Biological features of the Lophius piscatorius catch in Scottish waters

Here, data on 50 265 Lophius piscatorius sampled between 1998 and 2006 on board commercial fishing vessels during observer trips and chartered surveys at Shetland, west of Scotland, and Rockall are analysed. In each area, length differed significantly with depth (p, 0.001), there was an increase in modal size with increasing depth down to 450 m, and large fish dominated hauls in deeper water. The sex ratio of all data combined was 0.88 females:1 male, but it varied by area, depth, and season, with males greatly out-numbering females in deep water west of Scotland during the first quarter of the year. The proportion at length that were female differed significantly with depth, and the highest proportions of mature fish were in deep water at Rockall and west of Scotland. L50 % maturities, for all data combined, were 102.4 cm for females and 58.3 cm for males