Radiocarbon dating of prehistoric shell from New Zealand and calculation of the Delta R value using fish otoliths

We calculated a new Delta R for New Zealand waters using C-14 dates of historic shell previously presented by McFadgen and Manning (1990), and fish otoliths dated by Kalish (1993). We obtained it new estimate of-25 +/- 15 C-14 yr. To test the accuracy of this value for correcting conventional C-14 marine ages, we dated shell of a variety of different species excavated at the prehistoric site of Shag Mouth, North Otago. We compared the results with a pooled mean date for terrestrial samp]es and calculated a local Delta R value that we found statistically indistinguishable from the new Delta R estimate for New Zealand.