Comparative Evaluation of the Effectiveness of some local Fabrics for Zooplankton Harves

Abstract

A comparative evaluation of the effectiveness for zooplankton harvest for three local fabrics (a white poplin, 120mm; grey baft, 200mm; a nylon, 235mm) and an imported standard zooplankton net of mesh size 76mm were tested in this study. Mesh sizes and gauze constitution of the fabrics were determined with an ocular micrometer under a compound microscope. Filtration efficiency and clogging rates of the fabrics were also measured. All fabrics were effective in harvesting species of the copepods, the cladocerans and the large-sized rotifer, Asplanchna. The grey baft and the nylon net were not effective in harvesting the small-sized rotifer species like Keratella, Filinia and Trichocerca.All the fabrics effectively harvested Moina, an excellent freshwater cladoceran for fish larval-rearing. Clogging rate was found to be a function of gauze constitution, while filtration efficiency was an index of both gauze constitution and mesh size of fabrics. (Journal of Applied Sciences & Environmental Management: 2003 7(1): 57-60)