Validating bluenose and rubyfish ageing using radiocarbon dating
Project: Validating bluenose and rubyfish ageing using radiocarbon dating
Project Code: INS2004/01
Start Date: 1 October 2004
Completion Date: 30 September 2005
Vessel Use: Nil
Overall Objectives:
- Validating ageing methods for bluenose (Hyperoglyphe antarctica) and rubyfish (Plagiogeneion rubiginosum) from radiocarbon dating.
Specific Objectives:
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To determine a mathematical method for estimating the age of an otolith from radiocarbon dating, and the uncertainty of that estimate from multiple radiocarbon samples from otoliths.
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To describe the relationship between ring count methods and radiocarbon deduced ages to investigate the relationship between ring count and the age of fish.
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To estimate the uncertainty of the estimates for the samples of bluenose and rubyfish analysed in Project INS 2000/02.
Note:
This project has a medium priority and will proceed only if funding is available.
Rationale
General
A previous project on rubyfish and bluenose (INS 2000/02) revealed that the radiocarbon “bomb” method could be used to validate ageing in long-lived, deepwater teleosts if, inter alia, the rate of carbon sedimentation could be modelled. Modelling was also necessary to determine the variance of age estimates and thus samples sizes required for these species. The Inshore Working Group therefore recommended that appropriate modelling work be completed before additional projects using the “bomb” method are undertaken to age bluenose and rubyfish as well as middle depth and deepwater species.
Specific Objectives 1-3
While the number of samples of otoliths (10) and number of radiocarbon samples from each otolith (~5) in the previous study were small, it is possible to use these data to develop a mathematical method for estimating age, and to investigate the nature of uncertainty associated with this form of radiocarbon ageing.
The development of methods should allow estimation of the number of samples per otolith and the accuracy of those point samples that would be required in a full validation study. This information would be of use in the estimation of sample sizes required, and those areas where better parameter estimates would reduce the overall uncertainty.
Strategic Relevance
The objective of this project is consistent with the Fisheries Resources goal and Strategic Objectives in the Ministry of Fisheries Strategic Research Directions document.
Cost Recovery Information:
The percentage allocation for this project (based on an assessment of research effort according to rule 9.2 of the Fisheries (Cost Recovery) Rules 2001) is as follows:
All BNS Fishstocks 50%
All RBY Fishstocks 50%
The project is estimated to cost between $0-$50,000.