Abundance and Diversity of Zooplankton along the Gulf of Mannar Region, Southeast Coast of India

Abstract

The study addresses the abundance and diversity of zooplankton along the Gulf of Mannar. Sampling was done from the nine stations. The samples were collected by horizontal hauls using the zooplankton net (150μm mesh size, 0.5 m mouth diameter and length 1.5 m) fitted with digital flow meter. From the study we recorded a total of 114 species of which the copepods formed the dominant group in all the stations. Which consists of Acartia spinicauda, Acartia danae, Pseudodiaptomus aurivilli, Eucalanus elongatus, Labidocera acuta, Nannocalanus minor, Paracalanus parvus, Corycaeus speciosus, Dioithona rigida, Oithona similis, Metis jousseaumei, Favella brevis and Tintinnopsis directa . The other dominant groups were barnacle nauplii, bivalves, gastropods larvae etc. The highest abundance (11,733 Nos./m3) was recorded in station 2, while the lowest (1,913 Nos./m3) was recorded in station 6. Diversity (H) was higher in the station 4 whereas the lowest diversity was observed from station 5 and no significant differences in Evenness (J) and Richness (SR) were observed between stations. A chemometric analysis such as cluster analysis (CA) and principal component analysis (PCA) reveals that, relationship among the zooplankton groups and studied stations. There was not any significant difference in zooplankton abundance between stations (p> 0.05).