20 January 2010
A white-beaked dolphin was found stranded on a beach in St Mawes on Saturday 16th January. The 2.4 metre long dolphin was initially reported to the Cornwall Wildlife Trust Marine Strandings Network as a porpoise. However, the length of the animal and its description didn't fit the identification and when Jan Loveridge, the Network's Co-ordinator, received photos of it, she discovered it was a dolphin that is very rarely seen in Cornwall.
Dawn Andrews, a member of the public who reported the rare dolphin to the Network’s Hotline, says "Although it is sad to see a dead dolphin, it did give our children an opportunity to examine this beautiful creature close up. They were fascinated by the blow hole and its small, blunt teeth, and particularly by the smoothness of its skin." Twelve year old Josh Croft was another youngster who witnessed the stranded dolphin and was able to take some excellent photos, which he has given to the Marine Strandings Network for their archives.
"This is one of only nine stranded, white-beaked dolphins ever reported in Cornwall" says Jan Loveridge. "We're very pleased that so many people in St Mawes took the trouble to report it to us and it was great that the children took such an interest. There's nothing quite the same as seeing a dolphin close-up, although if a dead marine animal is found, it is advisable not to touch it as it could be carrying diseases that humans can catch." The hope is that, although witnessing such a scene can be distressing, may also inspire the public’s interest to help conserve marine wildlife.
The male dolphin was examined by James Barnett, a member of the Marine Strandings Network's team, who is also a veterinary pathologist and advisor to the Network. By the time help arrived to retrieve the dolphin, it had refloated on the incoming tide. The volunteers had to rely on the help of boatman Bill Whitton, and a local fisherman, who towed it back to the slipway where James and two other volunteers, Debs Wallis and Jeff Loveridge, were waiting to help lift the heavy dolphin into a trailer. It was then taken to the Veterinary Laboratories Agency in Truro where a post-mortem examination was performed. Sadly, this revealed that the dolphin was probably caught accidentally in fishing nets. Two common dolphins, which were found on the same day, one on the Lizard and the other near Penzance, were also examined.
In the UK, white-beaked dolphins are mostly found off northern Scotland and along parts of the Atlantic coast of Ireland. Sadly, they have been hunted and killed for food and oil in the seas off Canada, in Greenland, Iceland, the Faroe Islands and in Norway. They are fast, powerful swimmers and have a varied diet consisting of small schooling fish like herring, larger fish such as cod, whiting and haddock and other prey such as squid and octopus. They often hunt in groups and communicate with each other by whistles, tail slaps and leaps. Occasionally they may associate with large, feeding whales, such as humpback and minke whales and have been known to form mixed groups with some other dolphin species, including bottlenose and Atlantic white-sided dolphins.
The white beaked dolphin can grow up to 3.5 metres long and weigh up to 350kg and, like other North Atlantic marine mammals, can be contaminated by organochlorines and heavy metals which they ingest with their food. Little is known about the effects of these pollutants on the dolphins but, as has been found in other species, it is possible that their ability to reproduce may be affected, or their immune systems may be impaired to the extent that they become more likely to die from other causes.
"It is a sad end for this amazing dolphin," says Jan Loveridge, "but I'm pleased to say that as a result of this incident some local people have asked to train with us as Strandings Network volunteers. The Harbour Master has also kindly offered to alert us if any other unfortunate creatures get washed up." Last year alone, the Marine Strandings Network team was called out to 74 stranded whales, dolphins and porpoises. This is a lower number than usual, which has given them time to examine the strandings properly and learn more about how they died. Jan continues, "The more we know about them, the better we are able to fight for their protection."
The public are also urged to report stranded marine wildlife to the Network on their Hotline number, 0845 201 2626, which is monitored every day of the year.
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