Comparison of catch rates and catch composition among ‘research-angler’ diary and fishery-independent survey methods in Victoria, Australia

ABSTRACT‘Research-angler diary’ (RAD) and fishery-independent survey (FIS) methods were trialled for sampling recreational fish populations of estuary perch (Macquaria colonorum) black bream (Acanthopagrus butcheri), and Murray cod (Maccullochella peelii) in their respective habitats. Catch rates and catch length-frequency distribution were compared based on ‘catchability’ and its components ‘availability’, ‘encounterability’, and ‘selectivity’. The FIS consistently caught significantly more species at much higher numbers than the RAD. Catch rate and length-frequency patterns between RAD and FIS agreed better for fish above than below the legal minimum length (LML). All methods caught fish from a wide length-range, but the FIS caught smaller fish than the RAD. Higher catch rates for the FIS than the RAD for fish ≥ LML are explained by higher ‘encounterability’, whereas higher catch rates for fish < LML are explained by higher ‘encounterability’ and much higher ‘selectivity’ of the fishing gear. The FIS (d...