Abstract: This paper deals with the effects of pH, salinity, density and medium on the early stage-developmentand growth of Perinereis aibuhilnesis. The results show that the optimum pH for its hatching is 7.0-7.5, under which, suitable slinity is in the range of 15-40%, and The suitable density is less than 100 individuals per millilitre, The optimum pH for nectochaets growth is 6.0-9.5. During the periods offirst and second week after hatching,the optim、im salinity is 30-35% and 20-29% respectively, andthe optimum denxity ranges from 10 to 80 individtial；per milliltre,Muddy is a fine medium and the opti-mum density is 0.35 individuals·cm².

Key words: transgenic rice, wild relatives, gene flow, introgression.