DEVELOPMENT OF THE METHODOLOGY TO UNDERSTAND THE ECOLOGY OF MINKE WHALES USING ENVIRONMENTAL CONTAMINANTS AS CHEMICAL TRACERS

对1981~1999年在南大洋采集的约500头小须鲸样品和1994~1998年经日本鲸鱼研究计划(JARPA)特别许可从北太平洋采集的约160头小须鲸样品进行化学分析，得到以下结果：1)建立了监测小须鲸各器官组织中有机氯、有机锡和重金属含量的分析系统。这些污染物的体内分布结果表明，可以用有机氯化合物的脂肪和包括有机锡在内的重金属的肝脏作为阐明小须鲸生态和生物学的合适组织/器官。2)有机氯和有毒元素的残留水平因性别、食性和年龄的不同而不同，这表明为了区分小须鲸的种群数量，有必要对样品进行分类。3)在估算区分…时以某些重金属和有机氯为化学示踪剂，鄂霍次克海小须鲸的种群数量较多。鄂霍次克海小须鲸被分为两组，DDTS和PCbs的浓度明显较高，汞的浓度较低，Cd的浓度明显较高，而HCHs的浓度较低，表明前者主要生活在海或日本/黄海/东中国海，后者来自北太平洋西部。4)肝脏药物代谢酶活性的测定表明，南极小须鲸体内有机氯化合物残留水平较低，诱导了细胞色素P1a的产生。这意味着对这些污染物对小须鲸的毒性影响很敏感。通过对小须鲸的细胞色素P1a基因的分析，揭示了北太平洋北部小须鲸该基因上氨基酸序列的相似性。5)通过主成分分析对南方小须鲸种群的12种微量元素进行判别，发现南极海域III、IV、V区雄性动物的微量元素矩阵存在显著差异。这些种群似乎与迁徙、繁殖、食性等有关。这种利用动物皮肤中的微量元素的方法被证明是一种有效的非杀伤性方法来阐明小须鲸的生态和生物学。综合这些结果，本研究得出结论，有机氯和重金属等环境化学物质是了解小须鲸生态和生理方面的有用的化学示踪剂。较少

The minke whale samples including about 500 individuals collected from the Southern Ocean in the period of 1981 to 1999 and about 160 individuals from the North Pacific during 1994 to 1998 under the special permit of Japanese Whale Research Program(JARPA)were employed for chemical analysis and obtained the following results ;1)The analytical systems for monitoring the concentrations of organochlorines, organotins and heavy metals in various organs and tissues of minke whales were examined and constructed. The results of body distribution of these contaminants suggested to use the blubber for organochlorines and the liver for heavy metals including organotins as a proper tissue/organ to elucidate the ecology and biology of minke whales.2)The residue levels of organochlorines and toxic elements were varied according to sex, feeding habit and age, which suggests the necessity of classification of samples in order to discriminate the population of minke whales.3)When estimating the discrim … More ination of population in minke whales of North Pacific using some heavy metals and organochlorines as chemical tracers, the animals from the Sea of Okhotsk were classified into two groups with significantly higher concentrations of DDTs and PCBs and lower concentrations of Hg and with apparently higher concentrations of Cd and lower concentrations on HCHs, suggesting that the former group is principally inhabiting in the Sea or Japan/Yellow Sea/East China Sea and the latter group is immigrated from the western North Pacific.4)The determination of drug-metabolizing enzyme activities in the liver indicated the induction of CYP1A with low residue levels of organochlorines in the Antarctic minke whales, which implies sensitive to the toxic effects of these contaminants in minke whales. The CYP1A genes in minke whales revealed the similarity of amino acid sequences on that genes in Dall's porpoise from the northern North Pacific.5)The attempt to discriminate the population of southern minke whales using 12 trace elements found in skin and liver by the principal component analysis showed the significant difference in the matrix of trace elements among male animals from Area III, IV and V in Antarctic Ocean. These populations seemed to be segregated in association with immigration, reproduction, feeding habit etc. Thisapproach using the trace elements in the skin of animals is evidenced to be an effective non-killing method to elucidate the ecology and biology of minke whales.Considering all these results, the present study concluded that the environmental chemicals such as organochlorines and heavy metals were useful chemical tracers to understand the ecological and physiological aspects of minke whales yet to be known. Less