Onderzoeksoutput

Survival and growth of N. integer were detected within the whole range tested, but sexual maturation was only possible in the narrower range of 15–25 °C and 5–15 psu. The size at maturity of N. integer increased with decreasing temperature and increasing salinity. Salinity seems to have a stronger effect than temperature on the duration of maturation. The sigmoid von Bertalanffy growth model was fitted to the individual and pooled data, except for the 8 °C experiment where growth was linear. Estimates from pooled data were comparable with individually based estimates, but generally underestimated the asymptotic length. Temperature was negatively correlated with the asymptotic length and positively correlated with the growth constant K. Higher temperatures caused smaller intermoult periods but had no effect on the growth increment, while salinity effects were less straightforward and dependent on the water temperature. A tool is provided to estimate the age, moult number, intermoult period, growth factor and growth rate from the body standard length of N. integer. Experimentally derived von Bertalanffy parameter estimates resulted in a higher growth performance index compared with field-based estimates for the Schelde estuary and Galgenweel populations of N. integer.