Estimating Marine Migrations of Anadromous Rainbow Smelt Using Otolith Chemistry
Using otolith chemistry, researchers reconstructed the migratory histories of rainbow smelt in Great Bay, New Hampshire. The study reveals diverse patterns of freshwater, estuarine, and marine habitat use, highlighting the complex life histories of this anadromous fish and providing insights to support conservation and management efforts.
Subject Tags
- Fisheries
- Ecosystem management
- Habitat restoration
Abstract
Diadromous fish migrations connect freshwater, estuarine, and marine habitats, requiring detailed understanding of movements to prioritize conservation and management. Anadromous rainbow smelt along the northwestern Atlantic coast have experienced range contraction and exhibit potential signs of population stress that could affect their long-term resilience. Rainbow smelt movements and habitat use are understudied relative to other diadromous fishes and can vary within and among populations. We use otolith chemistry (Sr:Ca values) to characterize the habitat use and salinity histories of rainbow smelt collected from spawning tributaries in Great Bay, New Hampshire, USA in February-March 2021 (n = 78, 41 males, 37 females). Our findings corroborate known rainbow smelt life history paradigms, with most fish slowly transitioning to marine waters between their first fall and second spring, then returning to non-marine waters at ~ 1-year of age. Estimated duration of time spent in the marine environment varied widely among individuals between 0 and 43% over the first two years, representing up to 5 months per year. Small contingents (~ 5% of otoliths) of rainbow smelt exhibited either immediate marine Sr:Ca values, potentially indicating rapid transport from spawning tributaries to high-salinity waters, or rather, did not enter the marine environment in their first ~ 1.5 years of life. No significant differences in migratory patterns were observed between sexes. Collectively, these observations describe the diverse portfolio of migratory strategies in rainbow smelt that reveal considerable variation in habitat use of estuarine and marine waters and connectivity patterns across salinity gradients. This work highlights both the potentially complex habitat needs but also variations in life histories that need to be investigated for improved conservation and management.
Citation
Cacacie, A. J., Walther, B. D., Pearson, C. F., Miller, N., Mohan, J. A., & Furey, N. B. (2026). Estimating Marine Migrations of Anadromous Rainbow Smelt Using Otolith Chemistry. Estuaries and Coasts, 49(6), 193.
TNC Authors
-
Chloe Pearson
Freshwater Science Specialist. New Jersey
The Nature Conservancy
Email: chloe.pearson@tnc.org