上海大莲湖鱼类群落组成及生物多样性

于2009年4月11—19日、4月27—5月8日和5月20—29日3个时间段对大莲湖的鱼类群落特征及其多样性组成进行了调查,共收集鱼类样本24061尾,隶属11科17属22种。群落优势种为鲫(Carassius auratus),占样本个体总数的76.38%;Shannon-Wiener多样性指数(H′)为1.0027,Simpson优势度指数(λ)为0.5959,Pielous均匀度指数(J′)为0.3244,Margalef种类丰富度指标(D)为2.0816,相对稀有种数(R)为90.91%;鱼类群落可分为3个生态类型:江海洄游性鱼类有3种、河湖洄游性鱼类1种和定居性鱼类18种。鱼类食性可分为5种类型:食鱼性鱼类9种、食无脊椎动物性鱼类2种、杂食性鱼类7种、食浮游生物性鱼类有3种和草食性鱼类1种。研究结果表明:大莲湖鱼类群落的多样性指标处于较低水平,稳定性较低;相对于黄埔江下游地区,大莲湖的食鱼性鱼类比例较高,说明位于黄浦江上游的大莲湖之水质好于下游流域。为保护和持续利用大莲湖鱼类资源,应加强监管和对生态环境的保护。     

湖南壶瓶山国家级自然保护区山溪鱼类多样性调查与分析

2007年8月～2008年9月,作者对湖南壶瓶山国家级自然保护区山溪鱼类的物种多样性进行了调查和统计分析。共采集鱼类标本3 420尾,经分类鉴定为39种,隶属于4目11科15亚科35属。其中,草食性鱼类5种,肉食性鱼类18种,杂食性鱼类16种;四川爬岩鳅(Beaufortia szechuanensis)、鳗尾(Liobagrus anguillicauda)为湖南省鱼类新纪录。鱼类多样性指数(H′)为2.612,丰富度指数(D)为3.461,均匀度指数(J)为0.706。该区鱼类以适应山溪急流生活的21种土著鱼类为主体,占本次调查鱼类总物种数的51.2%。尖头(Phoxinus oxycephalus)和粗须白甲鱼(Onychostoma barbata)为保护区鱼类群落的优势种,相对多度指数分别为23.6%和23.4%。     

马鞍列岛多种生境中鱼类群聚的昼夜变化

为了解岛礁水域鱼类群聚的昼夜变化特征,以便更全面地设计采样方法和掌握采样的时间尺度,于2009年9月对马鞍列岛7种生境进行了共计24网次的刺网昼夜采样,结合排序和聚类方法,从种类组成、相对生物量和丰度、种类丰富度、多样性和相似性等方面对研究海域鱼类群聚特征的昼夜变化作了探讨.在采获的55种鱼类中,昼夜出现的分别为41和46种,数量差别不大,但其昼夜组成却随栖息水层的变化而不同,底层鱼类更趋向于夜间在硬相生境集群活动;近底层鱼类的昼夜集群随生境变化而变化,在同一生境中既有偏向白天也有趋向夜间的;中上层鱼类更多地出现在白天的人工生境(AH).AH白天的丰度渔获率显著大于晚上,而天然生境(NH)昼夜差别不大;生物量渔获率无论NH还是AH皆无显著昼夜差异.具体到种类,仅有小黄鱼Larimichthys polyactis和赤鼻棱鳗Thryssa kammalensis等少数种类的数量在AH有显著的昼夜差别,其他多数种类虽然昼夜的出现率大多有别,但渔获率昼夜差异皆不明显.多样性差异更多的表现在不同生境之间,而同一生境的昼夜差异往往不甚显著.各个生境中鱼类的昼夜种类交替现象非常明显,形成了以褐菖(鲐)Sebastiscus marmoratus和鳗鲇Plotosus anguillaris为代表的夜间优势类群为主的硬相生境群聚格局、以丝背细鳞鲀Stephanolepis cirrhifer和细刺鱼Microcanthus strigatus为代表的白天优势类群为主的硬相生境群聚格局以及缺乏底层优势类群、以石首鱼科鱼类为代表的近底层鱼类为绝对优势类群的软相生境群聚格局.因此,采用被动性渔具在近岸典型生境进行鱼类等相关生物调查时,应使采样时间覆盖昼夜两个时段,且至少保证24h.     

陕西化龙山国家自然保护区鱼类多样性分析

2011~2012年,对化龙山国家级自然保护区内南江河、岚河干支流的鱼类资源进行了考察,共捕获鱼类1 196尾,鉴定出鱼类27种,分属4目9科23属。鲤科鱼类12种;鳅科6种,分别占种数的44.44%和22.22%。并利用Simpson多样性指数(D)、Shannon-wiener多样性指数(H')、Brillouin指数(H)、均匀度指数(J')和Mclntosh指数(DMC)五种分析方法,对本保护区鱼类多样性进行了分析,得出鲤科为本保护区内优势群,其次为鳅科,且干流内鱼类资源的种类和数量、生物多样性情况均高于支流。     

中间眼

适应于不同的生活条件,在演化发展中,动物界有各种各样的感光器官。现存脊椎动物一般具有一对侧生眼。在七鳃鳗、硬鳞鱼类(ganoid fishes)、少数真骨鱼类(特别是幼体)、无尾类幼体、某些无尾类成体、喙头蜥(sphenodon)和某些蜥蜴类等,除侧生眼外还具有机能的第三眼,这种眼位于头顶正中线上,所以叫中间眼(median eyes)。     

长江口鳗苗生产量及影响因子的分析

鳗苗即鳗鲡(亦称河鳗,白鳝)的幼体,每年2月中下旬始见于上海长江口,5月中下旬结束,苗汛期约70—90天。鳗鲡是一种降海性(catadromous)洄游鱼类,分布于我国的这种河鳗为日本鳗鲡(Angailla japonica)。每年秋季(9—11月)在内陆水域肥育接近性成熟的亲鳗,纷纷集群,通过咸淡水交汇处,随水流游向深海产卵。受精卵经孵化,随海潮飘流约1年后,体重逐渐长到约0.15g,体长约50—70mm 的透明棒状体,春天由河口溯上陆地河川。白色透明的鳗苗(亦称玻璃鳗)不久转黑。约经4—5     

据于矢耳石Sr/Ca值的长江日本鳗鲡迁移格局多样性分析(英文)

长江口是中国日本鳗鳗苗的主要产区和仅存的成鳗渔业水域。日本鳗自长江河口至上游金沙江近3000km干流及许多支流中都有分布,但其迁移行为却不为人了解。该文分析了2008年9～11月采自长江靖江段(31o30′N,120o42′E)的153尾银色鳗样本的生物学特征,测定了其中27尾标本的矢耳石Sr/Ca值。结果显示,153尾样本中有雌性85尾、雄性68尾,雌雄性比1:0.8。雌性由3～7(平均5.52)龄组成,平均体长(669±80)mm,体重(555±229)g,丰满度1.77±0.22,性腺指数(GSI)1.32±0.31。雄性由3～5(平均4.38)龄组成,平均体长(518±51)mm,体重(234±76)g,丰满度1.62±0.18,GSI0.21±0.11。雌性的这些生物学参数均显著大于雄性(P<0.05)。依据矢耳石线鳗标志轮平均Sr/Ca值(7.99±1.05)×10-3进行判断,有17尾(即62.96%个体)为"淡水型",10尾(即37.04%个体)为"河口型"。16尾雌性中有13尾(即81.25%)为"淡水型",3尾为"河口型"。11尾雄性中仅36.36%为"淡水型",63.64%为"河口型"。对每个生长层组的Sr/Ca值分析表明,雌雄间2龄时无显著差异,但3龄、4龄和洄游龄组都有显著或极显著的差异,预示着2龄时两者的栖息水域比较一致,但后来出现了明显栖息地分化。     

崂山湾人工鱼礁区星康吉鳗摄食生态及食物网结构

根据2015年4月至2017年1月于崂山湾人工鱼礁区地笼网和延绳钓捕获的279尾星康吉鳗样本,从胃含物组成、食性类型、摄食等级、营养生态位和营养级等方面对其摄食生态进行研究,同时结合海区许氏平鲉、大泷六线鱼、斑头鱼、褐菖鲉、花鲈等9种鱼类的胃含物分析结果,构建人工鱼礁区鱼类关键种的简化食物网模型.食性研究结果表明:星康吉鳗共摄食7类30余种饵料,虾类是其最主要的饵料类群,其次为鱼类和头足类,大泷六线鱼、方氏云鳚、鹰爪虾、玉筋鱼和日本鼓虾等是其优势饵料.星康吉鳗的饵料生物组成随肛长和季节发生显著变化.四季均以鱼类和虾类为主,春季胃含物中包括头足类,秋季包括头足类和蟹类,冬季亦有蟹类出现.肛长≤120 mm的星康吉鳗主要摄食鱼卵和鹰爪虾,120~130 mm肛长组主要摄食玉筋鱼和日本鼓虾,肛长>130 mm的星康吉鳗主要摄食大泷六线鱼和方氏云鳚.其摄食强度也随季节和肛长而变化,空胃率的季节性差异显著,平均胃饱满系数的季节性差异不显著,不同肛长组的空胃率和平均胃饱满系数均不存在显著差异.人工鱼礁区简化食物网结构显示:鱼类关键种的营养级均在3级以上,星康吉鳗的营养级为4.636,处于海区食物网的最顶端.虾类、蟹类、端足类和软体动物等是鱼类关键种的主要饵料,甲壳类、方氏云鳚、大泷六线鱼和玉筋鱼是高营养级鱼类花鲈和星康吉鳗的主要饵料.     

长江河口潮间带鱼类群落的时空变化

根据2006年3-11月每月在长江口4个潮间带站点的36网次鱼类采样数据,分析了该水域鱼类群落组成的时空变化特征.结果表明：本次调查采获鱼类55种,隶属20科,其中,鲤科鱼类最多,有18种,占总种数的32.7%,虾虎鱼科其次,有8种,占14.5%,石首鱼科4种,占7.3%;调查水域潮间带鱼类群落可分为口内淡水区鱼类群落和河口咸淡水区鱼类群落2组,河口咸淡水区鱼类的物种多样性比口内淡水区略低,其中,口内淡水区以油似鳊和鳊等淡水鱼类为优势种,河口咸水区以斑尾刺虾虎鱼、鲻和棘头梅童等咸淡水鱼类为优势种;二组间鱼类种类组成的平均相异性为80.75%,23种鱼类对平均相异性的累积贡献率>90%,主要贡献来自油鲻、斑尾刺虾虎鱼、棘头梅童鱼、似鳊、红狼牙虾虎鱼、鲫、鳊和长蛇鮈等;春季的研究区鱼类群落丰度与夏、秋两季均存在一定程度的差异,而夏、秋两季间的差异相对较小.就单组鱼类群落丰度而言,水温对其季节变化的影响较盐度大,而盐度对整个河口鱼类群落的影响较水温大.     

大陈岛礁海域鱼类群落结构特征

基于2020年9月、2020年11月、2021年1月、2021年4月连续4个季度的大陈岛礁海域21个底拖网站位的鱼类样本,对局地尺度下大陈岛礁海域鱼类群落的时空格局进行了分析。结果表明：4个季度共采集鱼类99种,隶属15目48科81属,其中鲈形目占比最大(50.51%);优势鱼类中,龙头鱼(Harpadon nehereus)为全年优势种,六丝钝尾虾虎鱼(Amblychaeturichthys hexanema)是除夏季外其他季节的优势种,镰鲳(Pampus echinogaster)是夏秋季的优势种,而大头银姑鱼(Pennahia macrocephalus)、小黄鱼(Larimichthys polyactis)、灰海鳗(Muraenesox cinereus)和大黄鱼(Larimichthys crocea)等仅在单一季节成为优势种;聚类和排序分析显示,大陈岛礁海域的夏、秋和冬3季鱼类群落可明显分为岛礁近河口群落和开阔海域群落2种类型,而春季鱼类群落则可分为岛礁群落和非岛礁群落2类,且群落种类组成在各季节不同区域间均存在显著差异(P<0.05);冗余分析表明,深度、表层温度...     

基于鳗鱼道诱鱼技术研究花鳗鲡幼鱼光色趋向性

为保护我国花鳗鲡资源,提高鳗鱼道入口吸引力,本研究以3 W水下景观灯为光源,利用自制多功能圆池设计了3种试验工况,探索花鳗鲡幼鱼的光色趋向性.结果表明: 3种试验工况下,鱼类在光区与暗区单位面积出现比例分别为(8.7±0.3)%和(3.6±1.7)%、(8.4±0.2)%和(5.0±1.4)%、(9.0±0.2)%和(1.9±1.3)%,且分布在光区的幼鱼多处于玻璃鳗发育阶段,而暗区的幼鱼多处于线鳗阶段(或向线鳗发育).光色区中鱼类出现次数百分比排在前3的分别为黄光区[(29.4±4.9)%]、红光区[(24.1±3.9)%]和紫光区[(17.2±4.0)%];黄光区[(29.4±3.3)%]、紫光区[(25.2±3.7)%]和红光区[(18.2±2.9)%];红光区[(33.3±2.3)%]、紫光区[(25.6±3.8)%]和黄光区[(20.7±5.7)%].首先进入光区次数排在前3的分别为红、黄、紫光区;红、紫、黄光区;红、紫、黄光区.鱼类在上述3种光区中的总进出次数处于蓝绿光和五彩光之间,且红光和黄光下鱼类会出现视觉疲劳.花鳗鲡幼鱼对光的趋向性由其发育阶段决定,玻璃鳗对光色具有趋向性,尤喜爱红、黄和紫光,在鳗鱼道入口采用灯光诱鱼可帮助玻璃鳗找到生长洄游通道.     

American eels produce and release bile acid profiles that vary across life stage

The American eel (Anguilla rostrata) is an imperilled fish hypothesized to use conspecific cues, in part, to coordinate long-distance migration during their multistage life history. Here, holding water and tissue from multiple American eel life stages was collected and analysed for the presence, profile and concentration of bile acids. Distinct bile acid profiles were identified in glass, elver, yellow eel and silver eel holding waters using ultraperformance liquid chromatography high-resolution mass spectrometry and principal component analysis. Taurochenodeoxycholic acid, taurodeoxycholic acid, cholic acid, deoxycholic acid, taurolithocholic acid and taurocholic acid were detected in whole tissue of American glass eels and elvers, and in liver, intestine and gallbladder samples of late-stage yellow eels. Bile acids were not a major component of silver eel washings or tissue. This study is novel because little was previously known about bile acids produced and emitted into the environment by American eels. Future behavioural studies could evaluate whether any bile acids produced by American eels influence conspecific migratory behaviour.     

Donor life stage influences juvenile American eel Anguilla rostrata attraction to conspecific chemical cues

The present study investigated the potential role of conspecific chemical cues in inland juvenile American eel Anguilla rostrata migrations by assessing glass eel and 1 year old elver affinities to elver washings, and elver affinity to adult yellow eel washings. In two‐choice maze assays, glass eels were attracted to elver washings, but elvers were neither attracted to nor repulsed by multiple concentrations of elver washings or to yellow eel washings. These results suggest that A. rostrata responses to chemical cues may be life‐stage dependent and that glass eels moving inland may use the odour of the previous year class as information to guide migration. The role of chemical cues and olfaction in eel migrations warrants further investigation as a potential restoration tool.     

长江中游宜昌江段鱼类早期资源现状及水文影响条件

为了解长江中游鱼类的早期资源现状, 2017年和2018年5—7月在长江干流宜都断面开展鱼类早期资源调查, 采样网具包括弶网和圆锥网。调查期间共采集鱼卵21120粒和仔鱼2123尾。利用形态学和分子生物学等方法, 鉴定鱼类5目9科37种。其中, 鱼卵有29种, 仔鱼有27种。2017年和2018年通过宜都断面的鱼卵径流量分别为124.45×108粒和101.07×108粒, 优势种为四大家鱼和贝氏?(Hemiculter bleekeri); 仔鱼径流量分别为16.43×108尾和8.29×108尾, 优势种为贝氏?和寡鳞飘鱼(Pseudolanbuca engraulis)。根据发育期和流速分析, 四大家鱼鱼卵来源于三峡大坝下游至宜都断面之间的产卵场, 仔鱼来源于三峡大坝以上的产卵场。与2009—2010年相比, 2017—2018年通过宜都断面的鱼卵径流量增大了85.3%, 尤其是四大家鱼的鱼卵径流量与2005—2012年相比增加了约13倍。冗余分析(Redundancy Analysis, RDA)结果显示, 流量和流量日变化对产漂流性鱼卵密度有影响。研究结果表明, 2017—2018年仍有大量的鱼卵和仔鱼补充到长江中游江段。与历史数据相比, 三峡大坝下游宜昌江段鱼类产卵规模有明显的增加, 可能与长江中游四大家鱼亲鱼增殖放流和生态调度等保护措施的实施有关。为了更加有效地保护长江中游的鱼类资源, 建议除了已经逐步实施的长江全面禁渔措施之外, 还应恢复江湖连通, 保护和修复长江中游河漫滩生境, 继续开展重要经济鱼类亲本放流, 以及开展生态调度。     

Impact of glass eel fishery on by-catch fish species: a quantitative assessment

The present study evaluated the effect of the glass eel fishery on by-catch ichthyofauna in the Ebro River delta by investigating the primary responsible factors of discard mortality, in order to assess the adequacy of fishing and sorting procedures, and assess the ecological impact of this traditional activity. Results revealed that glass eel fishery had a negative impact on by-catch ichthyofauna mainly composed of mugilid fry and small-size estuarine species. Data showed that between 10 and 69% of incidental species died as a consequence of glass eel capture and sorting procedures. Differences in by-catch fish mortality rates depended on the glass eel sorting time, the total weight of catch, the discard ratio, by-catch fish size, and by-catch fish species composition. The total weight of the catch and the discard ratio were two of the main parameters affecting discarded fish mortality, since both had a direct effect on the period of time required for glass eel sorting during which by-catch fish were exposed to air and suffered from very aggressive sorting procedures that caused severe external and internal injuries. By-catch fish measuring less than 40 mm L _T were more susceptible to glass eel fishery procedures than those larger (>60 mm L _T), independent of the species considered or their stage of development. This fishery, similar to other ones, should strive to minimization the amount of discards and the mortality of discarded fish, by improving the selectivity of the fish trap and developing new sorting and selection procedures. E. Gisbert and M. A. López have contributed equally to this study. Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot Fish and diadromy in Europe (ecology, management, conservation)     

Factors that influence cover selection by Japanese eels at elver stage

Adult eels are known to prefer narrow spaces for cover but factors influencing cover selection at the elver stage are unclear. I examined factors likely to be important in cover selection by elvers of the Japanese eel (Anguilla japonica). Pipes with a range of diameters, lengths, internal illumination (brightness), and direction of flow were provided for elvers in small-, medium- and large-sized classes. All sizes chose pipes without preference for diameter. Medium and large elvers preferred longer pipes. All size classes selected darker environments for pipes with similar dimensions. Medium to large elvers chose pipes without preference for orientation to the current up to flow speeds at which they were unable to stay in the pipe. The proportion of small elvers that remained in the pipes was lower than that of medium and large elvers.     

Nutritional condition of Anguilla anguilla starved at various salinities during the elver phase

The effects of food deprivation and environmental salinity (<1, 10 and 20) on survival, fish morphology, organization of the digestive system and body lipid reserves in European eel Anguilla anguilla during the transition from glass eel to elver, were evaluated. Fasted elvers kept in fresh water were able to withstand starvation for >60 days, while those in brackish environments (salinity 10 and 20) reached the level of irreversible starvation at 37 and 35 days, respectively. The high level of lipid reserves contained in liver inclusions and the abdominal cavity (perivisceral deposits) in elvers might explain their long resistance to starvation and differences in fasting tolerance under different salinities. Fasting resulted in a significant reduction of the elvers' condition factor and body depth. There were severe histopathological changes in the digestive system and musculature, such as the alteration of the liver organization, and hepatic glycogen and lipid content, shrinkage of enterocytes and reduction of their height, pancreas degeneration, autolysis of the oesophageal and intestinal mucosa and disarrangement of myofibrils and degeneration of trunk musculature. Degeneration of the oesophageal and intestinal mucosa as a consequence of fasting might have impaired digestive and osmoregulatory functions in feed‐deprived fish, directly affecting the tolerance to starvation and survival. Length of food deprivation was associated with a significant increase in mortality, coefficient of variation, cannibalism and point of no return at high salinities. Mortality was dependent on food deprivation and salinity concentrations. Environmental salinity directly influenced the ability of elvers to withstand starvation; once glass eels metamorphosed into elvers, they tolerated starvation better in fresh water than in brackish environments.     

Relationships between locomotor behavior, morphometric characters and thyroid hormone levels give evidence of stage-dependent mechanisms in European eel upstream migration

In order to decipher movements during freshwater eel colonization, we experimentally characterized individual locomotor behavior of two eel life history stages: elvers and yellow eels. A ramp located at the flume tank upstream side required a specific locomotor behavior to be ascended. Placing individually tagged eels in the middle of the tank three times successively tested behavioral consistency. Eels climbing the ramp on each trial were classified as "upstream climbers" whereas eels settling in the tank middle were classified as "inactive". Both stages exhibited these two opposite consistent behaviors. However, elvers were predominantly "upstream climbers" (58.1%) whereas yellow eels were predominantly "inactive" (79.6%). We measured morphometric characters and thyroid hormones to determine if upstream activity was related to body condition and thyroid status. Elver upstream climbers had higher body condition as well as higher thyroxine (T(4)) and triiodothyronine (T(3)) levels compared with inactive elvers. Yellow eel upstream climbers had lower body length as well as higher T(3) and (T(3):T(4)) ratio compared with inactive yellow eels. This indicated that the physiological release factors for eel upstream migration may be stage dependent. For elvers, high thyroid gland activity, together with high body condition, may be the physiological release factors for migration. In contrast, for yellow eels, physiological stress may be the release factor with an increase in T(4) deiodination activity in the smallest eels. Our study revealed inter-stage and intra-stage locomotor behavior plasticity and suggested stage-dependent opposite impacts of physiological condition on eel upstream migration.     

Distribution and abundance of fish eggs and larvae in three tributaries of the Upper Uruguay River (Brazil)

The present study aimed to investigate the distribution and abundance of fish eggs and larvae in three important tributaries (Chapecó, Peixe, and Ligeiro rivers) of the Upper Uruguay River. The spatial and temporal distribution of fish eggs and larvae were studied as well as the correlation between environmental parameters and the abundance of ichthyoplankton species. The study was conducted between October 2005 and September 2006. Ichthyoplankton samples were collected at night with cylindroconical 0.5-mm mesh plankton nets every 5 days. Of the 591 samples collected, 170 contained ichthyoplankton organisms, resulting in the capture of 12,847 fish eggs and 962 fish larvae. Twenty-seven fish species were observed, of which 69% were Characiforms and 27% were Siluriforms. Among the fish species captured, the representatives were predominantly young forms of small and medium size fishes, with rheophilic species occurring infrequently. Eggs occurred exclusively between October and January, while the highest larvae occurrence was observed between November and December. Fish larvae assemblage structure was shown to be related to some environmental variables. There was a tendency of higher values of water temperature and velocity at the lower sampling sites than at the upper ones, as well an increase number of eggs and larvae. The study tributaries serve as reproduction sites and nursery areas for several fish species of the Upper Uruguay River; thus, the maintenance of their integrity is important for the preservation of diversity and enhancement of fisheries in the region.     

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。