Effects of temperature and energy use on fish passage and spawning success of American shad

American Shad (Alosa sappdissima) are the most numerous and economically important anadromous species on the east coast of the United States. Yet in many river systems their populations have experienced declines, primarily due to the impacts of dams and habitat loss. Although fish passage facilities have been constructed to mitigate the impacts of dams, many of these have not provided adequate passage success for self-sustaining populations or populations at levels that meet management goals. The negative impacts of fish passage facilities may be exacerbated by high temperature late in the migratory period, a phenomenon that is likely to become worse with higher freshwater temperatures associated with climate change. Migratory delays associated with low rates of dam passage appear to substantially aggravate this effect. Previous research and modeling have established that energetic considerations are a critical component of adult American shad migration, spawning success, and itero/semelparity (reproductive strategies). Key components of these models have relied on information from other species because the influence of temperature on maximum sustained swimming capacity, burst swimming capacity and oxygen demand of American shad are currently unknown, leading to great uncertainty in model predictions.