Rearing European eels in captivity throughout their life cycle in a complex task, hampered by our lack of knowledge about several phases of their life cycle. Recently published research has been exploring the challenge of first feeding in captivity.
To initiate first feeding, Dr Ian Butts (Technical University of Denmark) and fellow scientists gave European eel larvae one of five specially tailored diets. Four of the diets used rotifer paste, of which three included additives (one with cod roe, one with octopus juice, and one with live rotifers). The fifth diet consisted of defrosted plankton collected directly from the Sargasso Sea, where European eels spawn.
Once feeding commenced (after about two weeks), eels on the rotifer paste, rotifer paste with cod roe, and rotifer paste with live rotifers diets showed highest incidence of feeding, and spent much more time swimming then those on the other diets. After about three weeks, the rotifer paste with cod roe, and the rotifer paste with live rotifers seemed to generate the greatest amount of feeding.
Perhaps surprisingly, the larvae given the Sargasso Sea diet never showed any signs of ingesting the plankton.
This article was written for (and can be read in full at) The Fish Site.