Differences in diet of Atlantic bluefin tuna (Thunnus thynnus) at five seasonal feeding grounds on the New England continental shelf
Differences in diet of Atlantic bluefin tuna (Thunnus thynnus) at five seasonal feeding grounds on the New England continental shelf
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新英格兰大陆架五个季节性觅食地的大西洋蓝鳍金枪鱼 (Thunnus thynnus) 饮食差异
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发表时间：
2002
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通讯作者：
B. Chase
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作者：
B. Chase
对 1988 年至 1992 年采样的 819 条大西洋蓝鳍金枪鱼 (Thunnus thynnus) 的胃进行了分析，以比较新英格兰大陆架 (杰弗里斯礁、Stellwagen Bank、科德角湾、大南海峡和玛莎葡萄园岛南部) 五个捕捞地的饮食差异，这些捕捞地是美国大西洋商业捕捞的大部分地区。猎物的空间变化预计是蓝鳍金枪鱼季节性摄食迁徙期间分布的主要影响因素。就所有区域的出现频率和猎物重量百分比而言，沙矛鱼 (Ammodytes spp.)、大西洋鲱鱼 (Clupea harengus)、大西洋鲭鱼 (Scomber scombrus)、鱿鱼 (Cephalopoda) 和蓝鱼 (Pomatomus saltatrix) 是最高的猎物。研究区域之间的猎物组成不相关，但斯泰瓦根浅滩和大南海峡之间存在显着关联，其中沙矛鱼和大西洋鲱鱼最常出现。除大南海峡和科德角湾外，所有研究区域的平均胃内容物生物量差异显着。在缅因湾的四个地区中，杰弗里斯礁奇的平均胃内容物生物量最高（2.0 公斤），科德角湾的平均胃内容物生物量最低（0.4 公斤）。五个地区中有四个地区的饮食以一两种小型中上层猎物为主，其他几种中上层猎物的贡献较小。相比之下，科德角湾饮食中发现的猎物物种中有一半是底层物种，包括经常出现的无柄无花果海绵（Suberites ficus）。蓝鳍金枪鱼的猎物尺寸选择在各种长度上都是一致的。 2-4岁的沙矛鱼和大西洋鲱鱼以及0-1岁的鱿鱼和大西洋鲭鱼是各种尺寸的蓝鳍金枪鱼的常见猎物。这是第一项比较西大西洋蓝鳍金枪鱼在季节性迁徙到新英格兰大陆架期间不同觅食地的饮食组成并评估捕食者与猎物大小关系的研究。之前的研究并未发现底栖物种常见，也没有发现蓝鳍金枪鱼的饮食中大西洋鲱鱼占主导地位。
The stomachs of 819 Atlantic bluefin tuna (Thunnus thynnus) sampled from 1988 to 1992 were analyzed to compare dietary differences among five feeding grounds on the New England continental shelf (Jeffreys Ledge, Stellwagen Bank, Cape Cod Bay, Great South Channel, and South of Martha’s Vineyard) where a majority of the U.S. Atlantic commercial catch occurs. Spatial variation in prey was expected to be a primary influence on bluefin tuna distribution during seasonal feeding migrations. Sand lance (Ammodytes spp.), Atlantic herring (Clupea harengus), Atlantic mackerel (Scomber scombrus), squid (Cephalopoda), and bluefish (Pomatomus saltatrix) were the top prey in terms of frequency of occurrence and percent prey weight for all areas combined. Prey composition was uncorrelated between study areas, with the exception of a significant association between Stellwagen Bank and Great South Channel, where sand lance and Atlantic herring occurred most frequently. Mean stomach-contents biomass varied significantly for all study areas, except for Great South Channel and Cape Cod Bay. Jeffreys Ledge had the highest mean stomach-contents biomass (2.0 kg) among the four Gulf of Maine areas and Cape Cod Bay had the lowest (0.4 kg). Diet at four of the five areas was dominated by one or two small pelagic prey and several other pelagic prey made minor contributions. In contrast, half of the prey species found in the Cape Cod Bay diet were demersal species, including the frequent occurrence of the sessile fig sponge (Suberites ficus). Prey size selection was consistent over a wide range of bluefin length. Age 2–4 sand lance and Atlantic herring and age 0–1 squid and Atlantic mackerel were common prey for all sizes of bluefin tuna. This is the first study to compare diet composition of western Atlantic bluefin tuna among discrete feeding grounds during their seasonal migration to the New England continental shelf and to evaluate predator-prey size relationships. Previous studies have not found a common occurrence of demersal species or a pre-dominance of Atlantic herring in the diet of bluefin tuna.