Length–weight relationships and reproductive parameters of Amblyceps apangi Nath and Dey, 1989 from Nagaland,India

The present study describes certain biological parameters of a hill stream catfish, Amblyceps apangi Nath and Dey, 1989 first described from Arunachal Pradesh, India. The distributional range of the fish was later recorded from the states of Manipur and Nagaland. The fish is very rare and this is the first report on certain biological parameters based on collections (140 males, 105 females) from streams in the Doyang watershed, a tributary of the Brahmaputra River. The value of the allometric coefficient (b) indicated close to isometric growth in males (2.989) and negative allometric growth in females (2.945). The relative condition factor was found to be close to 1 in different size groups. Both males and females attained first maturity (M₅₀) in length group 6.0–7.0 cm. Peak values (Male 0.424, Female 1.465) in the gonadosomatic index (GSI) occurred from April to May, indicating one spawning season per year. The overall female to male ratio was 1 : 1.33. Absolute fecundity ranged from 17 to 122 for fishes of total length 6.34–10.3 cm.