 years ago 4 min read
Without direct action that would ensure a cleanup of marine habitats, or future regulations that would either ban, or place restrictions on the entry of pollutants in our world's oceans, the future of all wild orca populations, like the in the Pacific Northwest, remain uncertain., 

Around the world, many wild orca populations are affected by pollution caused by man-made toxins. These toxins are made of various chemicals that often are used on land for different purposes, only to end up in waterways through runoffs before making their way into the ocean as a form of pollution. These various chemicals include flame retardants, industrial pollutants, oils, and pesticides, and they have all been known to enter into oceanic waters through waterways and are now, having a major impact on marine wildlife, including the orcas. Speaking of orcas, a new study has recently confirmed that half of all of the known wild orca populations could be at risk of dying out as a result of exposure to the effects of toxins and ongoing pollution in various parts of the world.

While various chemicals, like PCBs, have been banned since the 1970s, they are still present in the marine ecosystem. For example, pollution can enter the marine food chain by getting sorted into the animals' body tissues once they are ingested. It can start with the zooplankton that feeds on the phytoplankton, then the krill that feeds on the zooplankton before moving on to the salmon that feeds on the krill, and finally, the orcas that feed on the salmon. This is because orcas are known to be one of the top predators of the marine ecosystem and that makes it very easy for the pollutants to become concentrated and reach dangerously high levels in their bodies. In addition, mother orcas can pass their fat-rich milk on very high doses to their newborn calves. This makes orcas one of the most contaminated animals on the planet.

PCB concentrations that have been found in orcas in Europe, New Zealand and North America are thought to be 100 times the safe level and can cause damage to their reproductive systems, resulting in the animals developing cancers, and damage their immune systems. Research done from such surveys have concluded that some orca populations could die out within the next 30-50 years if no action is taken. One population that is at risk can be found in the Pacific Northwest. There, resident orca populations in Washington, British Columbia, and Alaska are among the most intoxicated animals in the region, due to not only having to be forced to live as urban animals but also feeding on salmon that is contaminated with pollutants. Studies that have been done on these resident orca populations have shown that they have over 200 times more pollutants in their system than humans do. In Alaska, one resident orca population, known as the AB pod, are still struggling to recover thirty years after the Exxon Valdez oil spill off Prince William Sound in 1989. Several key breeding females, as well, as a number of juveniles and young calves, have died as a result of either the oil spill itself or the effects that were the result of the spill itself. Due to their slow recovery, researchers continue to monitor their slow recovery and celebrate the birth of each new calf that is born into this troubled resident orca population.

The problem with why some of these orca populations are very slow when it comes to recovery is because they actually have slower reproduction rates, even in healthier waters. For example, a female orca may sexually mature at around six to eight years old, but may not have a calf of their own for another six to twelve years, while males may not start breeding until they are eighteen years old, which is about eight years after reaching sexual maturity at around ten years of age. Meanwhile, the gestation period for orcas is about eighteen months.

PCBs, which are also known as polychlorinated biphenyls, are organic compounds that have 1-to-10 chlorine atoms attached to biphenyl, which are molecule compounds that have two benzene rings. Historically, they have been used as electrical components, plastics, and paints even though scientists have known about for about fifty years. While they have been banned in the 1970s, about 80 percent of products that have been produced with PCBs have yet to be destroyed and are continuing to leak into the oceans through waterways.

The study that explored how PCBs are effecting orca populations examined 351 wild orcas from different parts of the world by examining PCB contaminates that had been collected from the animals before looking at existing data to examine the link between PCBs, calf survival, and immune system in orcas by using it to model how orca populations could fare on a long-run. The final result showed that orca populations in the Pacific Northwest, the United Kingdom, Japan, Brazil, and Spain could be on the road to completely collapsing. However, in waters off of Norway, Northern Canada, Iceland, and the Faroes, due to the fewer concentration levels, wild orca populations in the high Arctic appear to be doing well.

Right now, the only action that needs to be taken if wild orca populations are to survive is for a global clean-up, is to be established. While it may take decades to complete, these orca populations could begin to recover and maybe, on a long run, be able to repopulate affected regions since they are one of the most adaptive mammals on Earth. People can also do their part in helping wild orcas by reducing, reusing, and recycling, cleaning up garbage on beaches, buy organic plants and food to reduce the use of pesticides, use biodegradable products, and finally, dispose of any paints, thinners, and oils to prevent them from ever going down in drainage systems.

wild animals

About the Creator

Jenna Deedy

Zoo and Aquarium Professional, Educator, Cosplayer, Writer and B.A. in Psychology whose got a lot to share when it comes to animals, zoos, aquariums, conservation, and more.

Instagram: @jennacostadeedy

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