The population of Carassius gibelio (Bloch, 1782) and its parasites in Madatapa Lake (South Georgia)

Abstract

Gibel carp is a very successful invasive fish species in the waters of Georgian inland and the only fish species in Lake Madatapa. However, almost nothing is known about its biology and morpho-ecological peculiarities at the national level and even the distribution data is not documented. For the first time, we studied the population characteristics of gibel carp in Lake Madatapa (South Georgia) with the aim to reveal the extent of its morphological variability, sex ratio, length-weight relationship and its parasitic community. We showed that the gibel carp population in Madatapa Lake has typical morphological characteristics. The sex ratio is significantly female biased (1/1.8) and the length-weight relationship is within the published margins. The gibel carp population is under the heavy parasitic load, but only two parasitic species (one cestoda and the other digenean species) affect the fishes. Within the framework of the obtained results, we discussed future research needs concerning the gibel carp in the lake.