Stock structure analysis of Johnius borneensis (Bleeker, 1851) from Indian waters

Johnius borneensis (Bleeker 1851) contributes substantially to the marine fishery of India. The stock structure analysis of the species is essential for its sustainable management and utilization. The study is based on 411 specimens of the species randomly collected from the commercial landings at four marine fish landing centres in India. A truss network with 28 distance variables, based on 10 landmarks, was developed utilizing the digital images of the specimens, by means of tps Dig2 and PAST software platforms. Multivariate test statistics - Mahalanobis distance, Wilks' lambda and Pillais' test indicated significant difference between the East coast stocks and some extent of mixing among West coast stocks. Truss measurements transformed for allometric variations were subjected to Canonical Discriminant analysis and bivariate plot between the canonical variables showed existence of different morphometric stocks of the species. Major truss distances that contributed to the delineation were that on the head and posterior region of the fish body. The truss morphometric traits, that best discriminated the stocks, were subjected to the discriminant function analysis which appropriately classified 80 % of the specimens to the particular location. The present study is the first account on the stock structure analysis of J. borneensis from India and will help in developing policies for the management of the fishery and the sustainable utilization of the resource.