Common Threats Facing Marine Mammals and How You Can Help
Written by Carleigh Stokes
Stranded humpback whale along the coast of Long Island, NY. Featured photo courtesy of AMSEAS.
There are many factors that impact the populations of marine mammal species worldwide. The shift in these animals’ habitat over time has promoted adaptability and resilience among them, as conditions are always changing. Even still, many of these animals continue to face increasing mortality rates due to a variety of threats. These threats can be broken down into anthropogenic threats (caused by human activity) such as vessel strikes and entanglement, and non-anthropogenic threats such as bacterial infections and parasitic abnormalities/infections.
A vessel strike is when a marine vessel or its propeller cuts and/or injures a marine mammal. Lacerations and other injuries of this kind can inhibit the animal’s ability to swim, lead to fatal infection, make the animal susceptible to predators, and cause many more difficulties that may ultimately lead to the animal’s death. Marine mammals such as whales are more prone to vessel strikes, as they need to surface to breathe and are large in size. Along the west coast, approximately 80 whales die every year from vessel strikes.
In addition to vessel strikes, other substantial human-induced threats impacting marine mammal populations include plastic pollution and fisheries interactions. The nearly 640,00 tonnes of plastic that enters the ocean every year can impact marine mammals through consumption and/or entanglement. Approximately “54% of the world’s dolphin, whale and porpoise species have consumed plastic,” and that statistic continues to grow every year. Consequences for marine mammals that ingest plastic include choking, internal injuries, and starvation, as some animals think they are full.
In the Atlantic region, a variety of whale species, such as humpback and blue whales, have faced entanglement in commercial fishing gear. According to the International Whaling Commission, “over 300,000 whales and dolphins die annually due to entanglement in fishing gear.” Gill nets also pose a threat to marine mammals, and sea turtles. These nets are vast and spread along the water column to trap large fish such as tuna salmon, commonly purchased in the commercial fishing industries. Many marine mammals and other species cannot see these nets in time to move out of their way and become trapped or entangled in them, leading to physical injuries and sometimes death.
Numerous species, including humpback whales, fin whales, harbor porpoises, bottlenose dolphins, common dolphins, sea lions, and gray seals, are threatened by these nets as they are commonly caught within them. Ghost gear poses an additional threat of entanglement to marine life. Ghost nets are defined as, “fishing nets that have been lost or abandoned in the ocean,” and account not only for entanglement and entrapment, but also for plastic pollution in the ocean and marine mammal ingestion. These entanglements can lead to starvation, infection, and drowning, as marine mammals are unable to reach the surface to breathe.
Since 2017, the Atlantic Marine Conservation Society has responded to nearly 1,085 marine animals, including 66 whales, in a stranding network with other conservation organizations along the Northeastern coastline. For every deceased marine mammal, our team conducts a necropsy, otherwise known as an animal autopsy, to learn more about the animal and how it lived in its environment, along with the cause of death. Some of the most common causes of death we’ve seen in marine mammals we’ve responded to are vessel strikes, marine debris ingestion and entanglement, along with natural causes, such as disease and parasites.
We encourage you to recycle and participate in beach cleanups near you. AMSEAS hosts weekly beach cleanups at many local and state parks in the Long Island area. You can view our upcoming events calendar here. Next time you are at a beach or park, try to pick up a piece of trash when you see some on the shore. It could save the life of a marine mammal as it's one less piece of waste in their habitat.
Other important things you can do to help decrease the threats marine mammals face every day include educating yourself and others on the importance of vessel safety by being mindful of those you are sharing the space with below the surface and keeping a lookout for marine mammals and sea turtles that are close to the surface and/or appear in distress. The more in control you are on the water and the higher awareness you have, the less likely you are to injure yourself, others and the marine animals in the water. Other beneficial things you can do to lower threats to marine mammals include to avoid using single-use plastics and report any marine mammal strandings to the New York State Stranding Hotline, (631) 369-9829.
Carleigh Stokes is an intern at AMSEAS working with our Business and Public Relations team.