Multi-Gear Comparisons of Catchability, Variability, and Gear Avoidance in Florida Lakes

Fisheries monitoring programs hinge upon understanding changes in survey gear catchability over time to reliably estimate abundance. Often the variability in catchability of standard fisheries surveys is ignored despite evidence that large variances are common. This can be ameliorated either by developing a relationship between catchability and environmental covariates or choosing survey gears with low variance in catchability. We quantified catchability and its variance across day and night electrofishing, standardized and non-standardized angling surveys, as well as camera surveys in four Florida lakes. Six years of recapture histories from Florida Bass, Micropterus floridanus, from PIT tags and external tags were used to estimate catchability and to quantify individual gear avoidance.  Ad-hoc corrections were formulated for surveys with additional detection inference. Differences between the mean catchabilities were reflective of previous studies, such as higher catchability at night versus day electrofishing, while low catchability was found for camera surveys. Variation in catchability was high for electrofishing and angling while low among stratified camera surveys. These comparisons lend themselves for discussion of survey gear choice and the importance of evaluating stationarity in catchability, especially for systems where abundance estimates are foundational to management decisions.