MORPHOLOGY AND BlOLOGY OF OCTOPUS MAORUM HUTTON 1880 IN NORTHERN NEW ZEALAND

摘要

Octopus maorum Hutton l880 is a temperate, shallow water, benthic octopus com- monly found in southern Australia and temperate to subantarctic regions of New Zealand. Individuals are found subtidally to depths >50 m, commonly associated with soft-sedi- ment 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), a maorum may be distingUished from other species by an orange-brown or purple- gray color with namerous 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-sum- mer spanner, 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 l8deg.C). Hatchlings are small-mediam in size (total length 5 .06 mm), planktonic, and have a unique and conservative founder chiomatophore pattern. Octopus maorum is an aggressive spe- cies that caunibalizes smaller individuals and eggs, and may also attack and eat co-occur- ring species (i.e., Octopus tetricus) regardless of size.