How do we know how many sharks are at risk?

According to Eco Watch, the world’s sharks are in peril, and their outlook may be worse than previously believed. This September, scientists from the IUCN Shark Specialist Group released a grim warning in their new Red List - one-third of the world’s sharks and related species are now threatened with extinction.

This alarming message, first published in the journal Current Biology, indicates that sharks and their relatives are much worse off than we thought. And, if our ocean environments continue on their current trajectory, time may soon run out. The last worldwide assessment of shark species was published in 2014 and found 24% of species at risk - a warning of what was to come. Sadly, based on the more recent statistics, it’s clear that we’re moving in the wrong direction.

Having complete information on the extinction risk for these species is essential to conservationists, scientists, policymakers, and the people who live and work near shark populations. But, researching and compiling a report of this size, especially during a pandemic, posed more than a few challenges. Scale was among the team’s chief concerns, and gathering the data required to assess each of the planet’s shark species required an incredible amount of effort. Over 350 experts from more than 70 countries worked in cooperation to complete the study, conducting research over a period of more than five years, with more than 20,000 cited sources informing the overall assessment.

“A room full of Westerners can’t effectively talk about conservation problems in a country they’ve never been to, and conservation challenges can be difficult to interpret if you don’t know the local context. We made the choice to go to these countries, bringing people together, which was great not just for analysing all this data, but for forming new collaborations and relationships.” Said Rima Jacado. Other factors, like ensuring gender equality among participants, were also essential for organisers, as was inviting a wide range of scientific professionals. 

The inclusive model used for this project is more effective than the problematic practices of “parachute science” or “colonial science,” with researchers from wealthy countries visiting field sites and working in isolation rather than cooperating with or helping local experts. 

Getting the people required to pull this project off together was one thing. Gathering, organising and condensing, and finally analysing the data was another. The process was overseen by a core team of Shark Specialist Group experts who attended numerous workshops and compiled all the data from the 1,199 individual species assessments. 

Determining the Red List status for each species required detailed information on distribution, threats, reproductive biology, and population trends. And, in cases where all this information was not available, a status of “data deficient” was assigned. 

During these workshops, days of data crunching, discussions, and deliberations took place. This is where local expertise became critical. Of course, a Western scientist halfway around the world can read foreign data, but only local expertise can provide key context and greater understanding. Local experts are also often aware of crucial data sources others may not have access to, such as fishing records and scientific papers published in foreign journals.

After each workshop concluded, the write-up for its target species was finalised. And, when all species assessments and reassessments were complete, the team began to write its summary paper. That’s when they started to uncover the devastating and sad results that made recent headlines.

Described as an index of both loss and hope, this new IUCN Red List describes each shark and its related species, including a detailed conservation assessment. This information helps determine the conservation priorities for each individual species, and also clarifies the bigger picture of risk to entire families and categories of sharks. Similar practices are used with other organisms, including mammals, amphibians and corals. The emergent data is compiled into what is known as a “Red List Index,” a document that demonstrates trends within Red List assessments and records the changes to a species’ threat of extinction over time. The IUCN’s summary paper determined a Red List Index for sharks, unfortunately indicating their collective decline.

The creation of this index is especially important as it brings the plight of our planet’s sharks to the attention of policymakers around the globe. And, because it is the very first Red List Index focused on marine vertebrates, it also reveals vital information on the biggest threat to the world’s oceans - overfishing. This destructive practice is especially detrimental to sharks, posing a threat to 100% of the IUCN designated “at-risk species” and acting as the sole threat to 67% of them. Combined with habitat loss, climate change, and pollution, it’s a recipe for disaster. 

The new assessment bore grim results, with population declines identified for multiple shark species, mostly due to overfishing, and probable extinctions announced for three species that haven’t been observed for over 80 years. While this study offers a bleak global perspective on the future of sharks and the impacts of overfishing on marine life, there is still hope. Conservation can be both challenging and depressing, but with projects of this magnitude taking place cooperatively, there is still a chance for positive progress.