Fishermen catch bluefin tuna
"There are many other fish in the sea," the cliché says. But is there really one? According to the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, 1,616 species of fish are endangered; Another 989 are endangered and 627 critically endangered. While habitat loss and pollution are significant factors in the decline of these species, by far the biggest threat is overfishing.
10: Atlantic halibut
Atlantic halibut is often the victim of bycatch in bottom trawling fisheries.
The Atlantic halibut is found in the New England/Mid-Atlantic region and is the largest flounder. It has a life of 50 years, can reach a length of 4.5 meters and weighs up to about 318 kilograms. But because this slow-growing fish doesn't mature sexually until it's 10 to 14 years old, it's particularly vulnerable to overfishing. Although Atlantic halibut are usually caught with hooks and lines, they are often caught as bycatch in bottom trawl fisheries. The IUCN lists them as endangered, and their numbers are not expected to recover in the near future. According to the National Oceanic and Atmospheric Administration, stocks of Atlantic halibut are at very low levels.
9: Beluga sturgeon
Beluga sturgeon is overfished for its popular roe.
While beluga sturgeon is popular for its fillets, its eggs are known as "real caviar" and are considered a delicacy. Native to the Caspian Sea, these ancient fish date back more than 200 million years, reach a length of up to 7 meters, weigh more than 1,588 kilograms, and live up to 100 years. Because of their egg popularity, they are severely overfished – often with gill nets – which is a major threat to the species. This is especially problematic because males reproduce for the first time at age 10-15, while females breed for the first time at 15-18 years of age, with an estimated generation length of 20-25 years.
In addition to fishing pressures, beluga sturgeon have suffered from habitat loss, losing 90% of their historic spawning grounds over the past few decades. As a result of these pressures, the IUCN classifies beluga sturgeon as critically endangered, and its population is expected to continue to decline. Statistics show that 573 tons were captured in 1992 and 36 tons in 2007, a 93% drop in catch. According to the World Wildlife Fund, 7,000 farm-raised small sturgeon were released into the Danube in 2020 to help reverse this declining trend.
8: Southern bluefin tuna
Due to the worldwide popularity of sushi, bluefin tuna has been heavily fished since the 1950s.
Southern bluefin tuna is found in the Atlantic, Indian and Pacific Oceans. They can reach a length of up to 2.4 meters, weigh up to 260 kilograms and live at least 40 years. The IUCN lists southern bluefin tuna as critically endangered because estimated spawning biomass declined by about 85% between 1973 and 2009. Due to the worldwide popularity of sushi, the species has been heavily fished since the 1950s. If current fish development continues, it is estimated that the population will drop below 500 within 100 years.
7: Orange Roughy
Orange salmon can live up to 140 years
The orange rough has a wide range of habitats, including New Zealand, Australia, Namibia, and the coasts of the Northeast Atlantic and Indo-Pacific. Its life expectancy can exceed 140 years and reach the age of sexual maturity between 20 and 32 years, making it the epitome of a species that is naturally vulnerable to overfishing. When fish gather to feed and reproduce, fishermen tend to trawl orange sea bream, exacerbating overfishing pressures. The resulting catch wiped out generations. Orange char is peeled and sliced, sold fresh or frozen, and is considered a delicacy in American restaurants. Although the IUCN has not formally reviewed the species to determine if it is endangered, many other organizations have recognized a significant decline in its numbers after only 25 years of commercial fishing. They can reach a length of 76 cm and weigh up to 6.8 kg.
6: Nassau Grouper
Nassau grouper lives in the tropical and subtropical waters of the western North Atlantic. This fish can grow up to 1.2 meters long, weigh up to 25 kilograms, and live up to 29 years. Nassau grouper is highly valued by commercial and recreational fisheries, which means that spawning populations are harvested in large quantities, which has led to serious declines in most countries. More than 30 of the 50 known aggregates in its range have disappeared. This devastating decline has earned the Nassau grouper critically endangered status by the IUCN.
5: Red Hand Fish
The red-handed fish was once found in eastern Tasmania, but now it is only found in two small subgroups in Frederick Henry Bay, Australia. The IUCN lists the redhand as critically endangered, leaving only about 100 adult individuals. According to IUCN, threats to the species include loss of spawning substrate, loss and degradation of habitat, water pollution and siltation, and increased density of native sea urchins. They are also bright red to light pink/brown and less than 10 cm long, making them difficult to find.
4: European eel
The unusual life cycle of European eels has spawned overfishing.
Mainly found in the North Atlantic, Baltic and Mediterranean Sea, European eels face a unique set of survival challenges. They have a confusing developmental cycle that begins when they are born at sea and continues thousands of miles inland in freshwater streams, where they can grow up to 1.5 meters long. When they reach sexual maturity, anywhere between 6 and 30 years old, they return to the sea to lay eggs. If their route to sea is blocked, they return to fresh water and can survive for 50 years. But if they return to salt water and multiply, they die. Because of this unusual life cycle, any eel caught at sea is a juvenile eel that has not yet had a chance to spawn. Other threats to the species include climate change, habitat loss/degradation, invasive species, parasitism, pollution, predation and unsustainable exploitation. This has led to catastrophic overfishing of European eels, as well as the critically endangered status of the IUCN.
3: Winter rays
The winter ray is a fascinating species that is known to deter predators and stun prey by a rapid electric current. Most are found in the northwestern Atlantic Ocean, from the Gulf of St. Lawrence in Canada to North Carolina in the United States. Winter rays, once considered "trash fish", are now harvested and processed into fishmeal and lobster bait, and even sold for human consumption. Increased trawling of the species has led to the accidental catch of juveniles, which can easily be mistaken for smaller, more abundant species. This has led to an alarming decline in the number of winter rays, which are slow to reach sexual maturity and have few offspring. Experts attribute these factors to a 90% decrease in the number of mature individuals since the 1970s. This devastating decline has given the winter ray endangered status by the International Union for Conservation of Nature.
2: Chinese sturgeon
A Chinese sturgeon swims in the Yangtze River in Yichang, Hubei Province, central China, April 10, 2021.
Historically, Chinese sturgeon has been found in China (Yellow, Yangtze, Pearl, Mingjiang and Qingtangjiang), Japan and southwestern Korea. However, it is now only found in the Yangtze and Pearl Rivers and the East and South China Seas. They've been alive for more than 140 million years, but now their days seem numbered. The species has historically been overfished, and the construction of the Gezhouba Dam in 1981 blocked the migration routes of Chinese sturgeon from reaching spawning grounds. There is only one spawning ground left, located under the Gezhou Dam. As a result, IUCN lists them as critically endangered. This very large fish can weigh up to 450 kg, grow to 4.8 meters and live for at least 35 years. Between 1983 and 2007, the government did try to stock 9 million sturgeon in the Yangtze River, but the population did not increase because there was no way to breed the fish. Currently, the annual reproduction rate is estimated to be between 0% and 4.5%.
1: Atlantic bluefin tuna
Perhaps the most iconic endangered fish, the Atlantic bluefin tuna occupies much of the North Atlantic. As one of the fastest fish in the sea, this species can grow up to 4.6 meters long and weigh more than 900 kilograms. The species' reputation as a fighter makes it a popular catch for recreational fishermen. At a price of up to $100,000 per fish, it is also highly rated by commercial fishermen. Bluefin tuna is severely overfished, and most experts believe that this slow-growing, slow-maturing species will become extinct if left unintervened. However, international regulation is tricky because bluefin tuna are known to migrate thousands of miles in the ocean. So far, efforts to control the harvest have largely failed. Atlantic bluefin tuna is threatened by IUCN in all respects, as populations in the East and West Atlantic have declined by at least 51% since 1970.