Mass-processing method for aging otoliths of walleye pollock Theragra chalcogramma using black resin
Version of Record online: 31 MAR 2008
© 2008 Japanese Society of Fisheries Science
Volume 74, Issue 2, pages 255–264, April 2008
How to Cite
KOOKA, K. and YABUKI, K. (2008), Mass-processing method for aging otoliths of walleye pollock Theragra chalcogramma using black resin. Fisheries Science, 74: 255–264. doi: 10.1111/j.1444-2906.2008.01520.x
- Issue online: 31 MAR 2008
- Version of Record online: 31 MAR 2008
- Received 19 July 2007. Accepted 8 November 2007.
- break–burn method;
- dominant year-class;
ABSTRACT: The reliability of a mass-processing aging method for walleye pollock Theragra chalcogramma was examined. The method is a half-otolith method, in which 10–20 otoliths are embedded simultaneously in black resin and the mass-processed half plane section is viewed under reflected light (black-resin method). Seasonal periodicity of otolith growth was confirmed by the monthly observations of the percent of translucent zone at the otolith edge, and interannual variation in age distribution detected the progression of dominant year-classes. These results support the assumption that the translucent zone is formed once a year. The black-resin method was compared to the break–burn method, which is the standard technique for this species. The estimated ages of these methods were not biased throughout the age range examined. The coefficient of variation in the black-resin method (4.9–5.7%) was similar to those of the break–burn method (3.5–5.5%). These results suggest that the black-resin method is reliable as an aging method for walleye pollock.