Using geostatistical analysis for simultaneous estimation of isoscapes and ontogenetic shifts in isotope ratios of highly migratory marine fish

Tracking migration of highly migratory marine fish using isotope analysis (iso-logging) has become a promising tool in recent years. However, application this method is often hampered by the lack essential information such as spatial variations ratios across habitats (isoscapes) and ontogenetic shifts target animals. Here, we test utility geostatistical to generate isoscapes δ 13 C 15 N western Pacific estimate values species. We first measured white muscle juvenile ( n = 210) adult 884) skipjack tuna Katsuwonus pelamis sampled northwest Pacific. Next fitted model account for observed fork length other environmental variables with random effects. then used best-fit models predict 2021. Furthermore, amino acids AAs ) 5) determine whether variation resulted from baseline or differences trophic position. The reasonably estimated both skipjack, showed that can clearly distinguish latitudinal supported results model, is, were largely derived shift rather than regional Thus, provide basic required iso-logging without compound-specific analysis.