Life-history of invasive common carp, <i>Cyprinus carpio</i> , within a natural lake (Groenvlei), South Africa

Common carp, <i>Cyprinus carpio</i>, is a global invasive species illegally introduced into the Groenvlei system, South Africa, in the 1990s for recreational angling. To manage this population effectively, basic information is needed on its biology including growth and reproduction. This study examined the growth trends of <i>C. carpio</i> using otolith growth zone deposition rates which were validated using a chemical mark–recapture experiment (<i>n</i> = 16). From a total of 140 <i>C. carpio</i>, length-at-age was best described using the Von Bertalanffy growth model for males and females. The average lengths-at-50% maturity were estimated at 314 mm <i>F</i>_L (males) and 262 mm <i>F</i>_L (females). Compared with other South African <i>C. carpio</i> populations, the Groenvlei population is relatively fast growing and long lived, with the oldest female aged 20 years and the oldest male aged 18 years, likely facilitated by relatively favourable environmental conditions at Groenvlei. Data from this study provide a baseline at the commencement of <i>C. carpio</i> management interventions at Groenvlei and an opportunity to monitor changes in population dynamics facilitated by these efforts.