Abstract: From the viewpoints of ethology,this paper dealt with the effects of environmental factors,such as the number of brood fish reproductive pairs per square meter,water transparency,and ground substance on the reproduction of jaguar cichlid (Cichlasoma managuense).The results showed that to some extent,the spawning rate (SR),fertilized rate (FR) and incubated rate (IR) of C.managuense were decreased with increasing number of its reproductive pairs per square meter.The spawning activity was rarely observed when the number of reproductive pairs per square meter was higher than four.Water transparency had a greater effect on FR and IR than on SR.The greater the water transparency,the longer the shortest distance between two spawning nests. C.managuense preferred to spawn on 0.20-0.50 mm-sieved sand granule,with its average SR,FR and IR up to 90%,87.78% and 79.44%,respectively.No spawning activity was observed on palm husks.The fish could spawn on coarse porcelain tiles,but its SR,FR and IR decreased markedly.

Key words: Rice production, Environmental cost, Ecological agriculture, Dongting lake area