Growth, reproduction and feeding biology of an endemic Sucker Catfish, Glyptothorax silviae Coad, 1981 (Actinopterygii: Sisoridae), in the Maroon River, Iran

This study was carried out to provide some information on the biological features of the endemic Sucker Catfish, Glyptothorax silviae, from the Maroon River in the Tigris basin, Iran. Samples were collected at monthly intervals throughout the year and 277 individuals of G. silviae were caught. The mean total length and weight were 8.1 ± 1.7 (±SD) cm and 5.8 ± 3.5 (±SD) g and maximum length and weight were 11.9 cm and 17.4 g, respectively. Length-Weight relationship of the total specimens was calculated as W = 0.006 TL3.205, (R2 = 0.956) indicating allometric growth and was not significantly different between males and females. The overall condition factor was 0.62. The sex-ratio (1.23M:1F) was not significantly different from the expected 1:1 ratio. Glyptothorax silviae reproduces during June-September. Absolute and relative fecundity was 1129 eggs/fish and 105 eggs/g body weight, respectively. The egg size ranged from 0.994 to 1.76 mm with a mean value of 1.29 ± 0.171 (±SD) mm. The highest values of gonadosomatic index were observed in June-July. The gut content analysis revealed that G. silviae feeds only on aquatic insects.