Ecology services

Sampling invertebrates on the River Irwell

  • 1. Salford Friendly Anglers' Society
  • 2. River water quality monitoring with invertebrates
  • 1. Salford Friendly Anglers' Society

    Ye Olde Anglers Club

    Manchester's most famous river, the River Irwell, flows down through north Manchester to become the Manchester Ship Canal. Salford is the twin city to Manchester and the River Irwell separates the city centre between the two. Founded in 1817, the Salford Friendly Anglers is the oldest established fishing club in the world. Visit the Salford Friendly website at for more information on free membership and the work that the group do.

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    2. River water quality monitoring with invertebrates

    Water quality in any one spot on a river varies greatly day-to-day with weather and flow. Rainfall, for example, dilutes pollutants, washes in debris, or causes sewers to overflow. Invertebrates, however, live on riverbeds for several years and their survival depends on the overall water quality to which they are exposed over time. The invertebrate community therefore indicates the long-term overall water quality. The nymph stages of well-known river flies (such as mayflies and caddis) spend the first year or more of their lives living amongst the gravels of the river bed, before hatching out as the adult flies. Trout are associated with clean waters because the flies on which they feed require clean water for successful reproduction – cleaner waters mean more abundant flies.

    The Riverfly Partnership set up the Anglers' Riverfly Monitoring Initiative (ARMI) scheme to give anglers a way to assess how clean their river environment is from the abundance of clean water flies. The AMI site score is an index of the abundance in the riverbed substrate of 8 groups of clean water indicator invertebrates. Essentially, the greater the abundance of indicator invertebrates picked up by a 3 minute kick sample the cleaner the typical water at that location is.

    In September 2011 members of the Salford Friendly Anglers' Society began collecting monthly samples to get a picture of the riverbed invertebrate community at a number of sites of interest to anglers through the Irwell catchment. We began with 14 sites and have achieved comprehensive data sets of at greater than one year coverage for 5 of these. All 5 sites have moderate water quality and reasonable cleanliness is indicated by the presence of sensitive Blue-Winged Olives and Stone Clingers. Hog-louse, Leech and Bloodworm tolerate poor water conditions but they are also found in cleaner waters and their presence does not indicate pollution.


    Results and report of baseline invertebrate communities. February 2014

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