Physiological ecology of exotic and native fishes in lakes of the Yunnan Plateau was comparatively studied in a series of experiments. Four species were selected as the experimental fishes: Hemiculter leucisculus and Anabarilius grahami (the exotic and native fishes for Lake Fuxian respectively), and Cyprinus carpio and Cyprinus pellegrini (the exotic and native fishes for Lake Xingyun respectively). Between those exotic and native fishes, difference in growth, the adaptation to eutrphication and the characteristics of nutrient utilization were compared. The main results were following:
1. There was no significant difference in growth rate between H. leucisculus and A. grahami, but A. grahami had the advantage in food utilization over H. leucisculus. The percentages increase over control in feeding rate, growth rate, food conversion efficiency, protein retention efficiency and energy retention efficiency of H. leucisculus reared in the moderate and high trophic status water were lower than those of A. grahami reared in the same type of water, or the percentages decrease over control in those parameters of H. leucisculus were higher than those of A. grahami. Those results show that the higher trophic status of water has more negative effects on the growth of H. leucisculus, and that the capability of H. leucisculus to adapt to eutrophication is lower than that of A. grahami in respect of growth.
2. Saprolegniasis resistance of H. leucisculus was higher than that of A. grahami；the higher trophic status of water could reduce the resistance to Saprolegniasis of A. grahami. Those results indicate the eutrophication adaptation capability of H. leucisculus is higher than that of A. grahami in the respect of saprolegniasis resistance.
3. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) gradually decreased with the increase of water trophic status for H. leucisculus and A. grahami. The percentages decrease over control in the activities of hepatic ALT，AST and LDH for H. leucisculus reared in high-trophic-status water were all higher than those for A. grahami reared in the same type of water. Those results indicate the normal hepatic functions of H. leucisculus and A. grahami are damaged by eutrophication to some extent, and that the capability of H. leucisculus in the adaptation to eutrophication is lower than that of A. grahami in respect of hepatic function.
4. Growth rate of C. carpio was higher than that of C. pellegrini. The ratio of nitrogen retention to nitrogen intake, apparent biological value of protein, the ratio of energy retention to energy intake and energy growth efficiency of C. carpio were all higher than those of C. pellegrini; Difference in nitrogen and energy budgets between them shows that C. carpio is better than C. pellegrini in protein and energy utilization.
5. Differences in growth and food utilization between C. carpio and C. pellegrini were affected by water temperature, and were higher under lower water temperature. This indicates that the low water temperature has more negative effects on growth and food utilization of C. pellegrini, and that C. carpio is more adaptive to low water temperature than C. pellegrini.