Estimation of age and growth of juvenile angler Lophius piscatorius in the Bay of Biscay from otolith microstructure analysis

The early life history of the angler Lophius piscatorius in the Bay of Biscay was investigated by growth increments in the lapillar otoliths, this being the first time this type of analysis was conducted for this species among specimens of the Iberian stock (ICES Divisions 8.c, 9.a). Lapilli of 34 juvenile fish collected during autumn bottom trawl surveys, were successfully aged between 113 and 198 days (116-213 mm fish length). Morphology and ultrastructure analyses of the otolith's check marks enabled us to determine the period of endogenous feeding (which according to these estimations would last between 9 and 19 days after hatching), as well as the settlement check, which indicated a relatively long pelagic phase (ca. 91 days). Hatch date was back-calculated from the date of capture indicating a spawning period from April to June, in agreement with that estimated for this population. The age-length relationship was described by the linear function L-T = 7.30 + 0.98 age (days) and showed an average growth rate of 0.98 mm day(-1). Our results present a faster growth pattern of 0+ juveniles L. piscatorius in the Bay of Biscay than previously estimated by annual growth studies, showing that juveniles of up to 213 mm length collected in October were hatched in the same year and belonged to age class 0. These results are relevant to the knowledge of the early life history of this species and are in agreement with those obtained in the only previous microstructural study of L. piscatorius in Atlantic waters. The implications of these findings on the annual age estimation protocol based on illicia are discussed. (C) 2019 Elsevier B.V. All rights reserved.