By Andy Cornish Ph.D., Leader of WWF Sharks: Restoring the Balance
Preventing extinctions has been a primary aim of shark and ray conservation for decades, but the numbers don’t lie. These efforts — including our own — haven’t kept pace with the threats. We all need to raise our level of ambition if we want to reverse the tragic loss of biodiversity in our ocean. More efforts are needed to actively recover depleted populations for the benefit of our ocean and people who depend on it.
Marine fish extinctions to date have been very rare, with the first confirmed case only in 2020. The victim was the smooth handfish, an odd frogfish-like species from Tasmania that was probably doomed by habitat loss and destructive fishing practices. But fish extinctions could rise dramatically in the coming decades, as more than 90 species of sharks and rays are considered critically endangered, and three are probably already extinct according to the IUCN Red List. The greatest driver of this threat to marine sharks and rays is overfishing, driven by demand for their products locally (meat) and internationally (fin).
Momentum is growing now to conserve sharks and rays, as can be seen by the 35 species listed on CITES (Convention on International Trade in Endangered Species) since 2014, the first global conservation strategy, as well as the creation of the Shark Conservation Fund in 2015, the biggest funder of shark and ray conservation work globally today.
Conserving highly threatened species or preventing extinctions could be interpreted simply as preventing further declines. Indeed, this seems to be the rationale for adding species to protected lists, or prohibiting fishers from catching or keeping them. Yet these lists and regulations may have little impact if the fishing methods that snag the animals are still used, if the animals tend to die before they are discovered and released, and if there is little enforcement.
Instead, the goal of conservation efforts to save highly threatened sharks and rays should be recovery, meaning declines are halted and populations start to increase. This level of ambition — explicitly acknowledged in the Global Shark & Ray Initiative conservation strategy — is important because it aims to recover the ecological function of the species while minimising the risk of extinction. Recovery also provides greater insurance for the survival of populations in the face of climate change.
The restoration of ecological function does not seem to have been well studied for the handful of successful shark and ray recoveries, but there are some inspiring examples from land animals. One example is the recovery of wolves in Europe, which is leading to healthier and more diverse ecosystems. Wolves, which are apex predators, not only eat other widespread predators such as foxes — but their presence influences the behaviour of other animals. The ripple effect has been observed in species as diverse as beavers, birds, fish and butterflies.
Similarly, tiger sharks have been shown to influence the behaviour of dugongs and turtles in seagrass meadows. The sharks keep these grazers moving, limiting overgrazing with knock-on benefits for the climate: more seagrass means more carbon storage.
Most species of sharks and rays are not apex predators, but the example of the European bison recovery demonstrates that herbivores can also be important ecological engineers. Bison open up dense undergrowth by walking through it, disperse seeds and create open soil when they wallow that gets colonised by plants that need such spaces. The resulting increase in the diversity of landscape and vegetation is supporting populations of smaller mammals, other grazers, birds and invertebrates.
While no shark or ray has yet been shown to be a keystone species as the wolf and European bison are, this may be because the ecological role of most of the 1,200+ species has yet to be studied in any depth. Nevertheless, we do know how important sharks and rays are for coral reefs, for example. Grey reef sharks help distribute nutrients around reefs simply by defecating — it’s been shown that these “top-ups” contribute to the health of coral reefs, which are generally nutrient poor. Pelagic species, on the other hand, help to maintain the ocean nutrient pump and fuel plankton productivity by feeding in the deep and excreting in the shallows, where nutrients are typically lacking.
There is still much left to discover and understand about ecological roles of many shark and ray species (and this will be increasingly difficult with populations of some species already too low to even study them). However, as until 100 years ago these animals were abundant in the tropical and temperate seas, it is reasonable to assume that, collectively at least, these predators were playing important ecological roles beyond those already known to science.
Halting declines and bending population curves upwards is the primary aim of the recently launched Shark and Ray Recovery Initiative (SARRI). It is a direct response to the growing shark and ray crisis and has been designed from the start to trigger a much broader wave of recovery efforts beyond the initiative itself. SARRI will provide open access to its recovery tools and methodologies, as well as free training for practitioners interested in recovering sharks and rays.
Working closely with coastal communities, local partners, and other experts, SARRI will initially introduce comprehensive recovery plans in at least eight sites, which will include securing “shark recovery zones” to protect critical habitats of the most threatened species. These will be enhanced by other management measures tailored for each location and species, such as methods to reduce bycatch in the surrounding areas. By testing and constantly improving the recovery approach in the field, SARRI aims to create a blueprint for recovering threatened sharks and rays around the world. Those already working in this field or interested in doing so are encouraged to get in touch and join the community through www.sarri.org.
SARRI is a partnership of leading shark and ray conservation experts from WWF, Elasmo Project, James Cook University, and Wildlife Conservation Society.