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Prey selectivity by juvenile Atlantic cod Gadus morhua in three coastal habitat types

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Author

Summary, in English

Coastal habitats are heavily subjected to eutrophication and commercial fisheries, and such alterations can affect organism interaction strengths and potentially influence trophic dynamics. A key species inhabiting coastal environments in temperate waters is the Atlantic cod Gadus morhua, which utilises coastal areas for food and shelter. We used an experimental mechanistic approach to assay prey selectivity by juvenile cod when foraging on grass shrimp Palaemon elegans and brown shrimp Crangon crangon, under light and dark conditions, in 3 of the most abundant habitat types in temperate coastal environments-sand, eelgrass (artificial vegetation mimicking Zostera marina), and bladderwrack Fucus vesiculosus. Using functional response relationships from single-prey experiments, we calculated the energetically best foraging strategy for cod in the 3 habitats, i.e. feeding selectively on either of the shrimp species or on a combination of both. These predictions were tested in experiments where the cod predator was offered both prey species. Cod selected both prey species in accordance with our predictions in eelgrass and in bladderwrack under light conditions, but a lower than predicted consumption of grass shrimp was found in sand and in bladderwrack under dark conditions. Cod decreasingly selected grass shrimp with increasing habitat complexity, i.e. the highest selectivity was in sand and the lowest selectivity was in bladderwrack. As the 2 shrimp species have different trophic roles, cod selective predation may have effects on lower trophic levels. We provide a quantitative prediction of cod selective predation in habitat types that undergo degradation, and suggest that such predation can influence the trophic consequences from environmental change.

Publishing year

2012

Language

English

Pages

215-223

Publication/Series

Marine Ecology - Progress Series

Volume

466

Document type

Journal article

Publisher

Inter-Research

Topic

  • Ecology

Keywords

  • Prey choice
  • Functional response
  • Trophic cascade
  • Seagrass
  • Macroalgae
  • Atlantic cod
  • Gadus morhua
  • Shrimp

Status

Published

Project

  • Återuppbyggnad av torskbestånd i en föränderlig miljö - betydelsen av inomartsinteraktioner hos juvenil torsk

Research group

  • Aquatic Ecology

ISBN/ISSN/Other

  • ISSN: 1616-1599