Gonad development and reproductive cycle of the white-spotted rabbitfish Siganus canaliculatus (Park, 1797) in Palompon, Leyte, Eastern Visayas, Philippines

Abstract

Summary The siganid production in the Philippines is continuously declining from 2007 up to present. In Palompon, Leyte, annual yield of siganids, particularly Siganus canaliculatus (Park, 1797) also showed a decreasing trend of total production. This is consistent that this stock is under heavy pressure, and when left unmanaged, this could lead to further overexploitation and the collapse of the stock in the long run. Regardless of this, detailed reproductive biology and potential of this species are very few in the Philippines. Therefore, this study was conducted to provide information on the reproductive biology and breeding cycle of S. canaliculatus in Palompon, Leyte where fishing pressure is high and sound management formulation is necessary. S. canaliculatus is a group‐synchronous, multiple spawners with skewed sex ratio where males predominates over females. Maturity stages based on macroscopic examinations identified four maturity stages (immature, developing, mature and spent) while six maturity stages (immature, developing, mature, spawning, spent and re‐developing) were identified through histological analysis. A single ovo‐testis was identified among the 669 specimens examined. Based on histological sections, the smallest size of mature male was 5.5 cm standard length, and the smallest mature female was 7.1 cm standard length. On the other hand, length at first maturity for mature fish were 8.1 cm standard length for males and 9.7 cm standard length for females. Two defined peaks of gonadosomatic index were identified in both sexes: a major peak from February to May and a minor protracted one from July to December. Mature and older ovaries and testes occurred throughout the year, an indication of your round breeding season of S. canaliculatus in Palompon. Implementing a fishing ban during the major and the minor breeding spawning peaks would allow the mature and older individuals to contribute first to the population; allowing the continuity of the stock.