Tomas Naeraa
Researcher
It’s elemental, my dear watson : Validating seasonal patterns in otolith chemical chronologies
Author
Summary, in English
Accurate age data are essential for reliable fish stock assessment. Yet many stocks suffer from inconsistencies in age interpretation. A new approach to obtain age makes use of the chemical composition of otoliths. This study validates the periodicity of recurrent patterns in25 Mg,31 P,34 K,55 Mn,63 Cu,64 Zn,66 Zn,85 Rb,88 Sr,138 Ba, and208 Pb in Baltic cod (Gadus morhua) otoliths from tag–recapture and known-age samples. Otolith P concentrations showed the highest consistency in seasonality over the years, with minima co-occurring with otolith winter zones in the known-age otoliths and in late winter – early spring when water temperatures are coldest in tagged cod . The timing of minima differs between stocks, occurring around February in western Baltic cod and 1 month later in eastern Baltic cod; seasonal maxima are also stock-specific, occurring in August and October, respectively. The amplitude in P is larger in faster-growing western compared with eastern Baltic cod. Seasonal patterns with minima in winter – late spring were also evident in Mg and Mn, but less consistent over time and fish size than P. Chronological patterns in P, and to a lesser extent Mg and Mn, may have the potential to supplement traditional age estimation or to guide the visual identification of translucent and opaque otolith patterns used in traditional age estimation.
Department/s
- Lithosphere and Biosphere Science
Publishing year
2021
Language
English
Pages
551-566
Publication/Series
Canadian Journal of Fisheries and Aquatic Sciences
Volume
78
Issue
5
Document type
Journal article
Publisher
Canadian Science Publishing, NRC Research Press
Topic
- Ecology
Status
Published
ISBN/ISSN/Other
- ISSN: 0706-652X