Here on Ardnamurchan we are fortunate to have four of the seven Lochaber burns which have Special Area of Conservation (SAC) designation for their pearl mussels, though those in the Sanna burn are far from healthy as almost all of them are over 60 years old, and even in the other burns most of the mussels are 40 or older, with little sign of young ones coming on.
Diane and Lucy's objective is to help with the transfer of the glochidia from the pearl mussel to the fish. They start by wading into a burn and finding about fifteen pearl mussels at a time, putting these into a bucket to bring ashore.
On the day I accompanied the researchers, three of the fifty or so mussels were carrying glochidia, but none had enough glochidia at stage five. Had several mussels been ready, then 10-15 trout or small salmon would have been caught from the river using electrodes (Lucy's picture, above, shows this) and immersed in a container....
Lucy and Diane will be returned shortly to Ardnamurchan as it appeared that most of the mussels had not yet produced their glochidia, which, like flying ants, is an event which is supposed to be co-ordinated at roughly the same time.
Many thanks indeed to Lucy and Diane for the time they gave me, and to Lucy for the additional pictures.