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How Does Marine Debris Impact Marine Wildlife?
NAMEPA
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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