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Fish age estimation based on 210Pb: 226Ra ratios in fish otoliths has been applied to a number of species1-4) includ ing the orange roughy Hoplostethus atlanticus.sl Ages esti mated from 210Pb: 226Ra ratios have been used to validate ages of H. atlanticus in the range 150+ years .6,7) Given the general positive correlation between size and age in teleosts,8) such old ages are surprising for a rather small fish that rarely exceeds 2.5kg; and are in striking contrast to maximum ages in the range of 16+ years to 29+ years ob tained from daily microincrement and opaque zone methods.9-12) The results of the 210Pb: 226Ra ratio method are the only validation for the estimates of 150+ years. Length modes, for example, are poorly expressed in catch curves for H. atlanticus beyond the first two to three year classes. 12,13) Consequently, the dogma of old age and slow growth upon which so much of the scientific management of this valuable fishery depends relies heavily on the radionuclide age validation procedure. The radionuclide method of otolith age validation has been strongly criti cized on a number of grounds, 14) one of which was that otoliths were permeable to 222Rn, like other calcium car bonates, 15) which was likely to compromise the assumption of closure that is essential to the method. An a-particle is released during the decay of 226Ra to 222Rn resulting in local damage to the crystal fabric within

Loss of <sup>222</sup>Rn from Otoliths of Orange Roughy, <i>Hoplostethus atlanticus</i>, Invalidates Old Ages