IDETIFICATION OF POSTLARVAE OF THE GENUS PENAEUS APPEARING IN SHORE WATERS

Abstract

Diagnostic features for the identification of postlarval Penaeus found in the shore waters of the Philippines are described and categorized based on specimens caught from the wild and those hatched and reared in the laboratory. Differentiating features for postlarval Penaeus are given which include the relative length of the antennular fiagellum， the shape of the rostrum and number of rostral teeth， the antennal spine， the spinules on the dorsal carina of the sixth ab- dominal segment， and chromatophore patterns. Postlarval Penaeus were classified into two species and two groups as follows: (1) P. moπodon， larger in size with dense chromatophores， and the long inner antennular fiagellum being more than 2.0 times the outer antennular fiagellum; (2) P. semisulcatus， the inner fiagellum being 1.6 to 2.0 times the outer antennular fiagellum， with the absence of chromatophore on the middle portion of the telson and uropods; (3) P. merguiensis group， less pigmented， the inner fiagellum being less than 1.6 times the outer fiagellum and (4) P. japonicus group， a short rostrum， presence of spinules on the dorsal carina of the sixth abdominal segment， and denschromatophores. The determinations were confirmed by rearing experiments.