Cornish whale and dolphin deaths raise concerns
Monday, 07 Jul 2008 12:43
Dolphins, whales and porpoises are being affected by bycatch
Science In Focus
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Intensive fishing practices could be to blame for a sharp rise in the number of whales, dolphins and porpoises found dead on Cornish beaches.
A report published in the journal Biodiversity and Conservation found that the frequency of these mammals, collectively known as cetaceans, on Cornwall's beaches has increased during the past eight years.
Researchers from the University of Exeter and the Cornwall Wildlife Trust discovered the rise after analysing nearly 100 years of data.
They studied records of cetacean strandings from 1911 to 2006 from around Cornwall's north and south coasts and the Isles of Scilly.
This revealed a marked increase from the early 1980s, with common dolphins and harbour porpoises being the worst-affected species.
In total, fewer than 50 cetacean strandings a year occurred in Cornwall in the 1980s but numbers since 2000 have ranged from 100 to 250 per annum.
The south coast of Cornwall experienced the most strandings, particularly around Mount's Bay (Penzance) and two of south-east Cornwall's most popular beaches - Looe Bay and Whitsand Bay.
Since 1990, at least 61 per cent of incidents in Cornwall are the result of fishing activity, with animals being caught up in nets in a phenomenon known as 'bycatch'.
Dr Brendan Godley of the University of Exeter's Cornwall campus said the study shows that bycatch is "clearly a major issue that needs to be addressed by all stakeholders from government and the fishing industry in addition to conservation organisations".
"Many people were shocked by the recent graphic images of the mass dolphin strandings in Cornwall; the cause of which is still a matter of conjecture," he added.
"We feel that the important message is that strandings have increased in recent years and that the majority are attributable to bycatch in marine fisheries."
Joana Doyle, marine conservation officer for Cornwall Wildlife Trust, commented: "There are several things we need to do in order to safeguard the future of Cornwall's cetaceans.
"These include establishing a network of marine conservation zones around our coast to protect the species and the habitats they depend on, working closely with the fisheries to develop and test bycatch mitigation measures and pushing for an EU wide ban of pair-trawling for seabass.
"The strandings and sightings data collected by Cornwall Wildlife Trust is incredibly important for monitoring the status of our cetacean species off the Cornish coast."