Enteroctopus megalocyathus (Gould, 1852) Southern Red Octopus

DWhatley

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First description of eggs, hatchlings and hatchling behaviour of Enteroctopus megalocyathus (Cephalopoda: Octopodidae) - March 2006
Nicolás Ortiz1,María Edith Ré1,Federico Márquez2

Full description available without subscription using the linked title at Journal of Plankton Research in both HTML display or PDF download.

Abstract:

As for many other commercially exploited octopodid species, there are no detailed descriptions of the eggs and hatchlings of Enteroctopus megalocyathus that can be used for the identification of individuals captured in plankton samples. Eggs, clutches and hatchlings are described here for the first time and compared with those of both other Patagonian octopodids and other Enteroctopus species. Relative to other Enteroctopus, hatchlings were large with total length (TL) 14.8–21.5 mm, mantle length (ML) 7–9.5 mm and arm length (AL) representing 90.5% of the mantle. Dorsal chromatophores were more abundant than ventral ones, and their shape and distribution created a very distinctive pattern. Eggs and hatchlings were found to have several characteristics that can be used for species identification. Although the mode of life of newly hatched cephalopods is often categorized as either planktonic or benthic, the hatchlings in aquaria showed no preference for swimming or settling. Additionally, the size of eggs and hatchlings which is correlated with the mode of life at hatching in other octopodid species, fitted both planktonic and benthic in E. megalocyathus. Furthermore, morphological and behavioural characteristics were similar to the pre-settlement stage of planktonic hatchlings of Octopus vulgaris. Therefore, we suggest that hatchlings of E. megalocyathus have an unusual, suprabenthic mode of life.

The reproductive cycle of the red octopus Enteroctopus megalocyathus in fishing areas of Northern Patagonian coast - 2011 Nicolás Ortiz,María E. Ré,Federico Márquez, Nora G. Glembocki

Full article requires subscription 2011


Abstract

The reproductive cycle of Enteroctopus megalocyathus was studied based on monthly diving surveys carried out between July 2004 and June 2007 over fishing areas at San José and Nuevo gulfs (Northern Patagonian coast, Argentine). Spermatophore production and storage and ovary-weight increase followed the trend in sea bottom temperatures, and reached maximum values at the beginning of summer. Mature males were found from mid winter onwards, while a low proportion of females showed spermatangia attached to the distal oviducts from mid spring to mid summer when they attained advanced maturity stages. A low frequency of spawning activity was observed during summer and winter months. There were no significant seasonal differences in the sex ratio. Total body weight (BW) and dorsal mantle length (ML) at 50% maturity were estimated at 1072 g and 135.4 mm for males and at 1613 g and 158.5 mm for females. Potential fecundity ranged from 1429 to 6427 oocytes and the number of fully developed spermatophores storage ranged from 1 to 13. Both, potential fecundity and number of spermatophores were significantly correlated with BW and ML. Although mating and breeding can occur in fishing areas, our results suggest that they are most likely to take place in sites deeper than the fishing grounds. This pattern is discussed considering the temperature-regulated aspects of cephalopods reproduction and the local oceanographic processes occurring in the gulfs.

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Highlights


► The reproductive cycle of the E. megalocyathus in Atlantic Patagonian coast. ► Two spawning periods were detected: one in summer and the other in winter. ► Males reach maturity earlier in the year and at smaller size than females. ► Reproductive output of male and female depend on body weight. ► Most animals would not complete the reproductive cycle in fishing sites.
 

DWhatley

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Key aspects of egg incubation in Patagonian red octopus (Enteroctopus megalocyathus) for cultivation purposes
Iker Uriarte, Viviana Espinoza, Ranferi Gutiérrez, Oscar Zúñiga, Alberto Olivares, Carlos Rosas, Soledad Pino, Ana Farías 2013 (subscription)

Abstract
Patagonian red octopus, Enteroctopus megalocyathus, is a valuable resource of the artisanal fishery in southern Chile, however, due to overfishing the E. megalocyathus fishery was banned for 3 years in Chile, therefore its cultivation became a target for the Chilean aquaculture. The rearing of octopus paralarvae is currently the biggest bottleneck for the aquaculture of merobenthic octopus species. Besides, the embryos of Patagonian red octopus require 5 months for embryonic development, a very long period of incubation that involves high risks of contamination and detachment, therefore, little advance has been achieved in the larviculture of this species. This study represents the first investigation to evaluate the embryo viability, embryo morphometrics, embryo growth and the biochemical composition and fatty acid dynamics during early development of Patagonian red octopus under captive reproduction. The eggs obtained from broodstock conditioning were incubated under maternal care and the embryos were studied until hatching in their main morphometric and biochemical features during development. Most females showed a tending behavior of the eggs along the incubation period, losing between 40 and 100% of the eggs in the first 3 months of incubation. The results of incubation at 11 °C were successful observing the complete gastrulation, onset of organogenesis and first inversion about 48 days after spawning, the complete organogenesis and second reversion were observed about 152 days after spawning, hatching was observed 168 days after spawning without any external yolk-sac on the hatched paralarvae. During their development, embryos showed an exponential growth rate in length and weight, fueled by the protein and lipids of external yolk-sac. Metabolism of lipids showed over a 70% depletion of the saturated fatty acids (SFA), and the fatty acids 16:1, 18:2n-6, 18:3n-3 and 22:5n-3 during development. The DHA/EPA ratio remained constant throughout the incubation period. The early embryos showed a fatty acid profile dominated by both SFA and highly unsaturated fatty acids (HUFA), while the newly hatched paralarvae showed a profile dominated by HUFA.
 

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