The David Noakes article that debunked the misguided belief that absolute numbers of fish can be captured in fresh waters: a lesson for early-career scientists

Abstract

AbstractThis article presents a personal account of the important contribution a publication from David Noakes’ lab (Pot, Noakes, Ferguson and Coker 1984, Quantitative sampling of fishes in a simple system: failure of conventional methods. Hydrobiologia 114:249–254) made to freshwater fish science in general and to the successful public defence of a doctoral thesis in particular. Pot et al. (1984) tested the accuracy of two conventional sampling approaches in their estimation of numbers of fish in a small pond (capture-mark-recapture and total sampling, following rotenone treatment). Their results demonstrated that even in a small and relatively uniform freshwater system (a pond of 0.1 ha), the so-called total sampling approach failed to provide the true number of any species of fish in the pond. The outcome of the study provided the evidence to debunk the assumption that absolute numbers of fishes can be obtained using rotenone treatment. This article therefore allowed me to defend my doctoral dissertation in the face of critical comments from a principal jury member, and firm proponent of ‘absolute sampling’, and it provided fish biologists with justification to focus on the development and application of sampling approaches, such as relative densities, which do not require futile attempts to obtain total fish numbers.