流溪河入侵鱼类豹纹脂身鲶繁殖生物学研究

2015年12月-2016年10月,在广州市流溪河采集入侵鱼类豹纹脂身鲶(Pterygoplichthys pardalis)283尾用于繁殖生物学研究。结果显示:流溪河豹纹脂身鲶在3-9月性成熟系数较高。雄性最小性成熟个体体长204mm,体重154.88 g;雌性最小性成熟个体体长201 mm,体重183.01 g;最早性成熟年龄均为1龄。其平均成熟卵径为1.87 mm,绝对繁殖力为636-6 148粒,平均绝对繁殖力为2 524.49粒,平均相对繁殖力为10.43粒/g。绝对繁殖力与体长和体重呈显著的正相关。繁殖群体性比为(♀∶♂)为1∶1.15,符合1∶1比例。卵径分布为单峰型。研究表明豹纹脂身鲶具有性成熟早、繁殖力高等特征,有利于其在分布区域迅速建群扩张,并对河流生态系统形成危害。     

长江铜陵段紫薄鳅个体生物学与资源保护

按常规生物学方法,对长江铜陵段紫薄鳅(Leptobotia taeniops)的形态特征、体长与体重关系、肥满度、食性、繁殖等个体生物学特征进行了初步研究。结果表明,所取样本体长范围为6.81～12.40cm,体重范围为7.00～36.24g;体长与体重呈显著的幂函数关系:W=0.0348L2.7480(r=0.9090);为偏动物食性的杂食性鱼类。以体长8.00～10.00cm组的肥满度为高,雄性的Fulton肥满度随体长的逐渐增加而降低。性成熟年龄在1+～2+龄,4～7月份产卵繁殖,卵为半漂浮性。种群性比为1:1.4,V期绝对怀卵量平均为2602粒,相对怀卵量平均为127粒/g,成熟卵的卵径达(1.47±0.10)mm。年龄分为3个组,其中2+龄个体占63.79%。     

白龙江上游黑体高原鳅生物学研究

对2006年5～10月和2007年7～8月采于白龙江上游的200尾黑体高原鳅进行生物学研究.体长40.3～117.26mm,体重1.20～20.19g.脊椎骨数4 35～41 1.年龄可分为5个龄组,1龄→5龄数量表现为逐渐减少趋势.体重与体长呈显著的幂函数相关:W♂ ♀=0.0136L2.993,(R2=0.92).Fulton肥满度雌体平均为1.37,雄体平均为1.33;Clark肥满度雌体平均为0.96,雄体平均为1.03.幼体主要摄食摇蚊幼虫;成体主要摄食钩虾,蜘蛛和昆虫幼虫.雄鱼最小性成熟个体体长和体重分别为80.89mm和8.32g,性成熟系数为1.26%;雌鱼最小成熟个体体长为64.03mm,体重为2.71g,绝对怀卵量为942粒.绝对繁殖力波动在942～9200粒/尾之间,平均为3652粒/尾.     

厚唇裸重唇鱼繁殖生物学

2001-2009年在黄河上游水系进行土著鱼类资源调查,对收集到的235尾厚唇裸重唇鱼开展繁殖生物学研究。研究发现,厚唇裸重唇鱼繁殖期为4-6月,盛期为5月,在繁殖季节可借第二性征辨别性别,雌鱼和雄鱼均于6龄达到性成熟,雌鱼最小性成熟体长30.8cm,体质量380.7g,成熟系数15.21%;雄鱼体长27.2cm,体质量335.7g,成熟系数10.18%。厚唇裸重唇鱼绝对怀卵量为3043～42 158粒,相对怀卵量为7.9～37.2粒/g。成熟卵径(2.1±0.1)mm,卵子数为134.9粒/g;测定了产卵场的理化因子,集群繁殖需要约8℃的水温及其他一些生态因子刺激(海拔、水流、饵料等)。     

长江铜陵段紫薄鳅个体生物学与资源保护

按常规生物学方法,对长江铜陵段紫薄鳅（Leptobotia taeniops）的形态特征、体长与体重关系、肥满度、食性、繁殖等个体生物学特征进行了初步研究。结果表明,所取样本体长范围为6.81～12.40cm,体重范围为7.00～36.24g;体长与体重呈显著的幂函数关系：W=0.0348L2.7480（r=0.9090）;为偏动物食性的杂食性鱼类。以体长8.00～10.00cm组的肥满度为高,雄性的Fulton肥满度随体长的逐渐增加而降低。性成熟年龄在1＋～2＋龄,4～7月份产卵繁殖,卵为半漂浮性。种群     

昆明裂腹鱼繁殖生物学研究

研究昆明裂腹鱼繁殖生物学周年变化,为开展昆明裂腹鱼人工繁殖、养殖以及对自然水域鱼类资源的增殖和保护提供理论基础。2014年7月-2015年5月,每月定期采集雌、雄昆明裂腹鱼各10尾。样品鱼为2008年子一代,均为6龄。雌鱼体长26~48 cm,体重380~1 600 g;雄鱼体长29~46 cm,体重425~1 250 g。结果显示:昆明裂腹鱼成熟系数雌鱼为(7.07±0.04)%,雄鱼为(3.72±0.01)%;属一次性产卵类型,繁殖期为2-4月,盛期为3-4月;Ⅳ期卵巢卵径1.6~1.8 mm占35%。绝对繁殖力为(9263±5241)粒,与体长呈曲线相关(F=2E-11L7.427,R2=0.912),与体重呈线性相关(F=0.017W-10.19,R2=0.958);相对繁殖力为(9.5±3.9)粒/g,与体长、体重均呈曲线正相关(Fw=0.05e0.156L、R2=0.846,Fw=14.37ln W-90.57、R2=0.871)。     

阿克苏河叶尔羌高原鳅Triplophysa(Hedinichthgs)yarkandensis(Day)生物学研究

本对阿克苏河叶尔羌高原鳅的形态特征、群体结构、繁殖、食性等生物学进行了研究。叶尔羌高原鳅体长分布在3．0～15．0cm之间，体重分布在1～33g之间。W=0．039748L^263049.Fulton肥满度雌体平均为1．54，雄体平均为1．46；Clark肥满度雌体平均为1．25，雄体平均1．16。雌体成熟个体最小体长为6．6cm，体重为5．5g，平均绝对怀卵量11543粒／尾。食性以底栖动物、水生昆虫以及鱼类幼体为主。     

铠平鲉的繁殖生物学特征及胚胎发育

为了解铠平鲉繁殖生物学特征及胚胎发育规律,完善铠平鲉繁殖生物学研究内容,为其种质资源保护和资源可持续利用提供基础资料,实验利用春季于青岛胶州湾海域采集的铠平鲉生殖群体样本,开展了其繁殖生物学研究,并使用显微数码摄像系统,观察了铠平鲉体内胚胎的发育过程,定性和定量描述了各发育阶段胚胎的形态特征。结果显示,实验采集样本的体长范围为62~137 mm,体质量范围为9.4~126.8 g,雌雄性比为1.85∶1,最小性成熟年龄为2龄,生殖群体主要由2~4龄个体组成,初次性成熟体长为70.6 mm。绝对怀卵量F为656~9235粒,平均3176粒,体长相对怀卵量FL为12~67粒/mm,体质量相对怀卵量FW为72~140粒/g。雌鱼体内受精卵呈正圆球形,平均卵径为(1.50±0.03)mm,淡黄色,自心跳期开始,受精卵逐渐由正圆球形变为梨形。受精卵在海水中为沉性,具多个油球,在胚胎发育早期存在油球聚合现象,一般至原肠胚末期时仅剩1个大油球。雌鱼体内初孵仔鱼全长(5.57±0.06)mm。研究表明,虽然卵胎生铠平鲉的胚胎发育规律与大多数海水硬骨鱼类基本相似,但胚胎发育中油球数量、色素分布和受精卵外部形态变化等仍具有其特异性。     

呼伦湖蒙古油[歺又鱼]繁殖生物学的研究

对蒙古油[歺又鱼]（Hemiculter bleekeri warpachowskyi）的繁殖季节、繁殖习性、繁殖力、性比等繁殖生物学指标进行了研究。结果表明：蒙古油[歺又鱼]属敞水性产卵类型,粘性卵,为一次产卵类型。蒙古油[歺又鱼]初次性成熟年龄为1龄,繁殖季节为6月中旬至7月下旬,以7月中旬为产卵盛期。蒙古油[歺又鱼]个体绝对生殖力F为2021～15470粒,个体体长相对生殖力FL为230～1137粒/cm,个体体重相对生殖力FW为273～700粒/g;个体体长相对生殖力、个体体重相对生殖力分别和体长、体重成二次方程和三次方程关系。繁殖前期雌雄性比1∶0.83,繁殖期雌雄性比为1∶1.11。     

阿克苏河长身高原鳅Triplophysa (Triplophysa) teunis (Day)生物学研究

本文对2004年3—10月份采集的阿克苏河长身高原鳅的形态特征,生活习性,群体结构,繁殖特点,食性等生物学进行了初步的研究。长身高原鳅体长分布在3．4—12．1cm之间,体重分布在0．31—13．7g之间。W=0．0090293L^2.9666（r=0．970）。Fulton肥满度雌体平均为0．88,雄体平均为0．86;Clark肥满度雌体平均为0．61,雄体平均为0．64。雌体成熟个体最小体长为5．4cm。体重为1．4g。平均怀卵量2451粒／尾。食性以底栖动物,昆虫幼体等动物性饵料为主,其次是植物碎片和有机碎屑。     

海河流域农业非点源污染评价

伴随着我国经济的快速增长,人类活动和资源环境的矛盾加剧,水资源短缺和水环境污染的形势严峻。海河流域是中国的政治、经济和文化中心,在国民经济中具有重要的战略地位,然而它却是中国水污染最严重的流域。本文通过分析评价现有大尺度流域非点源污染负荷估算方法,建立了适合现有数据条件并有一定精确性的大尺度流域农业非点源污染负荷估算方法一“三维”系数估算法,估算农业非点源污染负荷量,评价农业非点源污染对水体污染的影响,并在此基础之上,提出了介于环境资源的公共物品属性决定了控制农业非点源污染必须由政府主导、公众广泛参与。海河流域要重点抓好畜禽养殖污染的控制,大力推广生态畜牧业。积极推进“农村清洁工程”,改善农村生活条件。     

野生翘嘴红鲌的驯养及人工繁育试验

本研究以闽江流域野生翘嘴红鲌鱼苗为试验材料,经饵料驯化,使其食用人工配合饲料,再经过3年水库网箱养殖,使其完全适应网箱生活环境,养成平均尾重1.2 kg,且性成熟具备繁殖能力的翘嘴红鲌亲本。分别于2005、2006年优选自育的性成熟翘嘴红鲌个体为亲本,经过2个多月的强化培育至6月份,开展人工繁殖试验,采用LRH-A2(促黄体生成素释放激素类似物)+HCG(绒毛膜促性腺激素)的混合剂作为人工催产剂,经自然产卵、受精孵化、鱼苗培育,共获翘嘴红鲌夏花鱼苗160.2×104尾。     

长江流域典型区河-库水文网络连通综合评估

长江具备丰富的水资源和电力资源,近年来河网闸坝、水电等水利设施被大量建设,导致了连通性下降,从而带来一系列的生态环境问题,评估长江流域河-库连通性具有重要意义。本研究选择长江流域高坝大库（金沙江下游）、低坝枢纽（汉江中下游）和山区小水电（景谷）三种河-库连通类型进行研究。首先概化典型研究区河-库连通的水文网络模型,并将水电站、过渡区、河流汇聚点、闸坝作为重要的网络节点。然后基于网络的水文连通功能、生态环境功能和社会贡献功能构建水文网络连通评估指标体系,利用熵权模糊综合评估方法对典型河-库进行分析。结果表明,高坝大库和低坝枢纽连通性为四级（差）,山区小水电连通性为五级（极差）。并基于评估结果,对不同类型的河-库系统给出改善连通性的针对性建议。     

Early settlement and growth of stocked European glass eels in a fragmented watercourse

One of the actions that has been implemented to support the recovery of the panmictic population of European eel is stocking of waterbodies where natural recruitment is low or null. However, growth conditions of the stocked eels can vary greatly. This circumstance emphasises the importance to determine ideal habitat conditions to contribute to the success of stocking actions and, consequently, to increase the production of silver eels. This study aims to evaluate the early settlement and growth of stocked glass eels in the upper reaches of a fragmented river. Stocking was carried out, in 2014, at three sites of an inland tributary of the Mondego river basin (Central Portugal), and its monitoring was conducted during the following two years, until 2016, along with the collection of environmental and hydromorphological parameters. The results showed a successful dispersion throughout the study area. Growth varied spatially, although environmental parameters have not clearly explained this variation, but overall with high growth rates and a positive allometric growth in this early stage of stocking, suggesting a good condition of the stocked individuals. This study showed that these upper reaches of fragmented watercourses, a shared feature amongst most European rivers that are currently inaccessible for natural recruitment, may be suitable habitats for eel stocking.     

Dam cascade in run-of-river systems promotes homogenisation of fish functional traits in a plateau river

Impoundments caused by dams are often responsible for intense changes in physical, chemical, geomorphological and hydrological characteristics of rivers, and are one of the main causes in global freshwater biodiversity declines. When these changes derive from multiple cascading dams, the cumulative effect can amplify, causing more pronounced consequences than each individual reservoir, which may affect, among other factors, the biotic and functional conditions of fish fauna. We aim to evaluate the impact of dam cascades on fish functional diversity by applying trait-based analysis. We evaluate the functional attributes (functional indices and community-weighted means of trait values) and environmental variables at 11 sites, which encompassed different segments affected by the hydroelectric plants (transition, reservoir, reduced discharge section and tributary) in the Antas River Basin dam cascade system located in southern Brazil. The spatial differences of the functional indices (richness, evenness, divergence, dispersion and diversity) as well as the weighted averages of each functional trait were tested through analysis of variance. The most affected functional characteristics were those related to habitat exploration by detritivorous species, especially the use of food resources and body shape, as well as the type of swimming movement. These traits were more representative at the most downstream site of the complex. Thus, our results suggest that the cascade of dams acts in the functional homogenisation of the ichthyofauna in the intermediate stretches, mainly reflecting physical changes in habitat.     

Putting the fish into inland fisheries – A global allocation of historic inland fish catch

Inland waters support the livelihoods of up to 820 million people and provide fisheries that make an essential contribution towards food security, particularly in the developing world where 90% of inland fisheries catch is consumed. Despite their importance, inland fisheries are overlooked in favour of other water use sectors deemed more economically important. Inland fisheries are also driven by external factors such as climate change and habitat loss, which impedes our ability to manage them sustainably. Using a river basin approach to allocate fish catch, we have provided an integrated picture of how different inland water bodies contribute to global inland fisheries catches. There is a substantial amount of information available on inland fisheries, but it has never been synthesised to build this global picture. Fishery statistics from river basins, lakes, floodplains, hydrobasins, and countries covering a time span from 1960–2018 were analysed. Collation of basin-scale fisheries statistics suggests a global inland catch of ≈17.4 million tonnes (PSE = ±3.93 million tonnes) in 2010, considerably more than the 10.8 million tonnes published by the United Nations Food and Agriculture Organization (FAO), but in line with estimates based on household consumption. The figure is considered a likely maximum due to recent reductions in catches because of closures, threats, and fisheries declines in the most productive fisheries. It is recommended that sentinel fisheries, which are important for food provision, employment, or where threats facing a fishery could cause a deterioration in catch, are identified to provide the baseline for a global monitoring programme.     

Representativeness of national parks in protecting freshwater biodiversity: A case of Brazilian savanna

The establishment of national parks are an important and often-used tool to protect biodiversity. However, when considering freshwater ecosystems, many of these areas in Brazil are habitat mosaics in which a small part of the ecosystem is protected and strongly influenced by the surrounding environment. By assessing the fish fauna and their diversity patterns in five national parks (NPs) within the Brazilian savanna, we discuss whether the establishment of new NPs or the expansion of their current conservation limits would potentially conserve additional species. We selected all national parks within the third largest drainage area in Brazil. To sample fish communities, we explored 60 streams through a standardised field protocol. We also simulated the potential impact of the enlargement or implementation of a new national park. Our results reinforce the importance of national parks and their surrounding areas to preserve fish species. The enlargement of national parks would result in an increase of potentially protected species; however, the same achievement would be obtained if their buffer zones were effectively managed and protected. We recommend an alternative conservation approach to increase protection of tropical savanna fish biodiversity, especially in developing countries such as Brazil with scarce financial resources available for management, monitoring and creation of protected areas.     

River dolphin distribution in regulated river systems: implications for dry‐season flow regimes in the Gangetic basin

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Effectiveness of protected area networks in representing freshwater biodiversity: the case of a Mediterranean river basin (south‐eastern Spain)

• 1. Biodiversity is probably at greater risk in freshwater systems than in other ecosystems. Although protected areas (PAs) play a vital role in the protection of biodiversity and are the mainstay of most conservation polices, the coverage of biodiversity by existing PA networks is often inadequate and few reserves are created that take into consideration freshwater biota.
• 2. In this paper an attempt is made to address the performance of protected areas in the context of freshwater biodiversity conservation using data records for water beetles in a Mediterranean river basin.
• 3. Although the present PAs in the study area cover a relatively high number of water beetle species, the distribution and extent of reserves is still inadequate or insufficient to protect freshwater biodiversity, especially species of conservation concern.
• 4. Alternative area‐selection methods (hotspots and complementary) were more efficient than PAs for representing water beetles. Within these, complementarity was the most efficient approach, and was able to represent all species in a significantly lower area than the current PA network. On the other hand, the future Natura 2000 Network will result in a great increase in the total area of protected land as well as in the biodiversity represented.
• 5. Unfortunately, the occurrence of a species within a protected area is not a guarantee of long‐term survival because the extent of PAs is often insufficient and disturbances occur outside park boundaries. Thus, whole‐catchment management and natural‐flow maintenance are indispensable strategies for freshwater biodiversity conservation.

Copyright © 2006 John Wiley & Sons, Ltd.     

Ecological impacts of small hydropower plants on headwater stream fish: from individual to community effects

Hydroelectricity is increasingly used worldwide as a source of renewable energy, and many mountain ranges have dozens or hundreds of hydropower plants, with many more being under construction or planned. Although the ecological impacts of large dams are relatively well known, the effects of small hydropower plants and their weirs have been much less investigated. We studied the effects of water diversion of small hydropower plants on fish assemblages in the upper Ter river basin (Catalonia, NE Spain), which has headwater reaches with good water quality and no large dams but many of such plants. We studied fish populations and habitat features on control and impacted reaches for water diversion of 16 hydropower plants. In the impacted reaches, there was a significantly lower presence of refuges for fish, poorer habitat quality, more pools and less riffles and macrophytes, and shallower water levels. We also observed higher fish abundance, larger mean fish size and better fish condition in the control than in impacted reaches, although the results were species‐specific. Accordingly, species composition was also affected, with lower relative abundance of brown trout (Salmo trutta) and Pyrenean minnow (Phoxinus bigerri) in the impacted reaches and higher presence of stone loach (Barbatula quignardi) and Mediterranean barbel (Barbus meridionalis). Our study highlights the effects of water diversion of small hydropower plants from the individual to the population and community levels but probably underestimates them, urging for further assessment and mitigation of these ecological impacts.