Which Coast Has the Most Endangered Marine Life?

Oceans cover over 70 percent of our planet. Given that fact, it’s kind of incredible that the United States is home to 94 of the 157 worldwide endangered marine species. Endangered species are protected by the Endangered Species Act of 1973, which preserves not only threatened and endangered animals, but the ecosystems they live in.

If you live on the Atlantic or Pacific coast, endangered marine life is abundant. But which coast has more endangered species? Let’s find out.

Coastal Differences

The United States is surrounded by the two largest oceans on Earth, which is a big reason why we’re home to so many endangered species. Marine animals are constantly traveling throughout these vast oceans. In fact, ice breakdown in Northern Canada recently opened a passage, which has enabled some animals to travel freely between the two oceans into places they’ve never been before. But this atypical migration isn’t alway good for them. The Atlantic and Pacific Oceans provide very different habitats, and therefore draw different species.

The Atlantic Ocean is about half the size of the Pacific, and its currents flow south to north. It’s home to the Mid-Atlantic Ridge, the longest underwater mountain range in the world. It encompasses the warm waters of the Gulf Coast all the way to the chilly waters off the Maine coast. The Pacific Ocean is the largest in the world, covering about 30 percent of Earth’s surface. Its currents flow north to south along the U.S. coastline and include arctic regions along the Alaskan coast and tropical regions surrounding the Hawaiian Islands.

Atlantic Species

There are about 15 endangered marine species along the Atlantic coast, which fall into three categories:

Fish: Namely the Atlantic and shortnose sturgeon and the smalltooth sawfish, found along the mid-Atlantic coast. Sturgeon range from four to 14 feet. They’re black or brown with five rows of exposed bone running down their backs. They’re endangered mainly due to human intervention like the construction of dams, overfishing, and pollution leading to habitat degradation. The smalltooth sawfish, found along the south Florida peninsula, looks like a mash-up of a shark and a stingray with a long, saw-like snout. The sawfish is endangered because their snout makes it easy for them to get caught in fishing nets and they often die before being released.

Turtles: The Atlantic is home to the hawksbill sea turtle, Kemp’s Ridley sea turtle, and leatherback sea turtle. The hawksbill and Kemp’s Ridley sea turtle range from 100 to 150 pounds, while the leatherback sea turtle weighs in at a massive 200 pounds. Hawksbill sea turtles are mostly found near healthy coral reefs, so degeneration and bleaching of coral are a primary cause for their endangered status. The kemp’s ridley and leatherback sea turtles are endangered because of egg harvest and incidental capture in fishing nets.

Whales: Whales make up the majority of the endangered species in the Atlantic. Most of the whales in the Atlantic can be found worldwide, except the North Atlantic right whale. They’re large baleen whales, measuring in at about 50 feet, who spend summers off the New England coast and migrate south in the winter. Their endangered status is mostly thanks to human interaction like the collision with ships, fishing entanglement, and pollution.

Pacific Species

There are about 30 endangered marine species along the Pacific coast, which fall into five categories:

Fish and mollusks: The bocaccio rockfish is the only endangered fish along the Pacific coast. They’re mainly endangered due to fishing. The black and white abalone are small mollusks found wedged between rocks deep along the California coast. Their main threats include harvesting and pollution.

Turtles: The Pacific is home to all the turtles found along the Atlantic coast and then some. Olive Ridley sea turtles and Loggerhead sea turtles are all unique to the Pacific coast. The Olive Ridley sea turtle is considered the most common turtle in the world while the Loggerhead has a much more limited habitat. They’re both endangered due to fishing activity.

Whales: Endangered whales in the Pacific are abundant. Most of the whales unique to the Pacific can be found in the colder waters of the Northern Pacific, including the ever-popular killer whale. All of the endangered whales along the Pacific coast are threatened by ship strikes, fishing entanglement, and pollution.

Sharks: The scalloped hammerhead shark ranges from five to 11 feet long and lives off the California coast. Their main threat is fishing and shark fin trade. Shark finning has been illegal in United States waters since 2000, but buying and selling shark fins is still popular internationally.

Seals and sea lions: Alaska and Hawaii are home to the endangered stellar sea lion and Hawaiian monk seal, respectively. The Hawaiian monk seals are some of the rarest mammals in the world and are endangered due to limited food supply and beach erosion. Both the stellar sea lion and Hawaiian monk seal face threats of human interaction and pollution.


The Pacific may be home to more endangered marine life, but ocean conservation is essential along both coasts. Human interaction like fishing and pollution are recurring threats to endangered species, so we need to do our part to reverse the damage we’ve already done. Protecting endangered animals and their habitats are critical to their future and ours.

The Pegasus Foundation exists to protect and support animal welfare through grants and education, partnering with non-profit organizations to share resources, educate the public, and facilitate communication. For more information, please contact the Pegasus Foundation directly.