Advertisement

Marine Biology

, Volume 129, Issue 4, pp 681–687 | Cite as

Transition zone in otoliths of orange roughy (Hoplostethus atlanticus) and its relationship to the onset of maturity

  • R. I. C. C. Francis
  • P. L. Horn
Article

Abstract

A transition zone in the otoliths of orange roughy (Hoplostethus atlanticus) is described where annulus width decreases markedly. For fish sampled at spawning time, the relationship between gonad stage and the presence or absence of a transition zone is consistent with the hypothesis that this zone marks the onset of maturity, if allowance is made for some error in gonad staging and identification of the zone. Another data set from a non-spawning area after the spawning season is not consistent with the hypothesis. However, these latter data are considered less reliable because of the small size of the fish in the sample and difficulties in determining, outside the spawning season, whether a fish has been reproductively active. This hypothesis was used to provide estimates of the median age (30 yr) and length (31 cm) at the onset of maturity for the Chatham Rise, New Zealand population. These estimates are unaffected by the biases associated with the usual ogive method of estimation.

Keywords

Transition Zone Spawning Season Zealand Population Orange Roughy Gonad Stage 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • R. I. C. C. Francis
    • 1
  • P. L. Horn
    • 1
  1. 1.National Institute of Water and Atmospheric Research Ltd, P.O. Box 14–901, Kilbirnie, Wellington, New ZealandNZ

Personalised recommendations