What environmental condition causes the annual restocking of tilapia in South Carolina?

The necessity for annual restocking of tilapia in South Carolina is primarily due to their inability to survive the cold winter temperatures experienced in the region. Tilapia are warm-water species that thrive in temperatures ranging from the mid-70s to the low 80s Fahrenheit. When water temperatures drop significantly during winter, their survival rates decrease dramatically, often leading to a die-off in populations. This seasonal sensitivity necessitates the practice of restocking tilapia each year to maintain their presence in local waters for purposes such as recreational fishing and aquatic management.

The other factors, while potentially affecting fish populations, do not address the critical reason for restocking tilapia specifically in South Carolina's climate conditions.