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Forskningsartikel2022Vetenskapligt granskadÖppen tillgång

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

Finnas, Viktor; Lill, Jan-Olof; Saarinen, Timo; Lindqvist, Christer; Heimbrand, Yvette; Jokikokko, Erkki; Hagerstrand, Henry

Sammanfattning

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.

Nyckelord

Gulf of Bothnia; River Kemijoki; River Tornionjoki

Publicerad i

Fisheries Management and Ecology
2022, Volym: 29, nummer: 3, sidor: 233-240 Utgivare: WILEY