鱼类弹状病毒分子生物学研究动态

鱼类弹状病毒(Fish rhabdovirus)是一类引起鱼及其他水生动物致死性和流行性病害的重要病毒病原。对鱼类弹状病毒基因组的结构和功能研究,是深入探讨这类病毒感染和致病机理、研制病毒疫苗及诊断试剂的理论基础。本文就鱼类弹状病毒的基因组结构,包括N基因、P基因、M基因、G基因、NV基因、L基因及编码的相应蛋白、3′前导区和5′拖尾区、基因连接区等的组成及功能的研究进展作一综述,旨为抗病毒疫苗的研制及建立准确高效的检测方法提供借鉴。     

Ontogenetic movements of juvenile blacktip reef sharks: evidence of dispersal and connectivity between coastal habitats and coral reefs

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日粮中鱼蛋白水解物对黄颡鱼生长、体成分和血清生理指标的影响

为了探讨鱼蛋白水解物对黄颡鱼生产性能的影响,以日本鳀粉为对照,以实用型黄颡鱼饲料配方模式为基础开展实验:1以30.5%鱼粉为对照(FM),在相同配方模式下,以6%鱼蛋白水解物(MPH6)替代20%的鱼粉;2以30.5%鱼粉为对照(FM),在无鱼粉日粮中分别添加3%(FPH3)、6%(FPH6)、12%(FPH12)鱼蛋白水解物;共设计5组等氮等能实验日粮,在池塘网箱中养殖黄颡鱼[初始体质量(30.08±0.35)g]60 d。结果显示:与FM相比,FPH12在SGR、FCR、PRR和FRR方面均无显著差异,而MPH6、FPH3、FPH6组SGR降低了15.45%~24.39%,FCR升高了32.14%~42.86%,MPH6、FPH6差异显著,在PRR和FRR方面,MPH6、FPH3、FPH6组PRR降低了21.11%~27.78%,MPH6组FRR降低了41.51%;全鱼水分、粗蛋白、粗脂肪和灰分各组间差异不显著,FPH3、FPH6、FPH12肌肉多种游离氨基酸水平显著高于FM,其中Thr、Val、His与其在日粮中的水平显著相关;FPH6组HSI显著低于FM,鱼蛋白水解物对CP、VSI、肠体比的影响不显著;血清AST、ALT、HDL、LDL、TP、CHOL、TG无显著差异,FPH3组ALB显著低于FM。研究表明:黄颡鱼日粮中,12%鱼蛋白水解物(干物质)与30.5%鱼粉在生长速度、饲料效率、血清生理指标等方面具有一定的等效性;过高的植物蛋白日粮影响了黄颡鱼的生产性能;饲喂鱼蛋白水解物日粮使黄颡鱼肌肉游离氨基酸的含量升高,特别是呈味氨基酸的含量增加。     

冰衣结合保鲜剂处理对冻藏鱿鱼品质的影响

为研究冰衣对鱿鱼品质的影响,在鱿鱼冻藏过程中,以未镀冰衣的样品为对照组,对比纯水冰衣组及冰衣中分别添加聚丙烯酸钠、迷迭香酸、异抗坏血酸钠及其复配组,分析鱿鱼在-18℃下冻藏6个月的持水力、色泽、pH、质构、丙二醛、巯基含量、水分含量和游离氨基酸的变化。结果显示:鱿鱼冻藏过程中品质显著下降,镀冰衣处理能明显延缓质量损失、脂质氧化和蛋白质降解;含有聚丙烯酸钠的冰衣不易破裂,可有效维持鱿鱼的品质;冰衣中加入异抗坏血酸钠的比加入迷迭香酸有更好的保鲜效果;异抗坏血酸钠/聚丙烯酸钠复配冰衣可有效延缓冻藏期间鱿鱼品质下降,且能延长货架期。     

Using Bacillus subtilis E20‐fermented soybean meal as replacement for fish meal in the diet of orange‐spotted grouper (Epinephelus coioides,Hamilton)

The potential of Bacillus subtilis E20‐fermented soybean meal (FSBM) as a partial alternative component of fish meal (FM) in fed diets of orange‐spotted grouper (Epinephelus coioides) was evaluated in this study. An FM‐based diet and seven diets containing 10%, 20% and 30% and 10%, 20%, 30% and 40% of FM replaced by soybean meal (SBM) and FSBM, respectively, were fed to grouper for 84 days to evaluate possible substitution levels of FM by tracking growth performance, digestive enzyme activity and morphological changes in the liver and distal intestine. No significant differences in survival and muscle composition of grouper were found between controls and treatments. Growth performance and feed efficiency of fish fed diets with FM replaced by FSBM up to 30% were not significantly different from controls, whereas significantly decreased growth performance and feed efficiency occurred with diets containing >20% of SBM. Based on the feed efficiency, the maximum substituted levels of FM by SBM and FSBM in grouper diets were 18.36% and 29.32%, respectively, based on broken‐line analyses. Histopathological changes in the liver and distal intestine, and significantly lower activity levels of digestive enzymes, including pepsin in the stomach and trypsin, chymotrypsin, amylase and lipase in the distal intestine, were found in fish fed a diet containing 30% of FM replaced by SBM. However, these parameters were improved by the substitution of FSBM. It is therefore believed that FSBM has great potential to be used as a protein source in grouper diets in partial replacement of FM.     

From small-scale habitat loopholes to decadal cycles: a habitat-based hypothesis explaining fluctuation in pelagic fish populations off Peru

The Peru‐Humboldt Current system (HCS) supports the world's largest pelagic fisheries. Among the world's eastern boundary current systems, it is the most exposed to high climatic stress and is directly affected by El Niño and La Niña events. In this volatile ecosystem, fish have been led to develop adaptive strategies in space and time. In this paper, we attempt to understand the mechanisms underlying such strategies, focusing on the El Niño 1997–98 in Peru from which an extensive set of hydrographic, capture and acoustic survey data are available. An integrated analysis of the data is crucial, as each has substantial shortcomings individually; for example, both catch data and acoustic surveys may easily lead to wrong conclusions. Existing hypotheses on anchovy and sardine alternations lead us to a ‘habitat‐based’ synthetic hypothesis. Using our data, an integrated approach evaluated how fish responded to habitat variation, and determined the consequences in terms of fish‐population variability. Various factors occurring at a range of different spatio‐temporal scales were considered: interdecadal regime (warm ‘El Viejo’/cool ‘La Vieja’ decadal scale); strength and the duration of the El Niño Southern Oscillation event (interannual scale); population condition before the event (interannual scale); fishing pressure and other predation (annual scale); changes in reproductive behaviour (intra‐annual scale); presence of local upwelling (local scale). During El Niño 1997–98, anchovy was able to exploit a small‐scale temporal and spatial ‘loophole’ inside the general unfavourable conditions. Moreover, sardine did not do better than anchovy during this El Niño and was not able to take advantage of the ‘loophole’ opened by this short‐term event. Our results question the traditional view that El Niño is bad for anchovy and good for sardine.     

南海区驯养条石鲷亲鱼的初次性成熟和产卵

2008年4月初在广东省饶平县对2006年5月人工孵化和培育的2龄条石鲷（ Oplegnathus fasciatus）成熟亲鱼进行激素诱导,研究和观察条石鲷亲鱼初次性成熟的繁殖生物学。结果显示,在南海区全人工养殖的条石鲷亲鱼初次性成熟年龄为2龄,成熟亲鱼的最小型为全长245 mm、体质量610 g,最大个体为全长300 mm、体质量1450 g;产卵季节为4月10日~7月15日,产卵盛期为4月中旬至6月下旬;为升温产卵型鱼类,产卵温度为20.0~28.8℃,适宜的产卵温度为20.7~27.6℃;雌、雄亲鱼发育同步,个体大小和成熟年龄差别不大;雌鱼属于一年一次分批产卵类型,产卵期超过3个月;24尾初次性成熟雌性亲鱼的总产卵量为3180.0×104粒,日最高产卵量为341.5×104粒;其产卵量和受精卵质量与水温的变化关系密切,受精卵的浮卵率随温度的变化而变化,在水温相对衡定时,浮卵率相对稳定并维持在80%~95%的较高水平;受精卵平均卵径为（0.860±0.023）mm,油球径为（0.191±0.009）mm。     

Lessons from the past: the collapse of Jamaican coral reefs

Since Pre-Columbian times, humans have exploited Jamaican marine ecosystems with significant consequences for flora and fauna. This study focuses on the history of reef fish exploitation in Jamaica, from first human occupation to the present day, to determine how past fishing activities contributed to subsequent declines in the coral reef ecosystem. The pattern of declining reef fish populations was nonlinear. Reef fish first declined in prehistoric times but then potentially recovered, following genocide of the native human population. Reduced fishing pressure lasted until the mid-19th century. At that time, depletion of reef fish populations again occurred with a precipitous decline from the 1850s to the 1940s. The final shift from relatively abundant to overfished marine fauna corresponded to subtle changes in fish trap design as well as development of recreational fishing. Government subsidies throughout the second half of the 20th century exacerbated the declines. This analysis shows that local artisanal fisheries with relatively low levels of effort and seemingly subtle shifts in technology can significantly impact the coral reef ecosystem and that declines occurred decades to centuries before modern ecological studies began. This research shows how historical analysis can be a powerful tool to minimize shifted baselines and establish realistic targets for recovery and sustainable management of marine ecosystems.     

Angling for endangered fish: conservation problem or conservation action?

Recreational angling has been implicated in population declines of some marine and freshwater fish, but this activity is rarely considered as a threat or even halted when endangered species are targeted. Indeed, in some cases, anglers are drawn to fish for rare or endangered species. Conservation‐oriented behaviours such as catch‐and‐release are often practiced voluntarily due to the ethics of anglers, yet even in these cases, some fishing mortality occurs. Nonetheless, there are many indirect conservation benefits associated with recreational angling. Here, we present a series of case‐studies and consider whether catch‐and‐release angling for endangered fish is a conservation problem or a conservation action. If recreational angling activities contribute to population‐level consequences that are contrary to recovery strategies, then angling for endangered species would seem to be a poor option. However, as revealed by several case‐studies, there is much evidence that anglers are vocal and effective proponents of fish and habitat conservation, and for endangered species, they are often the only voice when other stakeholders are not engaged. Anglers may contribute directly to conservation actions via user fees (e.g. licences), philanthropic donations or by volunteering in research, education and restoration activities. However, it is important to quantify post‐release mortality as well as understand the full suite of factors influencing a given population or species to know the potential risks. A risk assessment approach outlined in the paper may be used by managers to determine when the benefits of angling for endangered species outweigh the risks.