The world’s waters are home to an estimated 1,250 species of sharks, skates, and rays (hereafter ‘sharks and rays’) — many of which represent some of the oldest living creatures on Earth.
In their 400‐million-year evolutionary history, sharks and rays have developed extraordinary adaptations: bioluminescence, pockets, saws, hammers, stings, and electricity, among others. More similar in reproductive strategy to marine mammals than bony fishes, over half give birth to fully formed young. The longest pregnancy on record is 31 months, and the Greenland Shark is thought to be the longest-lived vertebrate, maturing only after 150 years.
The biodiversity of shark and ray species is reflected in the diversity of fisheries that have proliferated in recent decades in response to burgeoning international and national demand for a variety of products: shark fin, liver oil, cartilage, leather, meat, and manta and devil ray gill plates. Catch levels in these fisheries increased to a peak in 2003, but declined by 20% the following decade. Shark and ray conservation and management systems have not evolved as rapidly as these market drivers, resulting in a vast array of underreported and unregulated fisheries connected through global and local marketplaces across at least 126 countries. This combination of rapidly expanding fisheries, increasingly diversified local and international markets, and uncontrolled trade is contributing to a dramatic decline in shark and ray populations worldwide—over a 90% contraction in some populations. More specifically, a recent analysis of shark and ray International Union for Conservation of Nature Red List assessments found that 249 of these species, nearly a quarter (24%), are threatened with extinction, while only 23% are judged of “Least Concern.”
The long‐term survival of sharks and rays is also critical to humans. Sharks and rays play a critical role as the top predators in coastal and ocean ecosystems, helping to ensure the long‐term sustainability of commercial and artisanal fisheries. Also, the direct benefit of sharks and rays on human livelihoods is important in both the provision of non‐consumptive services, such as ecotourism, as well and directed fisheries and associated food security in some of the world’s poorest fishing communities. Artisanal shark and ray fisheries are prominent in many of these communities, including those in the Western Indian Ocean, Bay of Bengal, and Indonesia.