Growth of North Alboran Sea sardine larvae estimated by otolith microstructure, nucleic acids and protein content

Wet mass and DNA, RNA and protein content increased significantly with stan dard length (Ls) of sardine Sardina pilchardus larvae, collected in January 1995, in the Bay of Malaga, North Alboran Sea. L-S, wet mass and DNA, RNA and protein content were closely related allometrically to otolith radius ( R). Larval daily length increments decreased but DNA, protein and wet mass daily increments increased with larval age. Daily length increments showed a negative and poor relationship with long-term otolith growth. In contrast , DNA, protein and wet mass daily increments were positively correlated. Di fferences between observed and back-calculated otolith radius-at-age indica ted that larvae with slow otolith growth were under represented in older ag e groups, suggesting the existence of growth-selective mortality. Recent ot olith growth, estimated from the mean widths of the last six increments, in creased with age and R. Individual RNA: DNA and protein: DNA ratios were co rrelated significantly, although weakly, with L-S and larval growth. (C) 20 01 The Fisheries Society of the British Isles