Notes on the external sex characters of Chanos chanos Forskal spawners

Abstract

In this study, the authors did not find any visible differences between the sexes with reference to external features such as coloration, shape of head, snout and operculum, presence of tubercles or nasal pores, length, size and shape as well as any roughness in the various fins. However, the anal region of the mature milkfish exhibits discernible anatomical differences in the male and female. In the males, there are 2 main openings visible externally. These are the anterior anus and the posterior urogenital opening at the tip of the urogenital papilla. Internally, the vasa deferentia (male genital ducts) from the testes join into a common duct about 5-10 mm from the urogenital pore. The urinary pore opens into this common duct from the dorsal side. In addition, there are 2 small pores situated on each side of the base of the urogenital papilla opening ventrally into the coelom. In the females, there are 3 main openings in the anal region instead of 2 as found in the males. The anteriormost opening is the anus followed by the genital pore. The third opening is the urinary pore which is posterior to the genital pore located at the tip of the urogenital papilla.