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在水温23.4-24.0℃、盐度33.00、pH7.78-8.02的培养条件下,半滑舌鳎初孵仔鱼全长为3.55±0.161mm(n=60),依照公式4/3π.R/2.(r/2)2计算其卵黄囊体积为0.606±0.106mm3(n=60)。1日龄仔鱼,全长为4.99±0.211mm(n=10),卵黄囊体积较初孵仔鱼缩小近10倍,约为0.066±0.008mm3(n=10);2日龄,仔鱼的巡游模式建立,仔鱼全长为5.61±0.069mm,卵黄囊体积为0.030±0.002mm3(n=10),口初开;2.5日龄,口完全裂开,口裂0.24±0.024mm(n=10),仔鱼进入摄食期;3日龄,仔鱼的外源性摄食关系初步建立;4日龄,仔鱼的摄食率达100%,完成了内源性营养向外源性营养的转换;5日龄,仔鱼的卵黄完全被吸收,仅剩聚成一团的小油球,仔鱼的混合营养期持续2.5天时间;21日龄,稚鱼全长为12.96±0.611mm(n=11),仍有40%的个体残余的油球还没有完全被吸收,其体积仅为0.0000005±0.000003mm3(n=11)。仔鱼发育过程中,其长度的生长存在内源性营养阶段的快速生长、混合营养阶段的慢速生长以及饥饿期间的负生长三个生长期相,平均增长率为0.45mm/d,依照TL=aD3+bD2+cD+d方程式对仔鱼的全长与日龄进行回归,其生长模型为TL(mm)=0.0026D3-0.0704D2+0.7993D+3.55(R2=0.9811,n=324)。仔鱼耐受饥饿的时间临界点发生在孵化后第10天(即9日龄)。仔鱼具有摄食能力的时间约6天,不可逆转饥饿期的时间约3天。残余的油球较长时间的存在,相对地延长了仔鱼混合营养期的时间,对仔鱼的发育、生长和存活有着至关重要的作用。5-20日龄的个体都具有胸角这个明显的形态学特征,只是饥饿个体和不可逆转饥饿期个体的胸角比摄食个体更为明显和尖锐,胸角不能作为区分健康仔鱼和饥饿仔鱼的形态学依据之一[动物学报51(6)1023-1033,2005]。
Under the conditions of water temperature 23.4-24.0 ℃, salinity 33.00, pH7.78-8.02, the length of newly hatched larvae was 3.55 ± 0.161mm (n = 60) according to the formula 4 / 3π.R / 2. (R / 2) 2 The yolk sac volume was calculated to be 0.606 ± 0.106 mm3 (n = 60). The larvae of one-day-old larvae had a total length of 4.99 ± 0.211mm (n = 10), the size of the yolk sac was nearly 10 times smaller than that of the first-hatched larvae (0.066 ± 0.008mm3, n = 10) The larval length was 5.61 ± 0.069mm and the volume of yolk sac was 0.030 ± 0.002mm3 (n = 10) Larvae entered the feeding period; 3-day-old larvae exogenous feeding relationship initially established; 4-day-old larvae feeding rate of 100%, completed the endogenous nutrition to exogenous nutrition conversion; 5-day-old, Of the yolk was completely absorbed, leaving only a small ball of oil gathered in a group of larvae mixed nutrition period lasts 2.5 days; 21-day-old juvenile full-length 12.96 ± 0.611mm (n = 11), there are still 40% Individual residual oil ball has not been completely absorbed, the volume of only 0.0000005 ± 0.000003mm3 (n = 11). During the development of larvae, the growth of the larvae had the rapid growth in the endogenous nutrition stage, the slow growth in the mixed nutrition stage and the negative growth phase in starvation. The average growth rate was 0.45 mm / d, according to TL = The regression equation of aD3 + bD2 + cD + d was obtained. The growth model was TL (mm) = 0.0026D3-0.0704D2 + 0.7993D + 3.55 (R2 = 0.9811, n = 324). The critical point of larval tolerance to starvation occurred on the 10th day after hatching (ie 9 days of age). Larvae have the ability to ingest about 6 days, irreversible hunger period of about 3 days. The existence of residual oil ball for a longer period of time, which relatively prolongs the period of mixed nutrition of larvae, plays a crucial role in the development, growth and survival of larvae. Individuals between 5 and 20 days of age have the obvious morphological characteristic of the chest, except that individuals with hunger and irreversible hunger tend to have a more pronounced and sharp chest angle than those who feed themselves, and the chest can not be used as a differentiator between healthy larvae and hungry larvae Morphological basis [Acta Zoologica Sinica 51 (6) 1023-1033, 2005].