几种淡水小型鱼类吞食粘性鱼卵的初步观察

通过在室内进行８种淡水小型鱼类吞食鱼卵的试验观察表明：小型鱼吞食鱼卵带有普遍性，吞食强度依次为宽鳍、麦穗鱼、马口鱼、虎鱼、棒花鱼、鱼旁鱼皮、银鱼句、，其中７种鱼具有昼夜摄食节律，高峰期各异，但每天皆有１６ｈ的停食期．由此可见，小型鱼类通过摄食鱼卵，对能够在湖泊水库中自然繁殖的经济鱼类及凶猛鱼类的种群具有一定调控作用，对公鱼等孵化期较长的鱼类移植效果产生不良影响     

六片式拖网在几内亚渔场的适用性

拖网渔具必须适应渔场和捕捞对象的特征，这对提高渔获效果是十分重要的。本文对几内亚渔场所使用的48．78×56．64m六片式拖网的规格和主要性能参数作了具体分析，并对网衣配置、装配工艺和几个部位的工艺性处理作了详细的说明。通过生产实践和与其它几种网型的比较，证明了该种类型的拖网的优越性，以期对今后的渔业生产有所帮助。     

鱼类脲酶比活力研究

通过对鲤、团头鲂、鲫、草鱼、乌鳢、革胡子鲶、黄鳝、鲢和鳙9种食性不同的鱼的脲酶比活力进行比较，结果显示：食性与脲酶比活力存在一定的相关性。草食性与滤食性的草鱼和鲢、鳙脲酶比活力明显高于其他几种鱼，肉食性与杂食性鱼脲酶比活力明显要低。9种鱼脲酶主要分布在前肠和中肠，后肠脲酶比活力很低，与前、中肠相比存在显著差异。     

中国鲤科鱼类分类专家系统的研究

采用ＴｕｒｂｏＰＲＯＬＯＧ语言,研究并设计出中国鲤科鱼类的分类专家系统,并完成了该系统中知识库的表达及推理机的设计工作。     

珠江口浅海8种经济鱼类的食性研究

[目的]了解珠江口浅海主要经济鱼类资源增殖的生态背景,为开展南海近海海洋生物资源养护工作提供技术支撑.[方法]基于2011~2014年珠江口浅海的调查资料,对鳓鱼(Itisha elongata)、银鲳(Pampus argenteus)、乌鲳(Fornio niger)、斑点马鲛(Scomberomorus guttatus)、线纹舌鳎(Cynoglossus lineolatus)、宽体舌鳎(Cynoglossus robustus)、半滑舌鳎(Cynoglossus semilaevis)、三线舌鳎(Cynoglossustrigrammus)8种经济鱼类样品的食物关系、营养级、食性类型的季节性差异和营养结构变化进行分析.[结果]珠江口浅海8种经济鱼类可分为3种食性类型:以浮游生物为主,兼食底栖生物和小型游泳动物的食性类型有鳓鱼、银鲳和乌鲳;以底栖生物为主,兼食浮游生物和小型游泳动物的食性类型有线纹舌鳎、宽体舌鳎、三线舌鳎和半滑舌鳎;以小型游泳动物为主,兼食底栖生物和浮游生物的食性类型有斑点马鲛.在营养级方面,珠江口浅海8种经济鱼类按食性可归属于3个营养级:杂食性鱼类属于第二营养级(鳓鱼),低级肉食性鱼类和中级肉食性鱼类属于第三营养级(银鲳、乌鲳、线纹舌鳎、宽体舌鳎、半滑舌鳎和三线舌鳎),高级肉食性鱼类属于第四营养级(斑点马鲛).[结论]桡足类、糠虾类、长尾类(细螯虾)、磷虾类和小型游泳动物(包括幼鱼)在珠江口浅海经济鱼类食物网中发挥重要作用,可以作为该海域中心渔场的生物学指标之一.     

远东拟隆头鱼的物种厘定及重新描述

远东拟隆头鱼Pseudolabrus eoethinus(Richardson,1846)曾为日本拟隆头鱼P.japonicus(Houttuyn,1782)的同物异名。由于这2种拟隆头鱼外部形态十分相似,导致其分类上的误鉴,目前部分文献中仍存在同物异名。本文对采自福建沿海的远东拟隆头鱼标本重新进行了形态描述,并与日本拟隆头鱼进行了形态学比较研究,发现两者间存在明显的形态差异。远东拟隆头鱼头部具1条自口角稍前向后经眼下缘伸达胸鳍基部的弧状纹线,侧线鳞孔纹为2次二分叉状,背鳍起点前鳞片数为8,背鳍鳍棘间无黑斑等特征,可与日本拟隆头鱼(头部纹线较为平直、后端不达胸鳍基部,侧线鳞孔纹为3次以上二分叉状,背鳍起点前鳞片数为5,背鳍第3-6鳍棘间具有1黑斑)相区别。     

四川鱼类分布的模糊聚类分析

应用模糊聚类法对四川鱼类分布进行了研究.结果表明,四川鱼类分布在λ=0.8000时,可分为8类:长江、岷江、金沙江、嘉陵江、乌江、大渡河、青衣江为一类;涪江、渠江、沱江、雅砻江、黄河、酉水、任河各为一类.当λ=0.7500时,可分为4类:黄河、酉水、任河各为一类,长江、岷江、金沙江、嘉陵江、乌江、大渡河、青衣江、涪江、渠江、沱江、雅砻江合为一类.     

Mitochondrial DNA sequence analyses in Bornean sucker fishes (Balitoridae: Teleostei: Gastromyzontinae)

Phylogenetic relationships among Bornean sucker fishes (Teleostei: Balitoridae: Gastromyzontinae) were investigated by comparing cytochrome b gene sequences from eight species. The results were in general agreement with previous morphology‐based studies. It was found that the genera Gastromyzon and Neogastromyzon are both monophyletic and that the Chinese homalopterid Crossostoma lacustre (Homalopterinae) is not related to the Bornean species. This molecular‐level study of cytochrome b gene variation in Bornean gastromyzontins will undoubtedly help to shed light on the molecular systematics of this unique freshwater fish.     

活鱼提升机电器控制电路的设计

本文介绍了真空静压活鱼提升设备中自动化电器控制的设计,叙述了实现自动控制的功能要求,电路设计,工作原理和部件的选择,并根据试验找出了产生问题的原因和解决方法。     

Using occupancy and species distribution models to assess the conservation status and habitat use of the goldline darter (Percina aurolineata) in Georgia,USA

The goldline darter (Percina aurolineata) is threatened by recent increases in urbanisation in the Coosawattee River watershed, but no studies have addressed their current status. Similarly, limited data on habitat use make it difficult to understand factors that may impact this species. We compared occurrence data before (1996–2000) and after (2009–2011) a period of rapid development and population growth within the watershed. Single‐season occupancy models were built to account for imperfect species detection and to identify habitat covariates. MaxEnt was used to identify important stream reaches for conservation and to understand landscape scale factors correlated with the distribution of goldline darters. Our results indicate a high proportion of sites occupied upstream of Carters Lake during the historic and recent time periods, with no evidence of decline. However, occurrences of goldline darters for sites in Talking Rock Creek and the lower Coosawattee River were sparse in the historic period and absent during the recent period. The probability of detecting goldline darters is low and was positively associated with the occurrence of small substrate. Species distribution models were strongly influenced by watershed area and elevation and indicated a high probability of suitable habitat within the Coosawattee River and large tributaries upstream of Carters Lake. While goldline darter occupancy is currently stable upstream of Carters Lake, continued urbanisation is a threat to long‐term persistence. We recommend additional monitoring and describe a protocol that allows for precise estimates of species occupancy while minimising the risk of sampling‐related mortality.