Influences of population density,temperature and latitude on the growth of invasive topmouth gudgeon Pseudorasbora parva

Plasticity in life‐history traits provides advantages for introduced fish in overcoming demographic bottlenecks that would otherwise inhibit establishment. Here, the influence of population density, temperature and latitude was tested on the growth increments and growth rates of invasive populations of topmouth gudgeon Pseudorasbora parva, a small Asian cyprinid fish that is invasive across Europe. Aquaria experiments tested the roles of fish number and temperature on growth increments under a fixed food supply, pond experiments tested the role of density on growth increments, and a field study completed in England and Wales tested the influence of density and latitude on growth rates. In aquaria experiments, whilst growth increments were higher at 21 and 23 °C than at 19 and 25 °C, fish number had a greater influence on growth than temperature. Higher growth increments were produced at lower densities. In experimental ponds, growth increments were significantly higher in ponds with low densities of P. parva compared with those at elevated densities. In the field study comprising 10 wild populations across a latitudinal gradient of 4.0°N, a difference in mean air temperatures of approximately 3 °C, and estimated densities between 0.5 and 65.0 m^?2, population density was the only significant predictor of growth rates. Whilst populations at very low densities comprised of significantly faster growing individuals, there were no significant differences when densities were between 15 and 65 m^?2. Thus, invasive P. parva populations have considerable growth plasticity, especially at low densities, with this likely to be important in their ability to colonise new environments.     

基于滤食鱼类天然产力的安康库区生态负荷量测定

为厘清汉江水体鱼类集约养殖与生态负荷量的关系，测定安康库区滤食性鱼类天然鱼产力，测算Ⅱ类水质限定条件下的安康库区生态负荷量，并与以水体磷含量为标准的计算结果比较。结果表明，设定网箱深度3 m，单位水体生态负荷量为193.44 g/m³，总产量控制为10.47×10⁴ t。库区网养单产为100 kg/m³时，网箱养殖面积控制为1.93‰，网箱生态养殖面积与单位面积产量呈反比。     

微生物对鱼粉中组胺含量的影响研究

我国鱼粉产品质量参差不齐,由于原料问题组胺含量普遍高于国际先进水平,过高的鱼粉含量易造成食品安全问题。为了降低过高的组胺含量对鱼粉品质的影响,本实验通过使用微生物参与降解鱼粉产品中的组胺。实验将降解时间与微生物添加比例作为变量,测试出较为适宜微生物降级组胺的条件,以及该条件下的实际效果。实验结果表明在设置的6个时间中(以6小时为时间梯),24h为较适宜的降解时间；在较适宜的降解时间中(24h)较适宜的微生物添加比例为10:1。此时鱼粉组胺含量为1622mg/kg,相较未加入微生物处理的鱼粉组胺含量(5298 mg/kg)降低69%。实验结果证明了微生物处理鱼粉中组胺具有显著的效果,为鱼粉生产、储存技术的改良提供了参考依据。     

Movement rules for juvenile steelhead: dynamic linking of movement behaviour to habitat and density

We incorporated explanatory factors including stream habitat type and fish density into individual‐based models with dynamic connections among adjacent habitat units to infer dispersal behaviour of juvenile steelhead Oncorhynchus mykiss in a Great Lakes watershed. We used mark–recapture data and an inverse modelling approach to estimate daily probability of steelhead moving out of a habitat unit, P(move), according to four competing models. The models used included (i) a null model where all fish had equal movement probability; (ii) a habitat‐dependent model where P(move) depended on the habitat type; (iii) a density‐dependent model of P(move); and (iv) a model where P(move) depended on both density and habitat type. The habitat‐dependent model provided the most parsimonious fit to the observed data according to Akaike's information criteria (AICc). In the null model, P(move) averaged 0.70, whereas P(move) averaged 0.75 in pools, 0.68 in riffles and 0.73 in runs in the habitat‐dependent model.     

Movement patterns of seaward migrating European eel (Anguilla anguilla) at a complex of riverine barriers: implications for conservation

River infrastructure such as weirs and hydropower stations commonly present migrating fish with multiple potential passage routes. Knowledge of the cues fish use to navigate such environments is required to protect migrants from hazardous areas and guide them towards safe passage; however, this is currently lacking for many species. Employing high‐resolution positioning telemetry, this study examined movements of downstream migrating adult European eel, Anguilla anguilla, as they encountered a complex of water control structures in one location on the River Stour, southern England. The distribution of eels across five potential routes of passage differed from that predicted based on proportion of discharge alone. Certain routes were consistently avoided, even when the majority of flow passed through them. Passage distribution was partially explained by avoidance in the vicinity of a floating debris boom. Movement paths were nonrandomly distributed across the forebay and eels moved predominantly within a zone 2–4 m from the channel walls. Understanding of avoidance and structure oriented movementation exhibited by eels will help advance effective guidance and downstream passage solutions for adults.     

秋浦花鳜多元养殖模式关键技术

秋浦花鳜是安徽地方水产优良养殖品种。基于当前秋浦花鳜主要的养殖模式,对相关技术要点进行总结,系统归纳了秋浦花鳜池塘主养、混养,网箱养殖,以及大水面增养殖等多元养殖模式及其关键技术。在不同的养殖模式下,秋浦花鳜均表现出优异的适应性,经济价值及社会价值,可进一步示范应用。     

动态高压微射流协同谷氨酰胺转氨酶复合修饰对鱼明胶凝胶特性和结构的影响

为了提高鱼明胶的凝胶特性,本试验采用动态高压微射流(DHPM)协同谷氨酰胺转氨酶(TG)交联(DHPM-TG)技术对鱼明胶进行复合修饰。结果表明,鱼明胶的亮度、特性粘度和胶融温度均随着TG含量的增加而增大,凝胶强度和硬度先增大后减小。与TG修饰技术相比,DHPM-TG复合修饰技术可显著提高鱼明胶的特性粘度、胶融温度、凝胶强度以及胶体的硬度和咀嚼性。此外,环境扫描电镜结果表明,DHPM-TG制备的鱼明胶胶体结构更加致密。综上,DHPM-TG复合修饰显著改善了鱼明胶的凝胶特性,为生产可替代哺乳动物明胶的高品质鱼明胶提供了新的理论依据。     

饲料脂质对养殖鱼类品质的影响

目前,高脂饲料在鱼类养殖中的应用已越来越广泛。然而,目前全球每年鱼油产量虽然基本恒定,但水产饲料中鱼油的需求量却在持续上升,到2010年,鱼油的使用量将超出产量的70%。鱼油的有限供给和过量消耗,以及其中可能积蓄的二噁英和多氯联苯,使鱼类养殖业迫切需要采用其他脂肪源来代替饲料中的鱼油。然而,高脂饲料或用其他脂肪源替代饲料中的鱼油不仅影响养殖鱼     

水产调味品鲫鱼汁的研制

随着人们生活水平的提高,对食品质量的要求也在不断的提高,调味品在食品质量中扮演着非常重要的角色。本实验以普通养殖鲫鱼为主要原料,研究水产调味品鲫鱼汁的最佳工艺。通过正交试验和感官评价,最终得到水产调味鲫鱼汁的最佳配方:黄原胶0.04%,鲫鱼汁30%,盐15%,糖5%,谷氨酸钠5%,5′-肌苷酸0.25%,叶黄素0.03%,鱼味香精0.03%,山梨酸钾0.05%,均质压力35MPa。水产调味品鲫鱼汁质地均匀,口感细腻,鱼鲜风味突出,色泽淡黄,气味芬芳,符合人们对于风味和营养的需求,具有广阔的市场前景。