Influence of Females’ Body Size on Reproductive Performance and Offspring Fitness in Rohu (Labeo rohita)

Abstract

Reproductive performance of broodstocks and their produced offspring fitness are crucially important for aquaculture especially in hatcheries. Considering this issue, a study has been carried out to explore whether females’ body size can influence their reproductive performance and also offspring fitness traits. In the experiment, there were three female size groups- 1) big (1.5-2.5 kg), 2) medium (>1kg) and 3) small (<1 kg). In each group, there were 13 females which were performed with some common males using a special breeding design. The analysis has revealed that bigger females produced significantly higher number of eggs than the smaller size group, while no variation in egg numbers has been observed between bigger and medium and medium and smaller size groups. The study has also found no significant variation in egg weight, egg diameter and egg area among those female size groups. A significantly higher hatching rate has been found in bigger and medium sized females rather than the smaller group, however no significant variation has been revealed between bigger and medium size group. It has been found a significantly lower number of deformed hatchlings produced by the bigger males than the smaller group, while no significant variation has been observed among bigger and medium and medium and smaller sized groups. The offspring fitness analyses have revealed that bigger mothers larvae became significantly larger (standard length and body area) within two weeks of experimental rearing period than medium and smaller sized groups, while medium sized females’ offspring also grew significantly larger than the smaller one. However, no significant variation has been found in offspring survival rate among these female size groups. The overall outcomes provide an important message to the hatchery owners, farmers and other stakeholders about which size of broodstocks they need to use for better production in terms of reproductive outputs as well as larval fitness.