Shelter use of familiar and unfamiliar groups of juvenile European catfish Silurus glanis
Publication Type: |
Journal Article |
Year of Publication: |
2012 |
Authors: |
Ondřej Slavík, Matúš Maciak, Pavel Horký |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
familiarity, sheltering behaviour, spatial distribution, welfare |
ISBN: |
0168-1591 |
Abstract:
Within aquaculture systems, shelters are often used to reduce cannibalism, minimise energy consumption, accelerate the start of exogenous feeding, support growth, and improve survival and welfare. However, stronger competition for shelters in aquaculture systems relative to that under wild conditions may result in a higher level of aggressiveness accompanied by an increase in energy consumption. Furthermore, fish stress can increase when unfamiliar conspecifics are introduced during fish farming. Agonistic behaviours, however, can be decreased by familiarity established based on the repeated contact of individuals. Under laboratory conditions, we observed the behaviour of two unfamiliar groups of juvenile 0+ European catfish. To study the spatial preferences of fish, we used passive integrated transponders, and we tested the hypothesis that familiarity would be a key factor affecting shelter occupancy if the number of shelters was less than the number of conspecifics. The results showed that the catfish preferred the shelter area. Conspecifics maintained the groups that were formed prior to mixing and displayed a tendency to control limited resources. This behaviour was indicated by the odds ratio for occupying the shelter vs. remaining in the original area of the familiar group, with a majority of familiar specimens being present in the shelter area. The logarithm of this odds ratio increased over time and reached the highest value at the end of the experiment, indicating there was a slightly greater than 9-fold higher likelihood of choosing a shelter in the presence of a familiar majority. The results presented herein indicate that available resources are primarily used on the basis of familiarity.