A Debreceni Déri Múzeum Évkönyve 2002-2003 (Debrecen, 2003)

Természettudomány - Juhász Lajos–Harka Ákos: The fish fauna of the Lake Tisza and protection

Lajos Juhász-Akos Harka THE FISH FAUNA OF THE LAKE TISZA AND PROTECTION The Lake Tisza has a valuable fish fauna which has been damaged by a cyanic and heavy metal contamination from Romania. The population of some fish species seriously injured (e.g. Accipenser ruthenus, Stizostedion luciperca ), other species lost one or more of age groups (e.g. Silurus glanis) which has destroyed the natural structure of the fish population.The fisch fauna is not destroyed completely, because the contamination was not in the period of the breeding season of the fishes (spring and summer). The polluted water flowed along the river Tisza in winter. The Lake Tisza is a refuge place for several fish species. The increased water level of the Lake was also protect several species. This type of water management will be adaptable in the future. The fish fauna is not destroyed irreversible. After the cyanic contamination presence of 45 fish species proved. Every species survived the pollution. The fishfauna of the Lake Tisza is influenced by the river Tisza, the ecologic conditions are favourable for species which prefer standing water. The Lake Tisza were saved from the contaminated water. The natural regeneration of the population in the river may cause the recover of the fauna. The rational utilization, reducing in the illegal fishing and the reasonable water management in the lake, in the channels and in the river Tisza will be acceptable in the future. The former type of fish management would be more effective in the future. To protect the fishfauna of the Lake Tisza in the future our suggestion are the follows, rational fishing, protection in several areas and continuous monitoring. 47