Illegal fishing in the Tisza River drainage within Ukraine: a threat for local fish stocks?

摘要

Illegal fishing in the Tisza River drainage within Ukraine: a threat for local fish stocks?Illegal fishing in watercourses of the Tisza River drainage in Ukraine (Transcarpathian region) was investigated focusing on the use of illegal gears and techniques. It was found that this activity is traditional and widespread in the region and is primarily practiced by low-income residents of rural communities. Fish are harvested mainly for personal consumption, which contributes to the diversification of diets and increase of protein intake for local people. The investigated illegal gears and techniques included gill nets, lift nets, screen nets, electrofishing devices, spears, and concussion. In total, 31 species were observed in poachers' catches, among which the most abundant were nase, Chondrosotma nasus (L.), Carpathian barbel, Barbus carpathicus Kotlik, Tsigenopoulos, Rab et Berrebi, and chub, Squalius cephalus (L.). Electrofishing devices were the most effective illegal fishing gears as they caught the largest total number and weight of fish. However, the highest mean weight of fish was caught in gill nets. Effects of poaching on local fish populations are currently probably lower than or comparable with that of recreational fishing.