VALIDATION OF OTOLITH-INCREMENT AGE ESTIMATES FOR A DEEP-WATER FISH SPECIES, THE WARTY OREO ALLOCYTTUS-VERRUCOSUS, BY RADIOMETRIC ANALYSIS

Bryce Donald Stewart, G E FENTON, D C SMITH, S A SHORT

Research output: Contribution to journalArticlepeer-review

Abstract

Otolith increment age estimates for a deepwater species, Allocyttus verrucosus, were validated by comparison with the results from Pb-210:Ra-226 radiometric analysis. Transverse sectioning and subsequent grinding of otoliths to a thickness of similar or equal to 0.2 mm revealed increments which provided age estimates for a range of fish sizes, Age estimates ranged from 7 yr for an immature fish of 15.2 cm total length (TL) to 130 yr for a female fish of 36.5 cm TL. Age at maturity was estimated as 28 yr for females and 24 yr for males. In comparison, radiometric analysis of whole otoliths, using a single linear otolith-mass growth-rate model suggested maximum ages of 130 to 170 yr for fish of 34 to 35 cm TL. Radiometric ages were also recalculated using a two-phase otolith-mass growth-rate model in which the growth rate was assumed to slow after maturity to 90% of the pre-maturity rate. This reduced the maximum age to 132 +/- 15 yr for a mean fish length of 34.5 cm. Age at maturity for females was estimated at 34 yr. The similarity between age estimates from otolith-increment counts and radiometric analysis strongly supports the accuracy of results from both methods, and encourages further use of such comparisons as an alternative to traditional validation techniques.

Original languageEnglish
JournalMarine Biology
Publication statusPublished - 1 Jul 1995
Externally publishedYes

Keywords

  • Age and growth
  • deep sea
  • longevity
  • Otoliths
  • Fisheries management

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