From Blake (1984: 150): "Microspio maori is present in densities ranging from 2600-6300 per m2 (x̅ = 4100 per m2) on intertidal sand flats of the Pauatahanui Inlet near Wellington. The sediments are moderately well sorted fine to very fine sands (Mz 2.9-3.3 phi) having a silt-clay content of 2-6%. Salinities range from 10-33‰. At Pauatahanui, the species is associated with a large maldanid, Axiothella serrata Kudenov and Read (1977), while in Wellington Harbor in organically rich, very fine sands, the most common associates are Boccardia spp."
Blake, James A. (1984). Four new species of Spionidae (Polychaeta) from New Zealand, with comments on a syntype of Spio aequalis Ehlers from Chatham Island. Proceedings of the Biological Society of Washington. 97(1): 148-159. available online athttps://biodiversitylibrary.org/page/34553466