MEPS 583:195-209 (2017)  -  DOI: https://doi.org/10.3354/meps12319

ABSTRACT: Information about species interactions at a spatial scale comparable to the perceptive abilities of the involved species is crucial for establishment of predictive food consumption models at the population level. Nevertheless, such information is sparse due to methodological constraints. We studied the diel vertical dynamics of species interactions between Atlantic cod Gadus morhua and its major clupeid prey, sprat Sprattus sprattus, at a location in the Bornholm Basin of the central Baltic Sea during late winter. This was accomplished by combining acoustic information on diel vertical fish distribution, time of ingestion of individual sprat estimated from cod stomach content data and observed vertical profiles of salinity, temperature and oxygen content. Predation by cod took place primarily at dusk and dawn during ascent and descent of sprat associated with school dissolution and formation, respectively. Cod resided close to the bottom outside these temporal predation windows. Sprat schools were located at the same depth as cod in the daylight hours, whereas at night dispersed sprat were situated higher in the water column. These vertical dynamics could be explained by fitness optimization using bioenergetics and trade-offs between temperature, oxygen saturation of the water and predation risk. This study forms a first step towards providing a mechanistic background for the predatory impact of cod at the basin scale and beyond.

KEY WORDS: Baltic Sea · Stomach content dynamics · Diel feeding cycle · Bioacoustics · Hydrography · Winter situation · Bioenergetics · Fitness optimization

Full text in pdf format Supplementary material

Cite this article as: Andersen NG, Lundgren B, Neuenfeldt S, Beyer JE (2017) Diel vertical interactions between Atlantic cod Gadus morhua and sprat Sprattus sprattus in a stratified water column. Mar Ecol Prog Ser 583:195-209. https://doi.org/10.3354/meps12319 Export citation Share:    Facebook - - linkedIn