The International Union for Conservation of Nature (IUCN) Red List of Threatened Species 2023 indicates that at least 37 per cent of the world’s sharks and rays, 33 per cent of coral reefs, 26 per cent of mammals and 21 per cent of reptiles are threatened with extinction. Many of these species live in oceans and marine environments, but overfishing, habitat loss and degradation, pollution and climate change, have plagued many animals to the brink of extinction. Mwangi Alberto looks at the most threatened
1. Vaquita
This timid and highly elusive dolphin is found exclusively on Mexico’s Gulf of California. Measuring in at just 1.5 metres, the vaquita is also the smallest of all cetacean species. Despite its relatively recent discovery in 1958, rampant and unregulated fishing practices, particularly the use of gill nets, in its limited habitats have pushed the animal to the brink of extinction with only a mere 10 individuals remaining in the wild. Bycatching alone, whereby large amounts of unwanted sea animals are captured during the fishing for a particular species, have led to a 94 per cent population decline between 1997 and 2016.
2. North Atlantic Right Whale
By 2021, the North Atlantic Right Whale population was estimated to have plummeted down to fewer than 340 individuals, a sharp decline from the 480 individuals in 2011. The dramatically decreasing whale population is doubly harmed by ship strikes and entanglement in fishing gear. Initiatives such as the deployment of ‘ropeless’ fishing gear aim to reduce ongoing threats to the species, but in many parts of the world, limited or lack of fishing restrictions have slowed conservation efforts.
3. Yangtze Finless Porpoise
The clue is in the name; this marine mammal is endemic to the Yangtze River in China — the longest river in Asia — and one of the few cetaceans that live in freshwater systems. The finless porpoise has been heavily impacted by local fisheries such as bycatching and entanglement. The waterways the porpoise live in are often packed with boat traffic, increasing the risk of collisions and injuries. The porpoise population plunged to only 1,040 (from the latest figures in 2017). The annual decline rate of 13 per cent means these animals are expected to become extinct within 10 years if there are no effective conservation actions in place.
4. Hawaiian Monk Seal
Native to the Northwestern Hawaiian Islands, the Hawaiian Monk Seal is one of the two remaining in the monk seal species and one of the earless seals living in warm beaches (instead of typically colder climates). Historically, the monk seal has been heavily poached and hunted for its meat, oil and skin, devastating its population numbers. But the survival of the species is further threatened by plastic pollution and marine debris and entanglement in fishing nets in and around Hawaiian waters. According to recent research, its total population is estimated to be about 1,400.
5. Hawksbill Turtles and Kemp’s Ridley Turtles
Of the seven species of sea turtle found all over the world, six of them are classified as either threatened or endangered. Hawksbill Turtles and Kemp’s Ridley Turtles, however, are considered critically endangered on the IUCN Red List, with the latter’s population estimated to be less than 10,000. Coastal development, marine pollution, overfishing and hunting are the biggest threats to these endangered species in the ocean. Over the past few decades, the sea turtles have been impacted by reduced amount of viable land where they can lay their eggs as well as targets from poachers for their eggs, shells, meat and skin.
6. Giant Manta Ray
A 2020 IUCN report found that Giant Manta Ray had undergone a population decline of between 50 per cent and 79 per cent within 87 years, which they attributed to be a direct result of unsustainable fishing practices. Giant Manta Rays are targeted and harvested for their gill plates, which they use to filter feed on small zooplankton from the water column, especially in the emerging market in Asia. Combined with the fact that Manta Rays give birth to just one offspring every few years in the wild, with the young often left unprotected, population recovery has been particularly slow and challenging. Giant Manta Ray population is estimated to range between 100 and 1,500 individuals.
7. Whale Shark
Among the most endangered species in the ocean are Whale Sharks. Contrary to its name, the Whale Shark is not actually a whale species, but is both the largest species of shark and the largest species of fish that are big contributors to the resilience of tropical marine ecosystems. They provide habitat and shelter for smaller sea creatures and maintain a mutually beneficial relationship with tuna. But anthropogenic threats such as fishing industry and cargo traffic (and noise pollution), are devastating the species. As a filter-feeder, the whale shark is also at greater risk of ingesting toxic or indigestible pollutants entering the oceans, including plastics and industrial runoffs.
8. Northern Fur Seal
Northern Fur Seals spend most of the year in water and only go to shore to breed. The seal was hunted extensively for their fur in the late 1800s until the US finally banned commercial harvest and placed the fur seals under the protection of the Marine Mammal Protection Act in 1985, making it illegal to kill them except for research or native subsistence. Despite the respite, there are only about 1.1 million individuals left worldwide and continues to face challenges such as competition with commercial fishing industries, bycatch, and climate change.
9. Southern Bluefin Tuna
This commercially important fish species has recently moved from being listed as a ‘critically endangered’ species to ‘endangered’ following a decade of regional fishing quotas and crack down on illegal fishing. But the threat of overfishing remains while some tuna stocks are still “severely depleted” in certain regions. Rising ocean temperatures poses another challenge for the Southern Bluefin Tuna affecting their respiratory and circulatory systems. And since tunas swim continuously and at high speed, therefore have a high demand for oxygen, climate change is also impacting the oxygen concentration in the water.
10. Coral reefs
Global coral reef systems have no doubt been hit hardest by rising ocean temperatures and climate change. Coral reefs are one of the most important and diverse marine ecosystems, despite covering only two per cent of the ocean area. Though stony corals make up most tropical reefs, there is a stunning variety of corals found across the ocean floor. Increasingly warmer waters and acidification in recent years have led to a number of major coral bleaching events, where corals loose their vibrant colours leaving only their exoskeleton, causing the death of many corals. In the latest Status of Coral Reefs of the World report, global coral cover has been halved since the 1950s, attributing to human-driven climate change, highly-damaging practices such as overfishing, dredging, quarrying, and bottom trawling, and pollution from poorly recycled sewage water and pervasive plastics. The shrinking of coral cover has translated into a 60 per cent loss in reef biodiversity and toll on coastal populations.
Source: earth.org
