Growth, mortality and hatch-date distributions of European hake larvae, Merluccius merluccius (L.), in the Bay of Biscay

European hake larvae (Merluccius merluccius) were collected in March-April 2002 in the Bay of Biscay applying an intensive sampling method in those areas where the presence of larvae was high or medium. In order to compare different years, hake larvae collected in 2001 from mackerel and horse-mackerel Triennial surveys were included in this study. Age and growth and mortality rates were estimated by counting and measuring otolith daily increments. Growth of larvae was best described by the equation: standard length = 2.446 × exp(0.0317 × age), while for larvae younger than 20 days old length-at-age data were represented by a linear model whose expression was: standard length = 2.12 + 0.137 × age. Growth rate values were quite similar to the ones recorded by other authors for larvae of other Meluccius species. Growth in weight of larvae was best described by the equation: weight = 9.364 × exp(0.134 × age). Larval age distribution was different between years 2001 and 2002 due, in part, to differences in the temporal sampling coverage. Daily growth rate (mm/day) was size dependent and independent of temperature. Daily mortality coefficients derived from the exponential decline model were 0.0916 and 0.1626 for 2001 and 2002, respectively. No statistical differences on daily mortality were observed between years.