Fatty Acid Profiling of Fish Fin Tissues: Implications for Non-Lethal Sampling Methods

Fatty acid (FA) profiling is crucial for understanding fish health and diet. However, the critical status of many fish species makes lethal sampling problematic and/or prohibited. This study evaluates the potential of fish fin tissues as non-lethal alternatives to muscle tissue for FA profiling using Atlantic Salmon (Salmo salar). Lipid extractions from the muscle, adipose fin, inner-caudal fin, and outer-caudal fin tissues of 11 individuals were analyzed using a modified version of the Mojonnier method. Linear regressions for FA composition and concentration revealed a strong relationship between adipose fin and muscle tissues (R ² = 0.98, p < 0.001 and R ² = 0.98, p < 0.001; respectively). The relationships between outer-caudal fin and muscle tissue for either FA composition and concentration were also significant (R ² = 0.64, p < 0.001 and R ² = 0.62, p < 0.001, respectively). Both outer-caudal and adipose fin tissues had lower intra-tissue variability than muscle tissue. This study suggests that adipose fin tissue may provide a suitable non-lethal alternative for FA profiling in fish, given its strong correlation with muscle tissue, minimal intra-tissue variation, and consistency in FA composition and concentration. Despite exhibiting distinct FA profiles relative to muscle tissue, outer-caudal fin tissue showed consistent proportional relationships that may support its application in non-lethal FA studies where adipose fins are unavailable. Non-lethal FA sampling methods support research and conservation efforts and offer an ecologically responsible tool for the study and protection of fish populations worldwide.