From small-scale habitat loopholes to decadal cycles: a habitat-based hypothesis explaining fluctuation in pelagic fish populations off Peru   总被引：22，自引：0，他引：22  

Arnaud Bertrand  Marceliano Segura  Mariano Gutiérrez  & Luis Vásquez 《Fish and Fisheries》2004,5(4):296-316

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.  相似文献   

脱脂蚕蛹替代日粮中鱼粉对建鲤肠道菌群的影响     

钟雷  吉红  夏耘  张建禄  李南充  马明洋  郁二蒙  谢骏 《中国水产科学》2014,21(3):531-540

利用免培养的16S rDNA梯度凝胶电泳技术(DGGE)研究脱脂蚕蛹替代鱼粉对建鲤(Cyprinus carpio var. jian)肠道菌群的影响。6个饲养组分别饲喂6种等氮等能饲料, 分别为含10%鱼粉的基础饲料、3种替代饲料(脱脂蚕蛹替代鱼粉蛋白, 替代水平分别为25%、50%和75%)及2组分别在50%和75%替代基础上分别再添加0.6%和0.7%晶体赖氨酸的饲料 (分别记为DSP0、DSP25、DSP50、DSP50-Lys、DSP75、DSP75-Lys)。饲养结束后采集肠道样品, 分析建立指纹图谱, DSP0、DSP25、DSP50、DSP50-Lys、DSP75、DSP75-Lys组分别产生了19、15、11、12、8和12条可鉴别条带, 各组均存在优势种群条带。DSP0和其他各组(DSP25、DSP50、DSP50-Lys、DSP75、DSP75-Lys)的相似性指数为50.7%、50.6%、69.0%、42.4%、66.7%。对PCR-DGGE指纹图谱主要条带进一步回收、克隆和测序, 共得到19条序列, 将得到的序列在NCBI数据库中进行同源分析, 发现建鲤肠道菌群归为芽孢杆菌纲、螺旋体纲、β-变形菌纲、梭菌纲、放线菌纲、γ-变形菌纲、蓝藻纲、拟杆菌纲、梭杆菌纲等, 大部分为不可培养细菌。研究发现, 脱脂蚕蛹替代鱼粉对建鲤肠道菌群组成产生显著影响, 随着脱脂蚕蛹替代水平的提高, 肠道菌群多样性下降, 细菌种类从19种锐减至8种, 而饲料中补充赖氨酸可减弱这种影响, 本研究可为蚕蛹在鲤配合饲料中的开发应用提供参考资料。

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斜带石斑鱼胚胎及仔稚幼鱼形态发育   总被引：14，自引：4，他引：14       下载免费PDF全文

张海发  刘晓春  刘付永忠  王云新  林蠡  黄国光  舒琥  罗国武  林浩然 《中国水产科学》2006,13(5):689-699

对斜带石斑鱼(Epinephelus coioides)的胚胎及仔稚幼鱼形态发育进行了观察与研究,详细描述从受精卵到初孵仔鱼的28个具体发育时期的形态特征和发育时间。根据研究观察结果,将斜带石斑鱼胚胎发育划分为卵裂期、囊胚期、原肠胚期、神经胚期和器官形成期。在水温(25±0.5)℃、盐度31.0p、H 7.8的海水中,斜带石斑鱼胚胎历时28 h 30 min完成整个胚胎发育孵化出膜。胚后发育主要根据卵黄囊、腹鳍棘及第二背鳍棘、鳞片、体色的变化分为仔鱼期、稚鱼期、幼鱼期。仔鱼期根据卵黄囊的有无又分为早期仔鱼和晚期仔鱼。在水温24.5~29.2℃,盐度28.8~33.5,pH 7.5~8.5的海水中,培育至36 d,发育最快的斜带石斑鱼结束仔鱼期进入稚鱼期;培育至42 d,发育最快的稚鱼完成变态,成为幼鱼。斜带石斑鱼胚后发育过程中最明显的变化是腹鳍棘与第二背鳍棘以及鳍棘上小刺的长出与收回。  相似文献   

Lessons from the past: the collapse of Jamaican coral reefs     

Marah J. Hardt 《Fish and Fisheries》2009,10(2):143-158

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.  相似文献   

Angling for endangered fish: conservation problem or conservation action?          下载免费PDF全文

Steven J Cooke  Zeb S Hogan  Paul A Butcher  Michael J W Stokesbury  Rajeev Raghavan  Austin J Gallagher  Neil Hammerschlag  Andy J Danylchuk 《Fish and Fisheries》2016,17(1):249-265

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.  相似文献   

Identification and characterization of multiple <Emphasis Type="Italic">lck</Emphasis> genes in ginbuna crucian carp <Emphasis Type="Italic">Carassius auratus langsdorfii</Emphasis>   总被引：1，自引：0，他引：1  

Kyosuke Araki  Kaori Hirano  Fumio Takizawa  Tadaaki Moritomo  Mitsuru Ototake  Teruyuki Nakanishi 《Fisheries Science》2007,73(5):1017-1024

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南海灯笼鱼加工优质鱼粉的关键工艺研究     

黄卉  杨贤庆  李来好  陈作志  岑剑伟  郝淑贤  马海霞  黄碧霞 《南方水产科学》2016,(4):103-109

以南海优势鱼种灯笼鱼(Myctophum)为原料,对生产优质鱼粉的关键工艺脱腥、蒸煮温度、蒸煮时间、蒸煮p H、干燥温度进行了研究,并测定了产品品质指标。结果表明,灯笼鱼生产优质鱼粉的最佳工艺参数为脱腥液脱腥60 min,蒸煮温度95℃,蒸煮时间10 min,蒸煮p H 6.0,干燥温度80℃。在此条件下得到的灯笼鱼鱼粉中各组分的质量分数为粗蛋白61.92%,粗脂肪9.07%,水分9.32%,盐分2.59%,粗灰分17.45%,鱼粉的胃蛋白酶消化率为86.82%。  相似文献   

浙江中北部沿岸春、夏季鱼卵和仔稚鱼种类组成与数量分布   总被引：8，自引：0，他引：8  

周永东  金海卫  蒋日进  张洪亮  张亚洲  潘国良 《水产学报》2011,35(6):880-889

根据2008年4,5,6月在浙江中北部沿岸禁渔区线内45个站位开展的产卵场调查资料,研究分析了该海域鱼卵、仔稚鱼的种类组成和数量分布。结果表明,本海区共出现鱼卵、仔稚鱼64个种类,分别隶属13目36科47属,能鉴定到种的有47种,鉴定到科的有17种。3个航次的调查共采集到鱼卵5 846个和仔稚鱼5 502个。其中4月最少,仅采集到鱼卵366个和仔稚鱼1 445个,分别占鱼卵和仔稚鱼总数量的6.26%、26.26%;5月份共采集到鱼卵1 530个和仔稚鱼1 551个,分别占鱼卵和仔稚鱼总数量的26.17%、28.19%;6月份数量最多,共采集到鱼卵3 950个和仔稚鱼2 506个,分别占总数的67.57%、45.55%,4—6月鱼卵、仔稚鱼的数量呈月递增趋势。鱼卵中石首鱼科未定种最多占10.06%,其次黄姑鱼占6.45%,再次为凤鲚占总数的6.06%。凤鲚仔稚鱼数量最多,占总种类数的34.06%,其次为虾虎鱼科仔稚鱼,占24.25%,再次为鲻科鱼类仔稚鱼,占23.57%。调查发现杭州湾是凤鲚的主要产卵场,其仔稚鱼也主要分布在杭州湾内,少量分布在舟山渔场和鱼山渔场。小黄鱼产卵场主要分布在舟山渔场、鱼山渔场外侧。从产卵时间和渔场分布来看,鱼山渔场是最早集中的水域,随着时间推移,产卵场的中心区向北部水域的舟山渔场转移。研究的海域内重要经济鱼类大黄鱼、小黄鱼、银鲳的鱼卵数量百分比明显下降,由1960年的优势种成为现在的非优势种;主要经济鱼类中鳓、凤鲚所占比例相对增加,但绝对数量有所下降。在某种程度上说明,沿岸水域资源补充量有所减少,这可能与水域环境变化及过度捕捞导致亲体量减少有关。  相似文献   

大亚湾鱼卵、仔稚鱼种群特征与环境因子的相关关系   总被引：2，自引：0，他引：2  

王九江  刘永  肖雅元  王腾  李纯厚 《中国水产科学》2019,26(1):14-25

为了解大亚湾鱼卵、稚仔鱼种群动态变化及其与环境因子的关系, 2015年采用浅水I型浮游生物拖网对大亚湾鱼卵、仔稚鱼进行了4个季度的调查,结果表明,4个季度共采获鱼卵31361粒,仔稚鱼244尾。经鉴定分析共有27种,其中鱼卵19种,隶属于6目16科18属;仔稚鱼18种,隶属于5目15科16属;鱼卵、仔稚鱼共有种11个。鱼卵平均丰度为614.55 ind/1000 m^3,稚仔鱼的平均丰度为3.69 ind/1000 m^3。鱼卵丰度季节变化由高到低依次为夏季、春季、冬季、秋季;空间分布显示,丰度由高到低依次为中央列岛、人工鱼礁区、湾口东岸。鱼卵多样性指数(H￠)范围为0.05～2.26,平均值为0.86,稚仔鱼多样性指数(H?)范围为0～2.53,平均值丰度0.82;鱼卵均匀度指数(J)范围为0.02～0.99,平均值为0.50;稚仔鱼均匀度指数(J)范围为0～1.00,平均值为0.52。根据Pearson相关性结果分析表明,与种群关系最密切的环境因子为温度和溶解氧(P<0.01)。研究结果显示,春夏季是大亚湾海域鱼类产卵的重要时期,中央列岛海域是大亚湾鱼类繁殖的关键区域。  相似文献   

Effects of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus   总被引：2，自引：0，他引：2  

S.R. Craig  B.S. Washburn  D.M. Gatlin III 《Fish physiology and biochemistry》1999,21(3):249-255

This study was conducted to evaluate the effects of different concentrations of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus. Diets were formulated to contain 40% crude protein from solvent-extracted menhaden fish meal and 0, 7, 14 or 21% lipid from menhaden fish oil. The basal diet, without supplemental fish oil, contained lipid at 0.4% of dry weight. The diets were fed to groups of 25 juvenile red drum initially averaging 7.3 ± 0.18 g fish^–1 in a recirculating culture system for 8 weeks and weight gain was recorded. After an additional 8 weeks, 16 fish from each treatment were sacrificed and the following measurements were recorded: hepatosomatic index (HSI), intraperitoneal fat (IPF) ratio, and liver -tocopherol, malondialdehyde (MDA) formation, and cytochrome P-4501A activity (measured as 7-ethoxyresorufin O-deethylase (EROD) activity). The activity of alanine and aspartate aminotransferases and concentrations of -tocopherol also were measured in plasma.Weight gain was significantly (p<0.05) affected by dietary lipid concentration, with values ranging from 361% of initial weight for fish fed the basal diet to 527% of initial weight for fish fed the diet containing 7% lipid. The HSI and IPF ratio values also were significantly affected by lipid with the lowest values recorded for fish fed the basal diet and the highest values observed in fish fed the diet containing 21% lipid. Increasing dietary lipid significantly increased oxidative stress as reflected in reduced -tocopherol in liver and plasma and increased MDA formation in the liver, although no overt pathological signs were observed. These findings suggest that lipid concentrations between 7 and 14%, when the diet contains 60 IU vitamin E kg^–1, are likely to limit oxidative stress and result in normal physiological responses of red drum.  相似文献