10 Most Endangered Marine Species

From sharks to sea turtles, here’s a look at the 10 most endangered marine species and the efforts being made to protect them.

Jun 18, 2024byLauren Rey
most endangered marine species

The world’s oceans are filled with extraordinary creatures–from the largest whales to the smallest dolphins! Sadly, many of them are in danger of extinction due to many human-caused factors like pollution, overfishing, and poaching. Conservation organizations around the world are working to identify key species in need of protection and enact plans for a path to recovery. Here’s a look at the 10 most endangered marine species and what is being done to protect them!

1. Whale Shark

whale shark
Image credit: Traveling Canucks

Whale sharks are found in tropical waters throughout the world but are increasingly becoming more endangered due to hunting and tourism. Although a fascinating shark species, whale sharks are known as “gentle giants”. They are typically slow-moving and feed only on plankton.

Beyond being hunted themselves, whale sharks are often caught in illegal ocean fishing nets intended for other species. The whale shark tourism industry, which typically involves groups snorkeling or diving with whale sharks, has also interfered with whale shark feeding and breeding habits, thus further contributing to their decline.

The World Wildlife Foundation is leading efforts to study whale sharks, promote conservation, and educate tour operators and tourists interactions with the sharks.

2. Hector’s Dolphin

hectors dolphin
Image credit: Shutterstock

Hector’s dolphins are the smallest dolphins in the world–reaching lengths of only about four feet. Found only in the waters off the coast of New Zealand, these small cetaceans are also one of the rarest.

Hector’s dolphins were officially added to the endangered species list in 2017, but their numbers have been decreasing for quite some time. Often victims of fishing net entanglements and boat strikes, the biggest threat to these dolphins is the fishing industry.

The World Wildlife Foundation as well as local conservationists have been working with New Zealand officials to protect Hector’s dolphin habitats. Banning specific types of fishing nets and reducing fishing in certain areas are two measures they are hoping will help the species recover. Losing Hector’s dolphin would be a tragedy, as these dolphins help support their ecosystem.

3. North Atlantic Right Whale

north atlantic right whale
Image credit: WKGC

Driven almost to extinction by the whaling industry almost a century ago, the North Atlantic right whale species has never been able to fully recover. They are one of the most endangered marine species and have been of the endangered list since 1970.

Although whaling is no longer a threat, an already reduced North Atlantic whale population now faces dangers from the fishing industry. Fishing net entanglements and boat strikes are the top causes of death among these whales.

There are only around 350 North Atlantic right whales left in their native Atlantic Ocean. NOAA has designated two areas of protected waters along the Atlantic coast believed to be critical feeding and breeding grounds for these whales.

4. Sea Otter

sea otter
Image credit: KRCR

Although they’ve been internationally protected since 1911, sea otters have never been able to recover from near-total decimation from the fur trade of the 1800s. These adorable little marine mammals have the densest fur of any animal on earth! This unfortunately made them highly sought after by hunters. They’ve been on the endangered list since 1977.

Sea otters live in their native Pacific coastal environments. They keep sea urchin populations in check that could otherwise damage kelp forests. Sea otter protection and recovery is crucial to their native ecosystems.

The California Sea Otter Fund helps drive legislation, protection, and scientific research to further sea otter conservation efforts.

5. Blue Whale

blue whale
Image credit: TheSeaCleaners

The majestic blue whale is the largest animal not only in our oceans but on Earth! Sadly, it is one of the most endangered marine species. Like many other endangered whale species, the blue whale first saw a population decline around the peak of whaling operations in the 1800s.

Today, blue whales are threatened by pollution, boat strikes, and fishing line entanglements. The Blue Whale Recovery Plan outlines steps to study and support the population with hopes of being removed from the endangered list one day.

6. Hawaiian Monk Seal

hawaiian monk seal
Image credit: Maui Magazine

Hawaiian monk seals are the most endangered species of seal in the world with only around 1,500 remaining. Beloved in their native Hawaii, these intelligent seals are often referred to as “Īlio-holo-i-ka-uaua” which translates to “dog that runs in rough water”. They can often be seen lying on the shores or playing in the surf of Hawaiian beaches.

There are many factors that play a role in the declining population of Hawaiian monk seals. Habitat loss, fishing line entanglements, and food scarcity are among the top reasons.

Conservation efforts by Hawaiian officials are underway, including habitat protection, redistributing seals to areas with more foraging opportunities, and monitoring for fishing line entanglements.

7. Bluefin Tuna

bluefin tuna
Image credit: Fox News

The bluefin tuna is the largest of all tuna species reaching weights upwards of 1,000 pounds! Sadly, they are also one of the world’s most endangered fish. Decreasing bluefin tuna populations can be detrimental to ocean ecosystems as they are considered a top predator on the food chain.

Threats to bluefin tuna come from overfishing. They are considered a culinary delicacy and can pull a high price tag at fish markets. Both commercial and unregulated fishing operations for bluefin tuna are contributing to declining populations.

The Center for Biological Diversity has launched a “Let Bluefin Tuna Off The Hook” campaign to increase public awareness on the plight of the bluefin tuna. The hope is to drive down demand for the fish and keep it off menus worldwide.

8. Fin Whale

fin whale
Image credit: Wikimedia

Fin whales are the second largest whale species found in oceans today, smaller only to their blue whale cousins. Like all endangered whales on this list, fin whale populations were greatly impacted by the whaling industry in the 1800s and have never recovered.

While whaling is no longer a threat, an already reduced fin whale population now struggles due to other threats. Boat strikes, fishing line entanglements, and a lack of food due to overfishing all contribute to the continued decline of fin whales.

Plans to address fin whale threats and promote more sustainable fishing practices that won’t impact whales are being implemented by NOAA and other conservation organizations.

9. Hawksbill Sea Turtle

hawksbill sea turtle
Image credit: Milwaukee With Kids

The hawksbill sea turtle is the most endangered of all sea turtle species, driven by demand for their ornate shells. Disruption to these turtles’ nesting habitats caused by both humans and nature are also a factor in their declining population.

Conservation efforts have been underway for quite some time with hawksbill sea turtles being recognized as a protected species and critical nesting habitats being monitored. Sea turtle rehabilitation programs are also operational around the world. Sea turtles can be treated for injuries such as boat strikes and fishing line entanglements and then returned to the ocean.

10. Vaquita

Image credit: World Wildlife Fund (WWF)

The vaquita porpoise sadly holds the title of the world’s most endangered marine mammal. Driven to the brink of extinction by the illegal fishing trade, vaquitas are considered critically endangered with less than 20 left.

Vaquita numbers have been declining rapidly since the 1970s due to illegal fishing operations in the California Gulf. They often become caught in nets and die of suffocation when they cannot return to the surface.

Operation Milagro by The Sea Shepherd has been fighting for the vaquita for years through direct patrolling of the waters and removing illegal fishing nets. It also works directly with government organizations to combat illegal fishing operations.

Lauren Rey
byLauren Rey

A lover of all animals, Lauren’s background is in the veterinary world, but she is now a content writer on travel, wildlife, and all things pets! She’s based in Florida, but when not writing, she’s usually plotting out a new road trip route with her partner-in-crime. Pickles is a mixed-breed rescue dog that loves hiking, road trips, and Starbucks just as much as her mom does!