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首页> 外文学位 >Nursery delineation, habitat utilization, movements, and migration of juvenile Carcharhinus plumbeus in Chesapeake Bay, Virginia, United States of America.
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Nursery delineation, habitat utilization, movements, and migration of juvenile Carcharhinus plumbeus in Chesapeake Bay, Virginia, United States of America.

机译：美利坚合众国弗吉尼亚州切萨皮克湾的幼稚Car鱼的保育圈划，栖息地利用，移动和迁移。

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摘要

Chesapeake Bay is possibly the largest summer nursery for Carcharhinus plumbeus in the western Atlantic. Longline sampling conducted from 1990--1999 was used to delineate this nursery spatially and temporally. Catch data from 83 longline stations sampled throughout the Virginia Chesapeake Bay were analyzed as a function of nine physical and environmental variables to delineate this nursery spatially. Tree-based models determined which variables best discriminated between stations with high and low catches and indicated that complex distribution patterns could be adequately modeled with few variables. The highest abundance of juvenile sharks was predicted where salinity was greater than 20.5 and depth was greater than 5.5 meters. Longline data from 100 sets made at two standard stations in the lower Bay indicated that immigration occurred in late May and early June and was highly correlated with increasing water temperature. Emigration from the estuary occurred in late September and early October and was highly correlated with decreasing day length. Between 1995 and 2000, 1846 juvenile C. plumbeus were tagged. With two exceptions, recaptures made in summer months were within 50 kilometers of the tagging location. Those recaptured in winter months were caught between 200 and 830 kilometers from the tagging location and indicated that the coastal waters of North Carolina and South Carolina serve as important winter nurseries from late October until May. Tag recaptures made in subsequent summers suggest that most juvenile sandbar sharks return to the same summer nurseries annually. Ultrasonic telemetry was used in investigate the diel activity patterns of juvenile C. plumbeus in Chesapeake Bay. Ten sharks were tracked for 10 to 50 consecutive hours. Swimming direction was correlated with mean direction of 2 tidal currents. Mean activity space was conservatively estimated to be 110 km2, which is two orders of magnitude greater than that reported for other carcharhiniform species. Swimming depth ranged from surface to 40 meters and was significantly deeper during the day (12.8 meters) than during the night (8.5 meters). This diel activity pattern and large activity space is hypothesized to be an adaptation for foraging on patchy prey in a productive, yet dynamic, temperate estuary.
机译：切萨皮克湾可能是西部大西洋上最大的真鲨属夏季托儿所。从1990--1999年进行的延绳钓抽样在空间和时间上描绘了这个苗圃。根据九个物理和环境变量对来自整个弗吉尼亚切萨皮克湾的83个延绳钓站的渔获量数据进行了分析，以在空间上描绘该苗圃。基于树的模型确定了哪些变量可以最好地区分高捕获量和低捕获量的站，并表明复杂的分布模式可以用很少的变量进行充分建模。盐度大于20.5且深度大于5.5米时，预计幼鲨的数量最多。来自下湾两个标准站的100套装置的延绳钓数据表明，移民发生在5月下旬和6月初，并且与水温升高高度相关。从河口移民发生在9月下旬和10月初，与日长的减少高度相关。在1995年至2000年之间，对1846年少年C. plumbeus进行了标记。除两个例外，夏季的重新捕获都在标记位置的50公里以内。冬季被俘的人距离标签位置200至830公里，并指出从10月下旬至5月，北卡罗来纳州和南卡罗来纳州的沿海水域是重要的冬季苗圃。在随后的夏季进行的标签捕获表明，大多数幼年的沙洲鲨每年都返回相同的夏季苗圃。超声遥测技术被用来研究切萨皮克湾少年梭状芽孢杆菌的diel活性模式。连续10到50个小时追踪了10条鲨鱼。游泳方向与2个潮流的平均方向相关。据保守估计，平均活动空间为110平方公里，比其他甲虫类动物报道的活动空间大两个数量级。游泳深度从地表到40米不等，白天（12.8米）比夜间（8.5米）深得多。这种diel的活动模式和较大的活动空间被认为是在生产性但动态的温带河口觅食斑驳猎物的一种适应方式。

著录项

  • 作者

    Grubbs, Ralph Dean.;

  • 作者单位

    The College of William and Mary.;

  • 授予单位 The College of William and Mary.;
  • 学科 Biology Ecology.;Agriculture Fisheries and Aquaculture.;Biology Zoology.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 234 p.
  • 总页数 234
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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