Intraspecific competition and density dependence of food consumption and growth in Arctic charr
Article first published online: 6 NOV 2006
Journal of Animal Ecology
Volume 76, Issue 1, pages 149–158, January 2007
How to Cite
AMUNDSEN, P.-A., KNUDSEN, R. and KLEMETSEN, A. (2007), Intraspecific competition and density dependence of food consumption and growth in Arctic charr. Journal of Animal Ecology, 76: 149–158. doi: 10.1111/j.1365-2656.2006.01179.x
- Issue published online: 6 NOV 2006
- Article first published online: 6 NOV 2006
- Received 26 April 2006; accepted 13 September 2006
- competitive interactions;
- freshwater fish;
- population abundance;
- resource limitation
- 1Intraspecific competition for restricted food resources is considered to play a fundamental part in density dependence of somatic growth and other population characteristics, but studies simultaneously addressing the interrelationships between population density, food acquisition and somatic growth have been missing.
- 2We explored the food consumption and individual growth rates of Arctic charr Salvelinus alpinus in a long-term survey following a large-scale density manipulation experiment in a subarctic lake.
- 3Prior to the initiation of the experiment, the population density was high and the somatic growth rates low, revealing a severely overcrowded and stunted fish population.
- 4During the 6-year period of stock depletion the population density of Arctic charr was reduced with about 75%, resulting in an almost twofold increase in food consumption rates and enhanced individual growth rates of the fish.
- 5Over the decade following the density manipulation experiment, the population density gradually rose to intermediate levels, accompanied by corresponding reductions in food consumption and somatic growth rates.
- 6The study revealed negative relationships with population density for both food consumption and individual growth rates, reflecting a strong positive correlation between quantitative food intake and somatic growth rates.
- 7Both the growth and consumption rate relationships with population density were well described by negative power curves, suggesting that large density perturbations are necessary to induce improved feeding conditions and growth rates in stunted fish populations.
- 8The findings demonstrate that quantitative food consumption represents the connective link between population density and individual growth rates, apparently being highly influenced by intraspecific competition for limited resources.