Quantitative sampling of fishes in a simple system: failure of conventional methods
- 1) Department of Zoology, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
In a capture-mark-recapture fish density estimate carried out in a small freshwater pond in southern Ontario, Canada, a lift net and minnow traps were used as catching gear. Both worked well for initial captures, but most recaptures were in the traps. Density estimates within reasonable confidence limits were possible for only two species, creek chub (Semotilus atromaculatus) and common shiner (Notropis cornutus). The other 13 species present were either missed entirely or not captured or recaptured sufficiently so estimates for them were inadequate. Subsequent collection of fishes after rotenone poisoning verified the estimates for the two species, if the size selectivity of the gear and the possible effects of marking and limitations of collecting after poisoning were considered.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 4 - ethologie animale