海南南渡江唇䱻染色体核型和银染分析

本研究以海南南渡江野生唇?(Hemibarbus labeo)为材料，采用腹腔注射植物血球凝集素(PHA)、秋水仙素，肾细胞直接制片法，分析唇?染色体核型和银染(Ag-NORs)。结果显示，唇?的二倍体染色体数目为50，核型公式为2n=18m+12sm+12st+8t，其染色体臂数(NF)为80，未发现异型染色体，Ag-NORs出现在第5对和第11对同源染色体的短臂末端。鮈亚科鱼类染色体进化综合分析结果表明，唇?具有鮈亚科鱼类的原始核型。本研究不仅补充了唇?的细胞遗传学数据，为研究鮈亚科/?属鱼类的分类与进化提供了数据资料，也为唇?的种质资源保护、种质改良等工作奠定了理论基础。     

Habitat of pike gudgeon Pseudogobio esocinus esocinus in Nakagawa River, northern Kyushu, Japan

ABSTRACT:   Habitat selection of the pike gudgeon Pseudogobio esocinus esocinus (Cyprinidae) was examined in the Nakagawa River in northern Kyushu, Japan. The study area was 80 m long with two meanders comprising three riffles and two pools, located 20 km upstream from the river mouth. The pike gudgeon were visually counted underwater. Larvae and juveniles were observed in the shallow and slow-flowing water near the shores. Simultaneously, young and adult individuals were observed to inhabit the river bed. Principal component analysis and cluster analysis were applied to estimate the microhabitat selections of the larvae, juveniles and other individuals by using four variables (water depth, current velocity, particle size of substrate and amount of organic matter). The larvae and juveniles inhabited the shallow (<30 cm) and slow-flowing waters (<6.5 cm/s) near the shore; habitat selection was independent of particle size of the substrate and the amount of organic matter present. Young and adult individuals inhabited the river bed independent of the four variables.     

长江近口段沿岸亚科鱼类的数量动态及其影响因子

为了解长江近口段沿岸水域中■亚科(Gobioninae)鱼类的数量动态及其影响因子,于2003—2017年在靖江段沿岸设置一顶定置张网,每月定期收集2～3份渔获样本,对■亚科鱼类的丰度动态与环境因子的相关性进行分析。结果显示,15年共采集渔获样本499份,其中,■亚科鱼类有23 668尾、65.6 kg,隶属于9属19种。■亚科均占鱼类总种数和总个体数的14.6%,是这一水域占优势的鱼类类群之一。■亚科的平均体质量仅为2.8 g,幼体为主。相对重要性指数(Relative Importance Index,IRI)分析表明,麦穗鱼(Pseudorasbora parva)、棒花鱼(Abbotina rivularis)、银■(Squalidus argentatus)、光唇蛇■(Saurogobio gymnocheilus)是这一水域的常见种,亮银■(Squalidus nitens)、长蛇■(Saurogobio dunerili)、蛇■(Saurogobio dabryi)为一般种。但■亚科占总渔获数量的比例在不同年份间波动很大,占比最高的年份是占比最低年份的7倍。CCA排序分析显示,气压和温度是影响■亚科物种丰度的重要因素。水温越高、气压越低,则种组Ⅰ的5个物种出现数量越多,而种组Ⅱ的2个物种出现数量越少。Spearman分析显示,■亚科的数量丰度与气压呈显著的负相关性(P=0.046 10.05)。与浊度的相关性也十分明显,当浊度小于100 NTU时,■亚科的数量丰度与浑浊度呈极显著的负相关性(P=0.009 20.01)。研究表明,靖江沿岸水域是■亚科幼体的重要栖息地,多个环境因子的变动均会对其种类和数量产生影响。     

海南南渡江唇染色体核型和银染分析

本研究以海南南渡江野生唇(Hemibarbus labeo)为材料,采用腹腔注射植物血球凝集素(PHA)、秋水仙素,肾细胞直接制片法,分析唇染色体核型和银染(Ag-NORs)。结果显示,唇的二倍体染色体数目为50,核型公式为2n=18m+12sm+12st+8t,其染色体臂数(NF)为80,未发现异型染色体,Ag-NORs出现在第5对和第11对同源染色体的短臂末端。亚科鱼类染色体进化综合分析结果表明,唇具有亚科鱼类的原始核型。本研究不仅补充了唇的细胞遗传学数据,为研究亚科/属鱼类的分类与进化提供了数据资料,也为唇的种质资源保护、种质改良等工作奠定了理论基础。