Characterization of cannibalism in early paralarvae of Patagonian red octopus, Enteroctopus megalocyathus (Gould, 1852), grown in a controlled environment

Abstract

In the experimental mariculture of Patagonian red octopus, Enteroctopus megalocyathus, paralarvae rearing showed the highest mortalities. Part of this mortality has been attributed to cannibalism, so we studied the joint effect of paralarvae density and prey availability upon cannibalism in the first 2 weeks after hatching. Three culture densities (1, 5, and 10 paralarvae/L) and three prey availabilities (0, 5, and 10 prey day −1 paralarvae −1) were tested. Two experiments were carried out in early paralarvae: one experiment where the prey consisted of artemia 5 mm in size (Experiment 1) and other experiment where the artemia size was 1 mm (Experiment 2). Results showed, in both experiments, that survival and cannibalism during the first 2 weeks after hatching were independent of the paralarvae density and the prey availability. In experiment 1, with artemia 5 mm in size, the mortality attributed to cannibalism decreased when the prey availability was increased, nor was there any effect Viviana Espinoza, Ana Farías, and Iker Uriarte belong to Interdisciplinary Network of Advanced Research for Marine Larviculture of Species with Complex Lifecycles (www.inlarvi.cl).

Trophic ecology of Octopus vulgaris paralarvae along the Iberian Canary current eastern boundary upwelling system

“…The oceanic squid Brachioteuthis was also detected in three O. vulgaris paralarvae collected in the oceanic area off Morocco, where Brachioteuthis was one of the most abundant cephalopod paralarvae sampled 21 . The methodology applied to characterise the diet does not allow the detection of predation in conspeci cs, but it may also constitute a potential prey since cannibalism has been detected in captivity in Octopus species 55,56 Other groups detected in the digestive tracts of the paralarvae, like rotifers, sponges or phytoplankton, might result from secondary predation 57 . Octopus paralarvae are visual predators that attack large prey compared with their size 12 , and these groups are too small to be captured by the paralarvae.…”

Assessment of culture density and prey availability for the management of cannibalism in paralarvae of Patagonian red octopus Enteroctopus megalocyathus

“…Fifteen paralarvae per replicate were distributed in 3, 5 or 20 L tanks with water volume according to the required densities. The preys consisted of Artemia salina reared from hatching to adult size of 5 ± 1 mm at 27°C and fed with T ‐ Isochrysis before harvesting, following Espinoza et al, (2020). Enrichment was carried out twice a day at a density of one Artemia ml −1, enriched with Nannochloropsis sp.…”

“…megalocyathus were not affected by paralarvae density in the range of 5 to 10 paralarvae L −1 fed under a wide range of prey availability. However, as proposed by these authors, in the early life of the paralarvae (until 15 DAH), the presence of viteline reserves can still mask part of the response to prey availability rearing density on cannibalism (Espinoza et al, 2020). The high percentages of cannibalism reported in the experiments of Miranda et al, (2011) for R .…”

“…megalocyathus , cannibalism starts early, 10 to 15 DAH, recording highly variable results of up to 60% of the total mortality in the first two weeks (Uriarte et al, 2013). Espinoza et al, (2020) documented for early paralarvae, under 15 DAH, that the survival and cannibalism of E . megalocyathus were not affected by paralarvae density in the range of 5 to 10 paralarvae L −1 fed under a wide range of prey availability.…”

The Lesser Pacific Striped Octopus, Octopus chierchiae: An Emerging Laboratory Model

“…(3) Safe containment: Octopuses are notoriously skilled at escaping containment (Wood and Anderson, 2004;Asada et al, 2021), therefore the design of octopus enclosures must include sufficient measures to prevent their escape. Additionally, cannibalism is common in many octopus species (Hanlon and Forsythe, 2008;Ibánez and Keyl, 2010;Miranda et al, 2011;Hernández-Urcera et al, 2014;Espinoza et al, 2021). Although some species of octopus have been reared in group tanks with moderate success (Domingues et al, 2012), individual enclosures remain the most ethical containment option to minimize the risk of cannibalism or stressful interactions with nearby octopuses.…”