electric fishing equipment and technique


image of electrofishing for juvenile trout from www.tetonwater.orgThere is a variety of information relating to electric fishing in the Annex 1 – Water Analysis – Sampling of Fish with Electricity, arising from the progress report from the FAO’s European Inland Fisheries Advisory Commission 21st Session, held in Budapest, Hungary, 1-7 June 2000.

An examination of the use of electrofishing is presented at www.fisheriesmanagement.co.uk:

Introduction
One of the key tools available to fisheries management is that of electrofishing. Electrofishing is a reasonably simple concept to explain practically, but theoretically it can be rather confusing. Simply, a field of electricity is passed through the water that causes a muscle response reaction from the fish forcing them towards the netsman. A full explanation can be found later on this page. The main purposes for electrofishing are stock assessment, sampling/health surveys, tagging, catching spawners, anaesthetising or eliminating species

Application
Electrofishing is an effective tool for fishery scientists because most aquatic organisms become motionless when the body voltage exceeds a certain value from nose to tail. Early methods were only applied to freshwater streams and small pools; this was due to limited knowledge of fish reactions.

The inherent nature of the process allows shallow water to be fished successfully; also there are limits on the total area that can be worked. Taking these two principals into consideration the ideal waters would be small shallow rivers, commonly chalk streams, drained canals or full navigational pathways with a maximum depth of 2.5 metres; the width of the canal is the main restriction. Conversely, the littoral zones of lakes and reservoirs lend their self to efficient electrofishing especially if there are many bank side features such as overhanging bushes, trees or reed beds. The aforementioned site descriptions tend to be very difficult to seine net thus electrofishing is the ideal replacement. On occasions fish traps can work well as an alternative if instant results are not required. Electrofishing can be undertaken in many forms with the most common applications being classical wading, classical boat fishing, trawling and screening/guiding.

New Zealand Qualifications Authority has offers an assessment standard entitled: Explain the principles of electric fishing and operate electric fishing equipment developed in association with the Seafood Industry Training Organisation (SITO).

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