带鱼保护区春秋季鱼类群落特征及与环境因子的关系

基于2014年5月(春季)和11月(秋季)在带鱼保护区进行的渔业资源底拖网调查数据,采用非度量多维标度(NMDS)、典范对应分析(CCA)和分类回归树(CART)方法研究了带鱼保护区春、秋季鱼类群落空间结构和群落多样性,以及它们与环境因子的关系。结果显示,该水域春季共捕获鱼类75种,隶属14目49科63属;秋季捕获鱼类78种,隶属15目50科64属。春、秋两季鱼类空间结构均可划分为2个组群,经单因子相似性(ANOSIM)分析,不同季节的2个组群间均存在显著性差异。CCA分析表明,影响春、秋季鱼类群落分布的主要环境因子有温度、盐度、水深以及浮游动物。春季多样性指数平均值为1.65±0.60,丰富度指数为2.46±0.90,秋季多样性指数平均值为1.42±0.53,丰富度指数为1.89±0.60。CART分析表明,影响春季多样性和丰富度的主要因素有Chl.a、DO、水深、p H和浮游动物(磷虾类和浮游幼体);秋季多样性主要受温度、水深和盐度的影响,丰富度主要受水深和温度的影响。     

长江口潮滩湿地生境修复对鱼类群落结构的影响

为查明长江口潮滩湿地生境修复对鱼类群落结构的影响,在2021年6月(春季)、2021年11月(秋季)、2022年1月(冬季)、2022年7月(夏季)于长江口南支采用定置插网对潮滩湿地生境修复区与对照区进行鱼类样品采集,比较分析修复区和对照区的鱼类物种数、个体数、生物量和多样性指数。结果表明,研究期间共采集到鱼类27种,隶属于8目9科21属,其中,修复区采集到鱼类22种,对照区采集到21种。修复区和对照区鱼类的个体数、生物量差异明显,均表现为修复区明显高于对照区。4季修复区鱼类群落总Margalef丰富度指数(D)为6.8,总Shannon-Wiener多样性指数(H′)为4.92,总Simpson单纯度指数(C)为2.47,总Pielou均匀度指数(J′)为2.99,生物多样性指数总体为17.18,高于对照区(15.82)。春季修复区鱼类幼体出现频率(67%)明显多于对照区(44%),表明幼鱼对修复区存在较强的偏好性。本研究结果表明在长江口潮滩湿地进行生境修复能够缓解长江口鱼类生物多样性所面临的生态危机,在一定程度上为幼鱼提供育幼场所,为进一步深入了解长江口潮滩湿地生境修复对鱼类育幼场...     

董箐库区渔获物组成及多样性

为了解库区建设对鱼类生物多样性的影响,掌握董箐库区内渔业资源群落组成和物种多样性变化情况。2013年--2015年在董箐库区进行6次生物采样和走访调查,采集渔获物共668尾,隶属3目8科29属39种,鲤科鱼类最多,占总数的60.8%;群落以杂食性鱼类和喜静缓流生态类型鱼类为主,唇鲮(Semilabeo notabilis)、花鱼骨(Hemibarbus maculatus)、鲤鱼(Cyprinus carpio)、鲫鱼(Carassius auratus)、云南光唇鱼(Acrossocheilus yunnanensis)、光倒刺鲃(S.hollandi)、黄颡鱼(Pelteobagrus fulvidracoi)为库区的优势种,对比历史资料发现库区鱼类群落结构已发生改变;董箐库区鱼类群落生物多样性采用Margalef 丰富度指数、Shannon-wiener多样性指数()、Pielou均匀度指数()、Wilhm改进指数()作为评价指标,各指标的平均值为3.811、0.914、2.649、2.529,分析数据发现鱼类生物多样性也有衰减。     

南海中部海域秋冬季中层渔业生物群落结构的初步研究

根据2014年对南海中部海域秋冬季2个航次中层拖网调查数据,分析了中层渔业生物种类组成、优势种和多样性等群落结构特征。共鉴定中层渔业生物241种,其中鱼类196种、头足类21种、甲壳类24种,冬季的渔获种类高于秋季,但单位捕捞努力量渔获量(CPUE)略低于秋季。相对重要性指数(index of relative importance,IRI)结果表明,秋季IRI≥100的优势种群有25种,其中IRI≥500的优势种有5种,包括蝰鱼(Chauliodus sloani)、尾明角灯鱼(Ceratoscopelus warmingii)、条带眶灯鱼(Diaphus brachycephalus)、日本乌鲂(Brama japonica)和条带多光鱼(Diplophos taenia);冬季IRI≥100的优势种群有26种,其中IRI≥500的优势种有3种,分别为典型刺虾(Oplphorus typus)、蝰鱼和太平洋帆乌贼(Histioteuthis pacifica)。秋冬季的IRI组成不存在显著性差异(P0.05)。以个体数计算的中层渔业生物丰富度指数、均匀度指数和多样性指数冬季高于秋季,但优势度指数是冬季低于秋季。以生物量计算的多样性指标中,冬季中层渔业生物丰富度指数和多样性指数高于秋季,而优势度指数和均匀度指数则低于秋季。利用数量生物量比较曲线(abundance-biomass comparison curves,ABC)方法分析南海中部海域中层渔业生物群落的状况,结果显示,秋季中层渔业生物群落处于较大干扰状况,冬季群落处于中等干扰状况。     

长江口海上风电场水域鱼类群落结构特征及其与环境因子的关系

为探明长江口海上风电场水域的鱼类群落结构及其影响因素, 本研究利用多元统计和冗余分析(RDA)等方法对该水域鱼类群落组成及其与环境因子的关系进行分析。春、秋季共获得鱼类 28 种, 隶属 6 目 15 科 26 属; 鲈形目鱼类占比最高(57.14%), 其中以虾虎鱼科鱼类最多(21.43%)。鱼类组成以海洋性、暖温性、底层鱼类为主。春季优势种为棘头梅童鱼 (Collichthys lucidus) 、刀鲚 (Coilia nasus) 、凤鲚 (Coilia mystus) 、拉氏狼牙虾虎鱼 (Odontamblyopus lacepedii)和鮸(Miichthys miiuy), 秋季优势种为龙头鱼(Harpadon nehereus)、凤鲚、棘头梅童鱼、 刀鲚和鮸。多样性分析和 ABC 曲线表明, 调查水域鱼类群落结构处于受干扰状态。T 检验显示, 风电场水域鱼类的丰度、生物量、丰富度指数(D)、均匀度指数(J'')和多样性指数(H'')均与邻近水域无显著性差异(P＞0.05)。等级聚类和非度量多维排序(NMDS)表明, 长江口海上风电场及邻近水域鱼类群落分为春季和秋季 2 个组群。相似性检验 (ANOSIM)显示 2 个组群差异极显著(R=0.726, P＜0.01), 群落结构的季节更替明显。RDA 表明鱼类群落结构受溶氧、 温度、深度和盐度的综合影响, 不同环境因子对不同生活史阶段优势种的影响作用不同。结果表明, 长江口海上风电场及邻近水域鱼类群落结构的干扰状态主要与季节和环境因素相关, 风电场对其影响有限。     

长江口青草沙水库正式供水前的鱼类群落结构特征

为研究上海青草沙水库的鱼类物种组成、多样性及其空间变化,2010年7--10月在该水库共捕获鱼类993尾,隶属5目,18种,其中淡水鲤形目鱼类最多,占总物种数的72.2％.群落优势种为贝氏(鳖)、刀鲚、鲫、光泽黄颡鱼.聚类分析表明,鱼类群落类型存在较显著的空间差异,刺网网目大小对渔获物物种组成有较显著的影响.物种多样性与丰富度和均匀度均显著正相关,但更多地受丰富度的影响.单因素方差分析表明,鱼类物种多样性在空间上无显著差异.4种摄食功能群中,无脊椎动物食性(44.4％)和杂食性(33.3％)鱼类物种数比例较高;4种生态类群中,定居性鱼类占绝对优势(77.8％).青草沙水库鱼类群落表现出淡水或长江口低盐淡水区鱼类区系的主要特征,与以近海鲈形目鱼类为优势的长江口邻近水域的鱼类群落差异巨大,推测水库建设导致的隔离与盐度下降是形成该水库鱼类群落趋于淡水区系的主要原因.     

海南岛东岸、南岸浅水礁区近10年珊瑚礁鱼类种类分布及多样性探讨

根据2004—2013年海南岛东岸、南岸浅水礁区珊瑚礁鱼类监控数据,利用截线样条法、分类学多样性指数、相对丰富度及相似性指数等方法技术对海南岛东岸、南岸浅水礁区珊瑚礁鱼类种类组成及生物多样性进行研究。结果显示,海南东岸、南岸浅水礁区近10年调查珊瑚礁鱼类共计6目32 科64属130种,其中鲈形目居绝对优势;珊瑚礁鱼类密度大致呈现由南向北逐渐递减的趋势;科级多样性平均值为4.41,属级多样性指数平均值为3.09,标准化的G-F指数平均值为0.30;鲈形目珊瑚礁鱼类相对丰富度占有绝对优势,相对丰富度较高的6个科分别为雀鲷科、隆头鱼科、蝴蝶鱼科、天竺鲷科、四齿鲀科及玻甲鱼科;珊瑚礁鱼类在目级极为相似,相似性指数在0.86～1之间;科、属、种级相似性指数较低,均在0.5以下,通过Jaccard's种类相似性指数分析,海南岛东岸、南岸珊瑚礁鱼类种类较多,物种丰富。珊瑚礁鱼体长范围6～10 cm区间的数量最多,其次为0 ～5 cm区间,21～40 cm区间的珊瑚礁鱼类在浅水礁区分布极少。本研究通过对海南岛东岸、南岸浅水礁区珊瑚礁鱼类近10 a的种类分布及多样性进行探讨,旨在为海南岛珊瑚礁生态系统及珊瑚礁鱼类保护与研究提供基础数据及理论依据。     

陕西米仓山国家级自然保护区鱼类多样性初步调查

2013年8月和12月,对陕西米仓山国家级自然保护区鱼类资源进行了调查。结果显示:保护区有鱼类1目(鲤形目)2科(鲤科Cobitidae、鳅科Cyprinidae)8属9种,其中鲤科5种,鳅科4种,保护区优势种为拉氏(Phoxinus lagowskii)和红尾荷马条鳅(Homatula variegata),稀有种为宽口光唇鱼(Acrossocheilus monticolus)和马口鱼(Opsariichthys bidens);鱼类物种多度格局近似正态分布,海拔900~1 000 m区域生物多样性最丰富,海拔1 000 m以上鱼类物种数急剧下降。总体而言,陕西米仓山保护区鱼类组成相对简单,群落结构脆弱,多样性程度不高,近年来渔业资源有所下降。     

嵊泗列岛邻近海域鱼类种类组成及多样性分析

根据2017年4月于嵊泗列岛邻近海域开展渔业资源底拖网调查的渔获数据,运用相对重要性指数、Shannon-Weaver指数、均匀度指数、丰富度指数、等级聚类和非度量多维度分析、生物量曲线等方法分析该海域鱼类种类组成、优势种、物种数量空间分布、生物多样性。该海域共鉴定出鱼类33种,其中优势种有棘头梅童鱼(Collichthys lucidus)、银鲳(Pampus argenteus)、龙头鱼(Harpodon nehereus)、凤鲚(Coilia mystus)等4种;与历史数据相比,该海域春季鱼类种类数锐减,优势种更替显著。根据适温性可分为暖温性和暖水性2类,分别为17和16种。各站位鱼类物种数在9～20种之间,整体呈嵊泗列岛北部海域高于南部海域的趋势。生物多样性分析表明,均匀度指数(J′)值较低,可能是舟山水域的污染导致多样性指数偏低。聚类分析结果表明,该海域鱼类群落结构空间差异较大。ABC曲线结果表明,舟山嵊泗列岛邻近海域鱼类群落结构处于严重干扰状态。综上所述,嵊泗列岛邻近海域鱼类资源受人类活动影响强烈,鱼类多样性指数偏低,群落结构空间差异较大。     

2015年夏季长江口及其邻近海域渔业生物群落结构分析

根据2015年6月(夏季)长江口及其邻近海域的底拖网调查数据,分析了该海域渔业生物种类组成、优势种、群落结构及其多样性特征。结果表明,调查共捕获渔业生物93种,其中底层鱼类56种、中上层鱼类7种、头足类10种和甲壳类20种,以底层鱼类和甲壳类为主。优势种包括小黄鱼(Larimichthy-spolyactis)、鳀(Engraulis japonicus)和带鱼(Trichiurus haumela)。鱼山渔场及舟山渔场近岸区和长江口渔场离岸区群落多样性较高,舟山渔场离岸区和大沙渔场南部多样性较低。渔业生物群落可分为3组:20 m等深线附近的近岸区、20~50 m水深的长江口渔场外部和大沙渔场南部、以及50~75 m水深的舟山渔场和鱼山渔场中外部。渔业生物群落结构不同组间差异主要由小黄鱼、鳀、带鱼和刺鲳(Psenopsis anomala)引起。     

长江十年禁渔后保护与发展

长江是我国鱼类多样性最高的河流，同时也是我国最重要的淡水渔业资源产区。然而，近几十年来受水域污染、水工程建设、湖泊围垦、航运发展、过度捕捞和外来种入侵等多重因素的影响，长江流域生态系统面临着逐渐衰退的困境，主要表现为鱼类种类数减少、鱼类濒危物种程度加剧、鱼类资源小型化趋势明显、鱼类资源呈衰退趋势和外来物种种类增多等。长江十年禁渔，对恢复长江水生态环境和保护水域生物多样性提供了重要的机遇。作者建议统筹协调长江生态保护与渔业发展的关系，创新流域管理体制与机制，根据长江水生态系统结构与功能变化，适时调整服务目标，其目的旨在实现对长江流域水生态环境的保护和渔业资源的可持续发展提供科学依据。     

Spatial distribution patterns of fish egg and larval assemblages in the lower reach of the Yangtze River: Potential implications for conservation and management

1. River fish diversity is threatened by anthropogenic environmental alteration to landscapes. The early life-history stages of fish play an important role in maintaining diversity and population recruitment and can be heavily influenced by landscape patterns. Information on temporal and spatial distribution patterns of fish eggs and larvae is also important for biodiversity conservation and management of fish resources.
2. The Yangtze River possesses a high diversity of fishes, including many commercially important species. The economy along the lower reach of the river is well developed, and most of the area is experiencing high pressure from human impacts. This section of the Yangtze River connects with the largest freshwater lake in China at the upstream end and flows into the estuary at the downstream end. These two landscape features are likely to have a significant impact upon the spatial distributions of fish egg and larval assemblages.
3. Environmental variables, fish eggs, and larval assemblages were sampled in three locations, at Hukou, Anqing, and Jingjiang, in the lower reach of the Yangtze River. The results suggest that the higher number of species and greater abundance in upstream sites reflect the critical function of connectivity of Poyang Lake with the river for fish recruitment in the lower Yangtze. The delayed bloom of larval fish, occurrence of estuarine species, and a lower species number and abundance of freshwater fish downstream reflect the influence of tidal intrusion from the estuary.
4. This study highlights the value of maintaining natural river–lakes connectivity in the Yangtze River as a conservation measure. The connected river–lake system should be designated as a priority area for fish resource protection in the lower reach of the Yangtze River. We recommend further measures to break down barriers between the river and other lakes and to restore the natural lateral connectivity of the floodplain ecosystem.

     

Effects of fish species richness and assemblage composition on stream ecosystem function

Abstract –  Biodiversity is declining across aquatic ecosystems because of biological invasions and species extinctions. Because fishes have pervasive effects on ecosystems through species-specific food web interactions, alterations to species and functional richness, and composition of natural assemblages could have negative effects on aquatic ecosystem function. In this study, I tested the effects of fish species and functional richness, and assemblage composition on primary production (PPR), benthic invertebrate density, and benthic particulate organic matter (BPOM) in a 42-day experiment in artificial stream mesocosms. I found that fish species richness and assemblage composition were important predictors of PPR in stream mesocosms. However, the effect of species richness on PPR increased with time, suggesting that richness-related effects might strengthen as the magnitude of community-level interactions increases in ecosystems. There was no effect of fish species or functional richness or assemblage composition on benthic invertebrate densities or BPOM. These data provide additional support that fishes can be important regulators of ecosystem function in aquatic systems, and suggest that positive effects of fishes on ecosystems can be strengthened by increased species richness and composition of the assemblage. This study broadens the applicability of the biodiversity ecosystem-function literature to a new suite of taxa, supporting the overall hypothesis that ecosystem functions and services are likely to decline in response to species extinctions.     

赤水河流域鱼类物种、功能和分类多样性研究

赤水河是长江上游的一条一级支流,同时也是长江上游珍稀特有鱼类国家级自然保护区的重要组成部分,在鱼类生物多样性保护方面具有重要价值。本文基于2019年和2020年对赤水河流域30个样区的鱼类调查数据,对鱼类物种丰富度(Richness)、Shannon-Weiner指数(H)、功能丰富度(FRic)、功能均匀度(FEve)、功能离散度(FDiv)、平均分类差异指数(Δ⁺)和分类差异变异指数(Λ⁺)等多样性指数的空间分布格局及其相关性进行了分析。调查期间共采集到鱼类125种(亚种),隶属于7目20科80属。其中,土著鱼类112种(亚种),隶属于6目17科71属;外来鱼类13种(亚种),隶属于5目6科11属。7个多样性指数均呈显著的纵向梯度格局,上游到下游也呈增加趋势,但FEve、FDiv和Δ⁺这三个指数在河段间的增量相对较小。不同生物多样性指数之间的相关性差异较大,从不显著到显著正相关,综合使用不同层面的多样性指数能够有助于更好地理解淡水鱼类分布格局,为鱼类资源保护提供科学依据。     

夏、秋季长江口鱼类群落结构

为了解生境变动条件下长江口鱼类群落的特征,为其鱼类资源的管理提供依据,2010年5月中旬至9月在长江口进行了张网鱼类资源调查(除8月外,采样频率为1周1次)。结果显示,调查期间总共出现6种生态类群、39种鱼类,海洋洄游鱼类和河口定居性鱼类的种类数目分居1、2位,包含种类数目最多的科是鳀科(6种),其次鰕虎鱼科和石首鱼科(4种),5-9月间种类和生态类群种类数目更替均无显著性差异;5-9月间各生态类群尾数/重量均以海洋洄游鱼类占首位,5-8月间各月平均每网尾数/重量均无显著性差异,但9月除了与7月尾数无显著性差异外,尾数和重量均较各月高,生态类群尾数/重量的排序变化均有统计学差异;对棘头梅童鱼、刀鲚、凤鲚、银鲳、灰鲳、龙头鱼等6种主要经济鱼类的幼鱼数量比例进行了分析,发现不同种类的变动有差异,如棘头梅童鱼、刀鲚、龙头鱼幼鱼基本呈下降趋势,而凤鲚则为上升趋势。此外,相同属的鱼类生态位有一定的分化,银鲳和灰鲳在时间上交替出现、而刀鲚和凤鲚在不同水域产卵,这是一种减少对食物、空间竞争的策略;按鱼类群落优势种综合丰盛度法,各月优势种比例均在95%以上,而各月间优势种更替无显著性差异;Braycurtis尾数/重量相似性系数聚类分析和非度量多维标度分析在60%的水平上将群落分为组Ⅰ(5月-8月前半月)和组Ⅱ(8月后半月-9月)。此外,长江口虽仍是棘头梅童鱼、银鲳、灰鲳等重要经济鱼类的育幼场,但群落结构已有了变化,特别是中华鲟、鲥等珍稀鱼类的消失,反映了因过度捕捞、环境污染、水利工程建设等引起了长江口鱼类资源的衰退。     

Freshwater fish community structured more by dispersal limitation than by environmental heterogeneity

Abstract –  We examined the relative contribution of environmental heterogeneity and dispersal limitation on freshwater fish community composition in 18 Greek protected lakes and reservoirs. Environmental heterogeneity was measured by spatial pattern metrics (calculated by digital map processing, e.g., patch richness density, area-weighted mean patch area), altitude, maximum lake depth and trophic status. Dispersal limitation was measured by straight-line distances among lake centres. Ecosystems were clustered according to species composition. We examined the correlation of similarity in species composition among ecosystems with that of environmental heterogeneity and with straight-line distances, for the entire dataset, as well as for the occurring clusters. Fish species richness increased with ecosystem area and decreased with altitude. The clusters identified (aquatic ecosystems of Northern vs. ecosystems of Western Greece), implied an underlying biogeographical pattern as defined, with Pindus range acting as a natural barrier. Between ecosystems similarity, based on fish species composition, showed a weak to insignificant correlation with environmental heterogeneity, but was significantly correlated to dispersal limitation for the entire dataset as well as within each occurring cluster. Thus, natural barriers, species biogeography and dispersal limitation played a more significant role in shaping freshwater fish communities than environmental heterogeneity.     

大型河流中鱼类组成的eDNA监测效率:以长江武汉江段为例

为了探讨大型河流中的 eDNA 监测效率, 以长江为大型河流的代表, 以鱼类为水生生物的代表, 分析传统捕捞监测和 eDNA 监测结果的差异, 研究 eDNA 监测技术对长江武汉江段鱼类组成的监测能力、监测效率、平行样设置等问题。结果显示: (1) 用 1 对 eDNA 宏条形码引物(mlCOIintF/jgHCO2198R)共监测到 89 种鱼类, 其中 30 种可与历史捕捞调查记录互相确认, 另外 59 种需要更完善的条形码数据库来解决序列比对注释问题; (2) 9 月在武汉监测断面, 可用单引物(mlCOIintF/jgHCO2198R) eDNA 监测到的物种最优估计约 99 种, 单样品 eDNA 监测的鱼类物种检出能力约为 26 种, 检出效率约为 25.8%; (3) 在 80%的检出度目标下, 需要约 10 个平行样, 在 95%的检出度目标下, 需要约 17 个平行样。本研究在长江武汉江段鱼类 eDNA 监测效率和平行样设置的相关量化结果可为长江其他断面及其他大型河流的 eDNA 监测提供量化参考。同时, 本研究表明, 更完善的 DNA 宏条形码数据库和合适的平行样设置是未来 eDNA 监测作为常规监测手段进行运用的前提。     

Exotic species,fisheries and conservation of freshwater biodiversity in tropical Asia: the case of the Sepik River,Papua New Guinea

1. Development of effective conservation strategies for freshwater biodiversity must take account of the trade‐off between species preservation and human use of ecosystem goods and services. The latter cannot be prevented, and attempts to manage ecosystems that focus solely on maximizing biodiversity will fail. 2. A compromise position of management for ecosystem functioning and human livelihoods — rather than preservation of every species — will provide a better basis for biodiversity conservation. This has implications for the management of exotic species. 3. There are some situations, in lentic habitats in Sri Lanka, for example, where the establishment of exotics has increased fishery yields without apparent detriment to native biodiversity. The Sepik River in Papua New Guinea provides another illustration of potential compromises between human livelihoods and biodiversity conservation. 4. The Sepik supports a relatively unproductive fishery. Two fish stocking projects (in 1987–93 and 1993–97), representing a partnership between the Papua New Guinea Government and the United Nations (UNDP/FAO), led to the introduction of a suite of exotic fish into the Sepik. Species were selected on the basis of their potential to occupy niches not filled by native fish. Unfortunately, the outcomes of these introductions are poorly documented, although there is preliminary evidence both of increased human use of exotic fish as well as declines of some native species associated with the spread of exotics. 5. Better understanding of the results of the Sepik fish introductions is important, because the pressures of burgeoning human populations in most of tropical Asia make it impossible to preserve near‐pristine environments such as the Sepik. While attempts to conserve natural or near‐natural systems must remain a priority, there is a need to develop strategies for the management of damaged or degraded ecosystems, which may contain exotics, with the aim of maintaining ecosystem functioning and, if possible, maximizing the persistence of native biodiversity. Copyright © 2006 John Wiley & Sons, Ltd.     

Salinity stress response in estuarine fishes from the Murray Estuary and Coorong,South Australia

Estuaries are unstable ecosystems and can be changed by the environmental and anthropogenic impact. The Murray Estuary and Coorong were degraded by drought and low freshwater input in the last decade and therefore transformed into the largest hyper-saline lagoon in Australia. This study evaluates the physiological stress of two estuarine fish species (small-mouthed hardyhead Atherinosoma microstoma and Tamar goby Afurcagobius tamarensis) to the induced salinity change in captivity. The test fishes were collected from the Coorong and transported to the laboratory in the water from the Coorong. Each fish species was exposed to different levels of salinity, and a number of enzymes were assessed to measure the stress response of fish to salinity change. The activity of reactive oxygen species was significantly increased with the salinity change in both fish species compared with the fish in the control. Significant salinity effect on superoxide dismutase activity was observed on Tamar goby but not on small-mouthed hardyhead. Conversely, the impact of salinity on catalase activity was detected on small-mouthed hardyhead but not on Tamar goby. The study reveals that the induction of physical stress by salinity changes occurred in both Tamar goby and small-mouthed hardyhead despite the varying response of antioxidant enzymes between fish species. The study provides an insight into the understanding of physiological adaptation in estuarine fish to salinity change. The results could improve our knowledge on stress response and resilience of estuarine fish to hypo- and hyper-salinity stress.     

基于环境DNA宏条形码的鄱阳湖真核浮游植物多样性研究

浮游植物作为水生生态系统的重要组成部分，其群落和分布特征可以反映水体的环境变化和营养状态。环境DNA宏条形码技术将传统的基于领域的生态学与深入的分子方法和先进的计算工具结合在一起，这在生物多样性的研究中具有巨大的优势。本研究旨在采用环境DNA宏条形码技术对鄱阳湖浮游植物多样性的组成及空间分布进行研究。于2019年的4月采集鄱阳湖环境水样，每个样点重复3次采集。使用0.45 μm的混合纤维素滤膜对水样进行真空抽滤。用试剂盒DNeasy? Blood & Tissue Kit进行滤膜DNA的提取，使用通用引物1380F：5’-TCCCTGCCHTTTGTACACAC-3’和1510R：5’-CCTTCYGCAGGTTCACCTAC-3’针对真核浮游植物 18S rDNA 基因的 V9 区域进行PCR扩增，高通量测序并结合生物信息学技术分析鄱阳湖浮游植物的群落组成。基于环境DNA宏条形码技术鉴定到浮游植物10门24纲54目101科166属，其中绿藻门和硅藻门种类较为丰富，检测到的属明显多于传统方法检测到的。中部区域的浮游植物群落多样性和均匀度较高，且鄱阳湖浮游植物整体丰富度较高。NMDS分析阐明，中部和北部区域( p = 0.004)、南部和北部区域之间群落结构差异显著( p = 0.011)。冗余分析表明，叶绿素a (Chl-a)、pH、流速(V)对各区域的浮游植物群落影响较显著。本研究使用环境DNA宏条形码技术评估了鄱阳湖浮游植物生物多样性，证明了环境DNA宏条形码技术检测浮游植物群落结构的可行性。环境DNA宏条形码作为一种新兴的生物多样性监测手段，其可用于快速检测鄱阳湖浮游植物生物多样性及其空间分布，为鄱阳湖生物多样性监测以及生态系统健康评估提供新的技术手段。