Sharks are under threat from ships as nearly a quarter of their natural habitat falls in industrial fishing areas, a study has found.
Researchers from countries including Australia, New Zealand and the UK found that sharks spend between two and six months in high risk zones annually.
Sharks migrate throughout the year, swimming in areas near boundaries in the sea between different water masses that attract fish and other sea life to increase their foraging opportunities.
Fishermen also travel to these areas to make their trips more commercially viable by ensuring they catch as many fish as possible.
Sharks are under threat from ships as nearly a quarter of their natural habitat falls in industrial fishing areas, a study has found. Pictured: a porbeagle shark off the coast of the UK
The study focused on longline fishing boats as it catches the most pelagic sharks (pictured: a blue shark after being caught by a longline)
What is longline fishing?
Longline fishing is a technique that uses a mainline that has a number of baited hooks attached to it.
In areas such as the North Pacific, commercial fishing boats can have as many as 2,500 baited hooks at any one time.
The technique can be used to catch fish such as tuna, cod and swordfish.
Longline fishing often catches species other than those intended, including sharks, turtles and dolphins.
Some estimates suggest that up to 40 per cent of caught sea life is bycatch, much of which is then thrown back overboard as it is not wanted.
Wildlife charities have urged fisheries to utilise new technologies to reduce the amount of bycatch to protect our oceans.
The study, published in Nature, tracked 1,681 large sharks and compared the data to longline fishing vessel movements.
It focused on these types of boats as the fishing gear used on board catches the most pelagic sharks – those that live in the open waters of the seas and oceans.
The study found that there are a number of overlap areas where sharks are at risk of being killed when they are unintentionally caught by fishermen.
These include the southern Great Barrier Reef, the Gulf Stream, and the California Current.
Commercially-exploited sharks, such as North Atlantic blue and shortfin makos sharks, are even more concentrated in high risk zones.
On average, 76 per cent of the space blue sharks swim in is in zones of longline fishing, while for shortfin makos it is 62 per cent.
Professor David Sims, who is based at the Marine Biological Association Laboratory in Plymouth, led the study.
More than three-quarters of the North Atlantic blue’s (pictured with a hook stuck in it) natural habitat is in areas where longline vessels fish
He said: ‘Our results show major high seas fishing activities are currently centred on ecologically important shark hotspots worldwide.’
The study suggests that one potential solution is the creation of large-scale marine protected areas.
These would be centred around shark hotspots to create refuges from industrial longline fishing efforts.
Professor Sims added: ‘Some of the shark hotspots we studied may not be there in as little as a few years’ time if management measures are not put in place now to conserve the sharks and the habitats on which they depend.’
ARE AMPHIBIANS AT RISK OF EXTINCTION?
More than 40 per cent of the world’s amphibian species, more than one-third of the marine mammals and nearly one-third of sharks and fish are threatened with extinction.
Analysis of the risks faced by the 8,000 or so known amphibian species by the UN and published in the IPBES report has found that up to 50 percent may be at risk of extinction, in a dramatic rise from earlier estimates.
The spike stems from the inclusion of roughly 2,200 species that were previously under-represented due to lack of data; now, based on the new models, researchers say at least another 1,000 species are facing the threat of extinction.
Researchers used a technique dubbed trait-based spatio-phylogenetic statistical framework to assess the extinction risks of data-deficient species.
This combined data on their ecology, geography, and evolutionary attributes with the associated extinction risks of each factor to make a prediction.
Only about 44 percent of amphibians currently have up-to-date risk assessments, the team notes.
‘We found that more than 1,000 data-deficient amphibians are threatened with extinction, and nearly 500 are Endangered or Critically Endangered, mainly in South America and Southeast Asia,’ said Pamela González-del-Pliego of the University of Sheffield and Yale University.
‘Urgent conservation actions are needed to avert the loss of these species.’
According to the researchers, the species most at risk likely also include those we know the least about, further adding to the complexity of their protection.
A study published earlier this year found 90 amphibian species have been wiped out thanks to a deadly fungal disease.
It affects frogs, toads and salamanders and has caused a dramatic population collapse in more than 400 species in the past 50 years.
The disease is called chytridiomycosis which eats away at the skin of amphibians and is threatening to send more animals extinct.
Originally from Asia, it is present in more than 60 countries – with the worst affected parts of the world are tropical Australia, Central America and South America.
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