Zooplankton seasonal dynamics in Ambon Bay, Maluku

Abstract

A seasonal study of zooplankton was conducted to understand the abundance and diversity of zooplankton in related to oceanographic condition in Ambon Bay, Maluku. The research was conducted in four months (March, April, July, and October) which represented the various seasons in Ambon Bay in the year of 2016. The abundance of zooplankton was determined from NORPAC net (mesh size 0.33 mm) with depth varied from 10m to surface. The samples were taken in 18 stations which 7 stations located in Inner Ambon Bay, 1 station in the sill, and 8 stations in Outer Ambon Bay. All samples were preserved in bottle containing 4% formaldehyde and then analyzed using microscope. We also used CTD equipment to measure the vertical and horizontal distribution of temperature and salinity from the surface into 10m depths. The result showed that the distribution of temperature and salinity in Ambon Bay were varied following the season. The total abundance of zooplankton in Ambon Bay was fluctuated between 403-42097 ind./m3 following the season. The highest average abundance of zooplankton occurred in March (northwest monsoon) where the temperature was higher than other season. The lowest average abundance occurred in April (transition) where the salinity was lower than other season. The number of Copepods from genus Acrocalanus and Eucalanus were presented in all season. In southwest monsoon, spawning of Annelida and Echinoderm larvae were the most indicated larvae. Meanwhile, in southeast monsoon we indicated that the Copepod eggs and larvae as the most abundance in the waters.