Identifying blue swimming crab (Portunus pelagicus) stocks with truss network analysis approach in Indonesian Fisheries Management Area 712

Abstract

The exploitation rate of the blue swimming crab (BSC) in Indonesian Fisheries Management Area (FMA) 712 is over-optimum level in 2016. Stocks concern in sustainable management is needed as an effort to maintain its availability. The objective of this study is to identify the stock unit of BSC based on Truss Network Analysis (TNA) of morphometric characters in FMA 712. The BSC was collect in five different locations, i.e. East Lampung, Lancang Island, Cirebon, Rembang, and Southern Madura. Measurements on TNA were carried out at 14 landmark points with 29 characters in carapace to analyze its morphometric characters. The cluster analysis showed that TNA method revealed two stocks units of BSC in FMA 712. The first stock was the BSC population of Southern Madura, and the other stock was the other four populations. The longest Euclidean distance was found at Southern Madura indicating similarity level with other populations was low. The discriminant analysis demonstrated different results. There were three group populations, in which every population in one group were able to represent the other population, namely Lancang Island-Cirebon, East Lampung-Rembang, and Southern Madura. Regarding this study, it is recommended to manage BSC in Southern Madura separately.