Tourists or residents? Life history strategies of Rainbow Smelt in Lake Champlain.

This article investigates the life history strategies of Rainbow Smelt (Osmerus mordax) in Lake Champlain, focusing on the presence of two size classes historically described as “normal” and “giant.” Using otolith microchemistry, diet analysis, stable isotope data, and age–length comparisons, the study finds that contemporary Rainbow Smelt in Lake Champlain are landlocked with no marine (anadromous) signatures. Larger individuals exhibit earlier shifts to piscivory and occupy potentially hypoxic niches, as indicated by elevated manganese-to-magnesium otolith ratios, which may facilitate faster growth. The findings suggest that size variation arises from differences in diet and environmental niche use combined with longevity, rather than from the coexistence of anadromous and landlocked populations. This research highlights the complexity of Rainbow Smelt life histories in a multibasin lake system and underscores the importance of habitat diversity in shaping ecological interactions.