The investigation of Mackerel (Rastrelliger spp.) fishing grounds in the Gulf of Thailand and the relationship between fishing grounds with oceanographic parameters based on data from Vessel Monitoring System (VMS) using geo-informatics technology
Abstract:
The objectives of this study were to investigate mackerel (Rastrelliger spp.) fishing grounds based on data from vessel monitoring system (VMS) and fishing logbook from surrounding net fisheries in the Gulf of Thailand in 2019. The relationships between mackerel fishing grounds, and satellite data of chlorophyll-a (Chl-a) and sea surface temperature (SST) from Aqua-MODISSensor were investigated using the Generalized Additive Model (GAM). The results showed that mackerel fishing grounds changed according to the monsoons. In the southwest monsoon (rains), fishing grounds were located from Surat Thani, Chumphon, and Prachuap Khiri Khan provinces to the Inner Gulf of Thailand. In the northeast monsoon (winter), fishing grounds were found to move from the Inner Gulf of Thailand to Prachuap Khiri Khan, Chumphon and Surat Thani provinces. During the inter-monsoon (summer), most fishing grounds were in Prachuap Khiri Khan Province. Fishing grounds were significantly related (p< 0.001) to Chl-a ranging between 0.2 0.5 milligram per cubic meter and SST between 29.5 -31.5 degree Celsius. Temporal variations in fishing areas were in line with seasonal circulations in the Gulf of Thailand. The potential fishing ground maps showed that areas with high potential catch in the southwest monsoon were located in the west and the east of the Gulf of Thailand. Conversely, the mouths of the Chaopraya, the Thachin, the Maeklong, and the Bangpakong River situated low potential fishing ground. In the northeast monsoon, the fishing potential was less than those in other monsoon seasons which high potential areas were mostly located in the east of the Gulf of Thailand in offshore Trat Province. During the inter-monsoon high catch potential was found in the west and the east of the Gulf of Thailand.