Understanding the impacts of climate warming on organisms, such as changes in ecological traits and northward shifts in distribution ranges, requires a macroecological perspective that examines ecological phenomena at broad spatial scales. Latitudinal variations in life-history traits have often been used to predict ecological responses to climate change. Diadromous fishes exhibit latitudinal clines of ocean/river dependency at both inter- and intra-species levels, with increasing the ocean dependency at high latitudes in relation to relative aquatic productivity. Such latitudinal clines of productivities may induce geographical variations in life-history diversity within migratory phenotypes. In this study, lifetime migratory patterns of ocean/river use and growth of migratory white-spotted charr Salvelinus leucomaenis, a regionally migrating salmonids, were analyzed with a broad latitudinal range to examine whether latitudinal clines exist in their migratory patterns, riverine feeding, and ocean dependence, as well as to project the effects of climate warming on these traits. Anadromous white-spotted charr were collected from 16 rivers flowing into the Sea of Japan, spanning from northern Hokkaido to Niigata Prefecture (38°N–45.5°N). Migratory history was reconstructed based on otolith microchemical analysis, feeding status upon river return was assessed, and fork lengths at previous ages were estimated using the otolith back-calculation method. Annual growth rates, growth proportions in river and ocean environments, and relative growth before and after the first seaward migration were calculated. Latitudinal clines in growth rates and ocean dependence were examined using generalized linear mixed models with latitude as an explanatory variable. Furthermore, the potential future impacts of climate change were assessed by integrating observed latitudinal trends in these life-history traits with the relationship between latitude and water temperature, based on projected temperature increases from the Intergovernmental Panel on Climate Change (IPCC). The latitudinal trends in life history traits (e.g., migratory diversity, river-feeding, growth) of migratory white-spotted charr indicated greater ocean dependence at higher latitudes. Such latitudinal clines of migratory traits suggested the potential impacts of future climate change on migratory patterns, including not only the loss of anadromous migratory behavior at the southern limit of the species' distribution but also a reduction in ocean dependency among anadromous migrants across their entire range.