Phyllosoma
Diet composition and water temperature are key determinants of phyllosoma health and survival. Phyllosomas are carnivorous, feeding on small zooplankton such as copepods (small crustaceans), planktonic marine worms, and the larvae of other invertebrates and fish (Gray 1992, Saunders et al. 2012, O’Rorke et al. 2012). They feed by sweeping their second pair of legs through the water. These legs have specialised hooks at the end, which pierce and hang on to their prey while they eat it. DNA and fatty acid composition analyses have indicated that mid and late-stage phyllosoma feed on multiple groups of transparent gelatinous zooplankton, including salps and small crustaceans (Phillips et al. 2006, O’Rorke et al. 2012). Feeding trials found that mid-late stage phyllosoma displayed pronounced prey preferences for nutritionally superior prey items (Saunders et al. 2012). Despite their clear ability to select and predate upon particular prey, phyllosoma appear to be feeding in oligotrophic food chains; that is food chains low in nutrients with a lack of macrozooplankton (Phillips et al. 2006, Saunders et al. 2012). The lack of larger prey items in these food chains means phyllosoma will need to supplement their diet with herbivorous and microbial grazing, and possibly faecal pellets and other detritus.
Puerulus
Studies on the anatomy and nutritional composition of puerulus indicate that they are non-feeding; they lack feeding structures and are nutritionally depleted after their cross-shelf journey (Lemmens 1994, Lemmens & Knott 1994). If feeding does occur in the puerulus stage, it would be facultative (occurring if the opportunity presents, but not required), possibly occurring in the post-settlement phase, and limited to small, soft food particles (Lemmens & Knott 1994).