Shellfish & pathogens

Changes in river flow can alter the salinity in estuarine habitats and effectively isolate organisms from their preferred habitats such as sea grass beds, rocky intertidal zones, or salt marshes. River flow also controls the depth and temperature of many estuarine habitats.

Shifting salinity gradients can have different effects on estuarine organisms depending on where they live. Benthic organisms, or those that live on the bottom of the estuary such as clams, mud snails, or the eggs of many species, generally move too slowly to adjust to changes in salinity and are often hit hardest by altered freshwater flows to estuaries. Organisms that move more readily will generally follow their preferred range of salinity around the estuary, but may have a smaller area of adequate habitat available to meet their needs for food or reproduction.

Aquatic Life