Fish manipulation as a lake restoration tool in shallow, eutrophic temperate lakes 1: cross-analysis of three Danish case-studies
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
The use of fish manipulation as a tool for lake restoration in eutrophic lakes has been investigated since 1986 in three shallow, eutrophic Danish lakes. The lakes differ with respect to nutrient loading and nutrient levels (130-1000 μg P l-1, 1-6 mg N l-1). A 50% removal of planktivorous fish in the less eutrophic cyanobacteria-diatom dominated Lake Væng caused marked changes in lower trophic levels, phosphorus concentration and transparency. Only minor changes occurred after a 78% removal of planktivorous fish in eutrophic cyanobacteria dominated Frederiksborg Castle Lake. In the hypertrophic, green algae dominated Lake Søbygård a low recruitment of all fish species and a 16% removal of fish biomass created substantial changes in trophic structure, but no decrease in phosphorus concentration. The different response pattern is interpreted as (1) a difference in density and persistence of bloomforming cyanobacteria caused by between-lake variations in nutrient levels and probably also mixing- and flushing rates, (2) a difference in specific loss rates through sedimentation of the algal community prevaling after the fish manipulation, (3) a decreased impact of planktivorous fish with increasing mean depth and (4) a lake specific difference in ability to create a self-increasing reduction in the phosphorus level in the lake water. This in turn seems related to the phosphorus loading.
Originalsprog | Engelsk |
---|---|
Tidsskrift | Hydrobiologia |
Vol/bind | 200-201 |
Udgave nummer | 1 |
Sider (fra-til) | 205-218 |
Antal sider | 14 |
ISSN | 0018-8158 |
DOI | |
Status | Udgivet - aug. 1990 |
ID: 281332703