A fishy question

[Spinney]

Cycling through Poolewe in Scotland last week, and spied this contraption in the river. The central bit was rotating slowly.

A woman in the shop at the Inverewe gardens said it was something to do with helping salmon to get up the river, but she didn't know how it worked.

I wasn't convinced. If salmon need help that close to the sea, in such a shallow river (i.e. not having to jump up waterfalls) then they aren't worth breeding anyway!

And how would it help fish up the river?

Anyone got any ideas what it IS for?

 

[mcshroom]

Looks like a survey trap. There was one on Countryfile recently and it traps fish without hurting them, then the conservation people collect them, count the species and release the fish. The slow spinning blades were to stop the fish from swimming back out

There's one halfway down this page

 

[Spinney]

Ah - that makes more sense than 'helping salmon'.