Orcas live in stable family units called pods that are comprised of up to 40+ members and led by their matriarch. Members of a pod generally stay with their mothers, hunting, playing, and living together for life. But this species isn’t as black and white as it first appears.
Scientists have also separated orcas into ecotypes. An ecotype is a distinct form or race within an animal species that occupies a specific habitat. One ecotype is genetically different from other ecotypes and has unique characteristics including body size and shape, coloration, habitat range, dietary preferences, vocalizations, and social structure. These ecotypes do not breed together even when sharing the same waters.
These differences are especially important when researching threats to the species. On the surface, it would seem the world’s orca population is thriving because they can be found in all climates eating a variety of prey. However, by studying these unique ecotypes, it’s clear to see that not all orca populations are thriving.
The Southern Resident orca is classified under the Endangered Species Act.
Despite listing this orca ecotype as endangered in 2005, the population of Southern Resident orcas has reached a 30 year low. As of January 14, 2019, the total population included just 75 individuals from three pods (J, K, and L-Pods). Until early this year there had been no successful births in this population since 2015. Researchers fear that living females will pass their child-bearing years without successful reproduction. This would create a downward spiral, driving the Southern Resident orca population into extinction.
Food is fate: Ocean plastic contributes to toxic contamination
In 2001, an international environmental treaty was signed in an effort to eliminate and/or restrict the production and use of persistent organic pollutants (POPs), a group of toxic, long-living chemical compounds that can harm both humans and wildlife. These include pesticides, industrial chemicals, and other byproducts like DDT, polychlorinated biphenyls (PCBs), and dioxins. Decades later, however, the threat to both wildlife and humanity remains.
POPs persist in the environment for long periods of time, can be transported to distant locations by wind and water, and can be absorbed by plastics in the environment. Plastics in the environment don’t biodegrade; they just become brittle and break apart into smaller and smaller pieces over time. These small pieces of plastic, called microplastics and nanoplastics, are consumed by prey species at the bottom of the food chain. These toxins bioaccumulate, or build up in the prey species’ fatty tissue over time.
As predators consume their prey, the prey’s toxic load of chemicals gets absorbed by the predator’s fatty tissue. Over time, these toxins build up inside the predator in a process called biomagnification. Higher POP concentrations are found in animals at the top of the food chain and orcas are apex predators. Researchers have found that they’re some of the most contaminated animals in the world.
Some concentrations of POPs, like PCB and PBDE, have also been shown to increase with age. In fact, concentrations of PBDEs are said to double every three to four years. Male orcas typically live for about 30 years but can live as long as 50 or 60 years. Meanwhile, female orcas typically live about 50 years but can live as long as 80 or 90 years.
Potential effects of various POPs on adult orcas include:
Orcas are mammals who nurse their young, so an even greater concern is the POP contamination that mothers are passing to their offspring. Orca milk is partially produced from the mother whale’s blubber, the fatty tissue where many of these contaminants are stored. A percentage of the mother’s toxic load is passed to her calf while it nurses. This toxic offload can cause changes in the calf’s metabolism, growth rates, and future fertility. It can also impede learning and impair memory, which means it can affect a young orca’s ability to forage for food and interact with its pod, which could also prove deadly.
Southern Residents are running out of Chinook salmon
Unlike other orcas that specialize in hunting marine mammals (like seals and sea lions), seabirds (like penguins), or cephalopods (like squid and octopus), Southern Residents have a sweet tooth for and feed almost exclusively on West Coast Chinook salmon. Research shows that up to 85% of their diet consists of salmon.
Chinook salmon are also endangered and harder to find after years of steep population declines. Many wild runs have already gone extinct. Overfishing, overuse of water resources, development, dams, and habitat loss continue to contribute to their decline.
Southern Resident orcas need to consume hundreds of pounds of salmon every day to remain healthy and survive. As the Chinook continue to disappear, they must work harder and travel longer to meet their dietary needs. Using more energy means they’re metabolizing more fat and releasing more of these toxic chemicals into their bloodstreams. This increases and amplifies the negative impacts even more. Since some POPs are neurotoxins that have the ability to disorient marine mammals, it can create a dangerous and continuous cycle that makes it even harder to find food and stay healthy.
Surface impacts, noise pollution, and other threats
As humans, we’ve placed Southern Resident orcas into an urban lifestyle. The waters they call home are extremely busy with maritime traffic. At the surface, orcas are competing with vessels for space. As air-breathing mammals, orcas must come to the surface to breathe which puts them at risk for collisions with any vessel on the water. Under the surface, noise pollution can interrupt communication between pod members and even interfere with echolocation, making it more difficult to navigate and hunt for food. Farmed Atlantic salmon net-pens in the Pacific Northwest are spreading diseases and feces into the ecosystem of critical habitat where Southern Resident orca and Chinook salmon reside. The damming of West Coast rivers has further contributed to the decline of wild Chinook salmon by blocking historical spawning grounds.
This bracelet helps raise awareness about the plight of orcas internationally. By purchasing an Orca Bracelet, you’ll remove one pound of trash from the ocean and coastlines. We’ll also donate to Orca Conservancy so we can #BeTheirVoice and help protect orca populations around the world.
In partnership with