Fish mouth dimensions and size selectivity in a Portuguese longline fishery

The relationship between fish total length (TL) and mouth size in six species was investigated in light of the implications for the modelling of size selectivity of hooks. Significant non-linear relationships were found in three species, suggesting that optimal size at capture is not a linear function of hook size. These results strongly support the choices made in modelling skew-normal selectivity with optimal size at capture as a function of hook size