Repeated Spawning Performance of Female Giant Freshwater Prawn (Macrobrachium rosenbergii de Man) in a Recirculating Water System

Abstract

Repeated spawning of female giant freshwater prawn (Macrobrachium rosenbergii de Man) is a promising strategy to enhance broodstock utilization and seed production efficiency. However, concerns persist regarding its potential impacts on reproductive performance and larval quality. This study evaluated the effects of repeated spawning in individually reared females maintained in floating perforated boxes under a single-pair mating system, with in vivo egg incubation over a 180-day period. Only 33.33% of the initial broodstock completed three spawning cycles. Although the realized larval yield (number of hatching larvae per female) remained stable across spawnings, the relative larval yield (number of larvae per gram of female body weight) significantly declined (p<0.05), despite consistently high hatching rates (88.40–89.89%). The spawning interval increased with each successive spawning (35.42–42.33 days). While post-larval weight remained unaffected (p≥0.05), post-larval quality deteriorated with repeated spawning, as evidenced by reduced survival rates, prolonged larval development duration, and decreased stress resistance (shorter time to 50% mortality after acute freshwater exposure), despite comparable weight per 100 post-larvae across spawning events. These findings highlight the trade-offs between maximizing broodstock use and maintaining seed quality, emphasizing the need for improved broodstock management strategies in repeated spawning systems.