Marine mammals are predators. Depending on their position in the food chain, chemical pollutants build up in varying degrees in the body. This is the phenomenon of bioaccumulation.
Large predators, at the top of the food chain, will build up increasing amounts of fatty tissue over the course of their lives.
Pollutants such as heavy metals, hydrocarbons, pesticides and other organic pollutants will cause endocrine disruption, affect fertility and degrade the renal, cardiac and respiratory systems. But it should not be forgotten that while they affect marine mammals which are protected, they also contaminate species consumed by humans!
Physical pollution, especially plastic in the form of waste of various sizes, has also spread to our oceans.
Although waste management is currently a major concern, millions of tons of waste are released into the environment each year. The majority of plastics polluting the oceans come from the land and are transported by rivers or air, the other part come from marine activities.
Plastics have a physical impact on marine mammals that ingest it or become entangled (in abandoned fishing nets, for example), and also a chemical impact by slowly decomposing in the marine environment. The ingested waste can obstruct the digestive system and prevent the animals from feeding.
If the animal doesn't die from its injuries, it can starve to death
Did you know?
In 1997, a floating mass of plastic waste was discovered in the northeast Pacific Ocean. It is almost 6 times the size of France.
Banner photo credit: L'Ecovoyage d'Arvik