不同营养模式下内蒙古沙漠小型盐湖卤虫种群特征与环境负载力

通过对桑根达莱淖尔卤虫的养殖实验与卵囊解剖,研究了内蒙古沙漠小型盐湖投饵、施肥与自然状态3种营养模式下卤虫的生境、种群动态、生殖特征,分析了环境对卤虫资源的负载力。结果表明:1在起始种群相同的情况下,不同营养模式对种群结构与密度有显著影响;2不同营养模式对个体生长速度影响存在差异,投饵对加快个体生长速度效果最明显,但在性成熟速度方面不同营养模式没有出现统计学显著差异;3不同营养模式对卤虫的怀卵量、卵生/卵胎生比例有显著影响;与空白组相比,投饵组平均怀卵量提高了35.52%—72.71%,施肥组提高了11.34%—26.15%;4卤虫资源的环境负载力为0.3—0.4 kg/m3,加以补充肥料,可提高到0.45 kg/m3,在投喂饲料的情况下可以达到0.5 kg/m3;5卤虫蛋白可开发量按环境负载力的1/3估计,对照组、施肥组和投饵组的相应年开发量分别为2.61—2.98 kg/m3、4.5—5.4 kg/m3和7.51—8.67 kg/m3,滞育卵产量分别为0.73、1.10 g/m3和1.17 g/m3。

Artemia population characteristics in different conditions, and environmental carrying capacity in small saline lakes in the Inner Mongolian desert

There are hundreds of saline lakes in the Inner Mongolian desert. To increase the income of herdsmen, and address the problem of supply and demand of Artemia, methods of farming brine shrimp in small saline lakes in the Inner Mongolian desert were examined between 2002 and 2010. The habitat, population dynamics and reproductive characteristics of Artemia were studied in six artificial ponds filled with water from a small salt lake nearby named Sanggendalainaoer in the Inner Mongolian desert. In two of the ponds the Artemia were fed 200-510 g of flour twice a day. In two other ponds the water was enriched with organic matter by adding 8-12.5 kg of dried cow-dung twice a week depending upon water color and transparency. The remaining two ponds had no additives and therefore served as natural state controls. For each of these, the environmental carrying capacity of Artemia resources was determined. The results revealed that in those ponds that had the same initial population density, different nutritional conditions had a significant effect on the population structure and density at the end of the experiments. When compared with the control group, the population density of Artemia increased by 19.53% in the organically enriched ponds, and by 31.82% in the ponds where Artemia were fed. Furthermore, the conditions in each experimental pond had a different effect on individual growth rate, with feeding having the greatest effect, especially on the older larval stages. The time to reach sexual maturity was not statistically significantly different between the three treatments. Ambient temperature had a significant effect on the rate of sexual maturity and different treatments had a significant influence on the fecundity of Artemia and the oviparous: viviparous ratio. Compared with the control group, the average fecundity increased by 35.52%-72.71% in Artemia that were fed and 11.34%-26.15% in brine shrimp in the organically enriched pond water, and the oviparous: viviparous ratio was enhanced by both treatments. The main growing period of Artemia was May to September, and the environmental carrying capacity of Artemia resources was about 0.3-0.4 kg/m³. In the case of the organic enrichment and feeding treatments, the environmental carrying capacity was increased to 0.45 kg/m³ and 0.5 kg/m³, respectively. If the exploitable capacity of Artemia protein is estimated as 1/3 of the environmental carrying capacity, it will be 2.61-2.98 kg/m³, 4.5-5.4 kg/m³ and 7.51-8.67 kg/m³ every year in the control, organic enrichment and feeding treatments, respectively. In addition, diapause egg production will be 0.73 g/m³, 1.10 g/m³ and 1.17 g/m³, respectively. The results show that Artemia resources in small saline lakes in Inner Mongolia have great proliferative potential, and that productivity and environmental carrying capacity of this species can be increased within these lakes through manual intervention.