Ecology. Can science rescue salmon?

At a press conference on 27 July, the National Marine Fisheries Service (NMFS) released a long-awaited plan to save the Columbia River's endangered salmon by restoring fish habitat, overhauling hatcheries, limiting harvest, and improving river flow. What the plan did not do, however, was call for immediate breaching of four dams on the Snake River, the Columbia's major tributary--an option that has been the subject of a nationwide environmental crusade. The NMFS will hold that option in abeyance while it sees whether the less drastic measures will do the trick. Responses from both sides were immediate and outraged.     

Differences in thermal tolerance among sockeye salmon populations

Climate change-induced increases in summer water temperature have been associated with elevated mortality of adult sockeye salmon (Oncorhynchus nerka) during river migration. We show that cardiorespiratory physiology varies at the population level among Fraser River sockeye salmon and relates to historical environmental conditions encountered while migrating. Fish from populations with more challenging migratory environments have greater aerobic scope, larger hearts, and better coronary supply. Furthermore, thermal optima for aerobic, cardiac, and heart rate scopes are consistent with the historic river temperature ranges for each population. This study suggests that physiological adaptation occurs at a very local scale, with population-specific thermal limits being set by physiological limitations in aerobic performance, possibly due to cardiac collapse at high temperatures.     

Declining wild salmon populations in relation to parasites from farm salmon

Rather than benefiting wild fish, industrial aquaculture may contribute to declines in ocean fisheries and ecosystems. Farm salmon are commonly infected with salmon lice (Lepeophtheirus salmonis), which are native ectoparasitic copepods. We show that recurrent louse infestations of wild juvenile pink salmon (Oncorhynchus gorbuscha), all associated with salmon farms, have depressed wild pink salmon populations and placed them on a trajectory toward rapid local extinction. The louse-induced mortality of pink salmon is commonly over 80% and exceeds previous fishing mortality. If outbreaks continue, then local extinction is certain, and a 99% collapse in pink salmon population abundance is expected in four salmon generations. These results suggest that salmon farms can cause parasite outbreaks that erode the capacity of a coastal ecosystem to support wild salmon populations.     

黑龙江水系(中国)秋大麻哈鱼回归群体变动分析

2008年分别对在禁渔期前(9月10日-9月30日)和禁渔期间(10月1日-10月20日)溯河至乌苏里江和在禁渔期前溯河至黑龙江(中国)的大麻哈鱼(Oncorhynchus keta)群体结构和数量进行了调查。调查表明黑龙江中大麻哈鱼年龄由4、5、6龄组成,而乌苏里江中大麻哈鱼由3、4、5龄组成。在禁渔期前溯河至黑龙江(中国)的大麻哈鱼以低龄小个体为主;在禁渔期前溯河至乌苏里江的大麻哈鱼主要以4龄中等个体为主,而在禁渔期溯河至乌苏里江的大麻哈鱼以低龄小个体为主。因此现行的禁渔政策是不科学的,会导致大麻哈鱼种群的小型化,应加以整改。     

黑龙江水系(中国)秋大麻哈鱼回归群体变动分析

2008年分别对在禁渔期前(9月10日-9月30日)和禁渔期间(10月1日-10月20日)溯河至乌苏里江和在禁渔期前溯河至黑龙江(中国)的大麻哈鱼(Oncorhynchus keta)群体结构和数量进行了调查。调查表明黑龙江中大麻哈鱼年龄由4、5、6龄组成,而乌苏里江中大麻哈鱼由3、4、5龄组成。在禁渔期前溯河至黑龙江(中国)的大麻哈鱼以低龄小个体为主;在禁渔期前溯河至乌苏里江的大麻哈鱼主要以4龄中等个体为主,而在禁渔期溯河至乌苏里江的大麻哈鱼以低龄小个体为主。因此现行的禁渔政策是不科学的,会导致大麻哈鱼种群的小型化,应加以整改。     

Genomic signatures predict migration and spawning failure in wild Canadian salmon

Long-term population viability of Fraser River sockeye salmon (Oncorhynchus nerka) is threatened by unusually high levels of mortality as they swim to their spawning areas before they spawn. Functional genomic studies on biopsied gill tissue from tagged wild adults that were tracked through ocean and river environments revealed physiological profiles predictive of successful migration and spawning. We identified a common genomic profile that was correlated with survival in each study. In ocean-tagged fish, a mortality-related genomic signature was associated with a 13.5-fold greater chance of dying en route. In river-tagged fish, the same genomic signature was associated with a 50% increase in mortality before reaching the spawning grounds in one of three stocks tested. At the spawning grounds, the same signature was associated with 3.7-fold greater odds of dying without spawning. Functional analysis raises the possibility that the mortality-related signature reflects a viral infection.     

密云水库上游河流硝态氮含量空间分布格局

为了揭示密云水库上游河流硝态氮含量的空间分布规律,探讨其主要的影响因素。笔者对密云水库上游河流进行了全流域的水样采集,调查和收集了有关人类活动的数据（如人口、土地利用、化肥施用量等）,利用流动注射分析仪测定了河水硝态氮含量。结果表明：密云水库上游东部的潮河水系的硝态氮含量高于西部的白河水系;河流硝态氮含量的空间分布格局与人类活动密切相关,表现在途径畜禽养殖场、居民点和农田时往往升高,而经过水坝、峡谷、森林时又常常降低,其排列次序依次是：畜禽养殖场>居民点>农田>水坝>峡谷>森林。河流硝态氮含量与人口密度、耕地比例和化肥氮施用量呈线性正相关关系。     

鼠害对长江中下游可持续农业发展的影响及防治对策

 长江中下游的地理位置和适宜的气候条件 ,决定了害鼠的种类丰富、繁殖力高。而灭鼠方法不科学和气候变化以及人类活动的影响 ,使鼠密度维持在较高水平 ,危害区域不断扩展。为了维护生态平衡和保护环境 ,促进农业可持续发展 ,对目前在鼠害防治中存在的滥用急性灭鼠剂和不科学的灭鼠方法必须予以重视。有必要掌握害鼠的发生发展规律 ,在鼠害防治中树立生态与综合治理的观念 ,加强科普宣传力度 ,提高群众的生态和环保意识 ,使用先进科学的灭鼠方法。众多的江河湖泊及每年水位的变化影响着该地害鼠种群的发生发展 ,经常暴发的洪灾有引发鼠传疾病流行的可能 ,灾后必须注意防治鼠害。重大水利工程对引起某些害鼠的暴发成灾方面已有正反两方面的经验 ,长江三峡工程也将对某些害鼠的发生发展产生影响。     

ECOLOGY: The Other H's

Fisheries scientists have long identified the factors implicated in salmon decline as the "four H's": hydropower dams, harvesting, habitat degradation, and hatchery misuse. According to a new plan by nine federal agencies, known as the "All-H Paper," improvements in the other three H's will provide benefits that are more certain and widespread than those from dam breaching. But addressing the other H's may be even more costly than breaching dams.     

硫酸铜和高锰酸钾对淇河鲫仔鱼的急性毒性研究

[目的]研究药物对淇河鲫仔鱼的急性毒性。[方法]在室内常温、静水条件下,以淇河鲫仔鱼为受试生物,以致死率为指标,研究了硫酸铜和高锰酸钾对淇河鲫仔鱼的急性毒性。[结果]：①在同一暴露时间,随着硫酸铜和高锰酸钾溶液浓度的增大,淇河鲫仔鱼的死亡率逐渐上升;②硫酸铜24、48和96h的半致死浓度（LC50）分别为3．8、2．5、1．6mg／L,安全浓度（SC）为0．16mg／L;高锰酸钾24、48和96h的半致死浓度（LC50）分别为5．14、3．95、3．04mg/L,安全浓度（SC）为0．304mg／L;③根据实验结果,建议在淇河鲫仔鱼疾病防治中,硫酸铜和高锰酸钾都应慎用或者适当降低使用浓度。     

Population dynamics of exploited fish stocks at low population levels

Models of population dynamics in which per capita reproductive success declines at low population levels (variously known as depensation, the Allee effect, and inverse density-dependence) predict that populations can have multiple equilibria and may suddenly shift from one equilibrium to another. If such depensatory dynamics exist, reduced mortality may be insufficient to allow recovery of a population after abundance has been severely reduced by harvesting. Estimates of spawner abundance and number of surviving progeny for 128 fish stocks indicated only 3 stocks with significant depensation. Estimates of the statistical power of the tests strengthen the conclusion that depensatory dynamics are not apparent for fish populations at the levels studied.     

Fault Zone along Northern Boundary of Western Snake River Plain,Idaho

Gravity, seismic, and geologic studies indicate that at least 9000 ft of aggregate throw along a zone of northwest-trending, high-angle faults has displaced the western Snake River Plain downward relative to highlands on the north. At least 5000 ft of movement occurred between the early and middle Pliocene. Progressively diminishing movement since then amounts to 4000 ft.     

Clostridium botulinum Type F: Isolation from Salmon from the Columbia River

Clostridium botulinum type F has been isolated from a salmon (Oncorhynchus nerka) taken from the Columbia River. Cultures of this type have been reported only twice before-once the bacterium was isolated.     

Mast cells can enhance resistance to snake and honeybee venoms

Snake or honeybee envenomation can cause substantial morbidity and mortality, and it has been proposed that the activation of mast cells by snake or insect venoms can contribute to these effects. We show, in contrast, that mast cells can significantly reduce snake-venom-induced pathology in mice, at least in part by releasing carboxypeptidase A and possibly other proteases, which can degrade venom components. Mast cells also significantly reduced the morbidity and mortality induced by honeybee venom. These findings identify a new biological function for mast cells in enhancing resistance to the morbidity and mortality induced by animal venoms.     

黑龙江中游与乌苏里江大麻哈鱼(Oncorhynchusketa Walbaum)生殖群体的比较

1999～ 2 0 0 0年对乌苏里江和黑龙江中游大麻哈鱼 (Oncorhynchus keta Walbaum )生殖群体进行了调查 ,分析了其形态特征、生物学特性及群体结构。采用形态学和生态学方法对乌苏里江和黑龙江大麻哈鱼生殖群体进行了种群鉴别。结果表明 ,乌苏里江大麻哈鱼较黑龙江大麻哈鱼吻短、眼大、鳞大、尾柄粗短、背鳍位置稍偏前 ,且背鳍条和臀鳍条均少。各龄鱼的体长生长速度明显快于洄游至黑龙江的大麻哈鱼 ,但肥满度较低 ,性成熟早 ,繁殖力低。产卵群体个体小并以 4龄鱼占优势 ,其各龄组体长、体重均高于黑龙江群体的同龄组鱼 ;而上溯至黑龙江的大麻哈鱼产卵群体的个体大 ,以 5龄鱼为主 ,其肥满度、成熟系数及怀卵量则均高于乌苏里江产卵群体。比较乌苏里江和黑龙江大麻哈鱼群体的生物特征和群体组成 ,其差异显著 ,二者应为两个不同的地理种群或生态群体。     

Identification and Genetic Diversity Analysis of Chinese Mitten Crab(Eriocheir sinensis) in the Liao River Area

Chinese mitten crab(Eriocheir sinensis) is an indigenous and ecologically and economically important species in the Liao River area, but its identification and genetic diversity remain poorly understood. To evaluate the germplasm resources of this species, samples were collected from these locations: four sub-populations from the Liao River area and one population from the Yangtze River area; one primer was used to distinguish between the Liao River and the Yangtze River crabs. Thirteen loci were used for crab genetic diversity analysis, and basic statistics showed that the collecting samples were purebred in the Liao River area. The average observed heterozygosity(H_0) of the Liao River population was 0.5931, and the expected heterozygosity(H_e) was 0.8064. The polymorphism information content(PIC) was 0.7753, which showed that the Liao River population had high genetic diversity. The genetic differentiation index(F_(ST)) averaged 0.0342, meaning a low degree of differentiation; cluster analysis indicated that Hujia(HJ), Xinli(XL) and Chenjia(CJ) sub-populations were allocated to the same cluster, while Baqiangzi(BQZ) sub-population was isolated. In summary, these data demonstrated that the crabs in the Liao River had high genetic diversity, but low genetic differentiation. Thus, the Liao River population had the potential for breeding selection. Furthermore, this study also provided valuable genetic information for the conservation of Chinese mitten crab.     

和田河流域胡杨、灰叶胡杨种群结构特征的比较研究

在和田河流域设置胡杨、灰叶胡杨样地14块,应用相邻格子法进行每木调查,对胡杨、灰叶胡杨种群结构及空间分布格局进行比较分析,结果表明：（1）和田河流域胡杨、灰叶胡杨的种群结构均呈纺锤形,以Ⅲ一Ⅵ径级的植株数量最多,幼苗严重不足,种群有衰退趋势;（2）胡杨、灰叶胡杨种群存活曲线均接近于DeeveylI型,但灰叶胡杨种群死亡率曲线呈双峰型,胡杨种群随径级增加呈递增趋势。（3）在生长发育过程中,胡杨、灰叶胡杨种群空间分布格局在I一Ⅵ龄级呈聚集分布,Ⅶ一Ⅷ龄级呈均匀分布。（4）在不同尺度上,胡杨、灰叶胡杨种群均呈聚集分布,但聚集强度在1S～6S尺度上胡杨种群大于灰叶胡杨种群,而在9S-25S尺度上,胡杨种群小于灰叶胡杨种群。     

中华绒螯蟹国内外群体遗传变异与适应性进化分析

中华绒螯蟹（Eriocheir sinensis）是我国极为重要的土著种类,现已移居到欧洲和北美等地。利用20对微卫星标记对中华绒螯蟹国内土著群体（长江和黄河）和国外移居群体（德国易北河、荷兰莱茵河、英国泰晤士河和美国旧金山湾）的遗传变异和多样性进行了分析。结果显示,中华绒螯蟹国内群体的遗传多样性（等位基因丰富度、多态信息含量和杂合度等）略高于国外移居群体;国内外群体间,以及国外不同群体间存在显著的遗传分化;贝叶斯遗传聚类分析显示国内土著群体、欧洲移居群体和美国移居群体分成明显的3个遗传聚类;主成分分析表明国外移居群体已产生了明显的遗传歧化;荷兰莱茵河群体检测到显著的遗传瓶颈效应。表明中华绒螯蟹在海外的入侵过程中已发生了较为明显的适应性进化。     

基于线粒体12SrRNA序列研究凤鲚两个野生群体的遗传多样性

对凤鲚Coilia mystus长江群体和珠江群体的线粒体DNA(m itochondrial DNA,m tDNA)的12SrRNA基因片断序列进行分析。排列比对后,获得该基因365 bp的一致序列。在所测得的42个序列中,共检测到6种单倍型,其中长江群体有2种,珠江群体有4种。长江群体和珠江群体的单倍型多样性指数分别为0.5263和0.6104,核苷酸多样性指数分别为0.144%和0.192%。凤鲚长江群体内部的遗传距离为0.3%,珠江群体内部的遗传距离为0.3%～0.5%,长江群体与珠江群体之间的遗传距离为0.8%～1.4%。邻接树显示长江凤鲚和珠江凤鲚各自形成一个单系类群。AMOVA分析显示群体间的变异占总变异的82.80%,提示两者可能有相互隔离的遗传结构。     

Population policy in transition in the developing world

Population growth remains rapid in the poorest countries, particularly in sub-Saharan Africa, despite substantial AIDS mortality. Voluntary family-planning programs reduce unplanned pregnancies by providing access to and information about contraception and by reducing socioeconomic obstacles to use. With sufficient political will and resources, well-run voluntary programs have been shown to bring about sustained declines in fertility and population growth across much of Asia, the Middle East, and Latin America, simply by permitting people to realize their individual reproductive goals. Such programs represent a cost-effective approach to relieving population pressures, stimulating economic development, improving health, and enhancing human freedom.