Evaluatie van de pilootherintrodutie van kwabaal in Grote Nete en Bosbeek
Book - Report
This study presents the first results of the evaluation study of the re-introduction of burbot (Lota lota) in Flanders (Belgium).
In the River Bosbeek (province of Limburg) and several tributaries of the River Grote Nete (province of Antwerp) more than 2.000.000 burbot larvae were re-introduced between February 23th and March 21st 2005. On October 28th 2005 respectively 2000 and 1000 ‘young of the year’ (YOY) burbot were released in the Rivers Grote Nete and Bosbeek. The burbot larvae and the YOY originated from the Aquaculture Research Centre which is part of the Research Institute for Nature and Forest.
A single sampling of the tributaries of the River Grote Nete and the River Bosbeek was performed 3 months after the release of the burbot larvae. It was assumed that the re-introduction had failed because the monitoring (with electric fishing techniques) of the tributaries in June 2006 resulted in no recaptures of juvenile burbot.
A second re-introduction with YOY burbot in October 2006 in the Rivers Grote Nete and Bosbeek on the other hand seemed to have been successful. Two months after their release juvenile burbot were caught on all sampled locations in both rivers. Another more limited sampling session on 2 locations in the River Grote Nete, 6 months after the release, showed that still the same density of burbot was present in comparison to the first sampling session (i.e. 2 months after release). All recaptured individuals seemed to be in good condition with a good growth rate. A further evaluation of the survival, growth, maturation and reproduction of the reintroduced burbot individuals is needed to see if self-sustaining and reproducing populations establish themselves in the studied rivers and tributaries.