Micro-X-ray fluorescence image analysis of otoliths to distinguish between wild-born and stocked river-spawning whitefish captured in the Baltic Sea

Abstract

Strontium concentrations are low in fresh waters compared to seawaters. Therefore, wild-born river-spawning and stocked freshwater-reared whitefish Coregonus lavaretus L. display regions with low concentrations of strontium in the centre of their otoliths. Strontium in otoliths from wild-born river-spawning whitefish ascending the River Tornionjoki, river-spawning whitefish stocked as one-summer-old fingerlings caught ascending the River Kemijoki, and sea-spawning whitefish caught near the angstrom land Islands was mapped using mu-XRF. The strontium-depleted regions in the centre of the whitefish otoliths, measured using ImageJ, had mean sizes of 0.18 +/- 0.2 mm(2) (River Tornionjoki) and 2.3 +/- 0.3 mm(2) (River Kemijoki), whereas the otoliths from whitefish caught at sea lacked a strontium-depleted region altogether. Measurement of the area of the strontium-depleted region in whitefish otoliths provides a convenient method with which to differentiate between whitefish of different provenance and to determine the origins of whitefish in mixed catches.

Keywords

Gulf of Bothnia; River Kemijoki; River Tornionjoki

Published in

Fisheries Management and Ecology
2022, volume: 29, number: 3, pages: 233-240
Publisher: WILEY

SLU Authors

• Heimbrand, Yvette

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Fish and Aquacultural Science

Publication identifier

• DOI: https://doi.org/10.1111/fme.12525

Permanent link to this page (URI)

https://res.slu.se/id/publ/115066