关键词: 农田防护林, 疏透度, 积雪深度, 分布格局

Abstract: A hatching experiment was conducted to investigate the effects of different water salinity on the embryonic development of rock bream Oplegnathus fasciatus, aimed to determine the optimal water salinity for hatching O. fasciatus.The eggs were hatched in the water with eight salinities at 23.0 ℃-25.2 ℃, and the embryonic development was investigated and described. Both low and high water salinity had durative damage to the embryos, making most of the embryos shrank and died at division stage and parts of them shrank and died after gastrula stage. Low water salinity led to the high deformity rate of newly hatched larvae, mainly inducing the L- or C-type bending of spine; while high water salinity led to the malformed development of tail since the blastopore closed. Through the analysis of the relationships between hatching rate, newly hatched larvae deformity rate, and water salinity, the relationship between the percentage of healthy larvae (PHL) and water salinity (S) could be described as PHL=-0.0018S²-0.1135S-0.8853 (R²＝0.948). It was suggested that at 23.0 ℃-25.2 ℃, the appropriate water salinity for hatching (PHL>70%) was 21-42, and the optimal water salinity for hatching (PHL>90%) was 30-33.

Key words: Windbreaks/shelterbelts, Porosity, Snow depth, Distribution pattern