Back in April - I reported an objective assessment of our experimental introduction of bankside anchored Large Woody Debris (LWD - or trees!) into a spate river near Stockport (the river Goyt).
(old report here: http://urbantrout.blogspot.com/2009/...k-on-goyt.html)
The April assessment noted that the aim of providing spate-condition shelter for juvenile fish (especially young grayling that are often washed out in spates) appeared to be successful. We observed significant "stilling" effects around the trees (evidenced by sediment deposition).

We've just had brand new electrofishing data that give direct (rather than indirect) proof positive that these tree installations are also providing juvenile trout with shelter. (as a slightly irrelevant aside - the word "data" is plural, one of my personal Victor Meldrew pedantisms)

No juvenile trout had been recorded in ANY previous electrofishing results. However, this summer when the electrodes were thrust underneath the trailing branches of the installed wood a total of 8 juvenile trout between 7 and 12 cm long were caught. Graph below (n.b. no surveying done in 2007):



So, this is a timely point to flag up our next WTT/Trout in the Town intentions to extend the first "trial" installations of "sheltering" type LWD and augment them with some LWD that will be positioned on riffle areas to

1.) Create localised scour holes for adult trout and grayling habitat
2.) Throw up ramps of additional spawning gravel (arising from the scour holes)

Updates to follow on the blog......

Paul

nope your wrong!!!!!
robin hood and his merry men lived in trees

The series of charts appears to show that introducing dead trees denudes the river of all decent sized trout.......

Or did you have some other explanation for the disappearance.

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Plusnet/Madasafish > Liars to the internet community

There is a general low number of trout (the river generally lacks structure/features) in that reach.

You just have to be lucky with your "one shot" survey if there are any adult trout hanging around when you turn up with the gear.

There is a difference between "sometimes not finding the low numbers of adult trout that have previously been noted" and "first ever record of fish recruitment in a reach" I hope you will agree

Oh, and we are only talking about a short reach here. The big fish just might be using habitat upstream or downstream.

Nah - they were all killed by the LWD (Large Weighty Device) - or by the heron which stands on it.....

Seriously #1 - not enough data to comment on population changes.

Seriously #2 - I really dislike dead trees in spate rivers - they can be a lethal hazard to a swimmer - sure the EA are advocating their use but I suspect that there is the potential for an interesting court case...

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Plusnet/Madasafish > Liars to the internet community

quote=DownStream;510878]they can be a lethal hazard to a swimmer [/quote]

you go swimming in spate rivers??
take it thats when they are not in spate.
maybe you mean trees are obstacles to canoes.
fill the rivers with dead trees. good for environment bad for canoes.
regards
bert

Have you ever fallen in while wading?

How many corpses have you recovered from a river?

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Plusnet/Madasafish > Liars to the internet community

you are now on a sticky.

answer 1 yes, but never because of trees.

answer 2 two, both because of rising spate water, not trees, and one was a very good friend.

habitat improvement is the only way to go, and if that means trees then do it
regards
bert

Good.

My total is four - only one died entangled in a tree.

If someone had placed the tree there - who would have been to blame?

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Plusnet/Madasafish > Liars to the internet community