Samaneh Ansari, Alireza Shayestehfar and Seyed Mehdi Talebi
Brachionus is an suitable live foods for fishes larve of Brachionidae family, in the present study inter and interapopulation variations of two species of family Brachionidae were investigated. For this purpose 90 individuals of geographical populations of these species were collected from different parts of Arak country and for each habitat five ecological factors were examined. Totally eleven quantitative morphological characters were examined from Lorica. The ANOVA test and also one–sample T-test showed significant difference for some morphological characters. In interpopulation section, 10 individuals were selected randomly for each population. Individuals were separated from each other in PCO, PCA, CA plots and UPGMA tree. Significant correlations negative/positive found between some of morphological characters with studied ecological factors of habitat. In addition, variations in morphological characters were seen between populations and they were separated in CA plot and also UPGMA tree. Ecological factors were different between habitat, Therefore habitats were separated in UPGMA tree and PCO, PCA, CA plots. This subject confirmed effect of different ecological factors on phenotypic plasticity of populations.
