Green case stuck to some plant stems underwater.
No identification made yet.
No interactions present.
Can you say what was the state of the water? Is there feed from, say, a factory or sewage system or intensive agrigulture? This doesn't look like pollution but is an unusual (algal?) formation.
Later, looking at the satellite image, Loch Hempton seems away from those things but even fish stocking can introduce such things.
I also see you live a long way away, so cannot go back to check. Oh dear!
THREE MARINE PROJECTS
Its main burn running into it is from Fell Loch, the only change this year is the Blizzard, we had in March, with very strong winds, the snow was not deep on the ground, but formed 10 ft drifts behind wall and in burns, the vegetation is on peat, short and thick. only small numbers of Cows and Sheep, over a large area, I can go back again, not sure what to look for.
Lat/Lng: 54.857, -4.6394
OS grid ref: NX306545