The status of stocks of particular fish species in the Tisza River after the cyanide spill

Abstract

The fish stock in the Tisza river remained mainly preserved after the cyanide spill that occurred in February 2000, as indicated by the insignificant difference in estimated relative biomass of carp and silver carp recorded between 1996 and August 2000. Only the zander stock in August 2000 was significantly less than that reported for 1996. The effect of the cyanide toxic wave on other fish species stocks whose relative biomass is reported here is impossible to evaluate, due to the lack of data for the previous period. It seems that the effect of cyanide was coped with as a result of both the long-lasting very high water level of the Tisza river and favorable environmental conditions in the winter. Specific conservation and fisheries measures for recovery of the zander stock are proposed.