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| Starvation and Point of No Return in Striped Knifejaw Oplegnathus fasciatus Larvae |
| PENG Zhi-lan,LIU Min-hai,LUO Hai-zhong,FU Rong-bing,ZHANG Feng-ping,MAO Zhi-zeng |
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Abstract Striped knifejaw Oplegnathus fasciatus larvae were starved to determine the point of no return(PNR)at water temperature of 22～24 ℃ and salinity of 29. The survival, and changes in oil globules and yolk-sac volume, growth and swimming behavior in the larvae were observed 0, 3, 6, 9, 12 and 15 days after starvation. The results showed that starvation led to delaying of the use of oil globules, and to the significantly smaller body length than that in the normal larvae in control group(P<0.05). The PNR occurred 5～5.5 days after hatch and the subsistence larvae 0, 3, 6, 9, 12 and 15 d after hatch were death 6.5, 6,5, 4, 6 and 5 days after starvation, respectively.The LC_(50) time of the larvae were 4, 3.5, 3.5, 3.5 d and 3.5 days, respectively, indicating that 9 days was the most sensitive stage to starvation in the early life stage in the larvae. The larvae had shorter body length, bigger head, thinner body and posterior cupped part of brain after being starved for long period. The behavioral responses of the larvae to starvation was divided into three stages:congregating in the surface water, swimming slowly and searching for food; slowly swimming; morphological transformation and resting in the water bottom.
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Received: 25 March 2010
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