Improving spawning synchrony in the Nile tilapia, Oreochromis niloticus (L.) |
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| Authors: | DC LITTLE D J MACINTOSH P EDWARDS |
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| Institution: | Division of Agricultural and Food Engineering, Asian Institute of Technology, Bangkok, Thailand;Institute of Aquaculture, University of Stirling, Stirling, Scotland;Division of Agricultural and Food Engineering, Asian Institute of Technology, Bangkok, Thailand |
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| Abstract: | Abstract. The development stage and number of seed (eggs and fry) removed from individual incubating Oreochromis niloticus (L.) broodfish at 10-day interharvest intervals (IHI) was compared with the harvest of free-swimming fry from undisturbed fish held in a tank within the same system. Spawning synchrony and productivity were compared for (1) total exchange of females for ‘conditioned’ females after each harvest, (2) exchange of only spawned females, and (3) return of females back into the spawning tank. Improved synchrony and seed production were positively related to removal of eggs and fry from incubating females and could have important implications for broodstock management in commercial hatcheries. Allowing fish to remain undisturbed in clear water tanks may lead to inhibition of spawning activity related to the formation of hierarchies. Individual weight loss by females during incubation was correlated with stage of seed harvested and thus with timing of spawning during the interharvest interval. |
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