Growth, reproduction and their interplay in blue whiting (Micromesistius poutassou, Risso, 1827) from the NW Mediterranean

•High variability in the size at age of Mediterranean blue whiting.•Blue whiting recruits to the demersal habitat at sizes between 3 and 7 cm TL.•There is a trade-off between the energy invested in growth and reproduction.•Most of the catch corresponds to immature and undersized individuals.