Introduction of detrital food webs into an aquaculture system by supplying single cell algal detritus produced from Laminaria japonica as a hatchery diet for Anemia nauplii

Abstract

A technique to change Laminaria japonica, a macrophyte, thalli into single cell detrital forms, namely, single cell detritus (SCD), was developed utilizing the prominent degrading ability of a marine bacterium, Alteromonas espejiana AR06 (FERM BP-5024). The SCD particles were about 2–10 μm in diameter and associated with many bacterial cells. The potential use of the SCD particles as a diet for suspension feeder animals was tested by feeding experiments with Artemia. The Laminaria thalli particles of 105–177 μm in diameter, which were difficult for Artemia to ingest and contributed little to the growth of Artemia, were transformed into a substantial nutrient source after they were degraded to SCD particles by bacteria. Feeding experiments with Laminaria thalli particles of less than 44 μm in diameter suggested that the axenically prepared SCD itself had a high potential as a hatchery diet and the colonization of the bacterial cells on the SCD would result in the catabolic loss of its total dietary values. This manuscript suggests a novel fish-feeding regime based on algal detritus food webs by converting the macrophyte biomass into SCD-hatchery diets for suspension feeder animals.