Interaction of Area with Catchability Indices Used in Analyzing Inland Recreational Fisheries

Catchability may be expressed as the catchability coefficient, q = F/g, or the “specific catchability,” c = F/f where F is the instantaneous catch rate, g is total fishing effort, and f is fishing intensity or effort per unit area. The latter will usually be most appropriate for analysis of recreational fisheries in relatively small, homogeneous, inland waters, particularly for comparisons between waters that differ in area, and for incorporation in predictive models for general use. Data from large waters may yield overestimates of catchability if total area, rather than the area utilized by the fish stock and the fishery, is used. These conclusions are supported by analysis of published data on stocked rainbow trout in 23 California waters.