Fishing Ground and Primary Production Analysis Based on DNB SNPP-VIIRS and Aqua-MODIS Imagery in Mentawai Island and Nias Waters

Abstract

Abstract The study of fishing grounds in coastal areas is part of fisheries management activities, especially capture fisheries by coastal fishermen. The absence of GPS, AIS and VMS systems on traditional fishing boats causes difficulties in monitoring the fishing grounds (FG) of coastal fishermen in the waters of Nias Island and Mentawai Islands. The objectives of this study to assess the fishing ground area and analyse its seasonal variability based on fishing light boats (FLB) from the DNB SNPP-VIIRS satellite imagery and the primary productivity condition in FG area from Aqua-MODIS imagery in the Nias Island and Mentawai Islands waters. FG is determined based on the clustering point density method, and statistical correlation analysis. Based on the FLB imagery (2015-2020), peak season fishing operation occurred twice a year in January/February and June/July, while the lowest fishing season occurs in April and October. In general, there are four main locations of fishing grounds in the study area, i.e Sibolga waters, Batu Islands, Mentawai Island and West Sumatra coastal. The FLB can describe the location of FG spatial and temporally, and it was correlated with the bathymetry and chlorophyll-a concentration rather than primary production in the waters of Nias Island and Mentawai Islands. Spatial and temporally distribution the fishing grounds and its density change by seasonal and inter-annual variations. The lowest conditions occurred in 2016 and the highest in 2019 which were each influenced by the nIOD and pIOD phenomena.