Length weight data were recorded for Ninety Mile tuatua in 2010, and for Dargaville toheroa in 2011; these data were analysed using least squares linear regression (Figure 21). Length weight data for the few toheroa found at Ninety Mile in 2010 were recorded, but were not included in the analysis. No length weight data were collected for tuatua at Dargaville in 2011. Length weight regression coefficients for each species sampled are shown in Table 3. The linear model fitted the data well for both species. Note that the length weight regression for tuatua applied only to tuatua found in the intertidal zone, and may not be suitable for predicting weight from the length of larger tuatua which normally occupy a lower position on the shore, in the lowest part of the intertidal into the shallow subtidal.