Fishing harvest has long been known to induce strong selective pressures on phenotypically desirable animals. The artificial selection of traits (e.g. size-selective harvest or targeting of spawning aggregations) differentially increases the risk of mortality for a specific phenotype, which in turn can result in life history changes within populations and altered food webs across community assemblages.

Behaviour is known to confer fitness advantages to an individual under a particular set of environmental conditions. For example, bolder individuals can have increased foraging efficiency or reproductive output, but with potential increases in predation or harvest risk. However, the effect of behavioural selectivity of fishing is poorly understood due to the challenge of drawing inferences about the cognitive mechanisms operating in wild animals. In this study, we investigate how size-selective fishing can impact on behavioural, morphological and physiological traits. In particular, we document how individual catchability relates to boldness, burst swim speed and fin aspect-ratios within and across three generations of zebrafish exposed to either sigmoidal or random size selection. The results from our study will be discussed in terms of the potential consequences of harvest-induced selection for sustainable fishery management within and across populations.