Studies on the reproductive biology of spiny eel, Macrognathus aral from upper Assam.

ABSTRACT

The one-stripe spiny eel, Macrognathus aral (Bloch and Schneider), has been gaining importance not only as a food fish but also as an aquarium fish for its body shape and behaviour. The overall MF ratio recorded 10.27, both the males and females were mostly mature in May-August. The peak values of gonado somatic ratio (GSR) attained during May for males (1.3) and August for females (12.4) indicating that the fish have only one breeding season during summer. The range of ova diameter was found to vary from 0.3 to 1.4 mm, the absolute fecundity ranged from 250 (21.6 cm / 27.4 g) to 5220.1 (27.2 cm / 66.3 g) while relative fecundity ranged from 9.1 to 128.9. The 50% maturity is attained in length group of 10.1-14 cm for males and 14.1-18 cm for females. The species is a moderately fecund, isochronal spawner and having a restricted breeding season. The relationship between fecundity and body weight and length has also been discussed.