Low Temperature Effect on Multiple Alizarin Immersion Mass-Marking of Juvenile Sea Trout Salmo trutta m. trutta L. otoliths

Özet

This study presents a protocol of immersing sea trout Salmo trutta m. trutta L. larvae within an alizarin red S (ARS)solution to provide highly visible single and double fluorescent marks in their otoliths. The 14 day interval and temperatureregime between the first and second batch marking sessions have been found to develop the proper distance between the ARSmarks in the otoliths. The mean values of increment widths between the first and second ARS marks in the otoliths of seatrout marked twice within 14 day period ranged between 21.11–34.98 μm, depending on the year of the experiment. Thedistance between ARS marks corresponded to temperature during the period between first and second fish immersions whichwas 4.4ºC, 7.5ºC and 6.7ºC, for year 2014, 2015, and 2016 respectively. As a result, this method can be used as a routineprocedure that provides clear and well-visible single and double alizarin marks in the otoliths and helps to distinguish fishoriginating from different stocking groups of wild-born individuals.