SS-strain rotifer culture for finfish larvae with small mouth gape

Abstract

In the aquaculture of temperate marine finfish, the rotifer Brachionus plicatilis (L-strain) has been the primary live food for early larval stages. As aquaculture has diversified to include tropical marine species the small strain rotifer, B. rotundiformis, is now routinely cultured. Many marine finfish have larvae with a small mouth gape that has required the selection of a super small (SS) strain of B. rotundiformis. However, even this SS-strain of rotifer is not an optimal size and a smaller size would be ideal for first-feeding finfish larvae.
The objective of this work was to develop culture techniques that would select for smaller sized rotifers and reduce the average size of rotifers in a population. A typical population of rotifers contains reproductive females of varying sizes with the distribution skewed toward the smaller animals. The aim was to apply selection pressures that would exaggerate this skewed distribution and result in a higher proportion of smaller rotifers.