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The influence of food quality and availability on trophic position, carbon signature, and growth rate of an omnivorous crayfish

  • Karin Olsson
  • Per Nyström
  • Patrik Stenroth
  • Erika Nilsson
  • Marie Svensson
  • Wilhelm Granéli
Publishing year: 2008
Language: English
Pages: 2293-2304
Publication/Series: Canadian Journal of Fisheries and Aquatic Sciences
Volume: 65
Issue: 10
Document type: Journal article
Publisher: National Research Council Canada

Abstract english

Fourteen sites in 13 streams were surveyed to address the importance of food quality and quantity on trophic position, carbon signature, and growth rate of noble crayfish (Astacus astacus) by combining the analyses of gut content, stable isotopes, and RNA-DNA ratio. The gut content analysis showed an omnivorous feeding habit, but total animal food sources contributed more to the nitrogen and carbon isotope signals of this species. The biomass of invertebrates (i.e., high quality food) influenced the trophic position, carbon signature, and growth rate. Our results show that crayfish in streams with a high biomass of invertebrates were at a higher trophic position and had a higher growth rate than crayfish in streams with a low biomass of invertebrates. A high biomass of relatively sedentary invertebrates indicates a habitat with high algae biomass, which is reflected in the more autochthonous carbon signature of crayfish. Further, noble crayfish in temperate streams seem to have dual functional roles by acting as predator and as shredder by processing large amounts of detritus.


  • Ecology


  • ISSN: 1205-7533
Wilhelm Granéli
E-mail: wilhelm [dot] graneli [at] biol [dot] lu [dot] se

Professor emeritus

Aquatic ecology

+46 70 279 82 34