3 Oct 2013

The need for a new ladder

So, in my river there's this old mill.
While i do appriciate the historical values of it (and do NOT want to see it torn down) it does present a stop for the fish in their migration upstream.

There are potentially two types of trout present in this river, the brook trout Salmo Trutta Fario and a large lakerun brown or Salmo Trutta Lacustris.
The stream resident Fario morph operate mainly above the mill but the lakerun variety need to be able to pass upstream to further the reaches of their spawning grounds.
Lake Siljan and the Orsa Lake trout are of a particularly large breed and are both valuabe and considered threatened.

There is an existing ladder although it functions poorly.

Clogged with logs and branches.
Low water levels leaves leafes in the ladder.

Above the inlet.
The reeds are taking over.

The inlet.
Clogged with twigs and branches.

 I cleaned out the log,branches and twigs and as much leafes as i could.
This years low water is a problem as the ladder is clogged.
The principle here is that the fish should go through V shapes up the ladder and further up the river.
With low water however, that is not at all possible.
I can safely say that not a single trout have passed here.

My suggestion therefore is to tear out this old ladder and install a new, more naturelike ladder that will allow, the fish to pass.
If the reeds above the inlet were to be cut down and a new ladder with a higher flow were to be installed they'd have a hard time growing back, making it more of a onetime job.
A higher and more natural flow would also eliminate the problem with leafes and make logs less of a problem.

I've mailed the lokal fishery society and are awaiting answers from there.
They'll probably not have the resource for such an operation and i'm probably gonna have to go further up, to the local government of Dalecarlia.

Would't it be great to hook one of these large browns not in the lake trolling but on a swung fly up in the river?
Of course, it's about all the species and not all about fishing.

Here's a great new report from the University of Karlstad on planning and building nature-like fish ladders.

It's a PDF in Swedish.

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