Growth And Morphological Development In Larvae And Juveniles Of Elopichthys Bambusa And The Influence Of Starvation And Different Temperature

(1)The morphological development, including the body proportions, fins, pigmentation, and survival rate for21days post hatching, of laboratory-reared larval and juvenile Elopichthys Bambusa is described. The average standard body length of newly hatched larva was5.50mm(5.20-5.72mm).Rearing at water temperature of26℃, larvae completed yolk absorption and entered the preflexion larva stage on the5th day after hatching at7.93mm BL. Notochord flexion started on the5th day at7.93mm BL. On the12th day, the hypurals were completed and entered the postflexion larva stage. Transformation from the larval to the juvenile stage occurred on19th day at21.91mm BL. Feeding was observed on day3in fish which had undergone complete yolk absoption following mouth and anus opening on day2.Myomere number were38+15=53.The range of body length for fins development was between9.62and24.21mm. All fins completed development when the larva entered the juvenile stage. A high survival rate of94.78%was estimated on day21.(2)The effects of starvation on growth, morphology and behavior of Elopichthys Bambusa larvae were studied to determine the optimal time of feeding and the point of no return (PNR). The results showed that the larvae began to feed on third day post hatching(dph) under the water temperature26.0℃. At this time the yolk sac decreased from1.55±0.28mm3to0.22±0.07mm3during this period, and absorbed on5dph. The period of mixed nutrition has only2days. Compared to the feeding group, the body length of the starvation group showed significant difference after6dph. The initial feeding rate of Elopichthys Bambusa larvae was only5%and the tiptop initial feeding rate occurred on6dph and7dph, holding two days, when the yolk was absolutely absorbed. The initial feeding rates fell to50%of the tiptop initial feeding rate and the larvae entered the PNR, which appeared from9dph to10dph, and the resistance ability of hunger was strong. In order to avoid feeding too early or too late, ensure the healthy growth and high survival rate. We should control the optimal feeding time around5to7dph.(3)The growth characteristics of Elopichthys Bambusa larvae were studied at different temperatures by aquarium. The results showed that the growth rate is significantly affected by the different water temperatures. The most suitable temperature is27℃. As the results also express as curve regression, the optimum model of body length growth is Cubic (R2>0.87), and that of the body weight growth is Growth (R2>0.91). The growth model is competent to estimate the culture production. The relationship between body length and body weight is different speed of growth(b>3). The fullness is significantly affected by the different water temperatures.