The Case of Size-Independent Selective Processes in a Small-Bodied Coastal Marine Fish Targeted By Recreational Angling

A common assumption in the fisheries literature is that fishing is positively size-selective, preferentially removing large fish. Positively size-selective fishing should, over time, lead to evolutionary downsizing of adult size. However, there is increasing evidence that “vulnerability to fishing” constitute a complex phenotypic trait involving physiological, morphological and behavioural components, which may or may not be correlated with the size of fish. This is especially arguable for many passive fishing gears such as recreational angling, where selection on behavioural traits can be expected to be prevalent because the capture process depends on the encounter probability and the active decision of an individual to bite onto a baited hook. Although behaviour and body size might be correlated, selection might more strongly operate on behaviour than on body size in angling fisheries. Here we present theoretical and empirical evidence that suggests that recreational angling selects on risk-taking and activity-related behavioural traits and related body shape, which in turn may lead to a selection response in the correlated life-history in the small-bodied marine coastal fish Serranus scriba.  We propose that trait-selective and intensive recreational angling could constitute a potential mechanism that contributes to downsizing of adult body size in heavily exploited coastal populations.