Centenarian lifespan confirmed
Orange roughy can live more than 100 years - really, they can!
Publication year 2009
Lead-radium dating of orange roughy (Hoplostethus altanticus): validation of a centenarian life span
Life-span estimates for orange roughy (Hoplostethus atlanticus) range from ~20 years to well over 100 years. In this study, an improved lead–radium dating technique provided independent age estimates from sagittal otoliths. This technique used the known properties of radioactivity for lead-210 and radium-226 to determine the validity of fish age estimates. An improvement to lead–radium dating using mass spectrometry allowed the use of smaller samples than previously possible; therefore, an application was made to otolith cores, the first few years of otolith growth. This approach circumvented the use of whole otoliths and alleviated many of the assumptions that were necessary in previous lead–radium dating applications. Hence, it was possible to critically evaluate lead–radium dating as a tool in fish age validation. The measurement of lead–radium ratios for a series of age groups that consisted of otolith cores, grouped based on growth-zone counts from thin sections, showed a high degree of correlation to the expected lead–radium ingrowth curve. This finding provided support for age estimation procedures using thin otolith sectioning. As independent estimates of age, the results indicated that fish in the oldest age group were at least 93 years old, providing robust support for a centenarian life span.
The findings here continue to address the question: Do deep dwelling fishes live longer?
Publication: Andrews A. H., Tracey, D. M., Dunn, M. R. (2009). Lead-radium dating of orange roughy (Hoplostethus altanticus): validation of a centenarian life span. Canadian Journal of Fisheries Aquatic Sciences 66, 1130-1140.
Publication:
Andrews et al 2009 Orange roughy-Corrected.pdf
This is one of two papers that resulted from my Ph.D in Ichthyology and Fisheries Science through Rhodes University.
LEAD-RADIUM DATING SKEPTICISM
I would like to add to the presentation of age data on orange roughy by introducing the late Robert Gauldie, a man that stood behind his and others perceptions of a short-lifespan for orange roughy. A short time back I tried to start a dialog with Dr. Gauldie to better understand the basis of their perspectives and it led to some interesting responses. I am still a bit confused by the recalcitrance in the short-lived orange roughy perspective, but I thought to provide the link to our last series of exchanges that are available at Dr. Gauldie’s website.
RIP Bob and thank you for the years of skepticism that kept me looking to test the assumptions of lead-radium dating. My belief in lead-radium dating as an accurate tool in age estimation of fishes in more substantiated because of you. Aloha.
“Reasons why the radiometric age estimation method using 226Ra:210Pb ratios appears to validate younger ages, not older ages, for the Orange Roughy, Hoplostethusatlanticus” (Please take note of my reply under Responses and Comments)
Orange roughy aggregation at depth off New Zealand (Photo credit: NIWA)
