Testing assumptions of otolith radiometric aging with two long-lived fishes from the northern Gulf of Mexico
In this study, we evaluate the assumptions for estimating ages with radiometric and elemental analyses of otoliths of red snapper (Lutjanus campechanus) and red drum (Sciaenops ocellatus) from the northern Gulf of Mexico. In whole otoliths of both red snapper and red drum, 226 Ra activity was invers...
| Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
2001
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f01-073 http://www.nrcresearchpress.com/doi/pdf/10.1139/f01-073 |
| Summary: | In this study, we evaluate the assumptions for estimating ages with radiometric and elemental analyses of otoliths of red snapper (Lutjanus campechanus) and red drum (Sciaenops ocellatus) from the northern Gulf of Mexico. In whole otoliths of both red snapper and red drum, 226 Ra activity was inversely correlated with the otolith mass increase with age, validating the assumption that 226 Ra accumulation in otoliths occurs at a rate proportional to that of Ca. 222 Rn emanation from otoliths decreased as otolith mass increased. 222 Rn loss occurred in all red snapper otolith samples ([Formula: see text]4.1%) and, to a lesser extent, in red drum otolith samples ([Formula: see text]0.6%) and decreased with increasing size (age) of the otolith. For red drum, the assumption that the initial activity ratio of 210 Po to 226 Ra in otoliths is essentially zero was indirectly validated with elemental analyses of Pb and Ba. Radiometric age estimation of shallow-water fishes from the northern Gulf of Mexico holds great promise, considering that 226 Ra activities observed in this study are some of the highest recorded to date for species to which the 210 Pb/ 226 Ra dating technique has been applied. |
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