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Atlantic coast feeding habits of striped bass: a synthesis supporting a coast-wide understanding of trophic biology 总被引:2,自引:0,他引:2
J. F. Walter III A. S. Overton K. H. Ferry & M. E. Mather 《Fisheries Management and Ecology》2003,10(5):349-360
The recent increase in the Atlantic coast population of striped bass, Morone saxatilis (Walbaum), prompted managers to re‐evaluate their predatory impact. Published and unpublished diet data for striped bass on the Atlantic Coast of North America were examined for geographical, ontogenetic and seasonal patterns in the diet and to assess diet for this species. Diets of young‐of‐the‐year (YOY) striped bass were similar across the Upper Atlantic (UPATL), Chesapeake and Delaware Bays (CBDEL) and North Carolina (NCARO) areas of the Atlantic coast where either fish or mysid shrimp dominate the diet. For age one and older striped bass, cluster analysis partitioned diets based on predominance of either Atlantic menhaden, Brevoortia tyrannus (Latrobe), characteristic of striped bass from the CBDEL and NCARO regions, or non‐menhaden fishes or invertebrates, characteristic of fish from the UPATL, in the diet. The predominance of invertebrates in the diets of striped bass in the UPATL region can be attributed to the absence of several important species groups in Northern waters, particularly sciaenid fishes, and to the sporadic occurrences of Atlantic menhaden to UPATL waters. In all regions, across most seasons and in most size classes of striped bass, the clupeiod fishes; menhaden, anchovies (Anchoa spp.) and river herrings (Alosa spp,) and Atlantic herring, Clupea harengus L., dominated the diets of striped bass above the first year of life. 相似文献
104.
张继兵 《吉林农业科技学院学报》2014,(1):90-91
良好的学习精神是时代的需求,更是每个人成长的需求.本文阐述了数学学习精神的内容及其重要性,并且提出了培养数学学习精神有以下几种政策,培养坚持精神的对策,培养钻研精神的对策,培养求美精神的对策以及培养良好学习习惯的对策. 相似文献
105.
[目的]综合评估不同结荚习性大豆(Glycine max)品种(系)的综合生产力表现,为大豆育种工作提供参考。[方法]用灰色关联度分析法对4个有限结荚习性大豆品种(铁99009-7、辽200045-2、铁00052-1、铁00027-5)和4个亚有限结荚习性大豆品种(铁97118-2、阜05-148、辽02品-4-3-1、铁丰33号)的主要农艺性状、光合速率、叶绿素含量和品质进行分析。[结果]等权关联度大小顺序依次为铁99009-7>铁00052-1>铁00027-5>阜05-148>辽02品-4-3-1>铁丰33号>辽000045-2>铁97118-2;加权关联度大小顺序依次为铁99009-7>铁00027-5>铁00052-1>辽000045-2>阜05-148>辽02品-4-3-1>铁丰33号>铁97118-2。所以有限结荚大豆品种铁99009-7综合表现最好,有限结荚大豆品种铁00052-1和铁00027-5次之,亚有限品种铁97118-2表现最差,其他品种居中。[结论]有限结荚习性品种综合表现优于亚有限结荚习性品种。 相似文献
106.
该研究旨在通过定点观察与人工授粉等方法,为黄菖蒲生殖生物学与杂交育种提供理论依据。对引种多年的黄菖蒲(Iris pseudacorus L.)的花器官特征、开花动态、花粉形态及活力、柱头可授性、繁育习性与访花昆虫进行了观察与研究,结果表明,黄菖蒲在南京地区为4月下—5月上开花,雌雄异熟;花粉活力与柱头可授性均为开花当天最强,随后下降;雌雄异位,开花过程中柱头向下弯曲,雄蕊始终短于柱头;花粉/胚珠比380.4,杂交指数为5。黄菖蒲的繁育习性为异交为主,部分自交亲和,需要传粉者,自然状态下存在花粉限制,不存在无融合生殖现象,黑纹食蚜蝇为潜在传粉者。 相似文献
107.
对暹罗斗鱼(Betta splendens)的生活习性、形态特征及分类地位等进行简要概述,并对经过了100多年人工改良所产生的暹罗斗鱼不同品系进行了详细介绍。根据用途可把暹罗斗鱼分为两大类:观赏型和搏击型斗鱼,其中观赏型斗鱼7种;根据鳞片的色层叠加顺序,暹罗斗鱼的颜色分为彩虹层颜色、金属层颜色和拓展层颜色,其中彩虹层颜色约15种,金属层颜色约7种,现阶段拓展层的终极表现形式为风靡的龙鳞;根据鳍膜的变化,又有蝶翼色和芥子色之分;根据鳞片的覆盖方式,定义了面具和黑头。详细了解暹罗斗鱼的品种分类特征,对于维持其品系的稳定性研究及其品种改良具有深远的意义。 相似文献
108.
本文针对青少年大量饮用碳酸饮料的现状,阐述了科学饮茶有利于青少年身体健康、修身养性、培养高尚的道德情操,提出了青少年如何科学合理饮茶、泡好茶,并希望茶产业推出更多适合青少年口味、绿色而又时尚的茶饮品。 相似文献
109.
通过田间观察和人工授粉等方法,对金银花的开花生物学和繁育特性进行了研究。结果表明,金银花盛花期在5月中旬至8月中旬。金银花花序为总状花序,开花顺序自下而上,多数花在8∶00~12∶00开放,开花时花药随之开裂,花冠颜色由绿色逐渐变为白色,枯萎时变为金黄色。单花期约15 d,花粉寿命为3 d,活力最大时达到72.5%。柱头在开花当天具有较大可授性。金银花花粉与柱头的有效可遇期为2 d,可同花自交。综合花粉/胚珠比、OCI值、人工授粉判断金银花属于兼性异交型。本试验还对金银花育种中适宜采用的杂交技术及育种途径进行了探讨。 相似文献
110.
RICHARD D. BRODEUR ELIZABETH A. DALY ROBERT A. SCHABETSBERGER KATHRYN L. MIER 《Fisheries Oceanography》2007,16(5):395-408
The feeding habits of juvenile coho salmon, Oncorhynchus kisutch, in the northern California Current were examined using samples from two different time periods (1980–85 and 1998–2003) of highly contrasting oceanographic conditions. The goal was to test the influence of interannual and interdecadal changes in taxonomic composition of prey, feeding intensity, and size spectra of teleost prey. Analyses were done for samples taken both early in the summer (June) shortly after the salmon enter the ocean, and also in late summer (September) following some ocean residency. Fish prey dominated coho salmon diets by weight during most years, but this trend was more pronounced during the 1980–85 sampling period. In terms of numerical composition, the diets were more variable on an interannual basis, but decapod larvae and euphausiids were important prey in most years. Pteropods and copepods were important prey during weak upwelling or El Niño years, whereas euphausiids were important during strong upwelling or otherwise highly productive years. Hyperiid amphipods comprised a substantial proportion of the diets only in 2000. Coho salmon showed highly significant differences in prey composition among years or between decades both in weight and numerical composition. The percentage of empty stomachs was highly variable by year in both June and September, but was significantly different only for September between decades. In contrast, an index of feeding intensity did not show many significant changes in either comparison. However, the relative size ratios for fish prey consumed were highly variable by year, and larger than average fish prey were consumed during 1998, leading to the highest feeding intensity observed. 相似文献