Variation in Feeding, Aggression, and Position Choice between Hatchery and Wild Cutthroat Trout in an Artificial Stream
- 1 November 1991
- journal article
- Published by Oxford University Press (OUP) in Transactions of the American Fisheries Society
- Vol. 120 (6) , 723-727
- https://doi.org/10.1577/1548-8659(1991)120<0723:vifaap>2.3.co;2
Abstract
I compared feeding, aggressive behavior, and spatial distribution of differently ranked individuals of hatchery and wild coastal cutthroat trout Oncorhynchus clarki clarki in an artificial stream. Both hatchery and wild groups established stable dominance hierarchies that seemed to be based on size differences. Hatchery and wild fish within a hierarchical rank fed at similar rates. Hatchery fish were more aggressive than their wild conspecifics, irrespective of rank. Dominant hatchery fish were evenly distributed in pools and riffles, whereas dominant wild fish were three times more often in pools than in riffles. In both groups, socially intermediate fish were almost evenly distributed between pools and riffles, and subordinate fish spent most of their time in pools. On average, hatchery fish spent 57% of their time in pools and 43% in riffles, whereas wild fish spent 71% of their time in pools and 29% in riffles. These results support the hypothesis that excessive expenditure of energy for unne...Keywords
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