Do the visual conditions at the point of escape affect european sea bass escape behaviour?

TitleDo the visual conditions at the point of escape affect european sea bass escape behaviour?
Publication TypeJournal Article
Year of Publication2013
AuthorsPapadakis, IE, Papadakis VM, Glaropoulos A, Petroutsos SI, Png González L, Kentouri M
JournalMediterranean Marine Science
Pages172 - 178
KeywordsBehaviour, Cage aquaculture, Escape, European sea bass, Net pen, Obstacle

European sea bass (Dicentrarchus labrax), an important species for the Mediterranean aquaculture industry, has been reported to escape from sea cage installations. Fish escapes are caused mainly by operational and technical failures that eventually create tears. Escapees may interact with wild stocks through interbreeding, transfer of pathogens and competition for food. The aim of this study was to examine to what extent the presence of a visible obstacle close to a tearin the net influences sea bass propensity to escape. Fish were initially confined into small sea cages, with a tear on one side. The escape behaviour was tested under experimental conditions. It is clearly demonstrated that sea bass were able to locate a tear in the net pen, immediately after its appearance. Crossings occurred in all cages, in singles or in a series of up to seven individuals. The presence of an obstacle close to the net tear altered the escape behaviour of D. labrax, resulting in a delay that eventually reduced the escape rate. To conclude, it is highly recommended that sea bass cages should be kept internally the culture array. Furthermore, the placement of artificial obstacles close to the sea cages could be an efficient practice that mitigates the escape risk after severe environmental conditions.


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