Understanding ontogenetic and temporal variability of Eastern Baltic cod diet using a multispecies model and stomach data

Nataliia Kulatska*, Stefan Neuenfeldt, Ulrika Beier, Bjarki Þór Elvarsson, Håkan Wennhage, Gunnar Stefansson, Valerio Bartolino

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Size of predator and prey determines, to a large extent, predator-prey interactions in aquatic systems. Understanding the relationship between predator and prey size in the individual predator’s food selection process is a cornerstone of ecological modelling. Stomach content data are used to inform such models, as they provide prey species specific information about the predator diet in the wild. These data are strongly relevant as direct observations of species trophic interactions, but they have limitations, and are costly. Our objective was to develop and test a model which is able to predict changes in the Baltic cod diet by reconstructing the dynamics of cod and its prey, herring and sprat, populations, their length distributions, and parametrizing trophic interactions between them. We analysed time-series of cod stomach data and built an age-length structured multispecies model using Gadget. Both observed and predicted diets of smaller (juvenile) cod consisted mainly of benthos, while larger cod fed mostly on fishes (herring and sprat). Our model could predict the main patterns in species and length composition of cod diet. We also identified important knowledge gaps, especially on benthos dynamics and processes affecting prey availability and predator preference.
Original languageEnglish
JournalFisheries Research
Volume211
Pages (from-to)338-349
ISSN0165-7836
DOIs
Publication statusPublished - 2018

Keywords

  • Predator-prey interactions
  • Length selection
  • Diet composition
  • Multi-species model

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