Validation of daily increment formation in otoliths of immature and adult Japanese anchovy Engraulis japonicus

Shigenobu Namiki, Hiroshige Tanaka, Satoshi Katayama, Osamu Funaki, Ichiro Aoki, Yoshioki Oozeki

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

In order to validate daily increment formation in otoliths of immature and adult Japanese anchovy Engraulis japonicus, three rearing experiments using chemical marking of otoliths were conducted on adult anchovy in summer 2004 and immature anchovy in summer 2005 and in winter 2006. In the two experiments conducted in summer, the number of otolith microincrements between alizarin complexone (ALC) marks showed that microincrements were formed daily. In the summer 2005 experiment, immature anchovy under conditions of reduced daily food rations also showed daily microincrement formation. Average increment width was 0.9 μm in adults and 1.8-3.1 μm in immature anchovy. In contrast, no clear increments were observed between ALC marks on the otoliths from the experiment in winter 2006, and scanning electron microscope (SEM) observations failed to confirm clear increment formation. We consider that low water temperatures (<13-14°C) restricted otolith growth and lowered the contrast between the discontinuous and the incremental zones of the otolith increments. For age estimation of Japanese anchovy, clear increments wider than about 1 μm in the otolith can be regarded as daily increments. However, daily age estimation of immature and adult anchovy that experience low water temperatures in winter may be difficult due to the obscurity of the increments.

Original languageEnglish
Pages (from-to)951-959
Number of pages9
JournalFisheries Science
Volume76
Issue number6
DOIs
Publication statusPublished - 2010 Oct 20
Externally publishedYes

Keywords

  • Daily age
  • Engraulis japoniccus
  • Japanese anchovy
  • Otolith microincrements
  • Validation

ASJC Scopus subject areas

  • Aquatic Science

Fingerprint Dive into the research topics of 'Validation of daily increment formation in otoliths of immature and adult Japanese anchovy Engraulis japonicus'. Together they form a unique fingerprint.

  • Cite this