諫早湾のアサリ養殖場における夏季大量へい死対策 : 底層溶存酸素の改善試験

概要

論文の詳細を見る
An experiment for preventing mass mortality of cultured short-neck clams due to hypoxic and anoxic conditions was conducted at the Kama tidal flat in northern Isahaya Bay, Nagasaki, in the middle of August 2008. Before the experiment, the starting date (11 August 2008) of hypoxia formation in the experimental site was predicted by reviewing historical data including dissolved oxygen (DO) in the bottom water, and other environmental conditions such as tidal range, wind speed and red tide incidence. A hypoxia prevention system that was composed of barriers against the hypoxic water intrusion and a micro-bubble generator for aeration was set in the experimental area (20m×20m), and time changes in DO concentration in the bottom water were monitored and compared with the time changes in the control area. The differences in survival rates of short-neck clams and contents of acid volatile sulfides in the sediment after the experiment were also compared between the experimental and control areas. Despite some troubles during the experiment it was revealed that the system mentioned above was effective for preventing hypoxia and for avoiding mass mortality of cultured short-neck clams at the Kama tidal flat.
2010-07-15