SGER: Impact of Severe ENSO Events on Insular Endemic Shorefish Populations

最近的气象预报表明，严重的厄尔尼诺/南方涛动将在1997年下半年发展并延续到1998年。预计这次ENSO事件将与1982/83年的事件相媲美或更强烈，那是本世纪有记录以来最强的ENSO事件。这项SGER研究将收集基线数据，以调查这种ENSO对加拉帕戈斯群岛珊瑚礁鱼类种群的补充和种群动态的影响。特别令人感兴趣的是1982/83年ENSO造成的入侵大陆物种和岛屿特有物种之间杂交和渗入的影响。最近的研究发现，有证据表明，在1982年至1983年期间，加拉帕戈斯群岛上出现了大量的大陆雀鲷物种——阿卡波科斯人（stegastacapulcoensis）。目前现存的S. acapulcoensis种群与岛上特有的stegaste arcilrons共存于加拉帕戈斯群岛。对成年鱼的耳石分析表明，第一批成年鱼于1983年抵达。人口随后增长，可能是由于当地的招募。此外，电泳蛋白分析还发现了相当大比例的杂交种。威灵顿博士预测另一次入侵将在1998年初至年中发生。他补充说，同事们将记录在加拉帕戈斯群岛上的阿卡普尔科s.a acapulcoensis的分布和招募强度。这些数据将提供预测气候变化对岛屿海洋生物的潜在影响所需的宝贵信息。

Recent meteorological predictions indicate that a severe El Nino/Southern Oscillation will develop during that latter part of 1997 and extend through 1998. This ENSO event is predicted to be comparable or more intense than the 1982/83 event the strongest ENSO recorded in this century. This SGER study will gather baseline data for investigating the effects of this ENSO on recruitment and population dynamics of reef fish populations in the Galapagos Islands. Of particular interest is the effects of hybridization and introgression observed between invading mainland species and island endemics that resulted from the 1982/83 ENSO. Recent work has found evidence to indicate that extensive recruitment of the mainland damselfish species, Stegastes acapulcoensis in Galapagos occurred during 1982 83. Currently extant populations of S. acapulcoensis coexist in Galapagos alongside the island endemic, Stegastes arcilrons. Otolith analyses of adult fish indicate that the first cohort of these adults arrived in 1983. The population has subsequently grown, presumably from local recruitment. In addition, a significant proportion of hybrids have been detected by electrophoretic protein analyses. Dr. Wellington predicts that another invasion will occur in early to mid 1998. He add associates will document the distribution and intensity of recruitment of S. acapulcoensis in the Galapagos Archipelago. These data will provide invaluable information needed to predict potential effects of climate change on insular marine organisms.