Reproductive Performance of Different Sized Wild and Pond-reared Penaeus paulensis Females |
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| Authors: | Ronaldo O Cavalli Marcos P Scardua Wilson Wasielesky Jr |
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| Institution: | Universidade do Rio Grande-Departamento de Oceanografia, Laboratório de Maricultura, C.P. 474 Rio Grande, RS 96201–900 Brazil |
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| Abstract: | The present study analyzes the reproductive performance of three size classes of wild (average weight of 46.5, 55.0, and 63.2 g) and three size classes of pond-reared (18.4, 21.3, and 25.1 g) Penaeus paulensis females. Unilaterally eyestalk ablated females were placed for 70 d in 3.6 m diameter tanks at 6 individuals/m2 and a 1.2:1 female-male ratio. Number of spawns, eggs, nauplii, fertilization and hatching rates were recorded every second day. The length of unfed protozoea I larvae was also recorded. Larger broodstock shrimp tended to suffer higher mortality rates. Smaller, pond-reared females started spawning at 28.2 ± 4.1 g. The number of eggs and nauplii per spawning event were not significantly different between experimental groups (P > 0.05), but due to their higher spawning frequency, small wild females (46.5 ± 3.7 g) outperformed medium (55.0 ± 1.8 g) and large ones (63.2 ± 7.0 g). No relationship between protozoea length and spawner size was found. Optimum size for the maturation of wild P. paulensis females was estimated to be from 30 to 60 g. It is suggested that the use of this size range can potentially enhance nauplii production of P. paulensis . |
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