What are the impacts of marine debris?

How does marine debris impact wildlife?

Marine debris causes a lot of problems for people and wildlife. Marine debris impacts an estimated 700 wildlife species, including coastal vegetation, plankton, invertebrates, fish, whales and dolphins, sea turtles, and seabirds. Because there are so many parts of the ocean that humans have not yet explored, there may be thousands more species being impacted by debris that we have not yet identified!

Whales, turtles, and other species become tangled up in fishing nets and plastic packing bands. These types of debris may wrap around animals, sometimes cutting into their bodies and making it difficult for them to swim, breathe, or eat. Lost fishing gear freely floating in the ocean can continue to trap fish and other animals for many months or even years.

Marine debris also impacts wildlife through ingestion. This is when an animal swallows debris. When this happens, the debris can block their stomach, puncture the inside of their bodies with sharp edges, and even create a false sense of being full. This can make the animal ill or cause it to starve. Some animals may mistake marine debris for their prey. For example, turtles may confuse plastic bags for one of their favorite types of food—Jellyfish! As plastic debris breaks up into smaller pieces, it is easier for smaller species, such as zooplankton, to consume it.

But small debris is not the only problem. Large debris—including lost fishing gear, boats, and appliances—can crush and smother sensitive habitats, such as coral reefs or seagrass beds.

Some marine debris can even pick up “hitchhikers” and transport non-native species. These are organisms that attach themselves to marine debris and travel to areas where they otherwise would not be found. For example, after the 2011 tsunami in Japan, marine debris began washing up on shorelines along the Pacific Coast of the United States and Canada. In 2012, a floating dock that was dislodged from the Port of Misawa in Japan during the tsunami washed up on the shores of Oregon. The dock was covered in more than 400 pounds of animal and plant life, representing a community of 60 species native to coastal Japan, including wakame kelp, a known invasive species on the West Coast of the United States.

How does marine debris impact people?

Marine debris not only harms wildlife and ecosystems, but also our economy. Marine debris littered beaches degrade the beauty of the environment and deters tourists from spending their time and money in coastal communities that rely on tourism. Local governments and volunteer organizations also have to spend their limited resources, including taxpayer dollars, to clean it up.

Marine debris can also harm commercial and recreational fishing. Lost fishing gear damages fish habitats, creates safety and navigation hazards, and continues to catch species (a process known as “ghost fishing”). This results in lost catch opportunities and financial loss for fishers. A study published in 2016 found that 3.3 million blue crabs are killed every year in derelict crab pots in the Chesapeake Bay, in addition to many other animals that are not even the target of the traps. The study found that removing some of those derelict pots in blue crab fishing areas would increase the harvest of the crabs by 38 million pounds and result in a $33.5 million increase in revenue (according to prices at the time of the study).

Marine debris can also be harmful to human health. Debris that is sharp or contains hazardous substances can hurt people at play or in the water. There could also be plastic in the seafood we eat. However, the health risks associated with different plastics and chemicals to people are still unknown.