What Are Signs of Oxygen Stress?
In the natural environment, it may be difficult to identify oxygen stress in hard clams. Clams have the ability to close their valves in response to hypoxic or anoxic conditions and can keep their valves closed for several days. Long-term responses may include gaping of the valves. Signs of adverse environmental conditions in juvenile or adult hard clams may go unnoticed because they are infaunal, which means that they live buried in the sediment. However, stressed clams may rise to the surface of the sediment or fail to bury. These signs are not necessarily specific indications of oxygen stress; they may also be associated with infectious or noninfectious diseases or other adverse environmental conditions such as high temperature and low salinity.
