Fish
Saltwater fish are important parts of the underwater ecosystem. However, many are listed as endangered. At the top of the food chain are the sharks. The basking, great white, oceanic white-tip, angel, silky and hammerhead sharks are some endangered subspecies. The smalltooth sawfish, which is similar in appearance to a shark, is another type of endangered fish. It's endangered due to overfishing, as its liver oil is used in medicines. It isn't just large fish species that are in danger. Small fish, like the Atlantic salmon, totoaba, steelhead trout, shortnose sturgeon and coha salmon, are also endangered.
Large Mammals
The saltwater biome has large mammals under threat from extinction. Whales are found in every ocean in the world. Several subspecies of whale have fewer than 400 left in the wild. Examples of these include the western Pacific gray, north Atlantic right and bowhead whales. Death by oil spills, boat accidents and whaling have threatened these species' survival. An endangered large mammal of the Arctic Circle is the walrus. The walrus can weigh up to one-and-a-half tons. Overhunting in the 18th and 19th centuries has severely reduced its numbers in the wild. Also, the manatee is found in coastal waters on both sides of the Atlantic. The slow-moving, herbivorous animal is vulnerable to hunters and boat accidents.
Small Mammals
Small mammals found across the saltwaters of the world are also endangered. Pinnipeds, which are more commonly known as seals and sea lions, are classed as endangered. Subspecies like the Hawaiian monk seals and the steller sea lions are both endangered as a result of overfishing. Other smaller mammals who are related to whales are porpoises. The Vaquita, Dall's and Harbour porpoise are the most endangered species. Porpoises are vulnerable to noise pollution and overfishing.
Reptiles
There are numerous endangered reptiles that spend their time in saltwater. The saltwater crocodile is native to southeast Asia and northern Australia. An adult male can grow up to 21 feet long. The animal is a formidable ambush predator. The crocodile's population has decreased particularly in Indonesia and Malaysia. Another type of endangered saltwater animal is the marine turtle. All seven of the subspecies are listed as endangered. They are the flatback, green, hawksbill, loggerhead, leatherback, Kemp's Ridley and Olive Ridley. Turtles live in open and coastal waters, including the Pacific, Indian and Atlantic Ocean. A turtle's survival rate is low due to predators, and human hunting.
Invertebrates
It is estimated in 30 years time that 30 percent of the coral reefs will be extinct. Coral reefs are made up of polyps, a type of underwater invertebrate. They are found in vibrantly-colored reefs in tropical waters, including the Pacific and Indian Oceans. Coral polyps are translucent animals that get their coloring from algae growing on them. The polyps are at risk from pollution and a change in water temperature due to global warming. Endangered coral includes acropora, cauliflower, knob, birdsnest, starry cup and whisker coral.