River herring thermal ecophysiology


     River herring (blueback herring, Alosa aestivalis, and alewife, Alosa pseudoharengus) are two anadromous Species of Concern native to the eastern United States. Both species are important sources of energy and nutrients to marine, freshwater, and terrestrial ecosystems, but are at historically low population levels.

     Among other barriers to their recovery (e.g. dams, bycatch), climate change has been linked to the disappearance of river herring populations in the southern part of their range; interestingly, blueback herring populations have appeared to be more stable than alewife populations. My research project focuses on understanding how temperature affects the physiology and ecology of freshwater early life stages (larvae and juvenile) of river herring. I use a combination of lab and field studies to test whether temperature-driven changes in growth rates or energetics could explain the observed range shifts.

     Thus far, laboratory experiments have shown some interesting trends for both species. In particular, we have seen that juvenile physiology is sensitive to food ration, and alewife appear to be more sensitive to temperature than blueback herring. We continue to run additional laboratory experiments and are now expanding to field studies to see how natural temperature and food regimes affect river herring.

River Herring Sampling Sites 2019

This year I collected fish from three separate projects! My home site was our lab at the Cronin Aquatic Resource Center. This is where I conducted temperature x food ration experiments (red fish). We collected fish from MA and NH sites (blue fish), which are mostly alewife-dominated systems. Additionally, we collected fish from several sites in the Connecticut River sites (green fish).