Background
River Invertebrate Monitoring for Anglers is an angler-led initiative, spearheaded by the Riverfly Partnership, which ensures that angling groups can take action to monitor and help conserve the river environment. The Riverfly Partnership consists of more than 35 member organisations, including the Environment Agency, the Freshwater Biological Association (FBA) and in Cumbria the Eden Rivers Trust and South Cumbria Rivers Trust (SCRT).

The Partnership aims to address perceived declines in the abundance of river flies, in particular Mayflies (Ephemeroptera), Caddis-flies (Trichoptera) and Stoneflies (Plecoptera).

A national programme (River Invertebrate Monitoring for Anglers) was launched to train angling groups to monitor the water quality of their local rivers using a simple invertebrate sampling methodology.  A number of angling clubs (and other interested parties) were represented at a South Cumbria training weekend held in April 2007 on the River Bela at Beetham.

Once trained, anglers or other interested parties (eg Forestry Commission staff on the R.Duddon catchment) are encouraged to set up monitoring sites following agreement with the Environment Agency contact (usually an Ecological Appraisal Officer).  Agreement on site location is needed to ensure avoidance of interference with established monitoring sites and with any Agency activity or ecological feature.

Riverfly sampling at Agency approved sites uses the same methodology as the Agency Ecological Appraisal teams use for routine monitoring -  a three-minute kick sample augmented by a one-minute hand search.  Whereas we try to identify all benthic macro-invertebrates in a sample (usually to a mixed taxonomic level), for Riverfly monitoring there are only eight target groups to identify:

Cased Caddis
Caseless Caddis
Ephemera Mayflies
Ephemerellidae Mayflies (Blue-winged Olives - "BWO's")
Heptageniidae Mayflies (Flat bodied Mayflies)
Baetidae Mayflies (Olives)
Stoneflies
Freshwater Shrimps (Gammarus pulex)

A relative abundance assessment is made for each of the target groups which are then given a score:
Abundance A (1-9 organisms in sample - accurate count) - Score 1
Abundance B (10-99 organisms in sample - nearest 10)  - Score 2
Abundance C (100 -999 organisms in sample - nearest 100) - Score 3
Abundance D (1000+ organisms in sample - nearest 1000) - Score 4

The score from each of the identified target groups is added together to give a total score for the sample - this total score is locally known as the "Angler's Score Index" (ASI).

Worked example:

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