Mussels. Handling and transport associated with reintroduction of covered freshwater mussels will most likely result in some temporary physiological stress, but these effects should dissipate shortly after release, if the mussels are placed in suitable habitat, which can differ according to the species. Similarly, capture and handling of covered mussels during monitoring efforts is expected to result in short-term physiological stress that will dissipate after the individual is returned to the substrate. Sites selected for mussel release should be able to support all life stages, including substrate conditions, appropriate host fish, food availability, and water quantity and quality. Timing of mussel release should be such that conditions are suitable for survival in the receiving habitat to minimize mussel stress and mortality. Periods of high flow can scour out translocated mussels, while very low water levels may cause additional metabolic stress from elevated water temperature and reduced dissolved oxygen. The stream hydrograph should be known so that mussels are not placed in an area likely to go dry at baseflow. Post-release monitoring activities should be frequent enough to detect the effects of stressors without causing undue disruption to the mussel bed. For juveniles, which are more sensitive to disturbance, this monitoring may be done within one (1) year after release, and subsequent long-term monitoring every three to five (3–5) years, as well as after events likely to disrupt a population (i.e., drought, flooding). Successful mussel reproduction relies on the presence of appropriate host fish for a given mussel species at periods when females are releasing glochidia. One of the many causes of freshwater mussel declines is the loss of appropriate host fish; without host fish, released mussels may grow to adulthood but no self-sustaining populations will be established. The presence of host fish in the system will be confirmed prior to mussel translocation (see monitoring activities described for fish in the previous subsection, Fish). Incidental take of covered mussel species associated with reintroduction and monitoring activities are expected to be less than 1% of the reintroduced population. Any impacts from incidental take would be outweighed by the expected benefits to the local or regional population from reintroduction and habitat management actions.
Mussels. Mussel surveys will provide supporting lines of evidence to inform XXX status. Current 2016 surveys should have similar levels of species encountered, distribution and abundance when compared to previous 2011 sampling efforts while taken in context of any statewide population or distribution trends.
Mussels. Several state-listed and at-risk mussels can be found within the Yazoo Study Area, including the Western fanshell (Cyprogenia aberti), pyramid pigtoe (Pleurobema rubrum), and spike (Eurynia dilatata) (Mississippi Natural Heritage Program, 2018). These species can be found in the Big Sunflower River, including areas outside the Yazoo Study Area that may be affected by the environmental flows mitigation feature. Mussel populations in general continue to decline in the Mississippi Delta due to poor water quality, elevated water temperature, and low-flow conditions, which also adversely affects host fish that mussels rely on for reproductive success.
Mussels. Shellfish are filter feeders and concentrate bacteria and viruses in their tissue, mainly in the digestive system, at levels more than 100-fold higher than in the surrounding seawater (Xxxxxxx, 1992). Furthermore, shellfish are often eaten raw or only lightly cooked. Diseases associated with excreted virus contamination of shellfish is mostly hepatitis A, but salmonelloses and enteric fevers, and poliomyelitis have also been associated with consuming shellfish from fecally polluted waters (Xxxxxxx, 1992).
