[1][2] M. maorum is one of the largest and most aggressive octopus species living in the New Zealand and Australian waters.

The morphological traits characteristic of this complex are a high number of gill lamellae, a robust conical copulatory organ and arms of varying length with long unequal dorsal arms generally four to six times longer than the mantle.

[2] Macroctopus maorum has 12–14 gill lamella per demibranch, the mantle is described as broadly ovoid and exhibits a skin pattern of longitudinal ridges.

[6] Fully mature male octopus consist of fully-formed spermatophores in the Needham’s sac.

[8] During brooding period female Macroctopus maorum will stop feeding so that it produce less wastes and ensure the water quality is good for the eggs.

[2] In New Zealand they are found off the coasts of both the North and South islands,[4] and is one of the most common species of octopus in the country.

[4] In Southeast Tasmania, at Eaglehawk Bay the site of a commercial fishery is the only known inshore location where the M. maorum have been known to gather in large numbers year round.

[4] Similar sightings of M. maorum in intertidal rock pools have been reported during the summer months in Kaikoura and Banks Peninsula.

[11] A study of M. maorum off the coast of southeastern Tasmania found evidence of 12 different species in the stomachs of sampled octopuses with the dominant prey being the crab P. gaimardii and other M.

[10] M. Maorum will eat bivalves, crustaceans and fish but are selective and show preference to lobster, crabs and scallops.

[2] As is the case with other octopus species, M. maorum injects prey with a toxin that slowly liquefies flesh so that it can be more easily digested.

[2] M. maorum is an extremely evolved hunter with a range of hunting methods including stalking, ambush, jet-propulsion and digging.

[11] Macroctopus maorum is preyed upon by fur seals, sea lions, pilot whales, other octopus and the northern royal albatross.

[4] A more recent study of the species adds wobbegongs, school and gummy sharks, mulloway, queen snapper and dolphins to the list of predators.

[14] M. maorum has a significant economic effect on rock lobster fisheries in New Zealand and Southern Australia.

[16] M. maorum are fished commercially in Eaglehawk Bay Tasmania where they congregate throughout the year in large numbers (as many as 70 octopuses).

However, SIA can only provide the relative age of the species, due to lack of knowledge surrounding the formation of the first stylet increment.