Investigation of extension gillnet properties for put under pressure of invasive Carassius gibelio species in Karakaya Dam Lake

This study was conducted in Karakaya Dam Lake to evaluate fishing strategies of Carassius gibelio ( Prussian carp), one of the common invasive species in Turkey's inland waters. Invasive fish species threaten the populations of native species due to their pressure on the ecosystem and lead to a decrease in biodiversity. Thanks to its high reproductive potential, wide environmental tolerance and gynogenetic reproductive ability, C. gibelio spreads rapidly and disrupts the ecological balance by competing with native species for food. Within the scope of the study, plain extension nets with different mesh sizes (76, 80, 84, 88 mm) and thicknesses (0.18, 0.20, 0.23 mm) were used and a total of 18 fishing operations were carried out. The results showed that C. gibelio constituted 89.19% of the catch composition. Especially nets with 84 mm mesh size and 0.23 mm thickness were found to be the most efficient fishing gears. It was determined that the species forms flocks in the winter months and increasing the catching pressure during these periods may be effective in the control. The data obtained in the study are important for determining appropriate fishing techniques for population control of invasive species. In order to reduce C. gibelio populations, it is recommended to organize incentive fishing organizations for amateur fishermen together with commercial fisheries. In addition, sustainable management strategies should be developed to minimize the long-term impacts of invasive species on the ecosystem