378
culated system is maintained with UV sterilization, temperature control, replacement
of sea water of 70 % tank day
−1
and O 2 concentration above 85 % saturation. After
reaching a weight of 1–2 g (Fig. 19.4a), juvenile octopuses are transferred to individual tanks of 27 L (Fig. 19.4b) and fed a fresh crab-based diet until they reach 20 g.
19.6 Ongrowing, Tank and Sea Cage Conditions
So far, the results in ongrowing of E� megalocyathus have not been published, but
there are studies of juveniles captured in the wild and brought to the laboratory for
ongrowing. González et al. (2008) reported for E� megalocyathus under individual
cultivation, from 300 to 1,500 g, a high dispersion in the growth rates related to the
type of feed used for ongrowing. The authors found that Patagonian red octopus did
not grow with a diet of bivalve molluscs, but did show significant growth when fed
crustaceans such as crabs, and also fish.
According to Farías et al. (2010), individuals that are cultivated from 300 to
1,500 g with formulated diets (pellet) do not show a good intake (0.3–0.7 % body
weight day
−1
), even though the digestibility was acceptable (47.1–61.8 %). The low
intake or rejection of the artificial diets explains the absence of growth, and it probably indicates that better attractants are needed. However, the best formulated diet
showed similar results to those tested with live crab, and for that reason it is assumed that it is possible to use a formulated diet, although it remains a challenge.
A comparative study on the energy physiology of O� maya and E� megalocyathus
carried out by Farías et al. (2009) showed that Patagonian red octopus has a high
growth rate that is similar to O� maya, despite the large difference in temperatures
of their habitats: 10 and 25 °C, respectively. This similarity in growth is due to a better energy efficiency of E� megalocyathus, despite being a cold-water species. This
better energy efficiency involves a higher food intake, a lower metabolic investment
(lower respiratory rate) and a more efficient use of protein towards energy. According to the authors, once the octopus is acclimated to its environmental conditions, it
can optimize its growth rate.
According to the results of Uriarte et al. (2011a), the exponential growth rates
of E� megalocyathus at 18 °C with a recirculation system varied between 0.33 and
1.25 % day
-1
for specimens between 10 and 500 g. Gutiérrez et al. (2013) show
that the exponential growth rate for juveniles fed natural diets is between 0.77 and
1.01 % day
−1
in octopuses weighing 297 g at temperatures of 12.9 °C with flowthrough systems.
The field results of ongrowing in a deep farming system have been reported by
Medrano and Godoy (2011). Their results showed SGR of 0.52 and 0.77 % day
−1
for
females and males at a density of 5 kg m
−3
and a reduction to 0.40 and 0.24 % day
−1
,
respectively, when density increases to 10 kg m
−3
(Table 19.3).
Í. Uriarte and A. Farías
culated system is maintained with UV sterilization, temperature control, replacement
of sea water of 70 % tank day
−1
and O 2 concentration above 85 % saturation. After
reaching a weight of 1–2 g (Fig. 19.4a), juvenile octopuses are transferred to individual tanks of 27 L (Fig. 19.4b) and fed a fresh crab-based diet until they reach 20 g.
19.6 Ongrowing, Tank and Sea Cage Conditions
So far, the results in ongrowing of E� megalocyathus have not been published, but
there are studies of juveniles captured in the wild and brought to the laboratory for
ongrowing. González et al. (2008) reported for E� megalocyathus under individual
cultivation, from 300 to 1,500 g, a high dispersion in the growth rates related to the
type of feed used for ongrowing. The authors found that Patagonian red octopus did
not grow with a diet of bivalve molluscs, but did show significant growth when fed
crustaceans such as crabs, and also fish.
According to Farías et al. (2010), individuals that are cultivated from 300 to
1,500 g with formulated diets (pellet) do not show a good intake (0.3–0.7 % body
weight day
−1
), even though the digestibility was acceptable (47.1–61.8 %). The low
intake or rejection of the artificial diets explains the absence of growth, and it probably indicates that better attractants are needed. However, the best formulated diet
showed similar results to those tested with live crab, and for that reason it is assumed that it is possible to use a formulated diet, although it remains a challenge.
A comparative study on the energy physiology of O� maya and E� megalocyathus
carried out by Farías et al. (2009) showed that Patagonian red octopus has a high
growth rate that is similar to O� maya, despite the large difference in temperatures
of their habitats: 10 and 25 °C, respectively. This similarity in growth is due to a better energy efficiency of E� megalocyathus, despite being a cold-water species. This
better energy efficiency involves a higher food intake, a lower metabolic investment
(lower respiratory rate) and a more efficient use of protein towards energy. According to the authors, once the octopus is acclimated to its environmental conditions, it
can optimize its growth rate.
According to the results of Uriarte et al. (2011a), the exponential growth rates
of E� megalocyathus at 18 °C with a recirculation system varied between 0.33 and
1.25 % day
-1
for specimens between 10 and 500 g. Gutiérrez et al. (2013) show
that the exponential growth rate for juveniles fed natural diets is between 0.77 and
1.01 % day
−1
in octopuses weighing 297 g at temperatures of 12.9 °C with flowthrough systems.
The field results of ongrowing in a deep farming system have been reported by
Medrano and Godoy (2011). Their results showed SGR of 0.52 and 0.77 % day
−1
for
females and males at a density of 5 kg m
−3
and a reduction to 0.40 and 0.24 % day
−1
,
respectively, when density increases to 10 kg m
−3
(Table 19.3).
Í. Uriarte and A. Farías