Analysis of middens shows a change in preference for shellfish species over time. For instance at Tairua, the lower layer (early 1400s) had rocky shore shellfish but the upper layer (early 1700s) had sandy beach species with pockets of rocky shore species perhaps suggesting isolated meals. At the Sunde site, rocky shore species dominate the lower midden under the Rangitoto Ash but pipi and cockle account for about 95% of shells in the upper or later midden, possibly explained by changes in the local beach environment as a result of the eruption of Rangitoto. Very detailed examination of the contents of the Sunde midden below the Rangitoto Ash on Motutapu found kina were the most important by meat weight, contributing more than other shellfish combined (Nichol 1988).
The first people in an area gathered the large rocky shore shellfish, probably following similar practices used in the Polynesian homeland on the extensive coastal platforms. The most commonly eaten rocky shore shellfish were mussel, cats eye, cooks turban, white rock shell, oysters and limpet.
Generally speaking there has been a trend over time away from the rocky shore and towards greater exploitation of estuarine and sandy beach environments. While the early sites have mainly rocky shore species with some sandy shore species, late sites are almost all cockle, pipi and tuatua with small numbers of gastropods such as Amphibola and Cominella. This is probably because the soft shore environment was more able to sustain regular harvesting.
Estimates of meat weight from various foods in middens indicate shellfish was a minor component in the diet of the early settlers. Fish and sea mammals such as seals formed the bulk of the protein eaten.
Shellfish commonly represented in middens include cockle, pipi, tuatua, oyster, paua, mussel, scallop, cats eye, Amphibola spp., Cominella spp., dog cockle, cooks turban and white rock shell. In some sites the shells of oyster, dog cockle, paua and cooks turban have been used to make ornaments and fishhooks.
Marine mammals
Evidence of sea mammals occurs only in sites dated 400–700 years ago (see Table 3). The remains of fur seals, sea lions and elephant seals are present in a number of sites. The bones of pups and juveniles indicate there were breeding colonies of seals in the vicinity of some of these sites. Winter hunting is suggested from the juvenile bones at Opito, Sarah's Gully and Tairua. Fur seals contributed enormously to the meat supply in some sites—for instance a minimum of 17 fur seals were eaten at N40/3 at Opito, eight at Sarah's Gully and six at Tairua (Smith 1981). With breeding colonies gone, the importance of seal declined but it is likely opportunistic killings of seals in northern waters continued.
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