Shark Week 2017

Let’s Hear It for Sharks: Our Ancient Ecological Providers

One quarter of known shark and ray species in the Western Indian Ocean are threatened by fishing and risk extinction in coming years if appropriate management measures are not put in place. Credit: Emily Darling/WCS.

By Alison Clausen
July 25, 2017

Let’s face it. Sharks get a really bad rap. If they’re in the news, there’s a good chance the news is bad.

Beginning with “Jaws” in 1975, most press seems to demonize these animals. It is true that there have been tragic and unfathomably sad incidents with sharks attacking humans. But there is also a lot about sharks that is not generally known that could help inform the debate on whether we should protect them and, if so, how we should protect them.

Shark Week, the Discovery network’s annual block of shark-based TV programming, is a good time to begin.

Firstly, from a purely historic and scientific point of view, sharks are the oldest jawed vertebrates — dating back at least 420 million years (by way of comparison, dinosaurs roamed the earth between 230–63 million years ago) — and have some of the greatest functional diversity of all vertebrates.

Sharks can potentially contribute to the greatest conundrum facing the world today: how to sustainably feed 7 billion people. Credit: ©Keith Ellenbogen

For evolution geeks, a recent study (Dulvy et al, 2017) notes that the average shark species exhibits three times more evolutionary distinctiveness than the average mammal species.

Sharks’ role in small-scale community fisheries in some of the world’s poorest countries is immense.

They also have immensely important social roles: providing food and income to coastal residents while helping to sustain coral reefs so that they can fulfill a myriad of functions — including coastal protection, healthy fisheries, and tourism for the millions of people living and working around coasts.

Sharks’ role in small-scale community fisheries in some of the world’s poorest countries is immense and they play an unmeasured but essential role in food security and provision of protein.

Gracefully gliding manta rays — with wingspans 7 meters long — give birth to only one live pup every 2–3 years. This makes sharks and rays especially vulnerable to over-fishing and slow to recover. Credit: Hollie Booth/WCS.

They likewise play an essential role in the maintenance of ecosystems. We know most about their role in coral reefs where they control invasive species, remove weak and sick prey, and cycle nutrients. The social and ecological importance of sharks is in evidence throughout the Western Indian Ocean (WIO) region.

This area, which is home to more than 40 million coastal people, is the second highest biodiversity hotspot for sharks. At least 211 shark and ray species are known to be found in the region — nearly a quarter of all shark and ray species globally. Close to 60 of those species are endemic and it is likely that many species remain undescribed.

Sadly, roughly one quarter of known shark and ray species in the region are threatened by targeted and incidental fishing and risk extinction in coming years if appropriate management measures are not put in place.

The Western Indian Ocean, home to more than 40 million coastal people, is the 2nd highest biodiversity hotspot for sharks.

Protecting sharks in the WIO as elsewhere is not all about fishing bans — although for some species that are particularly threatened or that have low reproduction rates this is probably essential. Recent scientific studies suggest that other more resilient species can be fished sustainably provided the correct controls and monitoring are put in place.

This means that sharks can potentially contribute to the greatest conundrum facing the world today: how to sustainably feed 7 billion people. Marine protected areas, particularly those that allow mixed uses including sustainable fishing combined with no-take zones, can be a particularly important tool for shark conservation.

Relatively small investments in such areas in the Western Indian Ocean could have significant benefits for sharks — and thus the people and ecosystems to which these fish are strongly linked. Credit: Paul Hilton/WCS.

A recent study found that relatively small investments in such areas in the Western Indian Ocean could have significant benefits for sharks — and thus the people and ecosystems to which these fish are strongly linked.

So the next time you think about sharks, don’t leap immediately to the iconic great white and its rows of razor-sharp teeth. Instead try to keep in mind these ancient animals’ importance to the lives of coastal communities and the earth’s broader biodiversity.

Now there’s some news you can use.

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Alison Clausen is Regional Director for Madagascar and the Western Indian Ocean at WCS (Wildlife Conservation Society).