Climatic and anthropogenic influences may alter the timing of the delivery of freshwater inflows to estuaries and impact estuarine resources by changing salinity levels. Estuaries are negatively affected by a decrease in quantity of spring freshwater inflows.
Life cycle cues of various fish and shellfish are signaled to high spring runoff occurrences causing alterations in timing that impact spawning and nursery cycles (Alber 2002). For example, a study done in Sabine Lake, Texas on the effects of building a dam found the dam affected inflow patterns by reducing the availability of both low salinity nursery habitat for brown shrimp in the spring and high salinity nursery habitat for white shrimp in the summer (White and Perret 1974, referenced in Alber et al 2002). Altering the timing of freshwater inflows changes salinity levels over time in estuaries. Organisms’ response to salinity change is complex and varies depending on a species’ salinity tolerance range.