Development and evaluation of a flat-bed passive integrated transponder detection system for recording movement of lowland river fishes through a baffled pass.

摘要

The migratory behaviour of non-salmonid fishes in lowland rivers is still poorly understood, as is their success inudusing fish passes to allow upstream movement. The use of an automated flat-bed passive integrated transponderud(PIT) detector array to study behaviour of fish at a baffled flume pass on the Yorkshire Dement, North East England,udis described. The array comprised four flat PIT detector plates, each connected to a control unit. Two detectorsudwere positioned at the downstream end of the fish pass, and two at the upstream end. Control units sent interrogationudsignals, received transponded signals from tags, and stored the data. Efficiency of the upstream detectors was validatedudas near 100% using tagged brown trout (Salmo trutta) introduced below the detectors and observed to swimudpast them. Between 22 May 1998 and 9 April 1999 a total of 40 1 fish, comprising 1 1 species with a combined lengthudrange of 9-104 cm, were PIT tagged and released downstream of the fish pass. Near-continuous recording betweenud23 May 1998 and 3 1 May 1999 demonstrated the effectiveness of the PIT array at this site for recording entry to, andudsuccessfi~el xit, of fishes from the pass. A total of 1271 records from 90 individual fish were recorded at the downstreamuddetectors, and 20 tagged fish were recorded successfully exiting from the top of the pass, giving a passudeficiency of 22.2 'YO, based on the proportion of different fish which ascended. Overall 22.4 %of tagged fish enteredudthe pass, comprising chub (Leuciscus cephalus), dace (Leuciscus leuciscus), roach (Rutilus rutilus), bleak (Alburnusudalburnus), perch (Percafluviatilis), pike (Esox lucius) and brown trout, with highest numbers in May and June.