Marine Biology

, Volume 109, Issue 2, pp 197-202

First online:

Age determination of orange roughy,Hoplostethus atlanticus (Pisces: Trachichthyidae) using210Pb:226Ra disequilibria

  • G. E. FentonAffiliated withZoology Department, University of Tasmania
  • , S. A. ShortAffiliated withEnvironmental Radiochemistry Laboratory, ANSTO
  • , D. A. RitzAffiliated withZoology Department, University of Tasmania

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


Natural levels of210Pb:226Ra in otoliths of orange roughy,Hoplostethus atlanticus, from south-east Australian waters, were measured to determine fish ages radiometrically. Up to maturity, radiometric age estimates were consistent with a single constant otolith growth rate. Radiometric ages for juveniles were comparable with, but greater than, those obtained in a recent, validated New Zealand study which employed counts of annuli on the surface of otoliths. Beyond maturity, radiometric ages were obtained by modelling with an otolith growth rate set at 45% of the juvenile rate. Radiometric ageing confirms that orange roughy is very slow-growing, with an age at maturity (32 cm standard length, SL) of ~ 32 yr, and is very long-lived, with fish 38 to 40 cm being 77 to 149 yr old. These results have important implications for the management of the fishery.