Abstract
Since the 1970’s lake Osensjøen has been widely researched and several changes to the population dynamics have been observed. In recent years and increase in the abundance of roach (Rutilus rutilus) has been observed. Using historical and new stable isotope data this study aims to look at changes to trophic position, isotopic niche and diet in 2010/2013 and 2021. The study provided some evidence to suggest that there has been some change to isotopic niches in roach and whitefish and vendace. Due to low sample size and methodological errors, any definitive statements about the systems should be reserved.