Successful reproduction of common carp Cyprinus carpio in irrigation waterways

Some key reproductive characters of invasive common carp, Cyprinus carpio L., were studied in an irrigation system of south-eastern Australia. Spawning occurred on a variety of natural (i.e. submerged vegetation, plant debris and stones) and artificial substrates, and the presence of 0+ individuals was an indicator of spawning success. Compared with other C.carpio stocks worldwide, the lower minimum length at maturity reflected the higher water temperatures of the region, whereas the relatively lower mean pseudo-gonadosomatic indices were attributed to less diverse food resources than those available in floodplain areas. The successful reproduction of feral C.carpio in irrigation waterways confirms its high adaptability and plasticity of traits and its classification into the phytolithophil guild, as opposed to the phytophil wild form. The findings of the present study should be given careful consideration in view of preventative measures for further spread of invasive C.carpio in similar waterways worldwide, but also for the enhancement of the species' fisheries in some man-made reservoirs.