摘要
The Seto Inland Sea is the largest enclosed coastal sea in Japan and is also a major fishing ground including aquacultures of fish, bivalves and seaweeds. The incidents of red tides dramatically increased in frequency and scale in the Seto Inland Sea along with serious eutrophication in the 1960s and 1970s. The maximum incident of 299 was recorded in 1976, but the incident has since shown a clear decreasing trend, reaching about 100 per year in the late 1980s by virtue of regulation by law, and this level has been maintained thereafter with the level of nutrients supporting red tide occurrences. The “Law Concerning Special Measures for Conservation of the Environment of the Seto Inland Sea” was legislated in 1973 and industrial loading was decreased to half the level of 1972. The important red tide organisms causing huge fishery damages by fish-kill are Chattonella antiqua, C. marina, C. ovata and Heterosigma akashiwo (Raphidophyceae), and Karenia mikimotoi and Cochlodinium polykrikoides (Dinophyceae). The maximum fishery damage (death of 14.2 million yellowtails) was 7.1 billion yen (about US $60 million) caused by C. antiqua in Harima-Nada in 1972. In 1988, a novel red-tide dinoflagellate species Heterocapsa circularisquama appeared for the first time, and has repeatedly killed both natural and aquacultured bivalves, with the highest damage of 3.9 billion yen to cultured oysters in Hiroshima Bay in 1998. Among the important red-tide organisms, C. antiqua, H. circularisquama and C. polykrikoides are rated as extremely harmful species that can easily reach the warning level of fishery damage by consuming only small amounts of nutrients. In toxic blooms, the dinoflagellate Alexandrium tamarense has become dominant in the Seto Inland Sea in the spring season, causing toxicity in short-necked clams and cultured oysters almost every year. Many countermeasures have been applied for harmful algal blooms in Japan. Laws for the regulation of water quality have been most effective in decreasing red-tide occurrences. No physical and chemical controls have been successful except for clay treatments. Clay spraying has been investigated and implemented in Kyushu and Korea for the removal of C. polykrikoides red tides. As environment-friendly mitigation strategies for red tides, biological controls using algicidal bacteria and viruses are proposed. A new finding of the abundant existence of algicidal bacteria on the surface of seaweeds suggests that co-culturing fish and seaweed is a prevention strategy for harmful algal blooms by virtue of the continuous release of many algicidal bacteria to the surrounding seawater. The artificial development of seaweed beds would also be effective as a prevention strategy for red tides.
摘要译文
濑户内海是国内最大的沿海围海在日本也是一个重要的渔场，包括鱼类，贝类和海藻aquacultures。赤潮事件急剧的频率和规模随着20世纪60年代和70年代的严重富营养化加大了在濑户内海。录得1976年299的最大事件，但事件以来表现出明显的下降趋势，凭借调节在80年代后期达到约每年100法律，与此水平一直保持后，用营养物支承红潮出现的水平。“法有关特别措施的濑户内海的环境的保护”被立法在1973年，工业负荷降至1972年水平的一半。最重要的赤潮生物造成巨大的损害渔业鱼杀的卡盾藻蝇，C.码头，C.卵形和赤潮异弯藻（Raphidophyceae）和米氏凯伦藻和Cochlodinium polykrikoides（甲藻纲）。最大的渔业损害（死亡1420万鰤）为7.1十亿日元（约合6000万美元）所引起的C.蝇在播磨滩于1972年在1988年，一个新的赤潮藻种Heterocapsa circularisquama出现的第一次，并一再杀害了自然和aquacultured双壳类，3.9十亿日元在广岛湾的牡蛎养殖在1998年的最高伤害其中重要的赤潮生物，C.蝇，H. circularisquama和C. polykrikoides被评为极其有害的物质，可以很容易地通过仅消耗少量的营养物质达到渔业损害的警告级别。在藻类毒素，对塔玛亚历山大藻已经成为占主导地位的濑户内海，在春暖花开的季节，造成毒性蛤蜊，几乎每年都培养牡蛎。许多措施已经应用在日本的有害藻华。法律对水质的监管一直非常有效地减少赤潮发生。无物理和化学控制已成功除了粘土处理。克莱喷涂已展开调查和实施九州和韩国的去除C. polykrikoides赤潮。至于赤潮环保减灾战略，用溶藻细菌和病毒生物控制提出了建议。海藻的王牌表明，共培养的鱼和海藻是一种预防策略的有害藻华凭借不断释放许多溶藻细菌周围的海水。对海草床的人工开发也将是有效的预防策略赤潮。
Ichiro Imai[1][2]; Mineo Yamaguchi[3];Yutaka Hori[4]. Eutrophication and occurrences of harmful algal blooms in the Seto Inland Sea, Japan[J]. Plankton and Benthos Research, 2006,1(2): 71-84