Lead-radium Dating - Golden tilefish
Lead‐radium dating of golden tilefish (Lopholatilus chamaeleonticeps)
UPDATED AND PUBLISHED
Publication year 2015 - Environmental Biology of Fishes
Age estimation and lead-radium dating of golden tilefish
Abstract - There is a growing concern over the lack of life history information for many deepwater fisheries species, including golden tilefish, Lopholatilus chamaeleonticeps. Fundamental life history characteristics, like age and growth, are required for effective, age- structured stock assessments and management decisions. A previous effort to validate golden tilefish age estimates using bomb radiocarbon dating was inconclusive, which led to an application of lead-radium dating in the current study. Lead-radium dating uses the radio- active disequilibrium of lead-210 (210Pb) and radium-226 (226Ra) in otoliths as an independent estimate of age. Ages were also estimated using traditional age estimates by counting growth zones in thin otolith sections and lead-radium dating was used to test these estimates. Radiometric ages (corrected for time since capture) were similar to age estimates from growth zone counts for two of the female age groups and the two oldest age groups of unknown sex, which confirmed an annual growth zone deposition. However, radiometric ages did not agree with age estimates from growth zone counts for males. The difference may be attributed to geographical variations in radium levels, growth rates and growth zone formation by gender or gender transition. Male sagittal otoliths revealed inconsistent growth zone patterns in thin sections, which may have contributed to underageing. Golden tilefish longevity was confirmed to 26 years.
Publication link:
Report 2009
Much of the complex life history of golden tilefish (Lopholatilus chamaeleonticeps) has been described, including age and growth, but validation of age estimates remains unresolved. Application of marginal increment analyses to fin ray and otolith sections have provided support for age estimates and procedures, but use of this technique requires an extrapolation of trends to the oldest ages. An attempt to apply the bomb radiocarbon technique to core material of adult golden tilefish provided complicated results that may have been the result of larvae or juveniles remaining in deep water. Thus, confidence in the ability to determine age and longevity is low for golden tilefish. Lead-radium dating was applied to otolith cores of golden tilefish to answer questions of age and longevity.
Report: A.H. Andrews 2009. Lead‐radium dating of golden tilefish (Lopholatilus chamaeleonticeps). SEDAR 22 - RD - 01.
