Assessment of Alternative Substrates for Culturing Lumbriculus variegatus

Abstract

The freshwater oligochaete, Lumbriculus variegatus, is tank-cultured to provide organisms for aquatic-habitat assessments, regeneration research and as a clean source of live food for aquarium fishes. Shredded paper is the typical substrate in cultures used to rear L. variegatus for these purposes. However, the effort needed to separate large numbers from decomposing paper can be prohibitive. Burlap and nylon mesh material were compared to paper as potential alternatives that could reduce this effort. Oligochaete production and the amount of time needed to separate animals from substrate were compared for eight weeks among experimental cultures containing burlap, nylon mesh and paper. Cultures with paper substrate increased in number and weight two to three times faster than those with burlap or nylon mesh substrates. The time needed to separate animals from substrate was initially two to three times longer with paper substrate than with burlap or nylon mesh substrates, but this difference increased to between 10 and 40 times longer after six weeks as the paper substrate decomposed. Feeding rates varied by treatment and were based on average wet weight at the time of water replacement. Elevated ammonia and nitrite concentrations resulting from excess food may have reduced production in nylon mesh treatments and was lethal in paper treatments during the final phases of the study. The type of substrate recommended may depend on the desired production rate of oligochaetes, space available for cultures and the amount of effort available for substrate renewal and separating the animals from the cultures.