SITUATIONS AND CONSERVATION STRATEGIES OF FISH RESOURCES IN THE YANGTZE RIVER BASIN北大核心CSCD

The Yangtze River basin harbors a high degree of fish diversity, with 378 fish species distributing in the mainstream and its attached waters, and 149 of these species are endemic to this river. Meanwhile, the Yangtze River is an important fishery ground in China, contributing more than 60% of the total catch of freshwater fishery. Therefore, the Yangtze River plays important roles in both biodiversity conservation and capture fisheries. However, due to the increasing human activities in the past decades, fish resources in the Yangtze River have declined sharply. Firstly, more and more species have been assessed as threatened and the endangerment categories of many species have been upgraded. Secondly, the population size of many iconic species, such as Acipenser sinensis, the four famous Chinese carps and Coreius guichenoti, have declined continuously. Thirdly, the miniaturization tendencies of major fishing targets have become more and more obvious. Last but not the least, the total fishery catch reduced significantly. Overfishing, water projects construction, enclosing-lake cultivation, water pollution and alien invasion were the main reasons contributing to these changes. In most situations, these factors interacted together, which imposed more damage to the fish resources and increased the difficulty of conservation. In order to protect the fish resources in the Yangtze River effectively, following conservation strategies are suggested: establishing specialized nature reserve, banning commercial fishing completely, implementing river ecological restoration, strengthening scientific research and establishing comprehensive regulation mechanism. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

水生所与三峡和葛洲坝水利工程中的鱼类保护

葛洲坝和三峡水利枢纽是世界上著名的大型水电工程, 对长江中下游防洪、发电、航运、水资源利用等产生了巨大的综合效益。如何减轻葛洲坝-三峡工程对长江流域生态环境及水生生物的影响经历了漫长而激烈的论证过程。中国科学院水生生物研究所(以下简称“水生所”)自始至终参加了这两个工程的水域生态环境影响评价和鱼类保护工作, 并且做出了重要的贡献。在葛洲坝工程的救鱼对象讨论中, 水生所指出救鱼的主要对象是中华鲟; 在救鱼的措施方面, 水生所科学论证了葛洲坝工程不必修建过鱼设施, 中华鲟在葛洲坝下能够自然繁殖, 中华鲟的救护措施以人工繁殖放流和产卵场的保护为主。在葛洲坝工程建设后, 水生所进一步预测了三峡工程对长江珍稀特有鱼类、重要经济鱼类以及渔业的影响, 并且建议在赤水河建立自然保护区, 作为长江上游珍稀特有鱼类的庇护所; 提出最早的生态调度想法, 通过三峡水库的调度形成人造洪峰, 刺激“四大家鱼”产卵等等。实践证明, 水生所做出的工程影响评价和鱼类保护建议是科学的、符合客观实际的, 对国家的决策起到了重要作用。     

新疆阿勒泰地区额尔齐斯河和乌伦古河流域鱼类多样性演变和流域健康评价

为了解阿勒泰地区额尔齐斯河和乌伦古河流域的鱼类多样性现状和历史演变, 本研究于2013-2016年间在该流域的鱼类多样性进行了连续调查, 并结合历史资料和标本, 以Margalef丰富度指数、Shannon-Wiener多样性指数、Pielou均匀度指数分析评估了流域内鱼类的多样性水平和时空变化。该流域历史上分布有土著鱼类23种, 当前记录到19种, 流域内还有外来鱼类15种。阿勒泰鱼类的区系组成以鲤科种类为主, 其中特有和珍稀濒危物种占比高, 具有重要的保护价值。多样性指数计算结果显示, 2013-2016年鱼类多样性情况整体稳定, 额尔齐斯河鱼类物种数多于乌伦古河。研究还基于鱼类生物完整性指数(Fish Index of Biological Integrity, F-IBI)对34个采集点的河流健康状况进行了评价, 结果显示额尔齐斯河流域大多数调查点的健康状况处于“亚健康”或“一般”水平, 乌伦古河流域多数调查点的健康状况处于“健康”水平。水利工程、外来物种、过度捕捞是影响阿勒泰地区鱼类多样性的重要因素。未来应通过水利工程的联合调度、下泄合理生态流量、布设鱼类通道、规范养殖渔业、严控外来物种、本地土著鱼类的人工增殖放流, 以及合理的就地保护措施对阿勒泰地区的鱼类多样性加以保护, 提升水体健康程度。     

长江安庆段仔稚鱼群落特征调查研究

安庆江段是长江下游重要渔业资源水域之一, 为了解该江段仔稚鱼群落特征及与环境因子的关系, 于2016年4月17日至8月15日对安庆江段仔稚鱼进行了逐日调查。结果显示: 研究共采集仔稚鱼个体92160尾, 鉴定90457尾, 隶属于7目11科49种, 其中鲤科(Cyprinidae)种类数居第一, 32种, 尾数占比为90.16%; 鰕虎鱼科(Gobiidae)居第二, 3种, 尾数占比为5.71%。在生态类型及产卵方式上, 淡水定居性鱼类和产漂流性卵鱼类数量占比最大, 分别为87.57%和88.30%。贝氏?(Hemiculter bleekeri)是该江段第一优势种, 数量占比44.53%, 其余优势种为?(Hemiculter leucisculus, 占比14.21%)、银鲴(Xenocypris argentea, 占比8.11%)、子陵吻鰕虎(Rhinogobius giurinus, 占比5.60%)、飘鱼(Pseudolaubuca sinensis, 占比4.75%)、似鳊(Pseudobrama simoni, 占比4.13%)、寡鳞飘鱼(Pseudolaubuca engraulis, 占比4.50%)、鳊(Parabramis pekinensis, 占比2.63%)、刀鲚(Coilia nasus, 占比1.89%)、鲢(Hypophthalmichthys molitrix, 占比1.57%)。仔稚鱼丰度出现4次明显的高峰时期, 第一次在5月1日, 后面三次集中出现在6月中下旬, 分别为1127.00、1608.44、1568.35 和1202.94 ind./100 m3。通过冗余分析(RDA)表明, 影响安庆江段仔稚鱼丰度的主要环境因子为水流量、水位、透明度(P<0.05), 大多数仔稚鱼丰度与水流量、水位呈现负相关, 与透明度呈现正相关, 可能与该年份过高的水流量、水位有关。研究表明, 安庆江段的仔稚鱼种类较丰富, 但主要以小型鱼类为主, 且经济性仔稚鱼类占比小。研究初步探明了安庆江段的仔稚鱼资源状况, 其结果为安庆鱼类早期资源进一步研究提供基础资料, 同时也为渔业资源保护策略制定提供科学依据。     

CURRENT STATUS AND CONSERVATION PLANNING OF FISH BIODIVERSITY IN THE UPPER YANGTZE RIVER BASIN IN THE CONTEXT OF HYDROPOWER DEVELOPMENT北大核心CSCD

Nearly 90% of the hydropower resources in the Yangtze River basin are concentrated in the upper reaches of the Yangtze River. The cascaded hydropower dams and river channelization have caused habitat fragmentation and loss of fish diversity, which has aggravated the contradictions between hydropower development and environmental protection. This paper collected data on aquatic reserves (i.e. natural reserves and aquatic germplasm resources conservation zones) and cascade dams in the upper reaches of the Yangtze River, and vectorized the data in ArcGIS. Taking into account the diversity, richness and distribution of fish, we analyzed the changes in fish resources and the problems in the construction and management of the upper reaches of the Yangtze River. Therefore, several strategies have been proposed to reduce the conflicts between hydropower development and aquatic ecosystem protection, including conducting reserve census, evaluating management effectiveness of the protected areas for spatial optimization of the reserve networks, implementing the ecological restoration of essential fish habitats, implementing the rescue action plan for the upper Yangtze endangered endemic fish, establishing an efficient ecological compensation mechanism, and strengthening scientific monitoring and related research. These recommendations will provide a scientific basis for the coordinated development of hydropower exploitation and river ecological protection in the upper Yangtze River. © 2019, Institute of Hydrobiology, Chinese Academy of Sciences. All rights reserved.     

三峡水库生态渔业发展策略与关键技术研究分析

针对三峡水库蓄水后水体资源丰富、水生态系统发育尚不完善、支流库湾藻类水华问题较严重、鱼类群落结构有待调控、水生生物资源未有效利用和转化的现状, 阐述了三峡水库生态渔业作为生态系统保护途径和绿色产业的必要性与重要性, 提出了三峡水库生态渔业发展的总体目标与基本原则, 认为三峡水库发展生态渔业应以生态安全保障和水质养护为首要任务, 严格控制外来物种的引种移植, 以土著鱼类自然繁殖保护和捕捞管理为主, 动态调控放流增殖的鱼类种类和数量为辅, 建立以鱼类群落合理配置和食物网结构优化为手段的水库生态系统调控技术体系, 促进高效的物质循环和能量流动, 实现环境保护和渔业增效的双赢。作者围绕渔业放流增殖、野生鱼类资源保护、捕捞管理、局部库区渔业调控、渔业生物控藻、社区渔业协调管理、生态渔业总体规划等方面, 分析了现阶段三峡水库生态渔业的重点研究任务与关键技术,同时建议加强相关生态学理论与方法研究、技术示范和成果应用, 为三峡水库以渔养水、渔-水和谐的综合管理提供决策依据。       

Freshwater fish biodiversity in the River Ganga (India): changing pattern, threats and conservation perspectives

The river Ganges is the largest river in India and the fifth longest in the world. Although, many studies on fish ecology and systematic have been conducted largely to improve fisheries but fish diversity and their distribution pattern from conservation point of view have never been adequately addressed in the Ganges. In this connection, current distribution and abundance of freshwater fishes of river Ganges was studied and assessed from April 2007 to March 2009. We documented and described 143 freshwater fish species in the all stretches of the river which is higher than what was reported earlier. Some species were observed with shift in their distribution ranges. First time, a total of 10 exotic fishes, including Pterygoplichthys anisitsi, which has never been reported from India found in the Ganges. Alterations of the hydrological pattern due to various types of hydro projects was seems to be the largest threat to fishes of Ganges. Indiscriminate and illegal fishing, pollution, water abstraction, siltation and invasion of exotic species are also threatening the fish diversity in the Ganges and as many as 29 species are listed under threatened category. The study advocates a need to identify critical fish habitats in the Ganga basin to declare them as conservation reserves to mitigate the loss of fish diversity from this mighty large river.     

长江常熟江段渔业群落结构及物种多样性初步研究

对2000～2006年长江常熟江段渔业群落及物种多样性进行了研究。该江段共有鱼、虾蟹类66种,分别隶属于13目29科。鲤形目鱼类最多,其次是鲈形目。按迁徙习性可分为江湖半洄游性鱼类、洄游性鱼类、河口鱼类和定居性鱼类4大类型。经济鱼类占优势,群落优势种为鳊、鲫、刀鲚、铜鱼、翘嘴红鲌和条。多样性特征值年间平均指标为:Margalef指数(R)1.68,Wilhm改进指数(H")2.50,McNaughton指数(Dw)0.37,Pielou指数(J')0.76。鱼类群落优势度较低,丰富度、均匀度、多样性处于较高水平。探讨了水利工程、水域污染及水利调度对该江段渔业资源的不利影响,提出了开发和保护该江段渔业资源的建议。     

怒江流域鱼类多样性及空间分布格局

怒江是我国西南地区重要的国际河流, 也是全球生物多样性热点区域之一。受地理位置和地形条件限制, 目前尚缺乏怒江流域鱼类物种多样性及其分布格局的系统研究。本研究利用近5年的全流域实地采样数据, 结合文献资料, 系统整理了怒江流域鱼类物种组成信息; 利用聚类和排序方法分析了怒江流域鱼类空间分布格局。结果表明, 怒江流域共有土著鱼类85种, 隶属于5目12科47属; 外来鱼类18种, 隶属于3目8科16属, 另外实地调查发现新记录外来种2种。怒江流域鱼类多样性从上游至下游呈明显的递增趋势。根据土著鱼类组成的聚类和排序分析结果, 可以将怒江25个亚流域分为3个部分: (1)西藏自治区内的上游河段, 分布有鱼类15种, 组成以裂腹鱼类、高原鳅类为主, 具有明显青藏高原冷水性鱼类区系特征。(2)贡山至泸水的中游河段, 分布有鱼类36种, 组成兼有上游冷水性鱼类和下游喜温的鲃亚科、野鲮亚科鱼类。(3)泸水以下的下游河段, 分布有鱼类74种。下游河段干流广泛分布有喜温的鲃亚科、野鲮亚科和 亚科鱼类, 支流则分布有数量众多的南鳅属(Schistura)、纹胸鮡属(Glyptothorax)鱼类, 鱼类组成以适应流水、激流环境的热带亚热带鱼类为主。2017-2021年的多次调查仅发现土著鱼类43种(占历史记录的50.6%), 土著鱼类资源衰退明显。过度捕捞、支流小水电开发、外来鱼类入侵等是主要威胁因素。随着人类活动的急剧增多, 怒江流域鱼类将面临更大的威胁, 亟需从流域层面开展系统的鱼类资源管理和保护规划。     

珠江水系鱼类群落多样性空间分布格局

珠江是我国南方第一大河,是我国重要淡水渔业生产基地和水生生物资源基因库。珠江鱼类在维持生物多样性、提供鱼类种质资源方面举足轻重。但是到目前为止,关于其鱼类空间分布格局的研究甚少。特别是近几十年来各种水工建设和过度捕捞使得渔业资源急剧衰退,鱼类空间分布的研究显得尤为重要。2015年对珠江全流域13个站位进行了全面调查,共采集渔获物10119尾,隶属于94种72属17科。鲤科鱼类占显著优势,其次种类较多的依次为鲿科、鳅科。采用非度量多维标度排序(NMDS)方法对鱼类群落空间分布特征进行了分析,结果表明珠江鱼类被划分为3个类群,即以餐、南方拟餐、黄颡鱼等小型鱼类为主的中上游类群、以赤眼鳟、鲮鱼、广东鲂等中型鱼类为主的中下游类群和以罗非鱼为主的重要支流类群。同时发现中下游物种多样性高,上游及河口江段多样性低的格局。采用冗余分析方法(RDA)分析了鱼类多样性与环境因子的关系,发现年均气温、降雨量、年均径流量、河流宽度与透明度是珠江水系河流鱼类群落结构差异的主要影响因子,其中年均气温是影响鱼类群落分布的最关键因子之一。与历史资料对比后发现,珠江鱼类种类明显减少、空间分布也发生了巨大改变。研究是珠江水系野生渔业资源长期调查的一部分,研究结果将对渔业资源的多样性保护和可持续利用具有指导意义。     

Use of artificial structures to enhance fish diversity in the Youjiang River,a dammed river of the Pearl River in China

The fragmentation and homogenization of habitats have seriously affected the fishery resources of the Pearl River. To protect the fishery resources, a novel artificial habitat, constructed using bamboo and palm slices, was deployed in the Youjiang River, a tributary of the Pearl River in China. The results of field and laboratory experiments showed that fish abundance, species richness and Shannon–Wiener diversity index were higher in the artificial habitats than at the control sites. There was no significant impact on fish biomass, as the artificial habitats attracted more Cultrinae and Gobioninae fish that are of a smaller size. Artificial habitats can serve as spawning grounds for fish that produce sticky eggs and refuges that improve the survival rates of juvenile fishes. This study revealed that this novel artificial habitat created suitable habitats and suitable spawning substrate for fish, improved fish richness and diversity in the structureless freshwater ecosystem like the Youjiang River.     

长江安庆新洲水域鱼类群落结构及多样性

沙洲水域环境良好,饵料资源丰富,栖息生境多样,为鱼类的生长繁殖提供了优良的生存环境。为了解长江安庆新洲水域鱼类群落结构特征,于2017年4月、7月、10月和12月对安庆江段新洲水域鱼类群落进行季节性调查。共采集鱼类64种,分属5目11科48属,其中62.5%为鲤科鱼类。以物种数和多样性指数分析群落多样性特征,结果表明新洲水域鱼类种类多样性水平较高。单因素方差分析表明,该群落多样性季节差异显著(P0.05),空间差异不明显。新洲水域鱼类群落优势种为鳊(Parabramis pekinensis Basilewsky, 1855)、鲤(Cyprinus carpio Linnaeus, 1758)、贝氏■(Hemiculter bleekeri Warpachowsky, 1887)、银鮈(Squalidus argentatus Sauvage et Dabry, 1874)和似鳊(Pseudobrama simoni Bleeker, 1864)。4种摄食功能群中,杂食性(42.19%)和肉食性(35.94%)鱼类物种数比例较高;3种生态类群中,淡水定居性鱼类占绝对优势(84.37%);3种栖息水层类型中,底层鱼类物种数比例较高,占37.50%。大型经济鱼类占总渔获物比例低(0.01%),但个体较大,因而相对重要性指数(IRI)高。总体上,新洲鱼类群落多样性和丰富度指数较高,均匀度指数偏低,个体小型化趋势明显。捕捞强度过大、水利工程建设导致的江湖阻隔及外来物种入侵是新洲水域渔业资源衰退的主要因素。由此,建议持续开展长江渔业资源监测,加强长江干流沙洲水域渔业资源保护。     

基于水声学频差技术的镇江长江豚类省级自然保护区鱼类资源时空特征

为掌握镇江长江豚类省级自然保护区鱼类资源现状,于2020年春季(4月)和秋季(9月)利用水声学频差技术和网具调查方法同步开展鱼类资源调查,评估调查江段鱼类资源时空特征。水声学调查结果表明,调查江段鱼类资源密度均值为(0.094±0.183)尾/m²,鱼类单体目标强度(Target strength, TS)均值为–(57.33±5.69) dB,主要分布在–62.5—–50.5 dB,随着水深的增加, TS逐渐增大;网具调查结果表明,调查江段共采集鱼类758尾、53.53 kg,鉴定鱼类种类达48种,其中以鲤形目(Cypriniformes)鱼类占优,中上层鱼类群体数量和质量占比分别为36.15%和66.12%,长江江豚饵料鱼类(体长小于20 cm、体高小于6 cm、体重小于100 g的中上层鱼类)数量和质量占比分别为23.22%和8.72%。在时间特征上, 4月和9月鱼类资源密度差异不显著(P>0.05), 4月鱼类TS均值小于9月,且4月鱼类平均规格小于9月。在空间特征上,鱼类资源主要分布于和畅洲北汊和焦北滩附近水域,中上层鱼类资源相对较多,且4月鱼类资...     

Fish and fisheries in the Upper Mekong: current assessment of the fish community, threats and conservation

The Mekong flows north to south, through six countries in south–east Asia. Many studies have concentrated on fish and fisheries in the Lower Mekong, which has been identified as one of the largest inland fisheries in the world with an incredibly rich diversity of species. In contrast, fish and fisheries in the Upper Mekong (Lancang River) have remained relatively undocumented. In this paper, we synthesized information on freshwater fish biodiversity and fisheries in the Upper Mekong and documented 173 species and subspecies (including 87 endemic species) among 7 orders, 23 families and 100 genera. We divided the Upper Mekong into 17 sub-basins based on Digital Elevation Model (DEM) and then used fish species data to cluster the sub-basins. Four parts (the headwater, the upper reach, the middle reach and the lower reach) and one lake have distinct fish species communities associated with them. There was a linear relationship between fish species (x) and endemic species (y) as y = 0.5464x − 3.2926. Relationship between species number or endemic species number (y) and mean altitude (x) can be described as y = −54.352 ln(x) + 460.79 or y = −30.381 ln(x) + 253.85, respectively. Fisheries kept as about 6,000 t from 1989 to 1998, and then steadily increased to 10,000 t in 2004. We reviewed the overall threats to the Upper Mekong fish and fisheries, and found that hydrological alteration is the largest threat in the basin, followed by over fishing and the introduction of exotic species. In terms of specific river sections, water pollution was the most serious threat to fishes in the upper reach of the Upper Mekong, whilst migratory fishes in the lower reach of the Upper Mekong are seriously threatened by the construction of cascade dams. The Buyuan River and the Nanla River were identified as important feeding and spawning habitats for upstream migrant species and should be considered as a priority for conservation.     

洪泽湖鱼类资源现状、历史变动和渔业管理策略

研究于2010年秋季和2011年夏季对南水北调东线工程最大调蓄湖泊洪泽湖的鱼类资源进行了调查,结合历史资料分析该湖鱼类资源变动情况,以期为渔业管理和生物多样性保护提供依据。自20世纪60年代以来,洪泽湖累计记录鱼类88种,本研究发现63种,其中新记录6种,分别为:点纹银 、彩副 、方氏鳑鲏、鲻、大眼鳜和波氏吻虾虎鱼;与历史记录比较,湖泊定居性鱼类所占比例由59%上升78%,而喜流水性鱼类和河海洄游性鱼类分别由22%和7%下降到3%和3%;未采集到的25种鱼类中,流水性鱼类计17种,占68%。网簖和丝网的渔获物分析表明,鲫、黄颡鱼、刀鲚和红鳍原鲌等小型鱼类具有较高的IRI值（相对重要性指数,Index of Relative Importance）,是鱼类群落的优势种,大型鱼类除鲤外,IRI值均不高,在群落中不占优势。20102011年洪泽湖渔业年产量为2200104 kg,以刀鲚和鲫为主的小型鱼类产量达1967104 kg,占89.4%;四大家鱼产量96104 kg,占4.4%;鳜、翘嘴鲌、乌鳢和鲇等大型食鱼性鱼类合计仅占0.89%。文章分析江湖阻隔、过度捕捞和生境破坏对洪泽湖鱼类资源的影响,提出相应的渔业管理策略,并初步预测南水北调东线工程对该湖鱼类和渔业的潜在影响。       

天鹅洲故道水生态研究进展

20世纪90年代初, 湖北长江天鹅洲故道水质良好, 鱼类资源丰富, 被认为是建立长江豚类半自然保护区和四大家鱼种质资源生态库的理想场所, 而对之开展了水生态研究, 之后由于成功实现了长江江豚的迁地保护而受到越来越多的关注。学者们从水质和沉积物等环境因素, 浮游植物、浮游动物、底栖动物和高等水生植物等生物因素, 水体初级生产力、渔产潜力和鱼类等资源因素多角度开展了天鹅洲故道水生态研究。天鹅洲故道水质呈恶化趋势。浮游植物数量增加了2个数量级, 且从单细胞个体转变为多细胞群体, 同时带有胶被的蓝藻在种类和密度上占有绝对优势; 浮游动物优势种呈小型化趋势; 底栖动物密度有所下降; 高等水生植物呈逐渐衰退趋势。鱼类资源量呈下降趋势。根据水质化学和生物学评价结果, 结合天鹅洲故道受人类活动的影响, 本文指出故道与长江阻隔、渔业活动和环境污染是天鹅洲故道水生态面临的主要问题, 其通过水质、饵料和栖息地等方面影响长江江豚的可持续性生存。同时, 提出5个方面的建议: 首先, 实施通江工程, 恢复故道水文特征, 提高故道理化环境异质性; 其次, 控制外源和内源营养负荷, 提高故道水体水质; 然后, 持续监测水质、沉积物和水生生物状况, 建立故道水生态数据库; 再次, 实施生态修复工程, 提高水生生物多样性; 最后, 规范渔业活动, 优化故道渔业资源, 为保护天鹅洲故道水环境质量和水生态健康, 维持江豚可持续生存提供依据。     

二滩水电站水库形成后鱼类种类组成的演变

本文对二滩水库建成前后,雅砻江下游长约380km河段的鱼类种类结构、生态类群及相对资源量的变化进行了研究。结果表明水库建成后不同区段的鱼类种类结构发生了变化,喜栖静水和缓流环境的种类逐渐在库区占主导地位,适应急流环境的种类主要分布于库尾和支流等局部水域中,一些外来种已经定居并在某些水域形成了优势种群。在水库建成后的头几年,由于鱼类种群密度增加还导致了渔业捕捞量大幅度上升。针对上述变化,结合雅砻江梯级电站建设可能带来的进一步环境改变,作者提出了建立自然保护江段、开展人工繁殖放流、进行水库生态调度以及防止外来种入侵等措施和建议。     

拉萨河鱼类调查及保护

拉萨河是雅鲁藏布江最大的支流, 其鱼类区系为隶属于裂腹鱼亚科、条鳅亚科和科的13 种鱼类以及裂腹鱼属的一个自然杂交种。最近十几年, 由于人类活动的影响, 导致了大量的外来鱼类进入拉萨河水体。文章介绍了2004 年至2006 年对拉萨河鱼类进行采样调查的情况。目前在拉萨河, 鱼类组成包括以往记录的14 种鱼类: 拉萨裂腹鱼Schizothorax waltoni (Regan)、异齿裂鱼 S. o’connori (Lloyd)、巨须裂腹鱼S.macropogon (Regan)、双须叶须鱼 Ptychobarbus dipogon (Regan)、尖裸鲤 Oxygymnocypris stewartii (Lloyd)、拉萨裸裂尻鱼Schizopygopsisyounghusbandi younghusbandi Regan、异齿裂腹鱼和拉萨裂腹鱼的一个自然杂交种、异尾高原鳅Triplophysa stewartii (Hora)、细尾高原鳅T. stenura (Herzenstein)、西藏高原鳅T. tibetana(Regan)、东方高原鳅T. orientalis (Herzenstein)、斯氏高原鳅T. stoliczkae (Steindachner)、短尾高原鳅T.brevicauda (Herzenstein)、黑斑原Glyptosternum maculatum (Regan); 8 种外来鱼类: 鲫Carassius auratus(Linnaeus)、麦穗鱼Pseudorasbora parva (Temminck et Schlegel)、泥鳅Misgurnus anguillicaudatus (Cantor)、黄黝鱼Hypseleotris swinhonis (Gunther)、鲤Cyprinus (C.) caupio Linnaeus、草鱼Ctenopharyngodon idellus(Cuvier et Valenciennes)、银鲫Carassius auratus gibelio (Bloch)、鲇Silurus asotus Linnaeus; 2 个未定种。调查结果表明拉萨河鱼类资源面临的两个主要问题是过度捕捞导致鱼类资源的减少和小型化以及外来鱼类入侵。文章针对这些情况作了分析和探讨, 并对土著鱼类的保护与合理利用提出了一些建议: 合理捕捞、严格禁渔期、控制外来鱼类、保护栖息地等。       

长江中华鲟繁殖群体资源现状的初步研究

根据1994—1998年获得的246尾标本,对中华鲟繁殖群体的性比、性腺发育成熟个体比例、年龄结构、体长和体重特征等进行了研究。并结合历史资料,对其种群资源现状进行评价,提出了相应的资源保护措施建议。     

Fish assemblage in the Pearl River Estuary: Spatial‐seasonal variation,environmental influence and trends over the past three decades

The Pearl River Estuary is the largest estuary in South China and plays a considerable role in the local fisheries economy, yet little is known about the current state of fish assemblage in this ecosystem. To quantify spatial‐seasonal variations, environmental influences, and trends over the past three decades of the fish assemblage in the Pearl River Estuary, we sampled 11 sites seasonally from December 2013 to September 2016. Throughout the study, 285 species from 88 families and 195 genera were collected. There were obvious spatial and seasonal variations of the fish assemblage in terms of the dominant species, species richness, and composition of ecological types. Mouth distance, NH₄⁺ N, chlorophyll‐a, flow, DO, salinity and water transparency were the main variables influencing the spatial‐temporal dynamic of fishes within the estuarine systems. Compared with the record of 330 species in the 1980s, the number of fish species in the Pearl River Estuary has declined by 45 fish species. The Jaccard's similarity of fish composition between the historical investigation (the 1980's) and the present investigation (2013–2016) was 0.62, with 95 species undiscovered and 50 species increased in the present study compared to the 1980s, indicating the assemblage structure has obviously changed. However, in term of ecological guilds, there was no significant difference in the composition of all the selected ecological traits between these two periods. Anthropogenic activities including overfishing, introducing alien fish, dam construction and pollution were considered the main disturbance on fish composition over the past three decades. We conclude that there existed pronounced spatiotemporal changes of fish assemblages, which arises from the compounding effects of environmental factors and anthropogenic activities. These findings are beneficial to understanding and developing suitable conservation strategies for the management and protection of fish resources in the Pearl River Estuary.