There are many different types of sea animals on the endangered species list for many different reasons. Often, human influence such as boating accidents, fishing, coastal development, and pollution attributes to high numbers of deaths among these sea animals. Occasionally, the causes of reduction in numbers is unknown. Sea mammals such as right whales, manatees, and dugongs have reduced greatly in numbers, along with turtles, some sea birds, sharks, and salmon.
Many sea animal deaths result from human influence. Human risk is not only posed from fishing, hunting, and whaling, but also from boat accidents. This is particularly common among shallow swimming animals that breathe air, such as various types of sea mammals and turtles. Pollution may also add to the list of endangered sea animals.
Many types of sea turtles are endangered. This phenomenon often results from the danger posed to the animals' eggs. Turtle eggs are laid on land, which is often destroyed by urban development close to shores. Coastal resorts and tourist areas tend to pose a threat to many types of sea animals.
Whales are among the most notoriously endangered sea animals. Right whales and bowhead whales in particular have seen dramatic decreases in numbers and have faced critical endangerment. The number of North Atlantic right whales has reduced dramatically for reasons unknown, but it is suspected that whaling has not caused this alone. This may be a result from boat collisions, pollution, or reproductive problems among the animals.
Reasons for the decrease in numbers of manatees and dugongs is believed to be from a high number of fatal boat collisions. Due to the grayish coloration of these animals, people in boats have difficulty seeing them. Additionally, manatees and dugongs are very slow moving, and may have difficulty escaping a fast moving boat. A high number of prenatal deaths have been reported among such animals, for reasons unknown to biologists.
Various types of sea birds have become endangered, including the brown pelican. This bird, once commonly found among North, Central, and South America, has faced a great number of deaths due to eggs being crushed during incubation. The egg shells of these birds are believed to have become dangerously thin due to the use of dichlorodiphenyltrichloroethane (DDT). Since the late 20th century, many forms of DDT have been banned in the United States.
Penguins have also made it to the endangered sea animals list. As a result of overfishing, food supplies for the Humboldt penguin, found in Chile and Peru, has diminished greatly. Many deaths among these penguins have also been attributed to entanglements in fishing nets.
Salmon, while often considered a fresh water fish, are also considered part of the list of endangered sea animals. These fish spawn in fresh water, but swim out to where the rivers and streams meet the sea. A decline in water quality as a result from pollution has decreased the salmon's numbers. Water management facilities, such as dams, have also adversely affected salmon spawning.