Key aspects of egg incubation in Patagonian red octopus (Enteroctopus megalocyathus) for cultivation purposes Iker Uriarte a,b, ⁎, Viviana Espinoza a , Ranferi Gutiérrez b , Oscar Zúñiga c , Alberto Olivares c , Carlos Rosas d , Soledad Pino b , Ana Farías a,b a Hatchery de Invertebrados Marinos, Instituto de Acuicultura, Universidad Austral de Chile, Puerto Montt, Chile b Centro Regional CIEN Austral, Los Pinos s/n Balneario Pelluco, Puerto Montt, Chile c Facultad de Recursos del Mar, Universidad Antofagasta, Avda. Universidad de Antofagasta 02800, Antofagasta, Chile d Unidad Multidisciplinaria de Docencia e Investigación de Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mérida, México abstract article info Article history: Received 25 September 2013 Received in revised form 16 December 2013 Accepted 19 December 2013 Available online 7 January 2014 Keywords: Enteroctopus megalocyathus Patagonian red octopus Captive reproduction Embryo development Fatty acids Energy metabolism 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 cul- tivation 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 con- tamination 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 ob- serving 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 ob- served 168 days after spawning without any external yolk-sac on the hatched paralarvae. During their develop- ment, 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. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Over the last few years, aquaculture research in Chile has been strongly focused towards the diversification of species that have prob- lems in fisheries and are demanded in the global markets. Two Chilean octopus species have been investigated as serious candidates for aqua- culture in terms of their biological and market potential, one of them is the Changos octopus (Octopus mimus), found from Tumbes, Northern Perú (3° 34′ 00″S) to San Vicente Bay in Chile (33° 37′ 60″N), and the other is found in Southern Chile (from 34° 20´S to 72° 00´W to the Beagle Channel in Chile, up to Southern Argentina), known as Patagonian red octopus, Enteroctopus megalocyathus (Cardoso et al., 2004; Ibáñez and Chong, 2008; Ortíz et al., 2006; Rocha and Vega, 2003). In November 2008, the E. megalocyathus fishery was banned for 3 years in Chile, a rea- son that has made their aquaculture an important issue (Uriarte et al. 2011). According to Uriarte et al. (2011), the embryo incubation is a bottle- neck for the aquaculture of this particular species, and this difficulty adds up to the problem of cultivating paralarvae of developing octopus- es with merobenthic development (Berger, 2010; Iglesias et al., 2007). It is highly likely that E. megalocyathus might be a species that stems from a predecessor of direct development belonging to clade 5 as pro- posed by Ibáñez et al. (2013) that re-evolved into a species with pelagic paralarva, therefore, according to these authors it should be a species with a low to moderate fertility, large eggs and a paralarva that should be very large, with ambiguous swimming behavior in between pelagic and benthic. The information available from the literature shows that E. megalocyathus fits well with the predictions of Ibáñez et al. (2013) be- cause under culture conditions this species has shown moderate spawning that does not exceed 5000 eggs sized approximately 10 mm Aquaculture 424–425 (2014) 158–166 ⁎ Corresponding author at: Instituto de Acuicultura, Universidad Austral de Chile, PO Box 1327, Puerto Montt, Chile. E-mail address: iuriarte@uach.cl (I. Uriarte). 0044-8486/$ – see front matter © 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.aquaculture.2013.12.039 Contents lists available at ScienceDirect Aquaculture journal homepage: www.elsevier.com/locate/aqua-online