Biological Aspects Of White Anglerfish (Lophius Piscatorius) In The Bay Of Biscay (ICES Division Viiia,B,D), In 1996·1997

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A total of 1129 White Anglerfish were analysed from monthly samples taken in the Bay of Biscay on board of commercial vessels and at the main fishing ports of the Basque Country during 1996-1997. The specimina length range was between 12.5-136.5 cm of total length. The total length (cm)-total weight (g) relationship was described by the multiplicative function: Wt = 0.2636 L2•84', r = 0.9883. Other relationships (total length-commercial gutted, -scientific gutted, -tail weight) have been also obtained.The conversion factor calculated for the commercial gutted (i.e. with Ii ver) to total weight relationship was 1.14, and for the tail to total weight relationship was 2. 79. The reproductive period in the Bay of Biscay, observed by macroscopic and histological studies, extends from May to August with a peak in May-June. The L50 was calculated at 52.7 cm in length for males, at 73.2 cm for females and at 68.2 cm for sexes combined. The A50 was calculated at 5.0 years for males, at 7.0 years for females and at 6.0 years for sexes combined. Sex ratio in fish below 80 cm in length did not appear to depart from l: I: above this length females clearly predominated. For growth studies I 385 exemplars were aged by illicia reading. Fish between I and 25 years old were found. Annual age-length keys were established. Annual parameters of the von Bertalanffy growth equation were calculated for both sexes: L_= 150, t, = -0.0236, K = 0.0882, for Males: L-= 100, 10 = - 0 . .1051, K = 0.1517 and for Females: L_= 150, to= -0.2961, K = 0.0882.