Wednesday, 17 August 2016

Pearl Mussel Project Returns.... Again

Diane Baum and Lucy Ballantyne, who work for Lochaber Fisheries Trust and are currently trying to increase local populations of the endangered Scottish pearl mussel, returned to Ardnamurchan yesterday to look at what our local mussels are doing. They're already been back twice since their first visit on 15th July - post here - but haven't yet found any mussels with spat which are ready to be transferred to host fish.

Picture shows Diane, top right, collecting mussels from the bed of a local burn, helped by Rachael, while....

....Lucy carefully opened each mussel and, if it showed signs of carrying spat....

....gently syphoned some of the spat into a syringe to transfer them to a portable microscope to see what stage they had reached.

While we were there, they must have looked at upwards of forty mussels from two burns. Hearteningly, about 50% were carrying spat, but almost all were at stages 1 to 3, and none had reached the vital stage 5, where the spat could be transferred to a host. With the water warming up following recent sunshine, Lucy and Diane will be back very shortly to try yet again.

Some patterns are emerging. Of the three burns where we have seen pearl mussels, one contains only a very ageing population; one has a predominately middle-aged to old population; and the third, the smallest burn, has a good number of young mussels - but also contains a large percentage of dead ones.

Please note that it is illegal to disturb pearl mussels. The Lochaber Fisheries Trust works under a special licence.

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