Species diversity of the ichthyocenosis of the lower course of the Becva river
2000
Spurny, P. | Mares, J. | Fiala , J. (Mendelova Zemedelska a Lesnicka Univ., Brno (Czech Republic). Ustav Rybarstvi a Hydrobiologie)
In 1998-1999 the authors investigated to what degree the stability of the fish community was disturbed in the lower course of the Becva river between Troubky and Osek nad Becvou (fishing section 1 and 2) due to the predation pressure of the overwintering great cormorant. The incidence of the great cormorant gradually increased from sporadic ones in 1979 to tens in 1990-1992, hundreds in l993, and more than 1,000 in 1998. Ichthyological research resulted in findings of 23 fish species, two of which belong to species under special protection. The most frequent were the rheophile species - nase, barbel, chub and vimba beam. Over the past 9 years the catch of rheophile fish in the Becva 1 decreased by 1.8 kg.ha-1, during the same period, the catch in the Becva 2 increased by 4.2 kg.ha-1.
显示更多 [+] 显示较少 [-]