Skip to main content
Research article - Peer-reviewed, 2020

Long-term changes in spatial overlap between interacting cod and flounder in the Baltic Sea

Orio, Alessandro; Bergström, Ulf; Florin, Ann-Britt; Šics, Ivo; Casini, Michele

Abstract

The strength of interspecific competition and predator-prey interactions depends on the area of co-occurrence of the interacting species. Therefore, it is necessary to quantify the changes in the spatial overlap of trophically connected species to understand the outcomes of species interactions. In the Baltic Sea, the interplay between cod and flounder has previously been neglected. In this study, we use four decades of data on cod and flounder distributions covering the southern and central Baltic Sea to: (1) model and map the changes in the distributions of the two species using generalized additive models; (2) quantify the temporal changes in the potential competitive and predator-prey interactions between them using spatial overlap indices; (3) relate these changes in overlap to the known dynamics of the different cod and flounder populations in the Baltic Sea. Competition overlap has continuously increased for cod, from the beginning of the time-series. This is a possible cause of the observed decline in feeding levels and body condition of small and intermediate sized cod. Flounder overlap with large cod instead has decreased substantially, suggesting a predation release of flounder, potentially triggering its increase in abundance and distribution range observed in the last decades.

Keywords

Cod; Competition; Flounder; Predation; Spatial modeling; Species interaction

Published in

Hydrobiologia
2020, volume: 847, number: 11, pages: 2541-2553

Authors' information

Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Šics, Ivo
Institute of Food Safety, Animal Health and Environment (BIOR)
Swedish University of Agricultural Sciences, Department of Aquatic Resources

Associated SLU-program

Coastal and sea areas

Sustainable Development Goals

SDG14 Life below water

UKÄ Subject classification

Fish and Aquacultural Science

Publication Identifiers

DOI: https://doi.org/10.1007/s10750-020-04272-4

URI (permanent link to this page)

https://res.slu.se/id/publ/105375