生态渔业养殖模式下汤逊湖鱼产力估算及对内源污染的影响

通过汤逊湖天然饵料生物量的调查,评估在不投肥、不投饵条件下汤逊湖的鱼产力情况;根据主要鱼产力生长代谢参数评估生态渔业养殖模式下由鱼的排泄和排粪作用产生的污染负荷量及由生长增重存储在鱼体内的营养盐量。结果表明:汤逊湖天然鱼产力约为2 975.49 t/a,生态渔业养殖模式下养殖密度可控制在29 g/m³左右;排泄和排粪产生的营养盐氮、磷量分别为309.28、13.06 t/a,其中氮量高于鱼类生长增重存储的营养盐量(73.10 t/a),磷量低于鱼类生长增重存储的营养盐量(15.90 t/a)。生态渔业养殖产生一定量的内源污染物氮,但能削减水体中内源污染物磷,可作为控制湖泊富营养化的措施之一。

Estimation of fish productivity in Tangxun Lake under ecological fishery culture model and its impact on endogenous pollution

The biomass of natural bait in Tangxun Lake was investigated to evaluate the fish productivity of Tangxun Lake under the condition of neither fertilizer nor bait. The pollution load generated by excretion and defecation and the amount of nutrients stored in fish body by growth gain in ecological fishery culture were evaluated according to the main fish productivity growth metabolic parameters. The results showed that, in Tangxun Lake, the natural fish productivity was around 2 975.49 t/a, and the ecological fishery stocking density could be controlled around 29 g/m3; nitrogen and phosphorus from the sources of excretion and defecation was 309.28 and 13.06 t/a, respectively; in which nitrogen was higher than the weight gained from the nutrition metabolism in fish bodies (73.10 t/a); and phosphorus was lower than the weight gained from the nutrition metabolism in fish bodies (15.90 t/a). Ecological fishery culture produced a certain amount of endogenous pollutant nitrogen, but it could reduce the endogenous pollutant phosphorus in water, which could be used as one of the measures to control lake eutrophication.