Records of Past Strandings (Under the shaddow of Ben Bulbin's shores! Note the profile of this mountain in the whale diagram!)

My first contribution to the ESAI server and news letter : Bill Crowe Fri 13 / 3 / 98 !

Marine Cetations regularly strand themselves around Irish coasts, causing distress to the general public, who do not know what to do under these circumstances and feel helpless. The North West Region of Ireland and in particular coastal regions around Sligo seem to have more than their fare share of strandings. Last spring in a 3 week period between mid February and early March there were over 14 recorded strandings of whales and dolphins. Some of these might have been saved if the right equipment and trained personnel had been around early enough. An example of some of the strandings which the proposer of this proposal has been involved in might serve to illustrate the problem.

Between 10.30 am and 12.30 p.m. Jim Ewing, John McGowan, James Donnellan and Stephen Butler, the latter in a wet suit, continued to bring the dolphins out to sea again every time they beached themselves. The smaller one had wart-like hard growths on its belly about the size of a 10p coin, probably caused by a fungus infection. The larger dolphin, estimated by the fishermen to be about 110 lbs. in weight, then swam fast straight towards the pier, hit itself hard against the pier, beached itself on the strand near the pier, shuddered and died suddenly. The other small one, remained at sea, so the diver call out was cancelled at about 3 p.m.

The stranded dolphin was measured on the shore by Bill Crowe, when he arrived at 3.30pm, and definitively identified by Don Cotton the following day. Bill Crowe also took some slide photographs of the animal. It was a Euphrosyne Dolphin, Stenella euphrosyne (Gray), often called a 'striped dolphin' and had a maximum length (from tip of its beak to the end of its tail, in the centre, of 1metre, 95cm, measured along the belly. Its maximum girth was 98cm, measured around the body just in front of the dorsal fin. The dorsal fin which was just behind the mid point of the body was 25cm long along the body, 16cm high perpendicular to the body, and the maximum length diagonally was 30cm. The pectoral fins (flippers) stretched 28 cm away from the body. The beak region in front of the head was long (13.5cm) and narrow with a girth of 24cm. The upper right jaw contained 42 teeth and the lower right jaw 43 teeth. The teeth to the front of the jaws were very small and there were probably some teeth in front of these which still had not broken through the gums of the jaw, especially in the upper jaws. The distance from the back of the beak to the blow-hole was 20cm. The distance from the front tip of the beak to the eye was 30 cm and from the front tip of the beak the front of the flipper was 50cm. The right tail fluke length measured along the body was 15cm, its width measured perpendicular to the body was 22cm and its maximum length measured diagonally was 26.5cm. The genital groove on the belly was 14cm long and had 2 slits either side of it of 2.5cm. For this reason it probably was a female. The smaller dolphin may have been her calf.

John McGowan brought the dead dolphin to a cold room at his home at Dunfore where it was later collected by Emer Rogan of Cork University's Department of Zoology and taken to Cork for a full autopsy.

In Atlantic waters there are six common dolphin and one common porpoise species. Dolphins and porpoise have almost central dorsal fins. Porpoises are small (less than 6 feet long and blunt nosed with no beak).The long thin beak, streamlined body, adult length of 6 to 9 feet, that is approximately 2 meters, would suggest that this stranded dolphin was either a Common or a Euphrosyne dolphin. All the other dolphins (Risso’s, Bottle-nosed, White beaked, and White-sided Dolphins) tend to be larger; 9 feet to 12 feet long as adults. Euphrosyne dolphins have a white area mainly on the lower sides only but may extend upward behind the dorsal fin, towards the dorsal (back, uppermost) surface. In Euphrosyne dolphins, and well seen in this individual, there are 3 distinct dark lines, one from the eye to the flipper, one from the eye to behind the flipper, and one from the eye to the anus, along the lower flank of the body. There is also sometimes a white streak upwards towards the dorsal fin. In the Common Dolphin there are generalised white areas on the side extending forward towards the head and extending upwards but not as far as the dorsal surface. There are light and dark areas on the body in a criss-cross or hourglass pattern. There is a dark line going from the flipper towards and under the eye along the jaw to the beak. The dorsal surface is generally darker than in Euphrosyne.

This specimen appeared to be in good condition, apart from having a clean deep 28cm long gash along the left flank, which was probably / possibly caused when the dolphin bashed against the pier. There were also superficial scratches on the left side of the dorsal fin, and scratches on the right pectoral fin and over the right eye.

This species was not recorded from Irish waters before the 1980s. It probably was common enough but may have been miss-identified as the commoner Common Dolphin , because of its great similarity in shape and colour. Since 1980 there have been several strandings of Euphrosyne dolphins in Sligo. Details may be obtained from Don Cotton. One stranding occurred at the same locality, Raughly pier, at almost the same time of the year in 1994. This might suggest there is a migration of this species past this region regularly at this time of year.

Two more strandings of dolphins occurred in Sligo both probably on the 28 February 1998. This was a period of storm conditions with high sea swells and high spring tidal conditions. A 2.5 meter long male White-sided dolphin, Lagenorhynchus acutus beached itself on Inishcrone Strand (Grid reference G282298) and a 2.25 meter long male Common dolphin, Delphinus delphis was stranded at Lackmeeltaun, Ballyconnell (Grid reference G564459). Both were photographed by Don Cotton. Neither had any serious damage or net marks and the White-sided dolphin visited on the 1 March was in fresh condition, but the Common dolphin, visited one day later than the first, was only in moderate condition.

Various reasons for mass strandings of dolphins have been proposed, ranging from, temporary local magnetic anomalies in regions interfering with their navigation systems, to strong social bonds between family members causing all members of a group to follow a sick dominant or leading animal ashore when it beaches itself.

Should anyone come across living or dead whales, or dolphins, in the Sligo area, they should contact either Don Cotton, or Bill Crowe, at the Institute of Technology, Sligo, or the Sligo Society for the Protection of Animals, if the animals are beached and still alive.

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