Comparative Study on the Structure of Plankton Community at Integrated Multi Trophic Aquaculture (IMTA) and Conventional Monoculture Net Cages at Coastal Area of Menjangan Besar, Karimunjawa Islands, Indonesia

¹ Center of Marine Ecology and Biomonitoring for Sustainable Aquaculture (Ce- MEBSA), Diponegoro University, Semarang, Indonesia
^2,3 Department of Biology, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia.
⁴ Department of Informatics, Faculty of Science and Mathematics, Diponegoro University, Semarang, Indonesia.

^* Corresponding author: saptoputro@live.undip.ac.id.

Abstract

Over the last decade, a modern sustainable aquaculture has become a driving force to speed up a production capacity but still pay attention to the carrying capacity of the environment for sustainability of the farming practice. We assessed the modern farming practice using stratified double net cage – Integrated Multi Trophic Aquaculture (SDNC-IMTA) to be compared to the conventional monoculture using structure of plankton community. The study was carried out at Menjangan Besar Island, Karimunjawa, Central Java during October 2021. The purpose of this study was to compare the plankton community's structure and determine the correlation between plankton abundance and water quality. Plankton sampling was carried out using the filtration method at three locations, i.e. monoculture cages, SDNC-IMTA cages, and reference sites. The abundance of phytoplankton and zooplankton were considerably higher at IMTA sites compared to the monoculture and reference sites. In particular, the highest abundance of zooplankton was found at the IMTA of 8569 ind.L^-1, while the lowest abundance of zooplankton was found at the reference location of 3098 ind.L^-1. The species considered as biological indicator were Ceratium sp., Dinophysis sp., Navicula sp., Pseudonitzchia sp., Oscillatoria sp., and Rhizolenia sp. The results of the NMDS ordination of phytoplankton data obtained a tendency of grouping the stations based on the three main sampling sites, while results from the zooplankton data did not show clustering between the sampling sites. The analysis of plankton abundance using with BIO ENV (Primary V 6.1.5) showed that the most abiotic factors affecting the abundance of plankton were temperature, turbidity, and salinity ( p_value = 0.176).