Effects of different monoalgal diets on egg production, hatching success and apoptosis induction in a Mediterranean population of the calanoid copepod Acartia tonsa (Dana)

Abstract

The influence of six monoalgal diets was tested on the reproductive success of the copepod Acartia tonsa over a 15-day period in order to define the most favorable diet for the optimization of this copepod species to be used in aquaculture and in ecotoxicology applications. The cryptophytes Rhinomonas reticulata and Rhodomonas baltica induced highest egg production rates (mean=24.4eggsfemale−1day−1and 21.9eggsfemale−1day−1) and hatching success (mean=76% and 86.1%) over the 15-day period, respectively. Lowest egg production rates were recorded with both diatoms Phaeodactylum tricornutum (mean=8.8eggsfemale−1day−1) and Skeletonema marinoi (mean=8.4eggsfemale−1day−1). These two diatoms also had detrimental effects on hatching success (mean=44.1% and 46.5%, respectively) and adult survival. No adults survived for longer than 13days with a diet of P. tricornutum. Moreover, nauplii produced by females that had fed on diatoms for >10 d, were positively stained for the apoptotic fluorescent marker TUNEL, indicating imminent death. The prasinophyta Tetraselmis suecica induced low fecundity (mean=13.4eggsfemale−1day−1) and hatching success (mean=62%), and after 15days only 37.5% of the adults survived. Isochrysis galbana induced low egg production per female (<10eggsfemale−1day−1) after 15days.