Bottoms up

I did say I would post a backblip for Thursday, we were home too late to post it that evening.

While this might make an excellent caption competition, I will explain what is going on here. This is a river in West Cumbria, and here we have three of my colleagues, looking through the flowing water at freshwater mussels anchored in the sediment. The two people nearest the camera are visitors, Head Office specialists who had never seen this mussel species before. Alison has the orange bathyscope which affords a clearer view through the water column. We had been giving Alastair and Glen a tour of certain lakes and rivers, and this was our final stop.

A better picture still would have been Alastair's delighted face afterwards when he reflected that the mussels he had been looking at were alive and mature when he was born, more than 50 years ago. As he said, this is a truly iconic species. A bivalve mollusc that lives for over a 100 years, and has an astonishing lifecycle that involves a stage when the tiny molluscs (then called glochidia) are attached to the gills of salmon. But this species is one of conservation concern, it depends on almost pristine conditions in the rivers in which it lives. We don't have many rivers like that in the UK, and most are in Scotland. In England and Wales, this mussel species has been reduced to a handful of sites, and many of those are like molluscan old peoples' homes - small numbers of ancient individuals. The mature molluscs are more tolerant of bad water quality, it is the first 15 years of their lives when they are at their most vulnerable.

The site we were visiting has the biggest population in England, and the best water quality - but there is still a big gap in the age profile, there are hardly any animals less than 40-50 years old. But the news is not all bad. A lot of people and organisations are contributing to a programme of actions to recreate the conditions that will allow the molluscs to successfully establish new generations to replace the mature ones as they eventually reach the end of their long lives.