|Onderzoek naar de biologie van de kwabaal ter voorbereiding van het herstel van de soort in het Vlaamse Gewest|
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Reference no: 02/008
Period: March 2002 till March 2004
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- Vlaamse overheid; Beleidsdomein Leefmilieu, Natuur en Energie; Instituut voor Natuur- en Bosonderzoek (INBO), more
|This research is part of a feasibility study for the recovery of the burbot in the Flemish Region, and is joined closely to two other researches conducted for this species (population genetics and artificial breeding under controlled circumstances). Besides a thorough literature study an extensive field campaign was conducted to explore the habitat use of the species.
In the literature study the population dynamics, habitat ecology, water quality requirements, the diet of different life stages, trophical relations (predation and competition), thermal ecology and possible diseases and parasites that might occur on burbot were studied.
Furthermore its actual distribution and its historic distribution in Flanders were investigated. The habitat use of the species was studied for different life stages in a reference biotope in the French Ardennes, in the river “La Bar”. This was done on three different scales of investigation for subadult and adult burbot: a regional scale over different river catchments, a
macroscale, within one river catchment, and a microscale, within one river. Habitat use of larval and juvenile burbot was investigated on the macroscale only. Furthermore radiotelemetry and fyke catches were used to investigate winter spawing migration. Most important conclusions of this research were that subadult and adult burbot prefer habitats with
shelter opportunities near the river bank, such as undercut banks, and that larval and juvenile burbot mainly occur in moderately flowing, highly vegetated tributaries. Adult burbot mainly migrated into the deeper tributaries and spawning migration was stimulated by a sudden increase of water level, after severe rainfall. These results allowed development and testing of habitat suitability models for subadult and adult burbot on one hand and for larval/juvenile/spawning habitat on the other hand. Application of these models on Flemish water courses lead to the formulation of measures of management for water- and fish stock managers, and two water courses were selected for a pilot reintroduction. Finally a field protocol was developed to evaluate habitat suitability of a river trajectory for subadult and adult burbot on one hand and for larvae, juveniles and spawning on the other hand.