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Deepwater desperation: The race to save sharks and rays

The international demand for liver oil and meat has led to a dire situation for deepwater sharks and rays, with overexploitation pushing these species towards an irreversible decline.

Characterized by their slow growth, lengthy lifespans, and sparse reproductive output, these marine animals are facing a battle against time and human activity. The urgency for immediate intervention in the form of trade and fishing regulations has never been clearer.

Refuge no more: The deepwater dilemma

Deepwater ecosystems, the final frontiers of natural biodiversity, stand as bastions against the encroaching influence of human activities. Despite their significance, these habitats are among the Earth’s least studied, leaving the biodiversity they harbor largely unquantified.

This gap in understanding poses a substantial hurdle to conservation efforts, particularly in the face of international commitments to protect 30% of the world’s oceans.

Sensitivity of sharks and rays

In response to the pressing need for data, Brittany Finucci and her team embarked on a comprehensive study of deepwater sharks and rays. Through their exhaustive research covering all 521 known species, the team sought to illuminate the global biodiversity changes, status, and threats faced by these marine vertebrates.

The findings highlight the extreme sensitivity of deepwater sharks and rays to overexploitation, casting a spotlight on the critical need for conservation.

A stark reality: The threat of extinction

The research unveils a grim reality: one-third of threatened deepwater shark species are targeted by fisheries, and half of those involved in the liver-oil trade are threatened with extinction.

The steep population declines observed underscore the difficulty of reversing the trend, given the species’ unique life histories. Alarmingly, many of these species lack the protection of current management strategies, further exacerbating their vulnerability.

Implementing protective measures for sharks and rays

Finucci’s study offers a glimmer of hope, suggesting that the introduction of worldwide depth limits on fishing activities and the expansion of no-fishing zones could significantly bolster the protection of deepwater species.

Yet, these measures alone are insufficient. A concerted effort to implement international fishing and trade regulations is imperative to turn the tide against the decline of these essential marine inhabitants.

A call to action for the deep

The plight of deepwater sharks and rays serves as a clarion call for immediate action. As custodians of the planet’s natural heritage, the global community must rally to enforce and expand conservation measures.

The preservation of these species is not merely an act of ecological stewardship but a necessary step towards maintaining the health of marine ecosystems worldwide. Both sharks and rays play vital roles in these ecosystems, often as top predators, and their conservation is essential for maintaining the balance of marine life.

The study is published in the journal Science.

More about sharks and rays

Sharks and rays are fascinating creatures that belong to a group of fish known as Elasmobranchii, which is part of the subclass Chondrichthyes. The group is characterized by their cartilaginous skeletons, rather than bones like most fish. Here are some key points about these intriguing animals:


There are over 500 species of sharks, ranging from the small dwarf lantern shark to the massive whale shark. They inhabit a wide range of aquatic environments, from shallow reefs to the deep sea.


Sharks have streamlined bodies that enable them to swim efficiently, and most species have several rows of sharp teeth. Their skeletons are made of cartilage, which is lighter and more flexible than bone.


Sharks have highly developed senses, including the ability to detect electrical fields produced by the movements of other animals, thanks to their ampullae of Lorenzini. They also have an acute sense of smell and can detect blood in the water from miles away.


Sharks reproduce in several ways, including oviparity (laying eggs), viviparity (bearing live young), and ovoviviparity (a combination where eggs hatch inside the female’s body).


Rays are closely related to sharks and include over 600 species, such as stingrays, manta rays, electric rays, and skates. They are known for their flattened bodies and long, whip-like tails.


Most rays live on the ocean floor, often buried in sand or mud, though some, like the manta rays, are pelagic and swim in open water.


Rays primarily feed on small fish, crustaceans, and mollusks. Many species use a method of suction to draw prey into their mouths, and some have developed specialized teeth for crushing hard shells.


Rays exhibit a variety of reproductive strategies, including oviparity and viviparity. Some species lay eggs encased in leathery pouches, while others bear live young.

The full study was published in the journal Science.


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