Tuhinga 3, 1995

Estimating live fish catches from archaeological bone fragments of snapper, Pagrus auratus

Foss Leach and Angela Boocock

ABSTRACT: Five paired cranial bones and the otoliths of a modern sample of 110 New Zealand snapper (Pagrus auratus) were weighed and measured and regression analysis performed against live fork length and ungutted weight. A number of regression models and alternative steps in arriving at estimates were examined. Detailed analysis of residuals was used to distinguish between strategies. Fork length could be estimated with a standard error  of less than 20mm, and weight to less than 140 g, For the latter, a two step procedure is suggested, from bone dimension to fork length and from this to live weight, using a sample of 833 fish. Coefficients are provided for 64 equations linking bone size to live characteristics. To reconstruct a size-frequency histogram of a prehistoric fish catch, it is acceptable to measure all bones from a particular species, even though the number of measurements may greatly exceed the MNI (Minimum Number of Individuals) for that species.