Effects of Environmental Enrichment on the Behavior of Octopus vulgaris in a Recirculating Aquaculture System

SIMPLE SUMMARY: Octopuses, like other cephalopods, have specific behaviors that correspond to a sequence of body patterns. Each pattern is the result of various components that, when performed simultaneously, have different outcomes. The vast repertoire in pattern production is associated with the complexity and variety of environmental enrichment. The greater the complexity of the environment, the greater the possibility of observing a wide variety of patterns. In this study, we evaluated how different environmental conditions affect subjects of Octopus vulgaris maintained in an aquaculture system through the observation of major body patterns. The results showed that octopuses kept in an enriched environment showed significantly more body patterns and gained significantly more weight than the subjects kept in a basic environment. The body patterns manifested by the octopuses maintained in a basic environment were similar to those exhibited under situations of hostility and inter/intra-specific conflict. They did not interact much with the surrounding habitat, the conspecifics, or the operator. Therefore, environmental enrichment is recommended for the individuals of this species that are kept in a recirculating aquaculture system (RAS). ABSTRACT: Octopus vulgaris is a commercially valuable species. It is overexploited in the natural environment and is considered to be an innovative species for aquaculture. However, large-scale farming is generally designed only based on economic requirements, disregarding any form of enrichment that induces the natural behavior of aquatic species. Although many studies have shown the influence of environmental enrichment on terrestrial vertebrates, fish, and cephalopod mollusks, information on the effect of environmental enrichment on the body patterns of O. vulgaris is limited. Therefore, in this study, we assessed how different environmental conditions (Basic vs. Enriched) affect sub-adults of O. vulgaris kept in recirculation systems, through qualitative–quantitative studies of the main body patterns and their potential application in the commercial production of this species. The results indicated that octopuses kept in the enriched environment showed several body patterns and gained a significantly higher weight than those kept in the basic environment. The body patterns displayed by the individuals kept in the basic environment were similar to those exhibited under situations of hostility and inter/intra-specific conflict. Hence, the environment of octopuses needs to be enriched, especially for the large-scale production of this species.