Sunday, 5 August 2012

Cetacean Corpse at Titchfield Haven

I had a call this afternoon, from Ed Bennett, a ranger at Titchfield Haven, that a cetacean corpse had been washed up on the beach at Hill Head. Ed suspected that the corpse was that of a Harbour Porpoise, and sent me a picture which seemed to suggest that it was, but being the sad person that I am, I decided to go and take a look.

Harbour Porpoise Corpse

The corpse was quite badly decomposed, and did wiff pretty badly, but still it was possible to make out what it was, although on I first impressions I did think that it might be a Common Dolphin.

Harbour Porpoise Corpse

The major difference between dolphins and porpoises is that dolphins have a pronounced beak, whereas porpoises have no beak and a blunt snout. As is possible to see below this corpse lacks a beak and has a blunt and rounded snout. Dolphins also have a more pointed and angled dorsal fin, whereas in porpoises it is blunt and less angled. The dorsal fin on this corpse did look quite pointed, although looking at the trailing edge, it is not as concave as would be expected in Common Dolphin.

Jaw Showing Rounded Snout

The dried and cracked tail stock is evidence that this corpse has been floating around at sea for a while, and I suspect it has drifted into The Solent from The English Channel. The colouration of the tail stock, with dark grey upperparts and pale underparts, was again consistent with Harbour Porpoise. Common Dolphin has an hourglass pattern on its flanks and therefore it should still be possible to see the two-tone pattern.

Dried and Cracked Tail Stock

Many Harbour Porpoises are killed each year, either as by-catch from the fishing industry or by collision with shipping vessels, so I was keen to see this corpse and see if there was any evidence of either. I could see no evidence of net entanglement or propeller cuts, so it maybe that this individual died from natural causes, but unfortunately we will never know.

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