Forth Fisheries Foundation

Quantitative monitoring of stream fish communities

Executive summary:

Monitoring of the status of the fish communities in freshwaters is an important tool in assessing their ecological status and provides data relevant to management and efforts to maximise fisheries production. By establishing a network of sites to be repeatedly sampled by full-quantitative electrofishing, the FFF aim to collect data on changes in fish communities through time and serve an important monitoring function. . Habitat variables relevant to the density and composition of the fish assemblage shall also be recorded, enabling greater interpretation of local variation, and an additional measure of environmental change through time. 

This project aims to establish the abundance and composition of fish communities at defined sites within the FFF area, and aims to record variation that can highlight change in the aquatic environment. Full SFCC electrofishing and habitat recording protocols will be adhered to throughout this project.

Management overview.

The ecological status of any particular watercourse can be inferred from investigation of many ecological indicators. The composition and relative abundance of the fish community is one such important indicator.

The relative potential for an area as a producer of fish relies on many factors including water quality, flow regime, access, composition of in-stream habitat and other factors that can affect the available food source. The standing stock of fish that can be supported by an area will have an upper limit placed upon it by many of these factors and the term "carrying capacity" is often used either to describe this for all fish, or for individual species. 

Estimation of the natural carrying capacity of freshwater areas can be provisioned by electrofishing surveys and is of relevance to those wishing to maximise the fisheries output of target species by undertaking enhancement works. It is integral to the success of any stock enhancement exercises.

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