A 15-year Study of the Spatial Distribution of Rutilus rutilus and Perca fluviatilis in Late Summer in Two Shallow Lakes With Contrasting Trophic State

Zeynep Pekcan Hekim,Martin Søndergaard,Torben Lauri̇dsen,Erik Jeppesen,Tserenpil Shurkhuu,Liselotte Johansson

doi:10.17216/limnofish.893563

Abstract

Roach (Rutilus rutilus) and perch (Perca fluviatilis) are dominant species in northern-temperate lakes of Europe, their relative importance depending on trophic state and habitat complexity. We studied the habitat distribution of roach and perch over a 15-year period in two Danish lakes, Lake Væng, undergoing major changes in water clarity and macrophyte coverage, and the permanent turbid Lake Søbygård. We used multi-mesh sized gill nets in 5-6 different sections of the lakes following the same program in all years. Both species were evenly distributed in the sections and among habitats, in Lake Væng during the turbid period and in Lake Søbygård during the whole study period. During the clear-water period in Lake Væng, however, the distribution of roach and perch was uneven and the density negatively correlated with macrophyte coverage and density, but the strength of the relationship differed between the two species and between small (≤ 8 cm for roach and &lt;10 cm for perch) and larger fish. Our results suggest that water clarity and macrophyte density were of key importance in determining roach and perch distribution in these two shallow lakes.

Highlights

Biotic, abiotic and spatial factors influence the habitat distribution of fish in lakes (Donald et al.2000)
No difference was observed for pH, dissolved oxygen concentration and water temperature (p> 0.5) (Table 1). pH, water temperature, oxygen concentration and Secchi depth did not differ significantly in Lake Søbygård between the two selected periods with macrophytes (1989-1996) and without macrophytes (1988, 1997-2002) in Lake Væng (Table 1)
Fish Proportionally, roach and perch were the species most frequently caught in both lakes during the sampling period of 1988-2002

Summary

Introduction

Abiotic and spatial factors influence the habitat distribution of fish in lakes (Donald et al.2000). Spatial complexity plays an important role in the distribution patterns of fish by offering a refuge from predators (Jacobsen and Berg 1998) or a habitat. The resource use of fish differs with size, potentially influencing their habitat choice (Werner and Hall 1979). High turbidity can reduce the predation risk and thereby enhance the foraging activity of the prey fish (Gregory and Northcote 1993) It can influence diel and seasonal migratory activity (Ginetz and Larkin 1976) by reducing the use of shelter and increasing the use of open water by prey fish (Miner and Stein 1996; Utne-Palm 2002; Snickars et al 2004; Pekcan-Hekim et al 2005)

Methods

Results

Conclusion