Strand shells after Cornish gales

On March 7th. of this year (1962) great damage was caused to harbour walls, roads and buildings on the South Cornish coast by hurricane force south-easterly gales, and on the 11th. March we saw the effect of the tremendous seas on the molluscan fauna at Crinnis beach near St. Austell, Cornwall, At the top of the beach there was a strand line consisting exclusively of Otter shells, Lutraria lutraria (L.). Many thousands could be counted, and although most were broken, measurements showed that the majority reached the maximum size of 5" x 2". Devoid of all living tissue these shells had been cleaned by various scavengers, and this together with their position on the beach above normal high tide mark suggests that they were churned out of their deep burrows by the turbulent seas at the height of the gale and that they marked the furthest reach of the Spring equinoct¬ial gales some four days previously. Lower on the beach and presumably representing the two foot slackening of the tidal reach, and the abating of the wind, was a more recent strand line, composed of mixed species, most of them still alive. There were numbers of empty Razor shells, Ensis sp., but of the living species, Rayed Trough shells, Mactra corallina (L.) occiirred in enormous numbers, Banded Wedge shells, Donax vittatus (da C.) - less numerous - and Thin Tellins, Tellina tenuis da C. in smaller numbers. Some specimens showed feeble response when their gaping shells were touched, but other, selected, specimens lived for many weeks in an aquarium. Besides these burrowing species others such as the Edible Mussel, Mytilus edulis L. and Limpets, Patella sp. which had been torn from the rocks were also present.

Some idea of the relative abundance of the various forms could be gauged from this event and valuable studies could certainly be made on the shell jetsam of a beach after such holocausts or, better still, comparisons made between several beaches. Mss Harvey of Padstow made some similar observations in the same gale period, and recorded one strand line composed entirely of Saddle Oysters, Anomia ephippium.

Barbara D. Stephens and Stella M. Turk