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太湖新银鱼入侵高原深水贫营养湖泊-抚仙湖的生态学效应
Alternative TitleEcological effects of the invasive icefish Neosalanx taihuensis in a deep oligotrophic plateau lake, Lake Fuxian
覃剑晖
Subtype博士
Thesis Advisor谢平
2005-12-24
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Keyword高原湖泊 食浮游动物鱼类 太湖新银鱼 鱇浪白鱼 渔业 食性 种间竞争
Abstract本文以我国高原深水贫营养型湖泊-抚仙湖为研究对象,开展了水质现状、鱼类群落结构和渔业资源调查,对我国高原湖泊中土著食浮游动物鱼类对外来食浮游动物鱼类入侵的生态学响应进行了探讨,为高原湖泊的生态多样性和湖泊环境的保护与恢复以及渔业资源的合理利用提供科学依据。主要结果如下: 抚仙湖目前处于贫营养状态,不同湖区间的营养水平没有差异。近20年来,湖泊的平均氮磷含量、叶绿素a含量呈上升趋势而透明度逐渐下降,具有一定的富营养化趋势。 2002-2003年间,抚仙湖共发现鱼类42种,隶属8目18科36属。外来鱼类成为抚仙湖的优势鱼类和主要渔业对象,年产量占总鱼产量的90%以上,而土著鱼类的产量却急剧下降。影响抚仙湖鱼类群落结构的主要因素有外来种入侵、酷捕滥渔、土著鱼类栖息地被破坏和渔业管理存在问题等。 浮游动物的周年调查表明,抚仙湖浮游动物结构没有显著变化,主要以桡足类的哲水蚤(舌状叶镖水蚤Phyllodiaptomus tunguidus)和小型枝角类(象鼻溞Bosmina)为主,在3 、4月份,枝角类的溞属种类也占有一定的优势。4月份浮游甲壳动物的密度达到最大值,其中北区密度达到142.28 ind./L。与历史数据比较有两点显著的差异:哲水蚤优势种由原先的西南荡镖水蚤转为舌状叶镖水蚤;上个世纪80年代以前有一定优势的大型肉食性枝角类(透明薄皮溞)在本研究中未被发现。抚仙湖的轮虫优势种类没有显著变化,但密度却增加了,最高密度可达145个/升。 鱇鱼良 白鱼(Anabarilius grahami)是抚仙湖原生优势土著鱼类,在太湖新银鱼(Neosalanx taihuensis)入侵前一直是抚仙湖的主要渔业对象。鱇鱼良 白鱼的产量1989年来急剧下降,其优势地位被太湖新银鱼取代,由1988年的395吨下降到2003年的不足1吨;而太湖新银鱼的产量由1988年的213吨上升到2003年的1538吨。对82尾鱇鱼良 白鱼的食性分析表明,鱇鱼良 白鱼的食性较上次调查时没有显著变化,仍以浮游动物为主要食物,但沿岸带和底栖生物种类的比例增加。对1118尾太湖新银鱼的周年食性分析表明,太湖新银鱼与鱇鱼良 白鱼的食性相似,主要选择小型枝角类和桡足类的哲水蚤。终身摄食浮游动物,并且受体长大小的影响。 比较太湖新银鱼与鱇鱼良 白鱼的生长与食性发现,两者均以抚仙湖中浮游动物的优势种类为主要食物,存在很高的食物重叠,食物重叠指数达到0.773。鱇鱼良 白鱼迫于竞争压力,其成体食性发生转变,且繁殖力有所上升。
Other AbstractWater quality, fish community structure and fisheries resources were investigated during 2002 to 2003 in the deep oligotrophic plateau Lake Fuxian in the subtropic China. The purpose of this work was to study the ecological responses of native zooplanktivorous fishes to the invasive zooplanktivorous fishes in plateau lakes in China, so as to provide scientific basis for conservation and restoration of biodiversity and lake environments. The main results as follows: Lake Fuxian is an oligotrophic lake with low nutrient status. However, the trophic level showed increase tendency in the last 20 years. Spatially, there were no significant difference in nutrient status between the north and south areas. During the survey from 2002 to 2003, 42 species of fishes belonging to 18 families were collected and identified. Exotic fishes dominated and comprised over 90% of the total fish yield, whereas the production of endemic fish declined dramatically. Such changes were due to various reasons such as the invasion of exotic fishes, over-fishing, alteration in living environment of endemic fishes and irrational fisheries management. The crustacean zooplanktons were dominated by copepods (Phyllodiaptomus tunguidus) and small-bodied cladocerans (Bosmina). During March to April, large-bodied cladocerans (Daphnia) were dominant, and the densities of crustacean zooplankton reached the highest (142.28 ind./L) in the north areas in April. During the past decades, there were no significant differences in the community structure of crustacean zooplankton, but dominant species changed obviously: Neutrodiaptomus mariadviagae mariadviagae was replaced by Phyllodiaptomus tunguidus, and the large-bodied picivorous cladocerans Leptodora kindti which was dominant in the 1980s was not found in this survey. The densities of rotifers were higherthan before, with a maximum density of 145 ind./L. Anabarilius grahami, a fish endemic to Lake Fuxian, dominated the fish community in the lake before the 1980s, but its dominance was replaced by the icefish Neosalanx taihuensis since 1989. The production of the endemic A. grahami declined dramatically from 395 tons in 1988 to less than 1 ton in 2003, meanwhile the production of the exotic icefish increased from 213 tons in 1988 to 1538 tons in 2003. The diet of A. grahami was studied by examining stomaches of 82 individuals and it was found that this fish fed mainly on zooplankton but shifted to benthic and picivorous preys more than before. The diets of N. taihuensis were also composed of small cladoceans and copepods in the whole life, which was affected by the body sizeof the fish. Based on Schoener’s index, there was significant diet overlap between A. grahami and N. taihuensis (D=0.773). Both the diet shift and the increase in the fecundity of A. grahami were due to inter-specific competition posed by the exotic N. taihuensis.
Pages115
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/11940
Collection学位论文
Recommended Citation
GB/T 7714
覃剑晖. 太湖新银鱼入侵高原深水贫营养湖泊-抚仙湖的生态学效应[D]. 水生生物研究所. 中国科学院水生生物研究所,2005.
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