Changes in fisheries discard rates and seabird communities

It is clear that discards from commercial fisheries are a key food resource for many seabird species around the world. But predicting the response of seabird communities to changes in discard rates is problematic and requires historical data to elucidate the confounding effects of other, more 'natural' ecological processes. In the North Sea, declining stocks, changes in technical measures, changes in population structure and the establishment of a recovery programme for cod (Gadus morhua) will alter the amount of fish discarded. This region also supports internationally important populations of seabirds, some of which feed extensively, but facultatively, on discards, in particular on undersized haddock (Melanogrammus aeglefinus) and whiting (Merlangius merlangus). Here we use long-term data sets from the northern North Sea to show that there is a direct link between discard availability and discard use by a generalist predator and scavenger--the great skua (Stercorarius skua). Reduced rates of discarding, particularly when coupled with reduced availability of small shoaling pelagic fish such as sandeel (Ammodytes marinus), result in an increase in predation by great skuas on other birds. This switching of prey by a facultative scavenger presents a potentially serious threat to some seabird communities.     

Fisheries. Population of origin of Atlantic cod

Most of the world's cod (Gadus morhua) fisheries are now tightly regulated or closed altogether. Being able to link individual fish to their population of origin would assist enormously in policing regulations and in identifying poachers. Here we show that microsatellite genetic markers can be used to assign individual cod from three different populations in the northeastern Atlantic Ocean to their population of origin.     

The genome sequence of Atlantic cod reveals a unique immune system

Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC)?II is a conserved feature of the adaptive immune system of jawed vertebrates, but we show that Atlantic cod has lost the genes for MHC?II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions. We find a highly expanded number of MHC?I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC?II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.     

Collapse and recovery of marine fishes

Overexploitation and subsequent collapse of marine fishes has focused attention on the ability of affected populations to recover to former abundance levels and on the degree to which their persistence is threatened by extinction. Although potential for recovery has been assessed indirectly, actual changes in population size following long-term declines have not been examined empirically. Here I show that there is very little evidence for rapid recovery from prolonged declines, in contrast to the perception that marine fishes are highly resilient to large population reductions. With the possible exception of herring and related species that mature early in life and are fished with highly selective equipment, my analysis of 90 stocks reveals that many gadids (for example, cod, haddock) and other non-clupeids (for example, flatfishes) have experienced little, if any, recovery as much as 15 years after 45-99% reductions in reproductive biomass. Although the effects of overfishing on single species may generally be reversible, the actual time required for recovery appears to be considerable. To exempt marine fishes from existing criteria used to assign extinction risk would be inconsistent with precautionary approaches to fisheries management and the conservation of marine biodiversity.     

Plankton effect on cod recruitment in the North Sea

The Atlantic cod (Gadus morhua L.) has been overexploited in the North Sea since the late 1960s and great concern has been expressed about the decline in cod biomass and recruitment. Here we show that, in addition to the effects of overfishing, fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). Survival of larval cod is shown to depend on three key biological parameters of their prey: the mean size of prey, seasonal timing and abundance. We suggest a mechanism, involving the match/mismatch hypothesis, by which variability in temperature affects larval cod survival and conclude that rising temperature since the mid-1980s has modified the plankton ecosystem in a way that reduces the survival of young cod.     

Leadership, social capital and incentives promote successful fisheries

One billion people depend on seafood as their primary source of protein and 25% of the world's total animal protein comes from fisheries. Yet a third of fish stocks worldwide are overexploited or depleted. Using individual case studies, many have argued that community-based co-management should prevent the tragedy of the commons because cooperative management by fishers, managers and scientists often results in sustainable fisheries. However, general and multidisciplinary evaluations of co-management regimes and the conditions for social, economic and ecological success within such regimes are lacking. Here we examine 130 co-managed fisheries in a wide range of countries with different degrees of development, ecosystems, fishing sectors and type of resources. We identified strong leadership as the most important attribute contributing to success, followed by individual or community quotas, social cohesion and protected areas. Less important conditions included enforcement mechanisms, long-term management policies and life history of the resources. Fisheries were most successful when at least eight co-management attributes were present, showing a strong positive relationship between the number of these attributes and success, owing to redundancy in management regulations. Our results demonstrate the critical importance of prominent community leaders and robust social capital, combined with clear incentives through catch shares and conservation benefits derived from protected areas, for successfully managing aquatic resources and securing the livelihoods of communities depending on them. Our study offers hope that co-management, the only realistic solution for the majority of the world's fisheries, can solve many of the problems facing global fisheries.     

马克思的世界历史思想及其当代价值——以《1844年经济学哲学手稿》《德意志意识形态》《共产党宣言》为例

马克思的世界历史思想是马克思关于社会发展理论的一个重要组成部分,是马克思科学剖析资本主义社会的一个重要理论成果。马克思的世界历史思想经历了从萌芽、发展到成熟的过程,在《共产党宣言》中,马克思和恩格斯从资本主义生产方式的变革、交往关系的发展和资产阶级力量的发展等多个维度对世界历史思想作了系统而精辟的阐述。马克思的世界历史思想是人们科学认识和正确把握当今资本主义社会的重要理论来源,它对我们认识资本主义的全球化仍然具有非常重要的意义和价值。     

浅谈3G的发展轨迹

3G以其强大的功能吸引着用户也改变着人们的生活。介绍了3G技术在欧美、日韩及国内的发展过程与概况,并将3G对生活的影响大致划分为4类,希望引起人们对3G在社会生活方面所起作用的关注。     

双重视角下对北方文化的多元重构——庞壮国20世纪80年代北方历史文化题材诗歌简评

20世纪80年代,庞壮国创作并发表了大量北方历史文化题材诗歌。这些诗歌以双重视角,即以人的视角和以自然的视角,对北方历史文化进行了发掘、审视和诗性确认,在情思和哲思交相辉映中形成了鲜明特色,以深刻的当代意识,完成了对北方历史文化的多元重构。     

北太平洋海气系统主要模态的年代际变化

结合北太平洋各种指数、海表温度和高度场,分析了北太平洋海气系统的突变特征及其与时间尺度分量的联系.研究结果表明:各种指数、海表温度和高度场在20世纪60年代、70年代和90年代末期均存在显著突变;海表温度60年代的突变主要分布于北太平洋北部,70年代的突变主要分布于北太平洋北部、中部和东南部,90年代突变则主要分布于北太平洋东南部和西南部;高度场突变主要分布于北太平洋北部、西北部和东南部,且突变范围从高层向低层递减.各种指数中60年代突变1～8a尺度分量的贡献较大,70年代突变是20～30a尺度分量的贡献较大,90年代的突变则是1～8a尺度和20～30a尺度分量作用相当.在3个突变时期中,海表温度和高度场的空间分布及相关性分析验证了这种联系的可能性.     

瓦氏夫人的修齐治平观和政治道德理想研究

瓦氏夫人是壮族土司岑猛的妻室,著名的抗倭将领。她一生的政治行为从个人生活史短时段的层面上看,可以折射出她个人的心路历程、修齐治平观和政治道德理想;从田州岑氏土司家族史中时段的层面上看瓦氏夫人的伦理政治,可以管窥壮族土司变迁史的一个横断面;从大历史、长时段的层面上看瓦氏夫人的政治道德理想,可以看作是儒家意识形态从中心向边缘传播过程的一个缩影。     

网络环境下大学生的行为特点与管理策略

互联网以更加快捷的速度传送和处理着日益增加的海量数据和信息。影响和改变着青年大学生的人际交往方式、学习方式和生活方式。因此，应根据网络环境下大学生的网络行为特点提出相应的管理策略。     

从《书所见》看赵翼忧民诗的诗史价值

赵翼晚年创作了一系列纪实性的忧民诗。对此研究可以采用文史互证的方法，以《书所见》为个案来进行，从中不仅可以看出诗人强烈的民胞物与的情怀与自觉的诗史意识，而且可以深刻地感受到所谓乾隆盛世的子民艰难的生活状态，透过该诗可以明晰地倾听到盛世之音下的凄凉之声。     

广东韶关“战国属楚”论质疑

传统史观认为韶关地区战国时期已属楚地，但从韶关地区考古文化所表现出来的特点及其与其相连的湘南地区同期考古文化的比较来看，当时韶关地区并不“属楚”。     

西藏当代现实主义小说创作中的叙事话语转变与现代性特征——以《格桑梅朵》《无性别的神》《祭语风中》为例

20世纪的西藏和中国其他地区一样,是西藏社会从传统向现代转变最为剧烈的时期。文学作品如何看待这一百年的历史,如何展现这一百年来人的精神世界所发生的巨大转变,体现了不同时代西藏文学的精神风貌和发展轨迹。文章以《格桑梅朵》《无性别的神》和《祭语风中》三部反映西藏不同历史阶段面貌的现实主义小说为例,分析不同时期的小说叙事话语和风格的转变及其所反映的西藏文学创作中现代性意识从确立、追溯到反思的特征,并结合西藏当代知识分子作家的生命历程和创作变化,来管窥西藏不同时期小说创作所折射的时代精神"症候"。     

重建新生活的倡议书——论王安忆《叔叔的故事》

《叔叔的故事》是重建新生活的倡议书，是对现实、历史以及小说自身的全面反思。作家不能光在小说中编造文本故事，更应在现实中耕耘自己的生活故事。忽视审美（游戏）与生活之间的距离，将生活彻底艺术化，便会陷入审美的迷津。苦难主义是对苦难历史的炫耀。如果不能很好地从苦难中吸取经验教训，而是遗忘历史，苟且偷欢，那么终将遭遇到历史的无情愚弄。     

Fishing elevates variability in the abundance of exploited species

The separation of the effects of environmental variability from the impacts of fishing has been elusive, but is essential for sound fisheries management. We distinguish environmental effects from fishing effects by comparing the temporal variability of exploited versus unexploited fish stocks living in the same environments. Using the unique suite of 50-year-long larval fish surveys from the California Cooperative Oceanic Fisheries Investigations we analyse fishing as a treatment effect in a long-term ecological experiment. Here we present evidence from the marine environment that exploited species exhibit higher temporal variability in abundance than unexploited species. This remains true after accounting for life-history effects, abundance, ecological traits and phylogeny. The increased variability of exploited populations is probably caused by fishery-induced truncation of the age structure, which reduces the capacity of populations to buffer environmental events. Therefore, to avoid collapse, fisheries must be managed not only to sustain the total viable biomass but also to prevent the significant truncation of age structure. The double jeopardy of fishing to potentially deplete stock sizes and, more immediately, to amplify the peaks and valleys of population variability, calls for a precautionary management approach.     

国外生活对根敦群培的影响

文章论述了藏族历史上的佛门奇僧、藏族学术大师根敦群培在国外的生活,剖析了国外生活在诸多方面对根敦群培造成的重大影响,包括从神学史观转向人文史观、国外学者全方位的影响、国外艺术风格的影响、国外新思潮对其思想的影响,指出国外生活使他获得了一个丰硕的人生,揭示了根敦群培具有传奇色彩的人生命运。     

Interdecadal variations of the East Asian winter surface air temperature and possible causes

Using the NCEP/NCAR and JRA-25 monthly analysis data from 1979 to 2011, this paper analyzes the interdecadal variations of winter (Dec.–Feb.) mean surface air temperature (SAT) over East Asia by means of the empirical orthogonal function (EOF) analysis method. Two dominant modes were extracted, with the leading mode basically depicting a sign consistent SAT variation and the second mode describing a meridional dipole structure between the northern and southern parts of East Asia. These two modes can explain more than 60% of the variance. The leading mode is closely related to the intensity of Siberian high and the East Asian winter monsoon. The second mode exhibits a notable interdecadal shift in the late 1990s, with a turning point around 1996/1997. Winter SAT in the northern (southern) part of East Asia tends to be cooler (warmer) since the late 1990. Winter sea level pressure (SLP) differences between 1997–2011 and 1979–1996 show negative (positive) anomalies over southern (northern) Eurasia. At 500-hPa, an anomalous blocking high occurs over northern Eurasia, while a cyclone anomaly appears over northern East Asia. In addition, the upper-level East Asian jet stream tends to shift northward and become stronger after the late 1990. Indeed, the interdecadal shift of winter SAT over East Asia is dynamical consistent with changes of the large-scale atmospheric circulation in the late 1990s. The result indicates that previous autumn sea surface temperature (SST) in the North Atlantic Ocean, the Northern Indian Ocean and the western North Pacific Ocean, as well as sea ice concentration (SIC) in the northern Eurasia marginal seas and the Beaufort Sea also experienced obvious changes in the late 1990s. In particular, the interdecadal shifts of both SST in the North Atlantic Ocean and SIC in the Arctic Ocean and its marginal seas are well coherent with that of the winter SAT over East Asia. The results indicate that the interdecadal shift of East Asian winter SAT may be related to changes in the North Atlantic SST and the Arctic SIC in the late 1990s.