Onawe wall mystery

Press, 16 July 1987, Page 21

Onawe wall mystery

By

MICHAEL M. TROTTER

Visitors to the Onawe Historic Reserve — that prominent peninsula jutting into the middle of Akaroa Harbour — may have noticed a semi-circular, stone wall bn the tidal mudflat on the western side. There are several theories as

to the origin and purpose, but I have not heard any that are particularly convincing. Onawe Peninsula is probably best known as the site of a large Maori pa that featured in one of the raids of the North Island chief Te Rauparaha in 1832. The

peninsula has a number of other attractions — the birds including penguins, the regrowth bush, the geological features around the shoreline, and even the physical geography of the land form which virtually becomes an island at high tide. The pa site occupies most of the relatively flat area between the peninsula’s tentative connection with the mainland and the base of the hill at the southern end. Many of its defensive earthworks are clearly visible. The interested visitor can perhaps get some idea of the enormous task involved in defending such a large area from even a small attacking force. From the western side of the pa, trenches gave protected access to the shore and a supply of fresh water. Not far from the lower ends of these trenches is the stone wall, forming a large semi-circle from the base of the cliffs and reaching out to below tide level. Although the wall is now in a state of disrepair, it is easy to see that it has been carefully built from two different types of local volcanic rock. But who were its builders? Were they Maori or pakeha? Why was it built? One theory is that it was a Maori fish trap or holding pen. It would probably have been little use as a holding pen — where fish caught elsewhere could be

kept alive until required, although such a store of food would have been invaluable while the pa was under siege. Even when the wall was in good repair it would not have been high enough to prevent fish escaping at high tide. As a fish trap it might have worked; fish swimming at high tide into the area contained by the wall would have been unable to escape when the outgoing tide took the water level below the top of the rocks. Another Maori origin theory is that it formed a canoe shelter, but this may be ruled out by its location and by the fact that it would provide little shelter at high tide and an obstruction to launching at low tide. A popular explanation is that the wall was built a few decades ago as an oyster farm; in support of that is documentary evidence of oyster farming and the presence of oysters on and near the wall even today. There seems little logic, however, in the shape of the enclosure for this purpose. A strong argument against it being the remains of an oyster farm, or a fish trap, or even a holding pen, is that the landward ends of the carefully constructed wall are usually well above water level — a totally unnecessary feature for the retention of oysters or fish. An archaeological investigation may be necessary to solve the mystery of the Onawe wall.