The question of whether sharks are heading toward extinction is complex, varying significantly depending on the specific species and region. Sharks, rays, and chimaeras—collectively known as cartilaginous fishes—are facing unprecedented pressure across the world’s oceans. While some species maintain healthy populations, a growing number are experiencing dramatic declines, indicating a widespread crisis. This situation stems from human activities and the unique biological characteristics that make sharks highly vulnerable to overexploitation.
Assessing Global Population Declines
The conservation status of shark species is formally tracked and categorized by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. This system classifies species into categories like Vulnerable, Endangered, and Critically Endangered based on population size reduction and geographic range decline. Current assessments indicate that approximately 37% of all shark, ray, and chimaera species are now threatened with extinction globally.
This overall figure includes 12% classified as Critically Endangered, 11% as Endangered, and 14% as Vulnerable. For oceanic species, the decline is particularly severe, with a study noting a 71% global decline in oceanic shark and ray abundance over the last 50 years. Three-quarters of oceanic shark and ray species are now classified as threatened.
Iconic pelagic species serve as clear indicators of this crisis. The oceanic whitetip shark, once abundant in the open ocean, is now classified as Critically Endangered globally due to a catastrophic population decline estimated to be over 98% in some regions. Similarly, the great hammerhead and scalloped hammerhead sharks have also been globally classified as Critically Endangered, with their populations crashing by over 80% in the last 70 years. The IUCN Red List provides the scientific basis for understanding that the threat is a measurable, ongoing collapse for many species.
Biological Traits Increasing Vulnerability
The inherent biology of sharks makes them exceptionally susceptible to overfishing and population collapse compared to most bony fishes. Sharks exhibit a life history strategy known as K-selection, characterized by traits that favor long lifespans and high investment in few offspring. This strategy works well in stable environments but leaves them unable to recover quickly from sudden population losses.
One significant factor is their late age of sexual maturity, meaning they must survive for many years before they can reproduce. For instance, larger shark species, like the dusky shark, do not reach sexual maturity until they are 17 to 20 years old. If fishing pressure removes these individuals before they reproduce even once, the species cannot sustain itself.
Sharks also have long gestation periods, often lasting a year or more, and produce very low numbers of pups, a trait known as low fecundity. A female shark might give birth to only a dozen or fewer pups in a reproductive cycle, contrasting sharply with bony fish that release millions of eggs. This combination of slow growth, delayed maturity, and limited reproductive output means that once a population is depleted, recovery can take decades.
Primary Human Drivers of Mortality
The overwhelming cause of shark mortality worldwide is fishing pressure, including targeted fishing, accidental capture, and illegal practices. Sharks are commercially valued for their meat, liver oil, skin, and fins, driving global fisheries that frequently lack adequate management. The global reported trade in shark meat has also increased significantly, adding another major economic driver to the fishing effort.
Bycatch, the unintentional capture of non-target species, accounts for a massive portion of shark deaths, as sharks are frequently caught in gear set for tuna, swordfish, and other commercially valuable fish. This incidental capture can quickly decimate slow-reproducing shark populations, especially in vast pelagic fisheries. A particularly destructive practice is shark finning, where fishers remove the fins and discard the body back into the ocean, leaving the animal to die.
Though overfishing is the primary threat, habitat degradation also contributes to population decline, particularly for coastal species. Many sharks, including hammerheads and bull sharks, rely on specific shallow-water areas like mangroves and estuaries as nursery grounds. The destruction of these coastal habitats from development and pollution reduces the survival of juvenile sharks, impeding the species’ ability to replenish its numbers. Illegal, unreported, and unregulated (IUU) fishing further compounds the problem by operating outside of established quotas or regulations, making conservation efforts difficult to monitor and enforce.
International Conservation and Management
Global efforts to protect sharks and manage their populations are coordinated through various international treaties and regional agreements. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) plays a significant role by regulating the international trade of specific threatened shark products. A CITES Appendix II listing requires permits to ensure that international trade in species like certain hammerheads, silky sharks, and oceanic whitetips is not detrimental to their survival.
Many countries and regional fishery management organizations (RFMOs) have implemented measures to limit catches, such as establishing fishing quotas and size limits for certain species. The creation of Marine Protected Areas (MPAs) offers a spatial approach to conservation, providing safe havens where fishing is restricted or banned entirely. These protected areas are important for safeguarding critical habitats like mating grounds or pupping nurseries.
Despite these efforts, management remains a challenge because many shark species are highly migratory, crossing the borders of multiple nations and international waters where governance is complex. Effective conservation requires individual nations to enforce national fishing regulations and cooperate through RFMOs to establish science-based catch limits that reflect the slow reproductive rate of these vulnerable species. The progress in international management is slow, often lagging behind the rapid rate of population decline, but it represents the primary mechanism for species recovery.