MANGROVE ZOOPLANKTON OF NORTH QUEENSLAND, AUSTRALIA II - COPEPOD EGG-PRODUCTION AND DIET

Egg production rates by the dominant copepod species in five rivers in Northeastern Australia were measured. An undescribed Oithona species produced 2.3-15.3 eggs female(-1) d(-1), Oithona aruensis 0.8-11.3 egg s female(-1) d(-1), Parvocalanus crassirostris 1.3-36.2 eggs female(-1 ) d(-1), and Bestiolina similis 3.6-51.4 eggs female(-1) d(-1) Oithona spp. appear to feed carnivorously, whereas the calanoid species B. si milis and P. crassirostris were suspension feeders. Acartia sinjiensis fed opportunistically as a carnivore or as a suspension feeder. Grazi ng rates directly measured in feeding experiments or calculated from e gg production rates were low (usually less than 31% of copepod body C per day), despite mangrove waters having apparently high food concentr ations. We suggest that in spite of high standing stocks of potential foods, copepods were in fact food-limited much of the time, and that t he deficit between metabolic costs and measured ingestion were met by intake of detritus by B. similis, P. crassirostris and Pseudodiaptomus griggae, and carnivory on larger prey items by A. sinjiensis and Oith ona spp. Turbulence and cannibalism may play important roles in the nu trition of mangrove copepods. Both phytoplankton-based and detritus-ba sed food chains appear important in mangrove pelagic secondary product ion.