Effect of age on the consecutive spawning of ablated Penaeus semisulcatus broodstock

G.J. Coman, P.J. Crocos-2003
Aquaculture, 219(4): 445-456

Abstract:

The effect of broodstock age on the consecutive spawning performance of wild-caught ablated Penaeus semisulcatus females was assessed for four age groupings (6, 8, 12, 14 months old). Age groupings were determined from time series size data (carapace length measurements) of the broodstock population. Spawning performance of the four age groupings was assessed in terms of the percentage of females spawning, eggs per spawning and hatch rates per spawning. The percentage of females spawning decreased more rapidly over consecutive spawnings for the 14-month age grouping than for the three younger age groupings. Additionally, a smaller percentage of the 6-month-old females spawned than 8- or 12-month-old females across all consecutive spawnings. The number of eggs produced per spawning declined with consecutive spawnings from the older spawners (12 and 14 months old), but not from the younger spawners (6 and 8 months old). The hatch rate did not decline with consecutive spawnings from any of the four age groupings, although the overall mean hatch rates were lower for the 6-month-old females than the older females. These results suggest that broodstock age (and/or size) affects the consecutive spawning performance of P. semisulcatus. Consequently, the reproductive performance expected from ablated shrimps over time in a hatchery may differ depending on the age of the broodstock.

(CSIRO Marine Research, PO Box 120, Queensland 4163, Australia, e-mail: greg.coman@csiro.au)

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