Egg survival and morphometric development of a merobenthic octopus, Octopus tetricus, embryos in an artificial octopus egg rearing system

Abstract

The major limiting factor for the development of commercial scale octopus aquaculture globally is the lack of hatchery technology for incubating, hatching and raising octopus larvae to provide the seed for growout. In the absence of a hatchery seed supply, octopus aquaculture currently relies on fattening wild-caught sub-adults to market size which is commercially unsustainable. This study examines the effectiveness of an artificial octopus egg incubation system which eliminates the costs associated with maintaining females for egg brooding. The development timetable and hatching of eggs from three broods of the common Sydney octopus, Octopus tetricus, was examined in an upwelling incubation system using four experimental combinations of seawater flow and aeration. Hatching success of over 90 % was achieved in upwelling incubation systems with added aeration for all three broods, compared to 10–40% in upwelling systems without aeration. In contrast, the higher rate of seawater flow only improved hatching success in the absence of aeration, suggesting that continuous turbulence is required around developing eggs for maintaining egg health and development, especially through the reduction of infection with pathogens. The results demonstrate that incubation of O. tetricus eggs is achievable in the absence of maternal care, an important first step toward greater efficiency in hatchery production of octopus seed to supply commercial aquaculture.