Seasonal Biomass and Biochemical Composition of Nearshore Holoplankton and Meroplankton off Visakhapatnam, East Coast of India

Purpose: The aim of the study is to investigate the biomass and biochemical composition of holoplankton and meroplankton, along with their seasonal variation, occurring in the nearshore areas of the Visakhapatnam coast, east coast of India. Design/Methodology/Approach: The study was carried out in three locations in Visakhapatnam- Fishing Harbour (FH), Rushikonda (RSK) and Mangmaripeta (MGP) for a period of one year (2022-23). The sampling was done by collecting zooplankton through a plankton net using horizontal towing from the nearshore seawater. Then, it was separated into holoplankton and meroplankton. Biomass was analysed using the gravitational method. The biochemical components were estimated using standard methods. Statistical methods like Redundancy Analysis (RDA) and PERMANOVA were applied. Research Limitation: The research did not incorporate more extensive spatial coverage or longer monitoring periods; therefore, the findings may not be generalisable. Findings: The highest biomass (Dry weight) for holoplankton was reported at Rushikonda (RSK) station in September 2023. For meroplankton, it was during February 2023 from MGP station. Protein was recorded as the highest among all biochemical contents in both holoplankton and meroplankton. RDA identified temperature and salinity as the major parameters explaining biomass distribution and biochemical composition across all stations and seasons. PERMANOVA indicated that the variation is more significant between seasons than between sites. Practical Implication: The results may support coastal ecosystem monitoring and fisheries management by improving understanding of zooplankton productivity and nutritional value. Social Implication: Understanding variability in zooplankton biomass and biochemical composition can improve knowledge of marine food web functioning and support better management of coastal resources that sustain fisheries and local livelihoods. Originality/Value: The study integrates biomass estimation with biochemical composition analysis of holoplankton and meroplankton together, offering new insights into their ecological role within the coastal food web.