Comparison Between Individual and Group Rearing Systems in Octopus vulgaris (Cuvier, 1797)

Abstract

Recently most research on cephalopod culture has focused on the development of new specific enrichments for paralarvae and compound feeds for juveniles and sub‐adults. However, little research has been conducted in order to test new rearing systems, specifically designed to meet the particularities of these species. This experiment was set to compare the biological performance of Octopus vulgaris reared under traditional group conditions in floating cages (5 m3) and individually in net cages (80 L), in two successive ongrowing trials. Octopuses (1565 ± 263 g) were fed a mixed diet containing crab and fish during 60 d. In general, higher mortality was observed in octopus reared under group conditions (28.1–36.7%) rather than individually (0–12.5%), related to breeding behavior and to weight dispersion along both trials. This led to highest biomass increment in octopus reared individually. However, the group rearing system had a positive effect on growth, reflecting in higher biomass increment and food conversion rates until 40–50 d of rearing. Accordingly, in order to maximize profitability of traditional group on growing, periodic grading and selection of males during the reproductive period are recommended. In addition, no difference in proximate composition and fatty acid profile was found in muscle regardless of rearing system.

Effect of two fresh diets and sexual maturation on the proximate and fatty acid profile of several tissues inOctopus vulgaris: specific retention of arachidonic acid in the gonads

“…In spite of these, this fish induced very high growth performance in O. vulgaris after 2 months of feeding (Estefanell et al . ), similar to that observed in octopuses fed on single crab diets (Estefanell et al . ), confirming the efficient lipid utilization in O. vulgaris during the adult stage (Estefanell et al .…”

“…This is in agreement with previous studies where octopuses were fed on the same diets (Estefanell et al . , ) or on comparable diets based on bogue provided by fisheries (Biandolino et al . ; Prato et al .…”

“…; Estefanell et al . ). Both bogue origins, despite presenting variable protein contents (505–770 g kg −1 dw), showed similar and suitable amino acid profiles in comparison with that of O. vulgaris (Cerezo Valverde et al .…”

“…However, previous studies showed that low dietary ARA resulted in decreasing ARA levels in muscle, with no apparent negative effect on growth, even in octopuses that trebled their initial weight after 2 months of rearing (Estefanell et al . ). This was perhaps associated with the particular increase in eicosapentaenoic acid (EPA) in muscle (Estefanell et al .…”

Biological performance ofOctopus vulgarisin ‘integrated aquaculture’ models: effect of two potential fresh diets, sex and sexual maturation during the grow-out phase

“…The following biological parameters were calculated per cage: ‘Weight dispersion’, WD = SD/W af ; ‘Mortality’, (This parameter was calculated daily and displayed graphically as accumulated mortality every 10 days of rearing); ‘Biomass Increment’, (This parameter was standardized to 60 days of rearing, BI standardized: ; ‘Apparent Feed Conversion Ratio’, , where SD = standard deviation; W af = final average weight (g); n f = final number of specimens; n i = initial number of specimens; B f = final biomass (g); B i = initial biomass (g); W ai = initial average weight (g). Daily mortality data and individual growth data allowed the estimation of biomass on a daily basis, which was represented as accumulated BI S every 10 days of rearing (Estefanell, Roo, Guirao, Fernández‐Palacios, Izquierdo & Socorro ).…”