[naiad]

They are endangered here too. The Bullhead (European, not American) is becoming quite rare, because it needs clean fast-flowing water, and it is also unpopular with anglers because it eats trout eggs and fry. I doubt that it has any significant impact on the trout population, and anyway trout will eat their own fry.

It was strange to see how much life there was hidden under the stones - from the surface it looks almost lifeless apart from the occasional fish, but under each stone there is a community of mayfly and stonefly nymphs, limpets, leeches, insect larvae and bullheads. They stick firmly to the stones to resist the strong current. The clumps of plants contain insects and shrimps. There were also a lot of adult mayflies and dragonflies around.

Certainly a very interesting dive site.