Precision of two methods for estimating age from burbot otoliths

Journal of Applied Ichthyology
By: , and 

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Abstract

Lower reproductive success and older age structure are associated with many burbot (Lota lota L.) populations that are declining or of conservation concern. Therefore, reliable methods for estimating the age of burbot are critical for effective assessment and management. In Lake Erie, burbot populations have declined in recent years due to the combined effects of an aging population (&xmacr; = 10 years in 2007) and extremely low recruitment since 2002. We examined otoliths from burbot (N = 91) collected in Lake Erie in 2007 and compared the estimates of burbot age by two agers, each using two established methods (cracked-and-burned and thin-section) of estimating ages from burbot otoliths. One ager was experienced at estimating age from otoliths, the other was a novice. Agreement (precision) between the two agers was higher for the thin-section method, particularly at ages 6–11 years, based on linear regression analyses and 95% confidence intervals. As expected, precision between the two methods was higher for the more experienced ager. Both agers reported that the thin sections offered clearer views of the annuli, particularly near the margins on otoliths from burbot ages ≥8. Slides for the thin sections required some costly equipment and more than 2 days to prepare. In contrast, preparing the cracked-and-burned samples was comparatively inexpensive and quick. We suggest use of the thin-section method for estimating the age structure of older burbot populations.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Precision of two methods for estimating age from burbot otoliths
Series title Journal of Applied Ichthyology
DOI 10.1111/j.1439-0426.2011.01842.x
Volume 27
Issue S1
Year Published 2011
Language English
Publisher Wiley
Publisher location Hoboken, NJ
Contributing office(s) Ohio Water Science Center
Description 6 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Applied Ichthyology
First page 43
Last page 48
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