Spatio-temporal variability in growth of juvenile sparid fishes from the Mediterranean littoral zone

Abstract

Populations of three species of juvenile Sparidae ( Diplodus puntazzo , Diplodus sargus and Diplodus vulgaris ) were sampled at different spatial scales in the north-western Mediterranean Sea over two years to follow growth after settlement. Length–frequency distributions were collected each week for periods of six months following the arrival of off-shore larvae in inshore habitats. Data were collected by underwater visual census along permanent transects. Growth rate measured as the slope of the linear relationship between mean size and time varied between species. Diplodus puntazzo (0.160 mm d −1 ) and D. vulgaris (0.202 mm d −1 ), which are settling in winter experienced slower growth than D. sargus (0.567 mm d −1 ) which settles in summer. It is concluded that the difference was in part due to water temperature. Analysis of growth rate within each species also revealed significant differences among sites probably related to the currents and the water mass temperatures.