How Does Marine Debris Impact Marine Wildlife?

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Marine debris can have serious impacts on both marine wildlife and humans.

Debris can entangle, maim, and even drown many wildlife species.

Animals can also mistake some debris for food; once ingested, these materials can cause starvation and/or choking.

Although almost any species can be harmed by marine debris, certain species – including seals, sea lions, seabirds and sea turtles – are more susceptible to its dangers than others.

TWO Main Threats to Marine WildlifeThe two primary threats that marine debris

poses to marine wildlife are entanglement and ingestion.

EntanglementSome entanglement occurs when the animal is

attracted to the debris as part of its normal behavior or out of curiosity.

Entanglement is harmful to wildlife for several reasons: It can cause wounds that can lead to infections or

loss of limbs. It may cause strangulation, choking, or suffocation. It can impair an animal’s ability to swim, which

may lead to drowning, or make it difficult for the animal to move, find food, and escape from predators.

IngestionIngestion occurs when an animal swallows

marine debris. Ingestion sometimes happens accidentally,

but generally animals ingest debris because it looks like food

Ingestion can lead to choking, starvation or malnutrition if the ingested items block the intestinal tract and prevent digestion, or accumulate in the digestive tract and make the animal feel “full”

Do you know what Threatened or

Endangered species are?

Endangered and Threatened SpeciesEndangered species: A species of animal or

plant that is in immediate danger of becoming extinct.

Threatened species: A species whose numbers are low or declining. A threatened species is not in immediate danger of extinction, but is likely to become endangered if it is not protected.

Marine debris can pose significant threats to

threatened and endangered species.

Affected Animals

Marine mammals, sea turtles, birds, fish, and crustaceans all have been affected by marine debris through entanglement or ingestion.

Unfortunately, many of the species most vulnerable to the impacts of marine debris are endangered or threatened.

A conservative estimate is that more than 100,000

marine mammals die every year from entanglement or ingestion of marine debris.

Of the different types of marine mammals, seals and sea lions are the most affected (primarily by incidents of entanglement) because of their natural curiosity and tendency investigate unusual objects in the environment

Fishing nets, fishing line, ropes, plastic sheeting and packing straps can be major problems for these animals.

Sea Turtles and DebrisAll six species of sea turtles found in the United

States have been found entangled in different types of marine debris, such as fishing line, rope and fishing nets.

however, ingestion of debris is an even greater problem for these species, as they are indiscriminate feeders.

Sea turtles have swallowed plastic bags because they look like jellyfish, one of their favorite foods.

Cases of turtles swallowing balloons, tar balls, and other debris that has become encrusted with algae and other marine forms have also been reported

Seabirds and Debris

Thousands of seabirds are thought to die from entanglement or ingestion each year. Since many seabirds feed on fish, they are often attracted to fish that have been caught or entangled in nets and fishing line.

Unfortunately, when birds prey upon entangled fish, they can become entangled themselves.

Entanglement in fishing line has been a particular problem for the brown pelican, which has been listed as an endangered species.

As many as 100 birds have been found in a single

abandoned net

Fish, Crustaceans and DebrisFish and crustaceans (such as lobsters and

crabs) are frequently caught in lost or discarded fishing nets and fishing line (also referred to as derelict fishing gear). This phenomenon is known as ghost fishing

Here are some animals that could be harmed

by marine debris

Giant Squids Architeuthis dux

• Largest invertebrate ever known to exist• Average 3-9 meters long• Largest eyes out of any animal

• Eat deep sea fishes and other squid species• Sperm whales and sleeper sharks are two known

predators

Moon Jellyfishes Aurelia aurita

• Range from 5-40cm in diameter• Swim horizontally• Found near the coast in warm and tropical waters• Occur in large numbers• Feed on zooplankton

Tiger Shark Galeocerdo cuvier• One of the largest sharks

in the world• Gray with tiger-stripe

markings• Found worldwide in

temperate and tropical seas• Widest variety in their diet

out of all shark species• Can be curious and

aggressive

Saltwater Crocodiles Crocodylus porosus• Largest living reptiles• Jaws contain between 64-68

teeth• Intelligent• Communicate with barks• Found on coasts of northern

Australia• Feed on cabs, turtles,

snakes, birds, buffalo, wild boar, and monkeys• Females lay between 4o-60

eggs• Harvested for their skin• Populations in some

countries are declining

Blue-ringed Octopuses Hapalochlaena maculosa

• Bright blue rings appear when alarmed• 5-10cm long (size of golf ball)• Deadliest of all cephalopods• Venom is 10,000 times more toxic than syonide• Powerful beak-like mouth

• Found in coral reefs and tide pools in Southern Australia

• http://www.youtube.com/watch?v=SNxJwCGJtsA

Atlantic Bluefin Tuna Thunnus thynnusOne of the largest bony

fishesDark blue and black with

silver belliesLive in subtropical and

temperate waters of the Atlantic Ocean, the Mediterranean, and Black Seas

Feed on smaller fishVictim of overfishing

Loggerhead Sea TurtlesNamed after large headsDive for 4 to 5 minutesBreath holding ability

affected by stress Can sleep underwater for hours,

but need air every few minutes under activity

Found in Atlantic OceanFeed on jellyfish, mollusks,

egg clusters, squids, and flying fishes

Live to be over 50 years old

Coral ReefsShelter marine life, used in

medicines, create recreation for humans, create sand for beaches, and serve as buffer for shoreline

Built by coral polyps (small animals similar to jellyfish)

Hard corals, soft corals, sea fans, tropical coral reefs

Extremely sensitive to environmental changes

Spinner Dolphins Stenella LongirostrisPerform playful stuntsDifferent shades of grayInhabit waters off the west

coast of central AmericaFeed at night on small fish

and squidPredators include sharks

and killer whales Often caught in fishing nets

Harp Seals Pagophilus groenlandicusLatin name translates to “ice

loving seal of Greenland”Baby seals have yellow coatsLive in waters of the Arctic

and Northern Atlantic OceansDiet of fish and crustaceansPredators are polar bears,

killer whales, and sharksHunted for their coats

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