Evaluation of reproductive performances of the common octopus (Octopus vulgaris) reared in water recirculation systems and fed different diets

Abstract

The reproductive performance of Octopus vulgaris broodstocks fed two different diets (mixed fish [F group, BW 1,048.14 g] or mixed crustaceans [C group, BW 998.44 g]) was analyzed using an experimental recirculating aquaculture system consisting of a tank equipped with spawning and incubation chambers. A total of 8 females (F1–4; C1–4), and 8 males (M1–M8) were selected. DI of the C group females was significantly (p < 0.05) higher (3.0 ± 0.29%) than the F group (2.16 ± 0.67%). SGR in C group was significantly higher (1.43 ± 0.12%) than the F group (1.18 ± 0.25%). Egg clusters, number of clusters, number of clusters/kg BW, and total length were more favorable in the C group than the F group. The number of clusters/kg BW of C females was 2.5 times higher than that of F females (78.1 ± 6.5 vs 31.1 ± 13.3). The total eggs number, number of eggs/cm, number of eggs/kg BW in the C group were significantly (p < 0.05) higher compared with the F group; the number of eggs/kg BW and paralarvae/kg BW were 5 times higher in the C group (115,928 ± 12,513 C vs 22,109 ± 7912 F and 114,953 ± 12,591 vs 20,729 ± 7104, respectively). Hatching rate of the C group was significantly (p < 0.05) higher compared to the F group.

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

“…Regarding zootechnical performance, ENR octopuses showed a greater weight gain than BAS ones. Additionally, the AGR and SGR values in the ENR tank showed three times higher values than the BAS tank, and these results correspond to those of other studies in which a suitable environment and a predominantly crustacean diet were found to promote octopus growth [64,86,87]. In contrast, octopuses kept in BAS tanks showed inappetence and rejection of food, which led to a decrease in their weight.…”

“…All octopuses underwent the conditioning program, which consisted of an increase in temperature of 1 • C/week until 20 • C and an increase in a photoperiod of 1 h/month up to 15 h light and 9 h dark [64]. The animals were fed ad libitum once a day with a mix of frozen (20%) and fresh (80%) fish and crustacean (40% Squilla mantis, 40% Carcinus sp., and 20% Boops boops) [64].…”

XXVIII Annual Meeting of the Italian Association for Laboratory Animal Sciences

“…This being said, a series of precautions must be taken concerning tank characteristics (rectangular, 700-1500 L, grey beige vs. blue, grids, covers, surface area/octopus), environmental enrichment (sand, rocks, stones, shells vs. NO), den (plastic vs. terracotta, size), ethological/behavioural needs (predator, solitary, territorial, cannibalism), eco-physiological conditioning programmes (temperature, photoperiod, salinity), feeding (ad libitum vs. rationed, crustaceans vs. fish, live vs. unfrozen) during the animal's various life stages (male/female, growth, sexual maturity, reproduction, senescence), water quality (pH, ammonia, nitrite), and animal handling (anaesthesia, confinement) [21]. Parallel to housing conditions, all the preceding phases are equally important, in particular, the catching method (trap vs. hand line), the transport system (type of tank, isolation, number of subjects, water quality, temperature), and timing (<24 h>), as if this is carried out in an unsuitable manner, it can cause stress/distress to the animal which is difficult to reverse and has repercussions in the relaying environment, even if all other conditions are optimal [22].…”