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Impacts of Marine Debris

Boat propeller fouled by discarded  fishing line

Photo Credit: Ocean Conservatory


During the summer of 1987, vacationers abandoned beaches when medical waste began washing up on the Jersey Shore. Tourists looking to escape the August heat were shocked to find hypodermic needles, pill bottles, and used gauze pads – improperly disposed medical waste from hospitals in New York – washing up on nearly seventy miles of coastline. When the tourists fled the area, New Jersey lost an estimated one billion dollars in revenues, not to mention the costs incurred by local and state governments while cleaning up the shoreline.

Crabs and fish are often caught in “ghost” nets or abandoned traps. A NOAA study found that ghost nets caused nearly one million dollars in losses to the local economy of Puget Sound between 2004 and 2007.

Floating or submerged marine debris can also be dangerous for recreational boaters and commercial shipping. A collision with a large piece of underwater debris can sink small boats, and discarded nets and lines can entangle engines and propellers.

In 2005, the US Coast Guard reported that marine debris caused 269 boating accidents, 116 injuries, 15 deaths, and three million dollars in property damage.


Birds often mistake small plastic objects for food

Photo Credit: Ocean Conservatory

Marine animals are harmed by marine debris in two ways; ingestion and entanglement.

Small pieces of floating debris are often mistaken for food by wild animals. Birds and other creatures starve to death if their stomachs fill with plastic debris, which creates a false feeling of fullness. Some birds have been found feeding plastic debris to their young.

Plastic bags are frequently found in the stomachs of many animals, including sea turtles and whales.

Entanglement is another hazard. A phenomenon known as “ghost fishing” occurs when discarded fishing gear like nets or traps are left in the water. These items continue to trap all kinds of marine life, leading to suffocation or starvation.

Marine debris can also threaten entire ecosystems.

Invasive species can use marine debris to ride across the ocean to new environments, threatening local plant and animal populations. Since modern marine debris is more buoyant and durable than natural modes of transportation like driftwood, it can increase the range of wandering species.

Marine debris can also damage the delicate ecosystems in coral reefs.