Based on the analysis of fish yield data of Lake Balaton, changes reflected in species composition and stock density can be followed for a long run. Their reasons can be connected with the intensity and/or selectivity of commercial fisheries, and with the environmental changes. Fish yields for the period of 1902-1990 have already been analyzed in several papers, however, the data for the years 1980-1999 have not been evaluated in detail in spite of the fact that water quality of the lake significantly improved since 1994-95.
Any comparison of statistical data for the last 20 years proved to be difficult, because of changes taken place in the technology of commercial fisheries, in the selectivity of fishing tools applied, as well as in the areal distribution of fishing intensity.
Commercial fishing yields can basically be influenced by the cascading effects of global climatic changes (e.g. elevated temperature, altered icephenology and increased UV-radiation. (Source: Proceedings of the XLII Hydrobiological Days, 4-6. October 2000, Tihany, Hungary in Journal of the Hungarian Hydrological Society, Vol. 81. No.5-6., September-December 2001)
Bíró Péter
Information & Contact:
Balaton Limnological Research Institute
Klebelsberg Kuno u. 3.
H-8237 Tihany
Phone: +36 87 448 244; +36 87 448 134
Fax: +36 87 448 006
Hungarian Hydrological Society
Ms. Ágnes Geszler (Managing Director)
F? utca 68
H-1027 Budapest
Phone: +36 1 201 7655
