Abstract

Eutrophication and reduced grazing have led to an expansion of the common reed (Phragmites australis) in ar-chipelago areas in the Baltic Sea, while at the same time the composition of submerged vegetation has changed. Although reed is important as nursery habitat for many fish species, extensive emergent vegetation may reduce biodiversity and abundance of predatory fish. Pike (Esox lucius) is a predatory fish whose larvae and young-of -the-year find both food and shelter in reed but use different micro-habitats during different life-stages. Here we investigate the influence of reed and submerged vegetation on abundance and body size of adult pike during the spawning season. We predicted that coastal bays with extensive but heterogeneous reed beds with higher cover of submerged vegetation would have more and larger pike than bays with smaller, homogenous reed belts or with less submerged vegetation. To test these predictions, we estimated abundance and size-structure of adult pike from catches in angling fishing among 22 bays in the Stockholm archipelago at the Swedish Baltic Sea coast. Our analyses show that catches of adult pike were positively associated with both extensive reed beds and cover of rooted submerged vegetation. However, pike size was not correlated with any vegetation variable, but instead increased with wave exposure and bay area. Our study suggests that reed beds and submerged vegetation are important for adult pike during the spawning season, and even the most extensive reed beds had no evident negative effect on pike populations. We could not see any clear relationship between emergent reed habitat and cover of submerged vegetation among the studied bays, and conclude that to maintain pike population during the spawning season it is important that coastal bays have sufficient amounts of both reed beds and rooted submerged vegetation.

Keywords

Reed expansion; Pike; Baltic Sea; Spatial distribution; Habitat utilization; Angling; Esox lucius; Phragmites australis

Published in

Fisheries Research
2023, Volume: 261, article number: 106621
Publisher: ELSEVIER

SLU Authors

• Niemi, Niklas

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

• Bergström, Ulf

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

• Östman, Örjan

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Conserve and sustainably use the oceans, seas and marine resources for sustainable development


UKÄ Subject classification

Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.1016/j.fishres.2023.106621

Permanent link to this page (URI)

https://res.slu.se/id/publ/121443