Geographical variation in the distribution of different calanid species in the Indian Ocean
Abstract
The species composition of Calanidae in the Indian Ocean was studied from zooplankton collections taken between 24 degrees N to 40 degrees S and 20 degrees E to 120 degrees E. Nannocalanus minor was widespread with high density along the African and Arabian coast. Calanus australis was confined to the vicinity of the subtropical convergence and the maximum population was encountered from South African Waters. Undinula vulgaris and Cosmocalanus darwin were abundant in the productive upwelling zones off Arabia, Somalia and Sumatra, the former being totally absent in the south central Indian Ocean. Canthocalanus pauper was widespread and abudant in the northern Indian Ocean. Neocalanus gracilis was well represented in the equatorial Indian Ocean and also at a few stations in the northern Arabian Sea. N. robustior was found to inhabit the equatorial and southern region, and N. tonsus was distributed in the southern provinces especially in the South African waters. Calanoides carinatus the copepod which is associated with upwelling was encountered along the Arabian and Somali coasts. This study also indicated occasional surfacing behaviour of C. carinatus. The hydrographical features that restrict the distribution of the above species are highlighted in this paper
Collections
- Scholarly literature [9000]