Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus)
Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from...
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ftrhodesunivcory:vital:5295 2023-05-15T17:54:42+02:00 Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) Andrews, Allen Hia 2009 192 leaves pdf http://hdl.handle.net/10962/d1005140 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5295 English eng Rhodes University Faculty of Science, Ichthyology and Fisheries Science vital:5295 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5295 http://hdl.handle.net/10962/d1005140 Andrews, Allen Hia Fishes -- Age determination Fishes -- Southern hemisphere -- Longevity Fishes -- Growth Radioactive dating Patagonian toothfish Patagonian toothfish -- Fisheries Orange roughy Orange roughy -- Fisheries Deep-sea fishes -- Southern hemisphere Deep-sea fisheries Deep-sea fisheries -- Southern hemisphere Thesis Doctoral PhD 2009 ftrhodesunivcory 2022-12-26T11:18:59Z Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies ... Doctoral or Postdoctoral Thesis Patagonian Toothfish Southern Ocean Rhodes University Cory: Repository Pacific Southern Ocean |
institution |
Open Polar |
collection |
Rhodes University Cory: Repository |
op_collection_id |
ftrhodesunivcory |
language |
English |
topic |
Fishes -- Age determination Fishes -- Southern hemisphere -- Longevity Fishes -- Growth Radioactive dating Patagonian toothfish Patagonian toothfish -- Fisheries Orange roughy Orange roughy -- Fisheries Deep-sea fishes -- Southern hemisphere Deep-sea fisheries Deep-sea fisheries -- Southern hemisphere |
spellingShingle |
Fishes -- Age determination Fishes -- Southern hemisphere -- Longevity Fishes -- Growth Radioactive dating Patagonian toothfish Patagonian toothfish -- Fisheries Orange roughy Orange roughy -- Fisheries Deep-sea fishes -- Southern hemisphere Deep-sea fisheries Deep-sea fisheries -- Southern hemisphere Andrews, Allen Hia Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
topic_facet |
Fishes -- Age determination Fishes -- Southern hemisphere -- Longevity Fishes -- Growth Radioactive dating Patagonian toothfish Patagonian toothfish -- Fisheries Orange roughy Orange roughy -- Fisheries Deep-sea fishes -- Southern hemisphere Deep-sea fisheries Deep-sea fisheries -- Southern hemisphere |
description |
Patagonian toothfish (Dissostichus eleginoides) or "Chilean sea bass" support a valuable and controversial fishery, but the life history is little known and longevity estimates range from ~20 to more than 40 or 50 yr. In this study, lead-radium dating provided validated age estimates from juveniles to older adults, supporting the use of otoliths as accurate indicators of age. The oldest age groups were near 30 yr, which provided support for age estimates exceeding 40 or 50 yr from grow zone counts in otolith sections. Hence, scale reading, which rarely exceeds 20 years, has the potential for age underestimation. Lead-radium dating revealed what may be minor differences in age interpretation between two facilities and findings may provide an age-validated opportunity for the CCAMLR Otolith Network to reassess otolith interpretations. Orange roughy (Hoplostethus atlanticus) support a major deep-sea fishery and stock assessments often depend on age analyses, but lifespan estimates range from ~20 to over 100 yr and validation of growth zone counts remained unresolved. An early application of lead-radium dating supported centenarian ages, but the findings were met with disbelief and some studies have attempted to discredit the technique and the long lifespan. In this study, an improved lead-radium dating technique used smaller samples than previously possible and circumvented assumptions that were previously necessary. Lead-radium dating of otolith cores, the first few years of growth, provided ratios that correlated well with the ingrowth curve. This provided robust support for age estimates from otolith thin sections. Use of radiometric ages as independent age estimates indicated the fish in the oldest group were at least 93 yr. Lead-radium dating has validated a centenarian lifespan for orange roughy. To date, radium-226 has been measured in otoliths of 39 fish species ranging from the northern Pacific and Atlantic Oceans to the Southern Ocean. In total, 367 reliable radium-226 measurements were made in 36 studies ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Andrews, Allen Hia |
author_facet |
Andrews, Allen Hia |
author_sort |
Andrews, Allen Hia |
title |
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
title_short |
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
title_full |
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
title_fullStr |
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
title_full_unstemmed |
Lead-radium dating of two deep-water fishes from the southern hemisphere, Patagonian toothfish (Dissostichus eleginoides) and Orange Roughy (Hoplostethus atlanticus) |
title_sort |
lead-radium dating of two deep-water fishes from the southern hemisphere, patagonian toothfish (dissostichus eleginoides) and orange roughy (hoplostethus atlanticus) |
publisher |
Rhodes University |
publishDate |
2009 |
url |
http://hdl.handle.net/10962/d1005140 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5295 |
geographic |
Pacific Southern Ocean |
geographic_facet |
Pacific Southern Ocean |
genre |
Patagonian Toothfish Southern Ocean |
genre_facet |
Patagonian Toothfish Southern Ocean |
op_relation |
vital:5295 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:5295 http://hdl.handle.net/10962/d1005140 |
op_rights |
Andrews, Allen Hia |
_version_ |
1766162515309363200 |