Skip to main content

We are a grandmother (and page visit counter added today)

A trial of the "Mayfly in the Classroom" apparatus (a very slight modification of Finlay's (2001) system developed in Australia) has produced its first offspring. A proud moment for MITC which is, itself, a child of Trout in the Town.
Back in November 2008 a basic set of equipment was assembled from very cheaply available materials (the most expensive item is the air pump at £8).
An assembly procedure that is simple enough even for the author to complete (and therefore a doddle for the schoolkids) housed 3 pairs of nymphs for 6 weeks in perfect happiness. These were released back into their native river just before Christmas 2008 and just one of their cohort retained for further work. After continuing to graze on the algae-covered pebbles in her mini-aquarium, Thursday last week heralded the point that the nymph decided it was high time for a major change of lifestyle. As a result, she emerged as the flying sub-imago (or dun). The nymphal "shuck" (or skin) left behind on the rock clearly shows the exit point of the sub-imago just behind the head (white strands and ragged edge)
The body shape that is typical of the Brook Dun (Ecdyonurus spp.) is easy to see against a white background
Even the species can be identified from the nymphal skin if you look closely at the tarsi (feet)... ...and the remains of the "negative" pattern (i.e. light dots/lines on a dark background) on the underside of the body. Together these indicate that our newly hatched sub-imago is Ecdyonurus torrentis Then, sometime between Saturday evening and Sunday morning, the sub-imago made her final change to become the imago (or spinner) with the longer tails, legs and the shimmering gossamer wings of the mature adult.

Here is the skin of the sub-imago (dun) from the final moult:
Here is the first official offspring produced in a Trout in the Town classroom setup:

She was released and placed in the vegetation of her native stream this morning - in the hope that she may be able to make her contribution to the next generation of Brook Dun mayflies.
Soon pupils at local schools will have the chance to look after their own mayflies, compare results and observations with other schools as well as learning all about the biology of these important insects. As part of this, mayflies' importance in the foodchain (including the value to trout and birds) will be highlighted, alongside their requirement for good quality, clean rivers in which to live. Some of these pupils will go on to become the custodians of their local urban rivers.

Comments

Andy Pritchard said…
Fantastic, really good photos too Paul.

Keep up the great work, hopefully we can get this going up in Colne in the not too distant future.

Popular posts from this blog

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

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)

Porter Brook - Channel Habitat Improvement in De-Culverted City Centre Stream

There will be more pictures and video to come to document this bold project by Sheffield City Council to uncover a section of stream that used to live beneath a factory floor. They are in the process of creating a "pocket park" that will provide new flood-water storage (when the rivers are in spate) and an improved public park amenity (when the rivers are calm). The pocket park itself will be excavated out from the current high ground level (and a major construction project is underway at the moment to achieve this). The Wild Trout Trust were brought in to design in-channel features and riverbed morphology that would maxmise the improvements for the ecology of the stream - including for the prospects of a small and fragmented native population of wild brown trout. The site after uncovering the stream - but before the in-channel works Part way through the Pocket Park Construction - new gabion walls and flood defenses Channel with boulder clusters, log deflector-consoli