Peter Coleman-Smith reports that he took a very interesting river fly sample at Cribbs Causeway yesterday morning.
Near the Porcelanosa carpark on the way to Cribbs Causeway, there’s a footpath which leads after 40 metres or so to the infant Hazel Brook (sometimes called the Henbury Trym). Peter reports that it was very low but the water was cool and crystal clear.
The sample yielded a few cased and caseless caddis (hydropsyche) larvae, some large dark olive nymphs (Baetis rhodani) and some freshwater shrimps which is as good as any site in the catchment area. Peter took the olive nymphs home to identify them at a species level and one hatched out in his car leaving its empty skin in the water.
It’s good to see such diversity, revealing that the poor water quality further down the Hazel Brook isn’t from the shops or commercial properties at Cribbs Causeway.