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首页> 外文期刊>ICES Journal of Marine Science >Diet and size-selective feeding by escaped hatchery rainbow trout Oncorhynchus mykiss (Walbaum)
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Diet and size-selective feeding by escaped hatchery rainbow trout Oncorhynchus mykiss (Walbaum)

机译：逃生的孵化场虹鳟Oncorhynchus mykiss（Walbaum）的饮食和体型选择喂养

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Escaped hatchery rainbow trout, Oncorhynchus mykiss (Walbaum), at post-smolt (120-340 g) and adult stages (800-3400 g) adapted differently to natural marine prey after escaping from two fish farms in northern Norway. About 1 month after escape (July), more than 57% of the post-smolt fed actively on fish larvae, which contributed 63-75% of the diet by weight. Surface insects were consumed by more than half the post-smolts and represented 24-48% of the diet during the 3-month period of sampling (June-August). One month after escaping, forage ratios (weight stomach/weight fish x 100) exceeded 1, similar to ratios recorded for other wild anadromous salmonid species in the area. Post-smolt weight increased during the sampling period and the condition factor was stable. In contrast, the condition factor of escaped adult fish reduced significantly and the forage ratios were consistently low (0.05-0.77) during the 15 months of sampling (March-August) following their escapement. These fish fed primarily on a variety of different indigestible items (especially particles of seaweed and small pieces of wood) that contributed about 70% of the stomach content weight. They took fish larvae only in July. Although generally contributing little to their overall diet, marine prey of great variety was consumed by the adult fish. The results indicate that young domestic rainbow trout more easily adjust to natural feeding after escape than the older, larger fish, which often fed on indigestible items similar in shape to the commercial pellets to which they were accustomed.
机译：从挪威北部的两个养鱼场逃脱后，在孵化后（120-340克）和成年阶段（800-3400克）的逃逸孵化场虹鳟Oncorhynchus mykiss（Walbaum）适应了不同的自然海洋猎物。逃逸后约1个月（7月），超过57％的后排t鱼以鱼幼虫为食，占日粮重量的63-75％。在采样的3个月期间（6月至8月），地表昆虫被一半以上的蜕皮动物所消耗，占饮食的24-48％。逃逸一个月后，草料比（胃/鱼的重量×100）超过了1，与该地区其他野生无性鲑科鱼类的记录相似。在采样期间，-后体重增加，条件因子稳定。相比之下，成年鱼逃逸后的15个月采样（3月至8月）中，成鱼逃逸的条件因子显着降低，饲草比率始终较低（0.05-0.77）。这些鱼主要以各种不同的不易消化的食物（尤其是海藻颗粒和小块木头）为食，这些食物占胃内容物重量的约70％。他们只在七月才取鱼幼虫。尽管一般来说对它们的整体饮食几乎没有贡献，但成年鱼食用了种类繁多的海洋猎物。结果表明，幼年虹鳟比逃脱后的自然鱼类更容易适应自然饲养，后者通常以形状类似于他们习惯的商业颗粒的不易消化的食物为食。

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