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Göteborgs universitets publikationer

Density-dependent growth rate in an age-structured population: a field study on stream-dwelling brown trout Salmo trutta

Författare och institution:
Rasmus Kaspersson (Zoologiska institutionen); Johan Höjesjö (Zoologiska institutionen)
Publicerad i:
Journal of Fish Biology, 74 ( 10 ) s. 2196-2215
Artikel, refereegranskad vetenskaplig
Sammanfattning (abstract):
A field experiment during autumn, winter and spring was performed in a small stream on the west coast of Sweden, aiming to examine the direct and indirect consequences of density-dependent intercohort competition in brown trout Salmo trutta. Individual growth rate, recapture rate and site fidelity were used as response variables in the young-of-the-year (YOY) age class, experiencing two different treatments: presence or absence of yearlings and over-yearlings (age ≥ 1+ year individuals). YOY individuals in stream sections with reduced density of age ≥ 1+ year individuals grew significantly faster than individuals experiencing natural cohort structure. In the latter, growth rate was negatively correlated with density and biomass of age ≥ 1+ year individuals, which may induce indirect effects on year-class strength through, for example, reduced fecundity and survival. Movement of YOY individuals and turnover rate (i.e. proportion of untagged individuals) were used to demonstrate potential effects of intercohort competition on site fidelity. While YOY movement was remarkably restricted (83% recaptured within 50 m from the release points), turnover rate was higher in sections with reduced density of age ≥1+ year individuals, suggesting that reduced density of age ≥1+ year individuals may have released favourable microhabitats.
Ämne (baseras på Högskoleverkets indelning av forskningsämnen):
Biologiska vetenskaper
competition, fish, intercohort, movement, survival, winter
Postens nummer:
Posten skapad:
2009-08-13 09:58

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