You are what you eat鈥攁nd for orcas, that鈥檚 bad news
Researchers have known for decades that orcas across the North Pacific have harmful pollutants in their system.
Now, a reveals orcas in the western North Atlantic, including those in the Arctic, are significantly more contaminated than animals in the east鈥攁 finding that 鈥渟hocked鈥� study leader Ana茂s Remili, a postdoctoral researcher at 不良研究所, working with Associate Professor Melissa McKinney in the university's Department of Natural Resource Sciences. The research strongly points to their diet playing a major role in the level of pollutants, rather than their location.
The study looked at the presence of persistent organic pollutants, or toxic chemicals that degrade slowly and accumulate in the body, in the blubber of orcas across the North Atlantic. These pollutants, relics of industrial and agricultural processes, 鈥渉ave a nasty tendency to bind to fat,鈥� says Remili, whose study was published in October in the journal Environmental Science & Technology. These chemicals weaken orcas鈥� immune systems, disrupt their endocrine function, impede growth and brain development, and even interfere with reproduction.
Contaminants amplify as they move up through the food chain, and the orcas that consume top predators鈥攆or example, those that primarily eat other marine mammals rather than fish鈥攁re most polluted. Thanks to their high body fat and position as apex predators, orcas are some of 鈥渢he most contaminated animals on the planet,鈥� Remili says.
As climate change worsens, so might orca pollution. For instance, warmer Arctic waters may draw more orcas north, where they鈥檒l feed on high-fat marine mammals, Remili speculates.
鈥淚t tells us that we need to start acting now,鈥� Remili says. She calls on countries to destroy toxic waste sitting in warehouses around the world and prevent new contaminants from being released.
鈥淜iller whales are majestic animals,鈥� she says. 鈥淚f we don't have killer whales anymore, our ecosystems are going to be completely out of balance.鈥�