ABSTRACT β‐diversity is effective for measuring the degree of compositional variation among communities and can be decomposed into local (LCBD) and species (SCBD) contributions to β‐diversity. Previous studies on β‐diversity have mostly been limited to the taxonomic level; relatively few studies have been conducted on functional diversity and its two components based on species functional traits, which have seriously hindered the potential application of β‐diversity in conservation biology. In addition, increasing anthropogenic disturbance has led to uncertainties in the β‐diversity of fish communities in stream ecosystems. In this study, we explored the relationships between multidimensional β‐diversity of fish communities and regional landscape factors, local environmental factors, community metrics, and species functional traits to reveal the main drivers of β‐diversity in headwater streams of the Xin'an River, China. LCBD and SCBD values were calculated based on species abundance and functional traits, that is, local and species contribution to taxonomic (TLCBD and TSCBD, respectively) and functional (FLCBD and FSCBD, respectively) β‐diversity. The results showed that LCBD and SCBD values were affected by biological and environmental factors. Among biological drivers, TLCBD values were positively related to species abundance. FLCBD values were positively related to species abundance, functional originality, specialization, and dispersion, that is, sampling sites with greater ecological uniqueness at the taxonomic level also had greater ecological uniqueness at the functional level. Among environmental drivers, TLCBD and FLCBD values were negatively related to water temperature, substrate coarseness, and agricultural and urban land use, that is, anthropogenic land use and local environmental changes reduce the ecological uniqueness of fish communities in the studied streams. For SCBD, both TSCBD and FSCBD values were affected by species abundance, occupancy, and niche position. We suggest that consideration of SCBD as part of a conservation approach needs to be coupled with species abundance and occupancy, which will help to prioritize areas for conservation and restoration in the study region.

Artificial fish nests are common tools in fisheries management, providing spawning grounds to enhance the size and diversity of fish populations. This study aimed to explore the effects of deployment locations on the reproductive efficiency and preferences of fish with adhesive and demersal eggs using artificial nests. Floating artificial nests were deployed in three regions (upstream, midstream, and downstream) of a reservoir in Zhejiang, China, at locations with three topographical types: steep slope (reservoir shore, slopes > 60 degrees), gentle slope (reservoir shore, slopes < 30 degrees), and confluence (middle thread of channel). The quantity, viability and species of eggs in artificial nests were recorded throughout the fish reproductive cycle. The mean density of viable eggs in artificial nests in the midstream region (1176 +/- 448 ind./m2) was significantly higher than that in the downstream (477 +/- 167 ind./m2) and upstream regions (350 +/- 148 ind./m2). The survival rate of fish eggs in the gentle slope area (56.94 +/- 11.97%) was significantly lower than that in the confluence (79.80 +/- 6.20%) and steep slope areas (74.47 +/- 11.40%). Different fish groups respond uniquely to environmental factors. We suggest that the construction and implementation of artificial nests should be based on the differences in upstream and downstream water bodies, as well as the specific ecological requirements of target fish species. Management practices should focus on site-specific environmental monitoring and adapt nest placement to optimize conditions for different species. Furthermore, future research should aim to develop predictive models that integrate environmental factors and species needs, providing a more robust basis for artificial nest placement and fisheries management.

Understanding the processes and mechanisms that shape the distribution patterns and variations of biodiversity along spatial gradients continues to be a priority for ecological research. We focused on the biodiversity of benthic diatom communities within a large near-natural watershed. The objectives are: (1) to explore the overall spatial patterns of benthic diatom biodiversity; (2) to investigate the effects associated with watercourse position and environmental variables, as well as both common and rare species on two facets (i.e., taxonomic and functional) of alpha and beta diversity; and (3) to unveil the mechanisms underlying their spatial variations. Alpha diversity indices along the stream watercourse showed a clear increasing trend from upstream to downstream sites. Results of random forest regression identified conductivity as the primary factor influencing functional alpha diversity, while elevation emerged as the predominant factor for taxonomic alpha diversity. Beta diversity partitioning revealed that taxonomic beta diversity generally exceeded functional beta diversity. These diversity measures exhibited different patterns along the watercourse position: taxonomic beta diversity remained relatively consistent along the watercourse, whereas functional total beta diversity and its two components of middle stream sites were lower than those of upstream and downstream sites. Functional beta diversity was sustained by dominant and common species, while rare species made significant contributions to taxonomic beta diversity. Both taxonomic and functional beta diversity and its components displayed a stronger influence from spatial factors than from local environmental, geo-climatic, and nutrient variables. Collectively, taxonomic and functional alpha and beta diversity demonstrated distinct responses to the main environmental gradients and spatial factors within our catchment, highlighting their different insights into diatom diversity. Furthermore, research is required to assess the generalizability of our findings to similar ecosystems. In addition, this study presents opportunities for expansion to include other taxa (e.g., macroinvertebrates and fish) to gain a comprehensive understanding of the driving mechanisms behind stream biodiversity.

新型稻渔综合种养是一种以因地制宜为原则的农业模式,其核心理念是将水稻种植与水产养殖相结合,在稳产保供前提下实现农村经济多元化发展,从而探索出的一条产出高效、产品安全、资源节约、环境友好的新型产业发展之路.与"稻田养鱼"的概念不同,稻渔综合种养系统是人类利用稻田浅水环境将水稻和水生生物种养在同一稻田空间而形成的独特稻作系统,是一种以稻为主的农业生态系统及所涉及的"种植"(水稻、莲藕、茭白等湿生作物的栽培)和"养殖"(包括田鲤鱼、龟、鳖、虾、蟹、鳅、螺等水生动物养殖)两业耦合共育的综合技术体系.

我国1983年引进大口黑鲈,1985年突破人工繁殖,经过30多年的发展,已经成为全世界大口黑鲈养殖产量最大的国家.2019年全国大口黑鲈养殖产量达到470 000吨,养殖面积18 700公顷(中国渔业统计年鉴,2020).

In this study, the complete mitochondrial genome of Niwaella nigrolinea (Cypriniformes: Cobitidae) from Zhejiang, China, was determined for the first time. We found that the sequenced length of the complete mitochondrial genome of N. nigrolinea was 16,565 bp. The genome contained 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, and two non-coding regions, identical to most other vertebrates. Our phylogenetic analysis results confirmed that N. nigrolinea was close to an unclassified Cobitis sp. and the fishes of the genus Cobitis. These data would contribute to the genetic conservation genetics and stock evaluation of N. nigrolinea.

This study determined the complete mitochondrial genome of Formosania galericula (Cypriniformes: Gastromyzontidae) from Zhejiang, China, for the first time. The complete mitochondrial genome of F. galericula was sequenced to be 16,555 bp in length. The genome contained 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, two central non-coding regions (the control region and the origin of light strand replication), identical to most other vertebrates. Phylogenetic analysis highly supported that F. galericula was close to Crossostoma lacustre and the genus Vanmanenia fish. However, F. galericula was not firstly clustered with Formosania chenyiyui but after the genus Vanmanenia fish. These data would explain the evolutionary mechanisms and biogeography of the family Gastromyzontidae and is helpful for the conservation of genetics and stock evaluation for F. galericula.

This study determined the mitochondrial genome of Sinobdella sinensis (Synbranchiformes: Mastacembelidae) from China's Qiantang River for the first time. The mitochondrial genome of S. sinensis was sequenced to be 16,543 bp in length, larger than S. sinensis from China's Yangtze River. The genome contains 13 protein-coding genes, 22 transfer RNAs, two ribosomal RNAs, two central non-coding regions (the control region and the origin of light strand replication), identical to most other vertebrates. Phylogenetic analysis highly supported that S. sinensis from China's Qiantang River was different from other Mastacembelus fish. However, it showed a close relationship with Macrognathus aculeatus. These data would explain the evolutionary mechanisms and biogeography of the family Mastacembelidae and is helpful for the conservation of genetics and stock evaluation for S. sinensis.

高体鳑鲏(Rhodeus ocellatus)色彩艳丽、体型优美,是一种很有市场前景的观赏鱼.对高体鳑鲏线粒体基因组(mitochondrial genome,mtGenome)进行测序和分析、探讨不同地理群体高体鳑鲏的mtGenome差异以及高体鳑鲏在鱊亚科的系统发育地位,有利于高体鳑鲏的系统发育研究.本研究通过PCR扩增、测序、软件拼接等方法获得瓯江高体鳑鲏mtGenome(GenBank No.MW007386),长度为16 675 bp,碱基组成为 A(28.98％)、G(17.09％)、C(26.51％)和 T(27.42％),包含 13个蛋白编码基因(protein-coding genes,PCGs)、22个tRNAs和2个rRNAs.瓯江高体鳑鲏mtGenome 与 PCGs 的(A+T)含量分别为56.41％和56.27％,均具有明显的AT偏好性.在22个tRNAs中,除tRNA-Ser(AGY)外均可形成典型的三叶草结构.基于BLAST的比较表明,瓯江高体鳑鲏与东江高体鳑鲏的序列一致性为83.84％,与日本高体鳑鲏的序列一致性为95.07％,与GenBank No.DQ026430的高体鳑鲏序列一致性为93.11％,与图们江兴凯鱊(Acanthorhodeus chankaensis)序列一致性为99.03％,与黑龙江兴凯鱊序列一致性为83.72％,与沅江兴凯鱊序列一致性为83.84％.另外,瓯江高体鳑鲏与图们江兴凯鱊之间的遗传距离最近,与日本高体鳑鲏遗传距离次之,与东江高体鳑鲏则较远.基于25种隶属于3个属的鱊亚科鱼类mtGenome构建的系统进化树分析表明,瓯江高体鳑鲏与图们江兴凯鱊亲缘关系较近,而与东江高体鳑鲏亲缘关系较远.本研究为瓯江高体鳑鲏的遗传多样性保护与育种提供了参考依据.

浙江省闲林水库作为新建水库,是杭州市的应急备用水源地,也是千岛湖配水工程的重要组成部分.为保护其水生生态环境,依据2019年的实测数据,采用综合营养指数法对水库水体进行营养状态评价.结果表明:闲林水库年均营养状态指数为46.25,处于中营养水平;总磷、总氮和叶绿素a对综合营养指数的贡献率最大,合计达到了78.5％.闲林水库总氮和总磷的年均浓度分别为2.24 mg·L-1和0.06 mg·L-1,磷是闲林水库的限制性营养盐.闲林水库各季节的营养状态指数在36.28～53.56,其中春季属于轻度富营养.基于闲林水库的生态特点,结合当地的实际情况,提出控制农业面源污染、构建稳定的水生态系统、建立常规监测系统等防治对策.

综述钱塘江流域开展的鱼类资源研究,并从鱼类多样性和区系组成、渔业资源特征研究、鱼类增殖放流研究、人类活动对鱼类的影响这4个方面进行归纳总结.参照国内外重要流域的生态保护和治理经验,同时结合钱塘江流域的实际情况,提出了4个方面的保护对策:全流域统筹,顶层设计;加强监测,科学管理;依法规范养殖,开发土著特色养殖;加大宣传,提高公众环保意识.

三角鲂是浙江省钱塘江流域的重要土著经济鱼类,近年来其养殖规模和效益日益增长,但瓶颈制约因素正逐步显现,主要原因是三角鲂种质资源退化,同时野外再难采集到三角鲂原种资源.本研究在天然水域人工繁殖三角鲂,对三角鲂种群,同时对其生长情况进行监测,旨在对三角鲂种质资源的保护提供依据.研究发现,三角鲂在铜山水库这种近野生状态下,其从幼体到亚成体再到成体的阶段中生长具有异速性,生长速度趋于减缓.本研究总结了水库放养三角鲂新老交替、水库资源利用最大化的合理放养区间,对三角鲂的种质资源保护及水库资源高效利用提供了有效的数据支撑.

研究比较了三角帆蚌(Hyriopsis cumingii)底播和悬挂2种放养方式对富营养化水体的净化效果.结果表明,三角帆蚌的2种放养方式能够显著降低富营养水体中的总氮(TN)、悬浮物(TSS)、化学需氧量(CODCr)和叶绿素a(Chla),但是对总磷(TP)的净化效果不显著;2种放养方式之间的净化效果差异不显著.

本文研究比较了背角无齿蚌和三角帆蚌对富营养化水体的净化效果.研究结果表明,背角无齿蚌和三角帆蚌能够有效控制水体富营养化,显著降低了富营养化水体中的总氮、 悬浮物、 化学需氧量和叶绿素a,其中对叶绿素a的净化效果最佳,分别达到96.8％和94.2％.2种河蚌对富营养化水体中总磷的净化效果不显著.在本试验中背角无齿蚌和三角帆蚌两者对水质的净化效果差异不显著,在使用河蚌净化水质时建议依据当地河蚌的价格以及取材的难易程度进行选择.

2019年春季,我们在杭州萧山围垦地区使用“高位池+大棚”的方式养殖南美白对虾,取得了较好的经济效益,现将情况总结如下. 一、材料与方法 1.池塘条件 养殖池设在杭州锋发水产养殖有限公司,位于萧山区围垦十八工段东.由于是第一次尝试,总共建造了4个高位池,每个池子的规格为27米×29米,深度2米.池子里铺防渗土工膜(地膜厚度0.35毫米),排污口设于池子中央.每个池子配置0.45千瓦的叶轮式增氧机3台,同时用纳米管立体增氧.棚为中间立柱,采用501钢管,塑料薄膜覆盖(图1).

杂交鲂是杭州市农业科学研究院水产研究所以三角鲂为母本、翘嘴红鲌为父本杂交的F1代,是一种较大型的经济鱼类,与亲本相比,其在生长性能方面存在明显的优势,且肌肉营养组成较好,为进一步提高杂交鲂的养殖技术,本研究进行了杂交鲂、三角鲂、青鱼、鲢鳙鱼等多品种池塘混养试验,并对其养殖效果进行评价.

To assess the effectiveness of different fisheries management strategies in freshwater reservoirs in China, we use hydroacoustic techniques to quantify the density, biomass, size, and patterns in distribution of fishes in Wanyao (WY), Laohutan (LHT), and Qiaodun (QD) reservoirs (Zhejiang Province), each of which has been managed differently. Significant differences in density, biomass and size distribution are reported among these reservoirs. In the overfished WY, fish density and biomass are lower than that in LHT (P < 0.05). In QD, where fishing has been prohibited from 2011 to 2015, fish density and biomass are higher than in LHT (P < 0.05). In LHT, where the larger-size fish (> 48 cm) were caught and the smaller ones were left in the reservoir, proportionally more mid-sized fish ((similar to)11-48 cm, 84.63%) are present than smaller or larger fish. Our research improves the understanding of the relationships between fisheries management strategies and the density, size and biomass of fishes in reservoirs.We demonstrate that fisheries management strategies play an important role in maintenance of fish resources in reservoirs, and that hydroacoustics techniques can be successfully used to quantify fish density and size distributions.

This study was carried out on water quality and main pollutants of Litopenaeus vannamei ponds in the reclama-tion region around Hangzhou Bay from July 2016 to October 2016 to evaluate the pollution status of the aquaculture water and reduce aquaculture risks.The water quality and main pollutants were evaluated by pollution index method and compre-hensive nutrition state index method.The results indicated that the water quality of Litopenaeus vannamei ponds in the recla-mation region around Hangzhou Bay was worse than class V surface water, TN, TP and COD were the main exceeding fac-tor.Pollution index evaluation method results revealed that the status of Litopenaeus vannamei ponds in the reclamation re-gion around Hangzhou Bay was heavy polluted, TP was the primary pollutant.Meanwhile, comprehensive nutrition state in-dex evaluation method results showed that TLI (Σ) value for most ponds was higher than 60, the water was evaluated as moderate-hypertrophic eutrophication.

An investigation was conducted on the zooplankton resources at 3 sampling sections in XiXi Wetland in May and November 2017, and the zooplankton species composition, temporal and spatial distribution, dominant species and biological diversity were analyzed. A total of 17 species or genera were collected, belonging to 9 families and 14 genera, and the Rotifera had the largest number of species, accounting for 47.06% of the total species number, followed by Cladocera accounting for 41.18%, there was only 1 species of Copepoda. The density and biomass of Zooplankton were generally low in spring. The most dominant species were Rotifera, biological diversity was low, and the structure of zooplankton community was not complex. The change of wetland habitat may be the main reason for the decline of zooplankton species. Measures were proposed to overcome the problems existing in the wetland management.

An investigation was conducted on the fish resources at 6 sampling sections in Xixi Wetland in May and October 2016,species composition,dominant species,temporal and spatial distribution of the fishes were analyzed.A total of 38 species were collected,which belonged to 6 orders,12 families and 36 genera,and Cyprinidae had the largest number of species,accounting for 63.16％ of the total number of species.There were 2 or 1 species belonging to other families,biological diversity was low,the structure of fish resources was not complex,the quantity of resources was small and tended to become medium and small in size.The two investigations conducted in May and October revealed that the number of Cyprinid fish species accounted for 58.62％ and 77.78％,respectively.The dominant species were Carassius auratus and Bostrichthys sinensis in the wetlands.The change of wetland habitat may be the main cause for the decline of fish resources.According to the problems existing in the protection of fish resource,strategies and measures were proposed to improve the situation.