369
19 Enteroctopus megalocyathus
with reproductive peaks in December and January (Ibáñez and Chong 2008), while
in the Patagonian waters of Argentina there is evidence of two annual laying periods,
one in winter and another starting in November–December (Ré 1980). Chong et al.
(2001) estimated the size of sexual maturity of females and males at 71.7 and 69.9 cm
total length (LT 50 % ), respectively, and 14.9 cm of mantle length (ML 50 % ) for both sexes. In the Patagonian coastal zone of Argentina, mature males are found during long
periods of time (April–November). Males show an average of seven spermatophores
in the Needham’s sac. As early as July, spermatangia are found in females. The sex
ratio remains 1:1 in breeding grounds, and in July the number of males increases due
to the displacement of fertilized females to deeper waters. A study on the reproductive
biology of E� megalocyathus in the Nuevo Gulf (42°49′58″S, 64°50′10″W) reported
the presence of a pseudohermaphroditic individual that could be classified externally
as male, but internally had female and male sexual structures (Ortiz and Ré 2006).
19.1.6 Natural Feeding
Most of the food items hunted by E� megalocyathus are brachiura and anomura
crustaceans, followed by fish and other octopuses (Ibáñez and Chong 2008). The
variability in the diet depends mainly on the size of Patagonian red octopus; therefore, small-sized octopuses feed on small crustaceans whereas larger specimens
prefer large crabs and octopuses of the same species, either juveniles or eggs. The
variation in the items available for hunting depends mainly on the habitat of the
octopus. Considering that they can reach a large size, and the abundance and type
of prey that is being hunted, it has been suggested that E� megalocyathus has a significant impact on the structure of the subtidal communities around the southern tip
of South America (Ibáñez and Chong 2008).
19.2 Broodstock Conditioning
Iglesias et al. (2000) concluded that reproduction is not a limiting factor on the
feasibility of cultivating the species O� vulgaris, and the diet during reproductive
conditioning should include crustaceans to ensure good quality of eggs. Similar
recommendations are given by Rosas et al. (2006) for the conditioning of the holobenthic species O� maya.
After courtship, in both species the mating occurs at ‘distance’ when the male
inseminates the female without embracing but introducing his hectocotylus into
the mantle of the female to pass one or more spermatophores (Rosas et al. 2006).
However, E� megalocyathus is a merobenthic species with a complex reproductive behaviour, with courtship preceding mating where the male mounts the female
(Gutiérrez et al. 2012). In this sense, Patagonian red octopus exhibits a reproductive behaviour similar to E� dofleini� Furthermore, the courtship and mating periods
depend on the size relation between the males and females (Gutiérrez et al. 2012).
19 Enteroctopus megalocyathus
with reproductive peaks in December and January (Ibáñez and Chong 2008), while
in the Patagonian waters of Argentina there is evidence of two annual laying periods,
one in winter and another starting in November–December (Ré 1980). Chong et al.
(2001) estimated the size of sexual maturity of females and males at 71.7 and 69.9 cm
total length (LT 50 % ), respectively, and 14.9 cm of mantle length (ML 50 % ) for both sexes. In the Patagonian coastal zone of Argentina, mature males are found during long
periods of time (April–November). Males show an average of seven spermatophores
in the Needham’s sac. As early as July, spermatangia are found in females. The sex
ratio remains 1:1 in breeding grounds, and in July the number of males increases due
to the displacement of fertilized females to deeper waters. A study on the reproductive
biology of E� megalocyathus in the Nuevo Gulf (42°49′58″S, 64°50′10″W) reported
the presence of a pseudohermaphroditic individual that could be classified externally
as male, but internally had female and male sexual structures (Ortiz and Ré 2006).
19.1.6 Natural Feeding
Most of the food items hunted by E� megalocyathus are brachiura and anomura
crustaceans, followed by fish and other octopuses (Ibáñez and Chong 2008). The
variability in the diet depends mainly on the size of Patagonian red octopus; therefore, small-sized octopuses feed on small crustaceans whereas larger specimens
prefer large crabs and octopuses of the same species, either juveniles or eggs. The
variation in the items available for hunting depends mainly on the habitat of the
octopus. Considering that they can reach a large size, and the abundance and type
of prey that is being hunted, it has been suggested that E� megalocyathus has a significant impact on the structure of the subtidal communities around the southern tip
of South America (Ibáñez and Chong 2008).
19.2 Broodstock Conditioning
Iglesias et al. (2000) concluded that reproduction is not a limiting factor on the
feasibility of cultivating the species O� vulgaris, and the diet during reproductive
conditioning should include crustaceans to ensure good quality of eggs. Similar
recommendations are given by Rosas et al. (2006) for the conditioning of the holobenthic species O� maya.
After courtship, in both species the mating occurs at ‘distance’ when the male
inseminates the female without embracing but introducing his hectocotylus into
the mantle of the female to pass one or more spermatophores (Rosas et al. 2006).
However, E� megalocyathus is a merobenthic species with a complex reproductive behaviour, with courtship preceding mating where the male mounts the female
(Gutiérrez et al. 2012). In this sense, Patagonian red octopus exhibits a reproductive behaviour similar to E� dofleini� Furthermore, the courtship and mating periods
depend on the size relation between the males and females (Gutiérrez et al. 2012).