Recently, I volunteered with the Shark’s Trust at the Dive Show in Birmingham helping to raise awareness about their ‘no limits no future‘ campaign to stop uncontrolled shark fishing. Shark and ray populations worldwide are under increasing pressure, and the total number of sharks caught annually may be over 100 million. One study1 published earlier this year (2014) estimated that up to a quarter of shark and ray species are threatened if assessed using the IUCN red list criteria. If we think about risks to shark populations we might think about shark finning in the Pacific, or sharks being caught as part of longline fisheries for tuna2 but the problem is actually a lot closer to home.
Originally, sharks were an unwanted part of the catch (bycatch) as fishermen pursued species such as cod and tuna, but now there is an increasing trend for the targeting and retention of these bycatch sharks. They are caught for their meat, their fins and their liver oil. Unfortunately, the life-history and behaviour of sharks makes them vulnerable to overfishing and populations are declining. Sharks reach maturity late and have relatively few young compared to other fish. In addition, they often congregate in groups of individuals that are either all a single sex, or are very close in age. Should a fisherman catch these sharks it has a bigger effect than catching the same number of sharks at random from the population.
In 2012 there were 280,000 tonnes of reported shark landings worldwide, with EU vessels landing 40% of this world total, the majority of which came from the Atlantic ocean and Mediterranean sea. One issue in that this is reported landings – the true level of landings is thought to be three to four times higher3. Worse still, most of this European catch from the Atlantic and Mediterranean is concentrated on just five species4.
These five species are:
- Blue shark (Prionace glauca), listed as near threatened.
- Shortfin mako (Isurus oxyrinchus), listed as vulnerable.
- Tope (Galeorhinus galeus), listed as vulnerable.
- Smoothhound (Mustelus asterias), listed as least concern, and
- Catsharks (Scyliorhinus canicula), listed as least concern, and Nursehound (Scyliorhinus stellaris), listed as near threatened.
97% of all sharks caught and landed from the Atlantic and Mediterranean in 2012 are no limits species, which has been estimated to amount to 6,400,000 individuals. This is why although some of the species above are currently listed as of ‘least concern’ it’s important to make the fisheries sustainable before the populations crash due to overfishing. Once overfished, there is no guarantee that populations will recover as demonstrated by the collapse of the cod fishery on the grand banks off the eastern coast of Canada. In addition, sharks are important components of ecosystems as top-level predators. The shark trust is campaigning for science-based catch limits. Please sign the petition, and see the ‘get involved‘ page for other ways to contribute.
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