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Research article - Peer-reviewed, 2021

It's elemental, my dear Watson: validating seasonal patterns in otolith chemical chronologies

Hussy, Karin; Kruger-Johnsen, Maria; Thomsen, Tonny Bernt; Heredia, Benjamin Dominguez; Naeraa, Tomas; Limburg, Karin E.; Heimbrand, Yvette; McQueen, Kate; Haase, Stefanie; Krumme, Uwe; Casini, Michele; Mion, Monica; Radtke, Krzysztof

Abstract

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 in Mg-25, P-31, K-34, Mn-55, Cu-63, Zn-64, Zn-66, Rb-85, Sr-88, Ba-138, and Pb-208 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.

Published in

Canadian Journal of Fisheries and Aquatic Sciences
2021, volume: 78, number: 5, pages: 551-566
Publisher: CANADIAN SCIENCE PUBLISHING

Authors' information

Hussy, Karin
Technical University of Denmark
Kruger-Johnsen, Maria
Technical University of Denmark
Thomsen, Tonny Bernt
Geological Survey Of Denmark and Greenland
Heredia, Benjamin Dominguez
Geological Survey Of Denmark and Greenland
Naeraa, Tomas
Lund University
Swedish University of Agricultural Sciences, Department of Aquatic Resources
State University of New York College of Environmental Science and Forestry (SUNY-ESF)
Swedish University of Agricultural Sciences, Department of Aquatic Resources
McQueen, Kate
Johann Heinrich von Thunen Institute
Haase, Stefanie
Johann Heinrich von Thunen Institute
Krumme, Uwe
Johann Heinrich von Thunen Institute
Swedish University of Agricultural Sciences, Department of Aquatic Resources
University of Bologna
Radtke, Krzysztof
National Marine Fisheries Research Institute
Swedish University of Agricultural Sciences, Department of Aquatic Resources

Associated SLU-program

Coastal and sea areas

UKÄ Subject classification

Fish and Wildlife Management
Ecology

Publication Identifiers

DOI: https://doi.org/10.1139/cjfas-2020-0388

URI (permanent link to this page)

https://res.slu.se/id/publ/112025