Skip to main content

Waving a Magic Wand(le)


Very hot news just in is that after many months (years!) of assessment, planning, design, negotiation and hard work; permission has just been granted for my design of habitat restoration and enhancement works to go ahead on the upper Carshalton arm of the Wandle.

Many thanks to Bella from the Wandle Trust hosting our E.A. flood risk assessor and putting our case so well and also great effort from Tanya in E.A. fisheries for making the weir removal programme happen.

An extensive array of structures will be installed over around 600 m of river which will create high quality spawning and adult holding habitat along with some additional juvenile habitat to complement the existing opportunities for young trout. When this is coupled with the increased connectivity along this section of the Wandle (through a combination of weir removals and fish pass installation), then the potential for robust self-sustaining populations of wild trout will be greatly increased.
The final piece of this part of the puzzle will come with the hoped-for opportunity to import wild trout parr from nearby in the catchment. Rather than depleting adult brood stock from the donor site - juveniles will be sourced from a population that is producing a natural surplus of parr (mixture of 0+ and 1+ age classes)in a comparable stream. In this way, with the phasing in of sterile "triploid" eggs for use in "Trout in the Classroom" instead of fertile hatchery strain fish - the adaptable and well-prepared wild fish will have the best chance of establishing themselves and successfully breeding in the Wandle once more. The classroom fish have done an admirable job in proving that survival, growth and even a little spawning can happen in stream (they have been the canaries in the cage). The next exciting phase is hoped to be to see how the streetwise wild fish take to their new home.

Comments

Regular Rod said…
Are there absolutely no trout in the Wandle to begin the spawning and regeneration? It would be so much better if no fish had to be brought in from elsewhere...
1 September 2010 at 10:05
Paul Gaskell said…
The original wild trout of the Wandle were finally lost about 80 years ago.
The presence of a number of impassable weirs has prevented recolonisation via (for example) sea trout.
The only trout in the Wandle at the moment are the product of their great educational efforts using "Trout in the Classroom". These are hatchery strain fish and have at least made some breeding attempts. However, because hatchery fish have only 10% of the survival and reproduction of wild fish, this cannot be the basis of a sustainable population. By 2015 legislation (and best practice) will mean that the classroom fish will be sterile triploids.
Hence the need for a "next nearest" wild parr source.
9 September 2010 at 01:13
Post a Comment

Popular posts from this blog

The Wild Trout Trust: A Film by Chalkstream Fly

Here is a great short piece that captures what the work of the Wild Trout Trust is all about. It was made for (and broadcast on) the very first "World Fishing Day" - a 24hr live fishing programme created by FishingTV.com . It features TV personalities (and WTT President & Vice President respectively!) Jon Beer and Matthew Wright as well as Director of the Trust, Shaun Leonard. You can see more work by the film-makers on Chalkstreamfly.co.uk  and, of course, you can join the Wild Trout Trust here: WTT Membership Paul Gaskell (Trout in the Town Conservation Officer)
Post a Comment
Read more

Why Presume to Remove Weirs? (with River Dove Case Study)

Weirs and the Backwards Ways that Rivers Work One of my favourite sayings on river restoration is a mangled quote from a movie "... boxing is an unnatural act. Everything in boxing is backwards: sometimes the best way to deliver a punch is to step backwards...but step back too far and you ain't fighting at all ". So my mangled version starts out "Everything in rivers is backwards...". Basically, I never seem to run out of new examples of "what SEEMS to happen in a river is actually the complete opposite of what really happens". The rest of this article looks at many of the "backwards" things about weirs and rivers - and finishes off with a real-world case-study that is playing out right now on the River Dove . One spoiler alert is that, from an ecological point of view, it is almost always safe to assume that: The best biological outcome for a river is the removal of some or all of an artificial weir.  Now, I don't exp
3 comments
Read more

Birmingham and Coventry's Urban Waterways

It's about time for a new blog post and I thought it would be good to flag up some of the investigations that I've been doing in conjunction with Waterside Care (which, in itself, is supported by Keep Britain Tidy ). As well as initial investigations on the River Cole around the Shire Country Park and Burberry Brickworks, more recent forays to the little Westley Brook, River Sowe, Stonehouse Brook and a little stream in the Holly Wood Local Nature Reserve (between Great Barr and Queslett) have seen me criss-crossing the M6 and M69 and the surrounding areas. What always surprises me is just how much of the Black Country/Coventry area is essentially "floating" on a vast network of underground watercourses which suddenly pop up into daylight in surprising places. Of course this puts a lot of pressure onto the biology of these streams - not only from the physical "encasing" of their channels in brick and concrete (both above and below ground). It is t
3 comments
Read more