Effects of commercial fishery on the bream population and the expansion of Chara aspera in Lake Veluwe

Authored by Egbert van Nes, EHRR Lammens, ML Meijer, den Berg MS van

Date Published: 2004

DOI: 10.1016/j.ecolmodel.2003.10.002

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

The fish community in the shallow Lake Veluwe (3400 ha) has recently changed in composition. The total biomass of fish decreased to ca. 35\% of the original biomass. The change in fish biomass followed the introduction of a commercial fishery and was in its turn followed by a rapid expansion of macrophyte beds dominated by Chara aspera Deth. ex Willd. An individual-based fish model was used to evaluate the causation of these events. We estimated natural mortality of the bream population (Abramis brama L.) using data on growth, recruitment and size distribution. The model predicted that without the fishery the biomass of the bream population would hardly change and that the fishery could explain the change in the biomass and size composition. The rapid expansion of C. aspera was unlikely without the fishery, as Chara needs transparency down to the bottom and undisturbed sediment. The reduction of the bream population created favourable conditions for zebra mussels Dreissena polymorpha (Pallas) to settle which in turn created the clear water, necessary for the development of the Chara beds. (C) 2003 Published by Elsevier B.V.

Tags

Individual-based model Dynamics Temperature Water-quality Growth-rate Size Communities Vegetation Mussel dreissena-polymorpha Shallow eutrophic lake