Morphology and Biology of Octopus Maorum Hutton 1880 in Northern New Zealand

Octopus maorum Hutton 1880 is a temperate, shallow water, benthic octopus commonly found in southern Australia and temperate to subantarctic regions of New Zealand. Individuals are found subtidally to depths >50 m, commonly associated with soft-sediment shellfish beds, but may be found less commonly traversing reefal habitats. Clearly a member of the Octopus macropus complex, and possibly the largest member (at 9.2 kg), O. maorum may be distinguished from other species by an orange-brown or purple-gray color with numerous small iridescent white spots on the arms, web and dorsal arm crown, but no spots on the mantle region. Octopus maorum appears to be a spring-summer spawner, at which time females lay thousands (7000) of eggs individually to the substratum. Eggs are 6.5–7.5 mm in size and take approximately 2 mo to hatch (at 18°C). Hatchlings are small-medium in size (total length 5.06 mm), planktonic, and have a unique and conservative founder chromatophore pattern. Octopus maorum is an aggressive species that cannibalizes smaller individuals and eggs, and may also attack and eat co-occurring species (i.e., Octopus tetricus) regardless of size.