Reproductive Biology, Captive Breeding and Larval Development of the Threatened Deocata Pipefish Microphis deocata (Syngnathidae)

Microphis deocata is the only freshwater syngnathid species from the Ganges and Brahmaputra River basins in India. However, this species suffers from rampant wild collections primarily as a lucrative ornamental freshwater fish of northeast India. Given this, the present study is undertaken to manage the threat primarily posed by aquarium fish trade through the initiation of culture and breeding of the species in aquaria for the first time. The paper also highlights important notes on reproductive biology and provides a baseline datum on the spawning and larval development of M. deocata. A female-biased sex ratio of 1.00 : 1.24 is observed based on n = 858 individuals caught-and-released on site from the Manas River (Brahmaputra basin), Assam, India. Data on rearing and successful breeding trials conducted with additional 15 individuals in aquaria (six males and nine females) between June–August, 2018 and October–November, 2018 are provided. The newly-hatched larvae measures ⁓14 mm in total length. Transformation of larvae to juveniles commence by 75 days post hatching. After 240 days, juveniles attain a maximum length of 11.9 ± 0.1 cm weighing 0.4–0.5 g, and the mean survival rate is 56.8 ± 8.7%.