Sharks falling victim as commercial fishing bycatch

July 29th, 2019

Commercial fishing fleets are increasingly entrapping large sharks
as bycatch leading to a significant decline in their populations, a new study
has found.

The study
conducted by an international team of scientist from 26 countries indicates
that large sharks, even those inhabiting the remotest parts of the ocean, are
falling victim to industrial fishing.

Scientists have examined the movement of 2,000 sharks through
satellite transmitted tags, concluding that commercial fishing has specifically
led to a significant drop in the populations of Shortfin Mako shark – the
fastest shark in the sea – that ends up entrapped in large fishing nets.

Researchers mapped “hotspots” for sharks in detail,
revealing a 24 per cent monthly overlap between those areas and spaces commonly
used by fishing vessels. Each boat was found to be capable of deploying 100km lines
bearing 1,200 baited hooks daily.

The overall was significantly higher for commercially exploited
sharks such as the Atlantic Blue and Shortfin Makos, with fishing vessels
overshadowing 76 per cent and 62 per cent of their space.

Large sharks living in the open ocean account for over half of all known shark catch internationally, including both targeted and bycatch.

The researched have suggested that the study’s results may be used
to produce a “blueprint” for earmarking marine protected areas (MPAs)
to preserve sharks from human exploitation.

Dr Tom Doyle, a lecturer in Zoology at University College Cork
(UCC) and one of Irish contributors to the study, expressed concern about the
new findings.

“We knew that blue sharks are one of the most frequently
captured sharks but to find such a high overlap between their space use and
fishing activity is worrying,” he said.

“So, despite being one of the most abundant and widespread
large predators in the North-East Atlantic, blue sharks have very few places to
hide.”

Dr Doyle and Luke Harman from UCC’s Environmental Research
Institute (ERI) provided track data from blue sharks tagged in Irish waters for
the study.

Professor David Sims, the study’s leader, also said that their
findings confirm “major high seas fishing activities are currently centred on
ecologically important shark hotspots worldwide”.

Certain types of sharks are already facing human-driven extinction
and are
classed as endangered
by the International Union for Conservation of
Nature.

Earlier in February, a
study by researchers at the University of Exeter
revealed that a group of
fish-and-chips shops in the UK were frying endangered marine species, including
Spiny dogfish, a small, threatened shark.

To attract customers loath to eating sharks, the eateries had mislabelled the species as “rock salmon”, according to the study.

About the Author

Shamim Malekmian

Shamim is a Senior Reporter at The Green News and a contributing writer to the Irish Examiner, Cork Evening Echo and the Dublin Inquirer.

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