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Showing posts from March, 2009

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) le

Bugs in the Cray

Following on from the water quality data analysis - here is some summarised information that TINTT has pulled together using data kindly supplied by the EA. These data are drawn from sites that are being considered for habitat restoration (with a possible long-term view of restoring native trout populations). First of all, it is apparent that there are examples of a number of invertebrate families that are happily living in the Cray that would not be able to exist in polluted environments. You can particularly see the good populations of Gammarus (freshwater shrimp). These shrimp are a valuable find because they have lifecycles that can take two years or more to complete. In addition, because they can't fly, they are not very good at migrating upstream over weirs to colonise new areas (i.e. they can only really re-colonise from upstream populations if they are wiped out). Taken together - their presence in healthy numbers indicates that water quality tends to be good enough to enab