Stunningly efficient electrofishing

Posted on June 26, 2010

Electrofishing, where an electric current is used to stun fish so that they are easy to catch, is a standard technique for sampling freshwater fish.  A common electrofishing practice is to sample a predetermined length of stream in a single pass.  Several studies have examined whether single-pass electrofishing gives a good index of the size of trout and salmon populations, but few have assessed its ability to accurately represent the multispecies structure of fish communities.  Canadian researchers electrofished 50 m stretches of stream nearLakeOntarioand found that single- and multiple-pass sampling provided very similar estimates of the relative importance of taxonomic families, feeding guilds, reproductive guilds and disturbance-sensitive fish species.  Thirty-three fish species were caught, including sunfish, trout, suckers and sculpins.  On average, only 0.7 extra species per site were collected by multiple-pass sampling compared to single-pass fishing, leading the authors to conclude that in their streams, species detection was best served by single-pass sampling at several sites rather than multiple-pass sampling at fewer sites.

Reference:  Reid, S.M., Yunker, G. & Jones, N.E.  2009.  Evaluation of single-pass backpack electric fishing for stream fish community monitoring.  Fisheries Management and Ecology 16, 1–9.