Using data gathered from a large number of collaborators between 2007 and 2016, Rebecca Dudley, currently pursuing an MRes at the University of Plymouth, has been analysing sightings and photographs of dolphins in the southwest region of the country and has been able to identify 98 individuals and define a distinct social group of 28 resident dolphins, present throughout the year in shallow coastal waters around the area.
‘This research is proof that we have a resident population and is incredibly exciting,’ said Ruth Williams, a marine conservation manager at Cornwall Wildlife Trust, which was among the contributors to the data. ‘We’ve always known we had bottlenose dolphins around the southwest and the Cornish coast and the Wildlife Trust, among others, has been taking reported sightings and monitoring them for the last 20 or 30 years, but we didn’t have the evidence we needed to make sure those dolphins were adequately protected.’
The species of bottlenose dolphin found in the waters of Cornwall is called tursiops truncatus, and individuals can be recognised by their dorsal fins, which have distinctive shapes and markings.
The collaborative effort that went into monitoring and documenting these dolphins was crucial as strong evidence is needed to show that an area is ‘important’ before protection is even considered.
The Cornwall Wildlife Trust has been attempting to prove the dolphin’s residency in the area for some time, and its 2016 report highlighted the need for action: ‘current estimates suggest that the resident population may have halved in numbers since the 1990s, causing them to be at serious risk of local extinction.’
Historically bottlenose dolphins have been around the coast as far back as records go, and even used some of estuaries up to the 1900s. But largely due to pollution and fishing practices, dolphins suddenly disappeared around the 1960s. Luckliy, quite out of the blue, they made an unexpected ressurgence in 1991.
‘When they first arrived in 1991, we thought there were about 50 animals in that group,’ says Williams. ‘The size of the groups we were seeing over the last few years have been much smaller than that, which is another reason that spurred this research. We needed to do something about it and get them on the map for better protection.’
The UK currently has two other resident bottlenose dolphin populations, one in the Moray Firth of Scotland, and the other in Cardigan Bay, Wales, both of which have already received protection. The collaborative team behind this research hope its findings will result in the same measures being taken for their English counterparts.
The primary threats to Britain’s bottlenose dolphins are the same that have led to many marine animals creeping their way up endangered species lists in recent years, including pollution from plastics and chemicals, injury by fishing nets, and disturbance from recreational activities.
No specific protection is currently offered to Cornwall’s new residents, but the data from this study demonstrating a year-round community provides solid grounds for official action to protect the species.
‘From the early discussions we’ve had with ministers and conservation bodies, the will is there, the gap was that we didn’t have the hard evidence to support our gut feeling,’ says Williams. ‘Well the evidence is there now and those people are behind us and wanting to do their bit to protect the dolphins.’
The report also identifies the continued collection of more evidence on the dolphins’ movements and behaviour, in order to strengthen this ever-growing case for the conservation importance of this paricular area of the southwest coast.
For the moment the situation is optimistic, as the study opens the door to making England’s first bottlenose dolphins permanent resisdents. But as Williams and the Cornwall Wildlife Trust are keen to stress, ‘the future of these iconic animals is in our hands and we need to make sure the few we currently have in the southwest are given the protection not just to survive, but to thrive.’
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