The relationships among polycultured fishes and an input output dynamics model in the high yield fish ponds
高产池塘混养鱼类相互关系及主体鱼资金投入产出模型的建立

The gray correlativity analysis was applied to study on the relationships among fishes in high yield poly culture pond. The results are as follows: the relation between the input of mud carp fingerlings and output of big head carps is the biggest( R =0.7921), and the relation between the input of grass carp fingerlings and output of mud carp is the second ( R =0.7415).The input mud carp fingerlings becomes superiority maternal factor, the output of big head carps becomes superiority junior factor. The gray dynamics model is applied to analyse the input output. and a dynamic equation is developed. The results indicate that the system can develop steadily only if a 30% of net yield value is remained for next year's carp fingering.