DETERMINING PREY PREFERENCE OF FIRST FEEDING MARINE ORNAMENTAL FISH LARVAE UTILIZING FLUORESCENT MICROSPHERES  

As the popularity of marine aquaria grows, potentially more marine ornamental fishes and invertebrates will be harvested from the oceans. Aquaculture of marine species is a sustainable alternative to wild caught individuals and may help to grow businesses and diversify species in production. Experiments were conducted with first-feeding larvae of reef butterflyfish (Chaetodon sedentarius), Pacific blue tang (Paracanthurus hepatus), African moony (Monodactylus sebae) and golden trevally (Gnathanodon speciosus). The objective was to define prey preferences at first-feeding between rotifers (Brachionus plicatiilis), copepod nauplii (Parvocalanus crassirostris), and ciliates (Euplotes sp.), by marking each prey with a different color of fluorescent microsphere and observing gut contents with a fluorescent microscope. Each fish species showed different prey preferences. Pacific blue tang larvae preferred rotifers above ciliates, and ciliates above copepod nauplii. African moony larvae preferred ciliates and nauplii equally over rotifers. Reef butterflyfish larvae preferred ciliates over rotifers and rotifers over nauplii. Golden trevally larvae preferred nauplii over ciliates, and ciliates over rotifers.

This study presents a new understanding of prey preference of first feeding ornamental marine larvae by utilizing fluorescent labelled microspheres. Microspheres are currently used in marine ecology research to trace microplastics throughout planktonic food webs. Ingestion of naked ciliates labeled with microspheres in fish larvae has been previously performed. However, microspheres have not been utilized to examine prey preference and consumption of live feeds. This marks the first use of microspheres in aquaculture with rotifers (Brachionus plicatilis) and copepod nauplii (Parvocalanus crassirostris).