2・3の海産浮游幼生に及ぼす高温と残溜塩素の影響について

• Main Authors: 平山 和次, 平野 礼次郎
• Format: Report
• Language: Japanese
• Published: 長崎大学水産学部 1970
• Subjects: Crassostrea gigas
• Online Access: http://hdl.handle.net/10069/31198; https://nagasaki-u.repo.nii.ac.jp/?action=repository_uri&item_id=8434; https://nagasaki-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=8434&item_no=1&attribute_id=18&file_no=1

Increased utilization of sea water for cooling purpose in electricity generating industry and in other industrial processes has made it necessary to consider the biological influences of its effluents on marine life in the adjacent area. Hence, as the direct influences of the effluents, the lethal points of high temperature and residual chlorine for marine planktonic larvae in various exposure periods were studied. The experiments against high temperature were performed with the purple sea urckin (Anthocidaries crassipina) larvae in early stage (2-4 cells), blastula stage and pluteus stage, with the rock barnacle (Balanus amphitrite albicostatus) larvae in nauplius stage, and with the oyster (Crassostrea gigas) larvae in blastula stage. The lethal influences of residual chlorine on the blue mussele (mytilus edulis) in early stage (2-4 cells) and trochophore stage were studied in detail in relation to the exposure periods. Results obtained are as follows. 1) As shown in Table 3, early stage larvae of the purple sea urckin have the least tolerance to high temperature among the examined larval animals. They cannot survive the treatment at the temperature of 33℃ for 20 minutes. Nauplius II larvae of the rock barnacle have the most tolerance to high temperature being able to tolerate 40 minutes' treatment at 40℃. 2) TLm (median tolerance limit) of chlorine for the blue mussele larvae for 5 and 10 minutes exposure periods are shown in Fig. 1. The 10 min-TLm values for early stage larvae (2-4 cells) and for trochophore stage larvae and the 5 min-TLm value for early stage larvae are shown as 1.15, 1.31 and 1.21 ppm., respectively. The differences among these values are minimal. However, the 5 min-TLm value for trochophore stage larvae, 2.37 ppm. is considerably high as compared with the other TLm values, Accordingly, it is clear that within 5 min exposure period, the blue mussele larvae in late stage become more tolerate to chlorine along with the larval development. These results suggest that within the extent of this ...