Upper Spey invertebrates

Whilst checking the smolt trap on Monday we collected a standard three minute invertebrate kick sample from the upper Spey at Kingussie. The site was a riffle/run typical of the habitat present in that area of the river between the big long glides. The substrate size was quite small; gravel and cobbles but it was surprisingly compacted at one side, although the faster flow near the left bank was looser. It was a relatively stable riffle with some moss and weeds present and a good coating of algae.

The sample took a lot of sorting and I am grateful to Donald Morrison, a student at UHI, who volunteered with us for a couple days, for his assistance in sorting and identification. To say there was an abundance would be to understate the case. A total of 2162 individual specimens were counted.

From top left: cased and caseless caddis; diptera, snails etc, stoneflies, mayflies

Clockwise from top left: cased and caseless caddis; diptera, snails etc; stoneflies and mayflies

Invertebrate population structure fro Ruthven Bridge sample Kingussie

Invertebrate population structure from Ruthven Bridge sample Kingussie

There were 736 mayflies, 520 of which were baetids, or olives to an angler. The rest were Olive uprights with a few March browns and a single Yellow May dun nymph.

648 stoneflies were by far the most we have come across in a sample. Six different families of stoneflies were present, including many of the large predatory type.

There were more caseless caddis than cased. No shrimps were recorded and there were low numbers of snails (4) , in comparison to the Castle Grant site. Several different types of diptera were recorded including 330 chironomid (midge) larvae and 96 Simulidae (black fly) larvae.

So a very rich and diverse sample from the upper river. It will in due course be interesting to make a comparison between these main stem samples and the tributaries.

 

 

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