Reproductive biology of Indian squid, Uroteuthis duvauceli (Orbigny, ۱۸۳۵), in the northern Gulf of Oman

Some aspects of the reproductive biology of the Indian squid, Uroteuthis duvauceli, were studied from June ۲۰۰۶ to May ۲۰۰۷. A total of ۱۲۰۰ specimens were collected from approximately ۳۰-۸۰m depths by trawling in ۵۰ stations, of which ۳۶۰ samples were studied for sex determination and fecundity. The minimum and maximum total and mantle length, and body weight were recorded in December and June, respectively. The highest range of total length (۴۱۰-۴۲۰mm), mantle length (۱۵۰-۱۶۰mm and body weight (۹۰-۱۰۰g) were encountered in September. The specimens were composed of ۳۴% male and ۶۶% female (M:F=۱:۲). This species was found to be more abundant in summer. The minimum and maximum ovary weighs were ۲.۱g and ۷.۹g with an average of ۴.۹g, respectively. These values for nidamental gland weight were ۰.۷۰ and ۲.۶۱g with an average of ۱.۶g. The minimum and maximum absolute fecundity were ۲۵۵۱۰ (in August) and ۳۷۵۶۰۰ (in April), respectively. These values for relative fecundity were ۵۲۰۷ (in April) and ۸۶۷ (in August), respectively. The highest gonadosomatic index (GSI) was in April (۱۴.۳۸) and the lowest was in July (۸.۶۳). This squid is, therefore, assumed to be a spring spawner. Minimum and maximum egg diameter were ۰.۷۲mm (in August) and ۲.۵mm (in April), respectively.

Keywords:

Indian squid , Uroteuthis duvauceli , Fecundity , GSI , Sex ratio , Gulf of Oman