Total Length–Weight Relationships and Condition Factor of Invasive Procambarus clarkii (Girard, 1852) in Caohai Lake, China

Caohai Lake, hailed as a gem on the Yunnan–Guizhou Plateau, is currently being faced with serious biological invasion threats. Among the most influential invasive species, the Procambarus clarkii (Girard, 1852) is causing various adverse effects on the lake’s ecosystem. However, there has been little attention paid to this issue for a long time. In light of this, this study conducted a sample collection in August 2022 to investigate the total length–weight relationships (LWRs) and condition factors (K) of the target species with the aim of providing fundamental data for the upcoming ecological restoration in Caohai Lake. The results are as follows: (1) P. clarkii was distributed throughout the lake, with females exhibiting larger body sizes than males; (2) the LWRs were expressed as: W_♂ = 2 × 10⁻⁶TL^3.66 (R² = 0.90 and n = 227); W_♀ = 4 × 10⁻⁶TL^3.39 (R² = 0.95 and n = 259), both showing positive allometric growth pattern and indicating, the weight gain rate of males is significantly faster than that of females during the growth period; (3) the K was 0.27 ± 0.04%, indicating robustness in P. clarkii in the lake. These findings underscore that urgent scientific measures should be taken to handle the rapid invasion of P. clarkii in Caohai Lake.