The Reproduction of Endemic Fish Opudi (Telmatherina prognatha Kottelat, 1991) in Lake Matano, South Sulawesi, Indonesia

Abstract

Telmatherina prognatha is an endemic fish of the Matano Lake, in Indonesia, which demands a very crucial reproductive study, especially based on habitat conservation. This research, therefore, aims at analyzing its reproduction function as basic information for resource management in Matano Lake. Furthermore, the investigation was conducted from March 2018 to February 2019 in six sampling spots, where the habitat conditions, including the physicochemical characteristics of the water, were observed monthly. Also, the fish were sampled using a multifilament net that was 0.5 inches in mesh size and subsequently measured for total length, body weight, and gonad maturity. Moreover, the total number of specimens were approximately 1809 individuals (n), encompassing both sexes of male (1059) and female (750), which possessed a total length in the ranges of 36.46 – 72.00 mm and 32.93 – 66.20 mm, respectively. However, the sex ratio obtained was 1.4: 1, and those with matured and maturing gonads were found in each sampling’s month, and most of all, including those with spent gonads, are commonly discovered in February, March, and April. Also, the 50% probability of maturity was estimated as 57.31 mm for males and 45.16 mm for females, while the mean gonadal somatic indices (GSI) were 1.72±1.39 and 4.12±1.74, respectively. Therefore, the fecundity of this species was estimated to be in a range of 77-299 eggs, and the oocyte diameter was between 0.11 mm and 1.37 mm.