Date: Fri, 11 Apr, 1997
Moby: The Final Word

From: J. C. Goold <oss123@sos.bangor.ac.uk>

"Moby" (for those who've forgotten, was the sperm whale which died recently in the Firth of Forth, Scotland).

Moby measured in at 14.6 metres, rather larger than originally estimated from boat observations, and was probably a lone male. Initial reports that 3 other sperm whales were sighted in the Firth are probably incorrect; these were never confirmed or resighted. What was found in the area, however, was a humpback whale and 2 minke whales so most probably these were "the other 3 sperm whales".

When we observed the humpback and minkes from a boat our echosounder showed dense shoals of fish. Reportedly herring and sprat had congregated along the northern shore for a Spring spawning, which coincided with very high spring tide. I speculate that these 3 whales had come in to feed (they disappeared after a few days).

The sperm whale "Moby" did not frequent the same area and showed a consistent (indeed irritating) tendency to travel south-west, which eventually put him on a mud-bank far up river where he died. This was a whale with almost as many lives as a cat, having previously grounded himself 3 times followed by successful refloations on the incoming tides. On these three occasions the whale was never totally without the support of water, which no doubt saved his life.

During shepherding operations to encourage the whale to move out to the (relatively) open North Sea, the whale could be heard making regular clicks through the hydrophone. Only when the animal grounded on a sandbank (stranding number 2) was any change to the vocalisations heard. When grounded the whale emitted "loud, sharp knocks", which sounded to me to be rather more narrow band than the clicks. When a window in my workload presents itself I'll have a look at these in more detail, and as I was using a calibrated hydrophone hopefully the "loud" bit can be quantified to some extent.

Although the humpback and minke whales were likely to have been feeding on spawning fish, a sperm whale is unlikely to be able to feed efficiently on such prey, and indeed there was no evidence to suggest it was. I would, however, be interested to know if there is evidence from elsewhere that sperm whales have followed fish shoals. As the whale was probably a lone male, not fully mature but possibly old enough to undertake a migration to the breeding latitudes, the south-westerly trend of movement suggests to me that the whale was on the wrong side of the British Isles. Had he been following the shelf-edge to the west of the British Isles the path to more southern latitudes would be have been open. If, for whatever reason, the whale had diverted from this course and entered the North-Sea this path would be largely obscured by the land mass of the British Isles.

John C. Goold
University of Wales Bangor
School of Ocean Sciences
Menai Bridge
Anglesey. LL59 5EY. UK
Tel. (0)1248 383752
Fax. (0)1248 716367
email: oss123@sos.bangor.ac.uk



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