Zooplankton standing and diversity in the Gulf of Kachchh with special reference to larvae of decapoda and pisces

Abstract

Zooplankton characteristics of the Gulf of Kachchh including the major creek systems of Nakti, Kandla and Hansthal were studied for monsoon, postmonsoon and pre-monsoon periods. Zooplankton collections were made at seven locations. The area was very rich in zooplankton standing stock showing a variation of 0.59 to 185.50 ml/10 m3. The maximum biomass was at st 5-112.6 ml/100 m3 in monsoon; population maximum were 942 no/100 m3 during monsoon, 109.91 ml/100 m3 in postmonsoon and 8027 no/100 m3 during premonsoon. Metapenaeus affinis, M. dobsoni, Penaeus indicus, Parapenaeopsis stylifera and P. hardwickii were the species of penaeid prawns present in the samples. Larvae of M. affinis were dominant in the creek and gulf during monsoon, whereas Acetes indicus dominated in the collections during premonsoon and postmonsoon. Among the fish larvae, majority of them were in the early stages of development and the size varied from 1 mm to 5 mm. Boleophthalmus glaucus, Engraulis mystax, and Clupeids were the most common fish larvae present in this area. The major species of larvae of prawns and fishes occurring in the gulf were compared with the adults caught from the area. The environmental parameters like salinity, temperature, oxygen and nutrients were taken to study the zooplankton population, its intensity and diversity.