History Categories of Aged Species
H1. Species which are production aged with age validation through known age fish or OTC
marks. Also ages are corroborated through experience and strong year-classes.
No major ageing problems are apparent.
H2. Species which are production aged and corroborated with a weaker validation such as radiometric Pb-210/Ra-226 or C14. Year classes
make sense, and no major ageing problems are apparent.
H3. Species which are production aged and are
corroborated through experience: marginal increment analysis and/or strong
year-classes. No major ageing problems are apparent.
H4. Species for which we have only very limited ageing
experience. However, no major ageing problems are apparent from the specimens
H5. Species for which we have substantial experience,
but where a significant number of specimens may be very difficult to age.
Research however indicates ages are reasonably correct and should provide good
statistics on average age and longevity.
H6. Species for which we have had little experience, but
will require more research to obtain usable age data. Ageing may require
special techniques and ages are only approximate.
Known age: otoliths from species of known age.
OTC: otoliths from
fish tagged with oxytetracycline.
Pb-210/Ra-226: radiometric age
Tags: recoveries or
otoliths from tagged fish.