See blog account here for how the Wild Trout Trust and the Wandle Trust hosted an event to support the UK-wide Trout in the Town project - which was combined with major habitat works event that both local and national Trout in the Town volunteers took part in.

Trout in the Town: Return of the Urban Conclave - even bigger and better than the original?


Adult Wandle Trout from "Trout in the Classroom" fry release



The volunteers get stuck in to the restoration training

Really a nice story and pictures. That's a fine looking trout that Wilson caught there.

Just curious, have you conducted any netting or electrofishing surveys and if so what are you seeing as far as natural reproduction?

Grouse

A cracker of a brownie Paul and a damn good read too...

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E.A. Fisheries and Vaughan Lewis (AEC Windrush consultancy) have done a number of surveys. At the moment there are only stickleback and bullhead upstream of the large weir where the fish pass is going to be fitted. Downstream of this weir there is a mixed bunch of stuff - including trout derived from the schools' projects. These trout do cut redds and, as of last year, there was a single "stream spawned" fry found by Theo during his "Riverfly" kick sampling (this was the week before the schools released their fry - so it could only have come from in-stream spawning).

The electrofishing surveys reveal mainly "adult" trout with a few smaller fish (they grow very fast) but currently the in-stream reproductive success is very low. Part of this will be due to a relative lack of good quality spawning habitat (or inability to access such habitat). There will also be a strong contributory factor from the fish being relatively domesticated due to their hatchery origin. Typically, domesticated fish have only one tenth of the reproduction and survival rate in the wild compared to wild fish.

Our plan is to use wild parr (which will be very much more genetically diverse and also chosen from a river with very similar characteristics to the Wandle). The pre-adaptation of such fish to surviving and reproducing in a similar wild environment (as well as the greater "adaptability" conferred by having greater genetic diversity) is the main reason for this approach.

Using parr, rather than adult fish, means that the donor river will not be depleted of their brood stock and one of the main criteria for choosing such a donor river will be that it produces a surplus of juvenile fish (i.e. they undergo "density dependent" mortality). It will also avoid the problems of artificial selection that are part and parcel of "wild broodstock" schemes. Recent work shows that even first generation fish produced from eggs and milt of pure wild fish differ significantly from any of the native breeding populations from which they are derived.

Our intention (subject to obtaining all the correct permissions) will be to use a mixture of 0+ and 1+ parr (fished from short sections of the donor river - turning off the electrodes for at least equivalent reach lengths between each "fished" section) and to repeat the "seeding" of parr over two years. In the interim we must ensure that there is plentiful cover for each different stage of juvenile fish (from swim up fry to 1+ parr) so that any instream spawning success is maximised by good juvenile survival. We already know from the school "Trout in the Classroom" fish that the adults grow and survive very well.

Fingers crossed.



Edit: The reason that the natural population has not been restarted by Thames seatrout migration is simply the number of impassable weirs on the system (for a chalkstream, the gradient is quite steep which made it a favourite for water-powered industry - hence hundreds of weirs!)

---------- Post added at 07:11 PM ---------- Previous post was at 07:08 PM ----------

Nice one Woz - how about that fish from Manchester!

PG

Yes Paul that was a beauty too...
I'm looking forward to getting back on the Tame to see if there's any signs of recovery after UU sent bleach through my local stretch, maybe it's wishful thinking and a little to soon though. I might go park my bum on the bank with a flask and the pooch and look for signs over the next few weeks for an hour or two here and there.

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And now - one of the two remaining barriers to the newly improved upstream habitat has been tackled by the E.A. fisheries team.

The habitat works completed by the Wandle Trust personnel under the Wild Trout Trust practical training visit will soon be connected to a much longer section of river via the removal of one final barrier.


Fish pass purchased and fitted to impassable barrier by local E.A. fisheries team

Following some more tweaks to the habitat works (and their ongoing maintenance) all that remains is to get permissions in place to source and introduce suitable juvenile wild trout. This approach is designed to allow a self-sustaining wild population of trout to become re-established (without depleting the donor stream of brood stock, or getting entangled by the pitfalls of artificial selection etc. found in egg boxes and broodstock stripping schemes).

The last recorded Wandle Trout that was recognised as being truly wild (i.e. from self-sustaining stocks) was noted in the 1930's. Lets hope its not too long before they are breeding and thriving once again.

All of this work has been made possible by the massive efforts of the Wandle Trust and the partnership with the Environment Agency. In the absence of either group, the habitat works designs, appropriate installation techniques and prioritisation schedule of barrier removal and strategy for re-establishing self sustaining trout populations would simply remain as quaint (but irrelevant) words and pictures on my laptop's hard drive.

Well done to all involved



And congratulations to Bella for being promoted to Director of the Wandle Trust