Effect of temperature increase on the embryonic development of Patagonian red octopusEnteroctopus megalocyathusin controlled culture

Abstract

One of the major problems involved in the controlled cultivation of Patagonian red octopus (Enteroctopus megalocyathus) is its long embryonic period ranging between 150-176 days, after which the hatching of planktonic paralarvae is achieved. The effect of temperature on the incubation of E. megalocyathus eggs was studied with the aim of establishing if a temperature higher than 12°C is effective to accelerate the embryonic development without altering their morphological and physiological conditions. Fertilized eggs obtained under controlled conditions at 11°C AE 0.1 were randomly distributed in 12 water baths of 30 L at 4 temperatures: 12, 14, 15 and 16°C AE 0.1°C. The experiment lasted until egg hatching occurred.The embryo growth rate was accelerated at 15-16°C, so the time spent in embryonic development can be reduced in 15% when compared with embryo development obtained from eggs incubated at 12°C. The embryos showed no significant differences in the final survival and were morphometrically similar in all stages of development at all temperatures. The increase in temperature from 12 to 16°C, even if it allowed a better growth, had high metabolic costs for embryos of E. megalocyathus. The activities of lipases and proteases were affected by interaction between temperature and the embryo stage, with high lipase activity observed in embryos of stage XV incubated at high temperatures and the highest levels of trypsin and chymotrypsin in stage XX at 14°C. The results suggest that 15°C could be the limit temperature to increase growth.

Effects of temperature on embryo development and metabolism of O. maya

“…Temperature accelerates the embryonic development of several cephalopods, including O. maya (Boletzky, 1989;Bouchaud and Daguzan, 1990;Caverivière et al, 1999;Repolho et al, 2014;Uriarte et al, 2012Uriarte et al, , 2015Warnke, 1999). Although organisms that hatch earlier increase population fitness because offspring are produced sooner, there is evidence that delaying embryonic development may alter biochemical characteristics of the yolk that could improve hatchling characteristics (Uriarte et al, 2012(Uriarte et al, , 2015.…”

“…There have been many attempts raise these species by aquaculture. Each species has biological characteristics which impose different research and technological challenges for management of paralarvae, juveniles and broodstock, including nutrition Navarro and Villanueva, 2003;Seixas et al, 2008Seixas et al, , 2010Villanueva, 1995), culture of embryos and paralarvae (Iglesias et al, 2007;Iglesisas and Fuentes, 2014;Uriarte et al, 2014;Vidal et al, 2014), type of tanks Uriarte et al, 2011), seed density (Domingues et al, 2010;Rosas et al, 2014b), and water quality (Uriarte et al, 2015), among others, which have been the subject of research since the second half of the twentieth century (for reviews, see Uriarte et al, 2011;Vidal et al, 2014).…”

“…Several studies have demonstrated that incubation time can be reduced when octopus embryos are incubated at an optimum range of temperatures and have identified the temperature limits for embryo development through morphological and physiological characteristics of embryos during development (Boletzky and Hanlon, 1983;Mangold et al, 1971;Repolho et al, 2014;Uriarte et al, 2012Uriarte et al, , 2015Warnke, 1999). In E. megalocyathus, a temperate sub-polar octopus species, the optimum range of temperatures for embryo development was 12-15°C, and embryo development could be reduced by 15% when embryos were maintained at 15-16°C (Uriarte et al, 2015).…”

“…In E. megalocyathus, a temperate sub-polar octopus species, the optimum range of temperatures for embryo development was 12-15°C, and embryo development could be reduced by 15% when embryos were maintained at 15-16°C (Uriarte et al, 2015). This reduction is important because it translates to a reduction of 30 d for egg incubation, reducing risks associated with the maintenance of embryos in culture.…”

“…Ectotherms develop over physical time that is affected by temperature; this is why a combination of physical time and temperature, called 'thermal time', has been used in different studies of cephalopods to describe processes such as egg development (Márquez et al, 2013;Uriarte et al, 2012Uriarte et al, , 2015. Thermal time can be briefly defined as the product of time and temperature above a certain temperature threshold (th) at which embryo development is zero (Campbell et al, 1974).…”