Morfometric Character of Longtail Tuna (Thunnus Tonggol)

Abstract

Longtail tuna is a pelagic fish that has a wide distribution from the Java Sea to the Natuna Sea or the South China Sea. This study aims to identified the character of the population and determine differences in population/stock of longtail tuna among stock in the Java Sea and the Natuna Sea. Sampling was carried out from May 2018 to April 2019, in Pekalongan representing the Java Sea, Pemangkat representing the west Natuna Sea and Tanjung Pinang representing the east Natuna Sea. The morphometric measurement consists of 20 characters, morphometric data is standardized by dividing all the morphometric characters by the standard length (SL). Principal components and discriminant functions analysis was employed to analyze morphometric variables to obtain distinguishing characters and stock identification. Discriminant Analysis to see the components of intra and inter-population sharing was carried out using SPPS ver.16 software. The results of Principal components analysis (PCA) found there are two distinguishing morphometric characters, namely: pelvic fin length (PeL) and anal fin length (PAF) characters. Canonical discriminant analysis found two subpopulation longtail tuna, which is one sub population Java Sea and west Natuna Sea, the other is east Natuna Sea sub population.