Fishers have a considerable knowledge about how fish stocks behave; knowledge that is difficult to acquire in other ways. Short-term fisher tactics employed on trip by trip basis can change significantly due to their targeting behaviour, which in turn can lead to changes in catch composition and production output. A stochastic distance function was used to examine a Mediterranean pelagic fleet's technical efficiency and fishers' ability to modulate their targeting behaviour. The purse seine fleet operated under increasing returns to scale, suggesting that the larger vessels could potentially amplify their short-term profitability by increasing the levels of inputs and harvests. Production was mainly joint, yet the possibility for limited substitution between species existed. The observed fishers' targeting behaviour was dissimilar between fleet segments due to differences in fishing effort and vessel characteristics, with larger vessels able to modify their revenue more than smaller ones. The estimated differences between the two fleet segments could be important in designing effective management regimes aimed at reducing resource overexploitation through individual input controls.