Energy balance of the Antarctic tunicate Salpa thompsoni Foxton

Abstract

In early austral autumn of 2002, Salpa thompsoni feeding rates and growth were assessed by incubation salps with two C14-labeled cultures of green algae Dunaliella maritima and Platymonas viridis. Daily carbon ingestion rates of blastozooids within the mass range of 0.9–28.3 mgC ind.−1 ranged from 2.8 to 60.3% of body carbon mass and were the function of the experimental food concentration nearly regardless of the individual salp mass. The absolute growth of salps was positively related to the salp size ranging from 0.64 to 6.50 µgC ind.−1day−1 and from 0.02 to 1.56 µgC ind.−1day−1 in oozooids and blastozooids, respectively. The linear individual length increase ranged from 0.33 to 1.93 mm day−1 and from 0.29 to 0.85 mm day−1 in blastozooids and oozooids. The mass-specific metabolic values (filtration, ingestion and growth) of salps under experimental conditions depend on food concentrations and the salp biomass, but weakly on their size.