Active metabolism in larval and juvenile fish: ontogenetic changes,effect of water temperature and fasting

Oxygen consumption, ammonia excretion and fish swimming speed were measured in fish induced to swim by optomotor reaction in a circular metabolism chamber. The relationship between the swimming speed and fish metabolism described by exponential equations allowed the extrapolation to the standard metabolism, i.e. at zero swimming speed. The partitioning of the catabolised protein in the energy supply was estimated based on AQ (volume of ammonia/ volume of oxygen) values. Weight specific standard metabolism, as expressed by the ammonia excretion rate, decreased by one order of magnitude in coregonids as the fish grew from 20 to 780 mg body weight. The slope of the relationship between oxygen uptake and swimming speed decreased in coregonid ontogenesis. In salmon, after 12 days of fasting 28% of energy used was derived from protein, whilst coregonid juveniles utilized mostly lipid. Active swimming in fasted juveniles of coregonid, as well as in salmon, led to the accelerated utilization of protein as a source of energy, based on AQ coefficients. In juveniles acclimated to a range of water temperatures from 14 to 26°C, the changes in standard or active metabolic rate (expressed as oxygen uptake or ammonia excretion) were described by Q₁₀ coefficients. They were generally higher for the ammonia excretion rate than for the oxygen uptake rate and for active metabolism than for standard metabolism. Utilization of protein as energy for swimming differed significantly between the species, being in general one order of magnitude higher in coregonids than in salmon. The use of protein for swimming activity tended to decrease during coregonid ontogenesis.     

通过小型探鱼无人船探测大型围网养殖区大黄鱼的分布特性

为了明确大黄鱼在大型围网养殖区内的分布规律,本实验通过集成、构建具备大黄鱼探测以及水温、盐度、光照、pH、溶解氧等海洋环境探测功能的小型探鱼无人船,并在浙江省舟山市桃花岛大黄鱼围网养殖基地内开展了6次现场监测试验。实验结果表明,①在水平分布方面,大黄鱼主要分布在大型围网养殖区内礁石丰富且水流相对较缓的区域;②在垂直分布方面,大黄鱼主要分布在加权相对深度0.6~0.9的养殖海区中下层;③围网养殖海区内温度、盐度、pH、溶解氧等海洋环境条件整体变化较小（p>0.05）,大黄鱼往往分布在光照强度分别为5921±2702lx、50799±50988x、5990±542lx、3494±695lx、6836±4761lx、15395±5531lx相对较弱的区域。本实验首次通过小型探鱼无人船系统地研究了围网养殖区内大黄鱼的分布特性及相应的海洋环境对其分布的影响,结果为大黄鱼围网养殖区的操作平台选址、投喂管理、起网设计等提供了依据。     

硬骨鱼类黄色素细胞的研究进展

色素细胞是动物体内产生色素的一类特化细胞,其色素颗粒可选择性吸收或反射特定波长的光产生多种颜色,从而形成动物的体色。色素细胞由胚胎神经嵴细胞分化形成,在动物警戒求偶、伪装、拟态、隐蔽以及环境适应性等一系列生物学过程中起着关键作用。黄色素细胞是仅次于黑色素细胞最受关注的研究对象。黄色素细胞合成含有类胡萝卜素和蝶啶成分的红/黄色素小体,可以形成从白色到红色等一系列的颜色,是研究色素细胞互作、色素沉着以及生物进化机制的理想模型。本综述介绍了鱼类色素细胞的来源和分布、黄色素细胞的发育和分化以及蝶啶色素合成代谢机制三个方向,并提出了现阶段黄色素细胞研究中存在的缺陷,为鱼类体色形成、色素细胞分化及体色性状分子选育提供参考依据。     

基于水声学方法的嘉陵江中游蓬安段鱼类资源研究

研究嘉陵江中游鱼类资源时空动态特征,了解变化过程及影响因素,提出嘉陵江鱼类资源保护的建议和措施,同时为长江上游及其支流的鱼类资源保护提供基础数据。运用Biosonics DT-X分裂波束科学回声探测仪于2018年7月（夏）、10月（秋）以及2019年1月（冬）、4月（春）对嘉陵江中游蓬安段金溪航电工程干流江段进行了水声学探测,并辅以常规渔获物调查。共采集到鱼类6科38种,其中蛇鮈、鲫、银飘鱼、黄尾鲴等中小型鱼类在数量上占优;鱼类密度分别为春季（0.8296±0.43）、夏季（0.8705±0.38 ）、秋季（0.5082±0.25）、冬季（0.3939±0.13）尾/m3;鱼体平均目标强度分别为春季（-63.15±5.03）、夏季（-52.85±14.45）、秋季（-46.42±15.85）、冬季（-44.77±15.28 ）dB;鱼体平均重量分别为春季0.03、夏季1.08 、秋季11.19 、冬季20.40 g/尾;鱼类资源量分别为春季0.4096、夏季0.2907 、秋季0.3919 、冬季0.5622 kg/m3;坝下鱼类密度显著高于坝上（F=12.67,P<0.05）;坝上（F=7.02,P<0.05）和坝下（F=19.99,P<0.05）3个水层之间的鱼类密度差异显著,中层鱼类密度显著高于上层和下层（P<0.05）,且总体上夏季各水层的鱼类密度要高于其他季节。后续研究应加强对该江段鱼类资源的动态监测,并重点探讨引起鱼类资源动态变化的关键影响因子。     

Structure and Management Issues of the Emerging Ornamental Fish Trade In Eritrea

Following independence from Ethiopia in 1993, Eritrea resumed exploiting Red Sea and Arabian fish species for the ornamental trade in 1995 as a means to earn foreign exchange from sparsely exploited marine resources. This paper describes the findings of research conducted in 1997, in collaboration with the Eritrean Ministry of Fisheries. The capture, transport and export of aquarium fish were reviewed and potential impacts and the status of management were investigated through liaison with stakeholders and researchers. From 1995 to 1997 two companies exported approximately 60,000 fish per year, mainly to the USA, worth US$65,000 (export value). Seventy-five species (from 22 families) were exported. Damselfishes made up two-thirds of total exports but more valuable families (angelfishes and butterflyfishes) were more economically significant. To earn revenue for Eritrea, a 20% export tax was imposed, although this was calculated from declarations by the operators. The emerging nature of the trade allowed detailed monitoring by the Ministry of Fisheries. However, management efforts were constrained by a lack of capacity for enforcement and baseline research. Several potential effects of the trade exist but other, land-based impacts may be more pressing concerns for Eritrea's reefs. Research priorities for management are discussed as well as the implications of mariculture of Eritrean species by other nations.     

赛里木湖高白鲑和凹目白鲑肌肉、卵的营养分析评价

2003年作对赛里木湖高白鲑和凹日白鲑肌肉、卵的营养成分进行测定。结果表明：高白鲑和凹目白鲑肌肉蛋白质含量分别为18．83％和19．78％(鲜重)；肌肉脂肪含量分别为13．75％和10．40％；氨基酸总量分别为17．48％和17．71％，其中必需氨基酸含量分别为9．16％和9．24％，占氨基酸总量的52．40％和52．17％；高度不饱和脂肪酸占脂肪酸总量的16．08％和22．73％。高白鲑和凹目白鲑卵的蛋白质含量分别为24．16％和24．48％。     

南海北部拖网35．2与30．3mm方目网囊渔获选择性比较

根据1997年10月和2000年11~12月的拖网网囊网目选择性试验资料,对网目内径35.2mm方目和30.3mm方目网囊的渔获选择性进行了比较和分析。对比试验结果表明,35.2mm方目网囊渔获尾数总逃逸率为39.28%、重量总逃逸率为16.18%,高于30.3mm方目网囊的28.40%和7.47%,35.2mm方目网囊的渔获选择性有所提高;2种规格方目网囊及其套网中出现的渔获种类较为相似,具有释放鱼类种类少、数量低的共同特点,且在渔获选择性能上的差别还不明显,对渔获种类数量的释放效果都相当有限;作为优势释放种类,大头狗母鱼、条尾绯鲤和多齿蛇鲻在2种规格方目网囊中的尾数逃逸率和重量逃逸率分别在42.9%~65.8%和24.2%~45.0%之间;其中条尾绯鲤和多齿蛇鲻的50%选择体长均未达到最低可捕标准。总体来看,2种规格方目网囊对渔获的总体释放效果还不理想,要实现负责任捕鱼,需进一步放大拖网方目网囊的网目尺寸。     

海水经济鱼类遗传育种研究进展

近二三十年来，海水养殖方式与设备的不断发展与完善，促进了海水养殖业的发展。但是，由于海水经济鱼类缺乏优良品种，大多数养殖种类为野生种或半野生种，许多养殖种群在累代繁殖后，出现品质退化、生长速度慢、发病率高等不良症状，严重地阻碍着海水经济鱼类养殖业的发展。因此，近年来，世界各国纷纷加强海水鱼类的遗传育种研究工作，     

Fish utilisation of managed realignments

Abstract  One area of ecological benefit not yet fully evaluated in European waters is the utilisation of restored saltmarsh habitats by fish species. This study examines the utilisation of managed realignments and relic saltmarsh by fish species. Factors affecting habitat heterogeneity and fish populations are discussed, and recommendations are made with respect to scheme design and management that will maximise the biological and socio-economic values. Fish populations in the high intertidal areas were assessed using a suite of techniques, including observations on feeding behaviour. Each microhabitat was discussed as a function of the extent of fish colonisation. A positive relationship between the degree of fish utilisation and habitat heterogeneity was ascertained using species richness, abundance and behavioural observations. This study will aid habitat valuation for economic justification of managed realignments, over and above existing drivers, such as compensatory habitat for encroachment, flood defence and the European Union Habitats Directive. The work now forms part of a wider European Interreg IIIb project, COMCOAST.