Prevalence of stocked whitefish in River Kemijoki, Finland, inferred by micro X-ray fluorescence analysis of otoliths



: Viktor Finnäs, Jan-Olof Lill, Yvette Heimbrand, Martina Blass, Timo Saarinen, Yann Lahaye, Erkki Jokikokko, Henry Hägerstrand

Publisher: WILEY

: 2020

: Fisheries Management and Ecology

: FISHERIES MANAGEMENT AND ECOLOGY

: FISHERIES MANAG ECOL

: 27

: 5

: 8

: 0969-997X

: 1365-2400

DOI: https://doi.org/10.1111/fme.12430

: https://research.utu.fi/converis/portal/detail/Publication/48477075


Micro X-ray fluorescence (mu-XRF) analysis of otoliths was evaluated as a method to estimate the proportion of stocked one-summer-old whitefish Coregonus lavaretus L. in catches of adult fish (n = 20) ascending the River Kemijoki to spawn. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis was applied as control. Polished otoliths were scanned with mu-XRF to obtain strontium maps that were used to infer visually the provenance of the whitefish. Thirteen of the fish showed signs of being stocked as one-summer-old fingerlings. LA-ICP-MS was applied to determine the elemental composition in a spot outside the core of the otolith. The results were largely consistent with the visual inspection of the mu-XRF mapped otoliths. In conclusion, mu-XRF mapping successfully identified whitefish stocked as one-summer-old fingerlings. The vast majority of whitefish returning to the River Kemijoki to spawn were stocked fish.

Last updated on 2024-26-11 at 18:37