Fishery, reproductive biology and diet characteristics of Bombay duck Harpadon nehereus from the Saurashtra coast

Fishery, reproductive biology and diet characteristics of Bombay duck Harpadon nehereus landed by dol netters along the Saurashtra coast was studied during 2006 – 2009. Annual average catch was 25,479 t with catch rate of 378.6 kg unit-1 forming 22.44% of the total dol net catches. Bulk of the catch was landed during September – January and in May. Length weight relation differed significantly between males, females and indeterminates. Growth was isometric in males but allometric in females and indeterminates. Overall sex ratio was 1.05 and length at first maturity was 214.5 mm. Gravid and ripe females were observed throughout the year with peak occurrence during April – June. Mature ovaries contained immature (0.2 - 0.39 mm), maturing (0.5 - 0.69 mm) and mature ova (0.8 - 0.89 mm). Total fecundity was between 8467 and 102079. Non penaeid prawns viz., Acetes and Nematopalaemon tenuipes was the most important food item in the diet followed by sciaenids, unicorn cod and juveniles of Bombay duck. Fishes with empty stomachs were encountered in high numbers. Juveniles fed mostly on non penaeid prawns while adults preferred both finfishes and prawns. Feeding intensity was more in adults and less in juveniles. The reproductive biology and food and feeding were found to vary significantly between years.