Willis, T.J.; Millar, R.B.; Babcock, R.C. 2000. Detection of spatial variability in relative density of fishes: comparison of visual census, angling, and baited underwater video. Marine Ecology Progress Series 198: 249–260.
The ability to make accurate estimates of fish relative abundance is the basis of both ecological and environmental effects studies. This paper compares surveys of snapper and blue cod conducted using three methods (underwater visual census, experimental angling, and baited underwater video). Angling and baited video gave consistent estimates of snapper density, whereas visual surveys provided the least reliable measure, with adults only detected at locations where fish have been habituated to divers by hand feeding. Blue cod, however, were well estimated using visual census. The study indicates that methodological standardisation across all species is not always appropriate for environmental effects studies.
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