21 Octopus mimus
399
mon even in animals kept at low densities (5 kg m
-3
) with an ad libitum food supply.
Also, a well-equilibrated diet needs to be formulated that ensures that all nutritional
requirements are covered and that such a diet enhances the conversion index so far
observed. That means that the animals reared in captivity must be larger and heavier
than those captured by the fishery. In terms of larval culture, the current results are
not very promising due to the high mortality occurring just before settlement of
paralarvae on the substratum, which is attributable to the lack of adequate food.
In our experiments, different stages of Artemia nauplii enriched with microalgae
and nutritional mixes, zoeas of decapods, rotifers and mashed crustacean eggs have
been used as food in paralarvae culture. The best paralarval survival rates have been
recorded when using densities of 25–50 paralarvae L
-1
. Although tested, survival
rates were not enhanced using water filtered at 1 μm, ultraviolet (UV) light, open
flow, different light intensities and tank colours. Also, survivals rates were not enhanced when paralarvae were fed with food stained with vegetal dye which seems
to facilitate the visualization and ingestion of food (unpublished data).
21.3 Broodstock and Spawning Process
21.3.1 Feeding
O� mimus is an opportunistic predator with a wide spectrum of prey. Studies using
animals from the Tarapaca (Chile), Ilo and Callao (Perú) regions found that this species can consume 25 different prey species. Predator preferences vary depending on
sex, maturity stage and seasonality, although a main order of preference consisted of
decapods crustacean, bivalves, echinoderms and teleost fishes (Cortez et al. 1995a,
1999; Cardoso et al. 2004).
Based on prey information, different laboratory and field studies have been carried out in order to assess the feasibility of O� mimus culture using fresh and frozen
food (Baltazar et al. 2000; Carrasco and Guisado 2010; Zúñiga et al. 2011). For
instance, Cortez et al. (1999) fed octopuses just with fresh molluscs obtaining on
an average very low growth rates (5.33 %/day in 40 days). Carrasco and Guisado
(2010) reported a specific growth rate (SGR) of 0.26 % body weight/day in subadult
octopus fed with the razor clam ( Tagelus dombeii) in laboratory conditions. Lower
rates were obtained when octopus were fed with the crabs Mursia gaudichaudi.
Thus, these results showed that O� mimus growth may depend on specific food
items since not all crustaceans and molluscs can satisfy the nutritional requirements.
In order to optimize O� mimus culture, Zúniga et al. (2011) used a diet consisting of
sausages made of fish and molluscs and obtained an absolute growth rate (AGR) of
7 g day
−1
, SGR of 0.7 % body weight day
−1
and survival close to 100 % on individuals kept in tanks with seawater flow of 60 L h
-1
.
It has been observed that maturity stages are influenced by the diet of O� mimus,
suggesting that energy and nutritional requirements may depend on maturity and
399
mon even in animals kept at low densities (5 kg m
-3
) with an ad libitum food supply.
Also, a well-equilibrated diet needs to be formulated that ensures that all nutritional
requirements are covered and that such a diet enhances the conversion index so far
observed. That means that the animals reared in captivity must be larger and heavier
than those captured by the fishery. In terms of larval culture, the current results are
not very promising due to the high mortality occurring just before settlement of
paralarvae on the substratum, which is attributable to the lack of adequate food.
In our experiments, different stages of Artemia nauplii enriched with microalgae
and nutritional mixes, zoeas of decapods, rotifers and mashed crustacean eggs have
been used as food in paralarvae culture. The best paralarval survival rates have been
recorded when using densities of 25–50 paralarvae L
-1
. Although tested, survival
rates were not enhanced using water filtered at 1 μm, ultraviolet (UV) light, open
flow, different light intensities and tank colours. Also, survivals rates were not enhanced when paralarvae were fed with food stained with vegetal dye which seems
to facilitate the visualization and ingestion of food (unpublished data).
21.3 Broodstock and Spawning Process
21.3.1 Feeding
O� mimus is an opportunistic predator with a wide spectrum of prey. Studies using
animals from the Tarapaca (Chile), Ilo and Callao (Perú) regions found that this species can consume 25 different prey species. Predator preferences vary depending on
sex, maturity stage and seasonality, although a main order of preference consisted of
decapods crustacean, bivalves, echinoderms and teleost fishes (Cortez et al. 1995a,
1999; Cardoso et al. 2004).
Based on prey information, different laboratory and field studies have been carried out in order to assess the feasibility of O� mimus culture using fresh and frozen
food (Baltazar et al. 2000; Carrasco and Guisado 2010; Zúñiga et al. 2011). For
instance, Cortez et al. (1999) fed octopuses just with fresh molluscs obtaining on
an average very low growth rates (5.33 %/day in 40 days). Carrasco and Guisado
(2010) reported a specific growth rate (SGR) of 0.26 % body weight/day in subadult
octopus fed with the razor clam ( Tagelus dombeii) in laboratory conditions. Lower
rates were obtained when octopus were fed with the crabs Mursia gaudichaudi.
Thus, these results showed that O� mimus growth may depend on specific food
items since not all crustaceans and molluscs can satisfy the nutritional requirements.
In order to optimize O� mimus culture, Zúniga et al. (2011) used a diet consisting of
sausages made of fish and molluscs and obtained an absolute growth rate (AGR) of
7 g day
−1
, SGR of 0.7 % body weight day
−1
and survival close to 100 % on individuals kept in tanks with seawater flow of 60 L h
-1
.
It has been observed that maturity stages are influenced by the diet of O� mimus,
suggesting that energy and nutritional requirements may depend on maturity and