Whitehead, N.E.; Ditchburn, R.G. 1996 Dating Hapuka otoliths using 210Pb/226Ra, with comments on dating Orange Roughy otoliths. Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences science report 96/15. 17 p.
Abstract: It is shown that Hapuka otoliths cannot be reliably dated using the 210Pb/226Ra method because contrary to previous assumptions, excess 210Pb is incorporated into the outer layers of otoliths which have been taken from old fish, though the 226Ra incorporation remains normal. This is shown to apply also to Orange Roughy otoliths. Ages based on calculations using previously published methods will be artificially old. (auth)