Variation in nitrogenous compounds and gonad index in fed and starved sea urchins (Paracentrotus lividus) during live storage

Abstract

Wild-caught Paracentrotus lividus were fed either Ulva lactuca or starved during the post-spawning period of their biological cycle. Growth and the gonad indices were monitored throughout the experimental period in order to determine the relationships between nutritional state and the allocation of resources to body components. No variation in the wet weight of starved or fed urchins occurred but a significantly increased gonadal growth occurred in the fed urchins after 36days and established a direct relationship between food availability and gonad development.Initial mean values of ammonia and nitrate excretion of 46.03±4.28 5mol NH4-N individual−1 h−1 and 0.45±0.04mg NO3 individual−1 h−1, respectively, dropped to 2.55±0.33NH4-N μmol individual−1 h−1 and 0.1±0.02mg NO3 individual−1 h−1 after 5days (p<0.05; one-way ANOVA in each case). Concomitantly, free amino acid concentrations dropped in the gonads and the coelomic fluid. Coelomic fluid TMA concentrations were constant throughout all the conditioning period; however, an increase of the gonad TMA level occurred after 5days to reach a mean of 0.37±0.02μmol TMA g−1 and then remained stable to the end of the experiment (36days).