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 (such as dams and fisheries 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. There has been only limited work on the impact of temperature on survival and growth of these species, and no direct comparisons of their thermal physiology.

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The overall goal of this project is to conduct research to fill critical information gaps about juvenile river herring productivity and emigration. We will achieve this through two major objectives: 1) We will determine the limits to juvenile river herring productivity by using a combination of lab and field experiments to examine the impact of temperature, food availability, and turbidity on survival, growth, swimming performance, and seawater tolerance of blueback herring; and 2) We will assess factors influencing juvenile river herring emigration rates and timing by comparing biotic characteristic (size, age and growth rates) of emigrating and non-emigrating juveniles to assess factors influencing emigration timing, as well as determining the timing and rates of juvenile emigration in lake and river systems.