ADULT BIOLOGY OF THE RIVER LAMPREY (LAMPETRA-AYRESI) AND THE PACIFIC LAMPREY (LAMPETRA-TRIDENTATA) FROM THE PACIFIC COAST OF CANADA
ADULT BIOLOGY OF THE RIVER LAMPREY (LAMPETRA-AYRESI) AND THE PACIFIC LAMPREY (LAMPETRA-TRIDENTATA) FROM THE PACIFIC COAST OF CANADA
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DOI：
10.1139/f80-232
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发表时间：
1980-01-01
影响因子：
2.4
通讯作者：
BEAMISH, RJ
中科院分区：
文献类型：
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作者：
BEAMISH, RJ
七叶鳗(Lampetra Ayresi)在七月下旬发生变性，随后一年(5月至7月)向下游迁徙。一旦成虫进入盐水，它们就会立即开始进食，主要是从鲱鱼和幼鲑鱼中摄取大块的肉。从6月到9月，它们的大小估计增加了11-14 cm和12-18 g。1975年，佐治亚州海峡估计有667 000 000的七鳃鳗，导致60 000 G000-000的幼鱼死亡。从9月到冬末，七鳃鳗回到淡水中。产卵发生在春季，从4月到6月，成虫在产卵后死亡。从开始变态到产卵死亡的成虫寿命为2 年。太平洋七鳃鳗(Lampetra Tridentata)在7月开始变态，已知的进入咸水的时间是从12月到6月。到10月中旬，可以在淡水或咸水中开始喂养。太平洋七鳃鳗活动于20-70 米深的水中，存在于加拿大西海岸外的所有主要渔场。观察到在准备返回淡水的红鱼和粉红鲑鱼上聚集的七鳃鳗攻击的发生率相对较高。在这项研究中发现的最小的成熟或成熟的太平洋七鳃鳗长16 厘米，最大的长72 厘米。成虫可能会在4月至6月期间在盐水中度过，然后在4月至6月返回淡水中，并在9月下旬完成上游迁徙。春季返回的种群表现出特殊的迁徙本能，通常在4月至次年7月产卵之前，在淡水中相当长的距离迁徙到支流的最上面区域。进入淡水后，在产卵之前，成鱼的身长缩短了约20%。从开始变态到产卵死亡的平均寿命可能为5 年。一种似乎是一种新物种的非淡水期形式存在于湖泊中，并攻击了很大比例的栖息鲑鱼。关键词：太平洋七鳗鱼，河七鳗鱼，生活史，鱼类寄生虫，太平洋鱼类
River lamprey (Lampetra ayresi) metamorphoseinlate July with downstream migration occurring in the following year from May to July. Once adults enter salt water they begin to feed immediately by consuming chunks of flesh primarily from herring and young salmon. From June until September they increase in size by an estimated 11–14 cm and 12–18 g. In 1975, 667 000 lamprey were estimated to be in the Strait of Georgia resulting in the deaths of 60 000-000 juvenile fish. Between September and late winter river lamprey return to freshwater. Spawning occurs in the spring, from April to June and adults die after spawning. The length of adult life from the onset of metamorphosis until death following spawning is 2 yr. Pacific lamprey (Lampetra tridentata) begin metamorphosis in July and the known period of entry into salt water is from December until June. Feeding can commence in freshwater or salt water by mid-October. Pacific lamprey move into water deeper than 20–70 m and are present in all major fishing grounds off Canada's west coast. A relatively high incidence of lamprey attacks has been observed on sockeye and pink salmon that are aggregating in preparation to return to freshwater. The smallest mature or maturing pacific lamprey found in this study measured 16 cm and the largest measured 72 cm. Adults may spend in salt water before returning to freshwater from April to June and completing their upstream migrations by late September. Stocks that return in the spring exhibit exceptional migratory instincts often migrating considerable distances in freshwater to the uppermost regions of tributary streams before they spawn from April to July in the following year. After entry into freshwater and prior to spawning, adults shrink in length by approximately 20%. The average life span from the onset of metamorphosis until death following spawning probably is 5 yr. A nonanadromous form that appears to be a new species exists in lakes and attacks a large percentage of resident salmonids.Key words: Pacific lamprey, river lamprey, life history, fish parasites, Pacific fishes