Habitat Use by 0+ Fishes in Small Rivers of Lithuania

Abstract

Studies of habitat use by the most common 0+ fish species in 16 small rivers of Lithuania were performed. The density of 0+ fish was proved to be most heavily dependent on environmental variables of the microhabitat, whereas species diversity of 0+ juveniles turned out to be almost evenly affected by environmental variables of all levels. Abiotic microhabitat variables were the ones that exerted a somewhat stronger influence on the share of 0+ juveniles in communities. The influence of mesohabitat variables on the share of 0+ fish in communities was proved to be comparatively weak, the impact of macrohabitat variables being the strongest. River temperature conditions exerted reliable influence on the greatest number of 0+ fish species. Stone loach, freshwater sculpin and three-spined stickleback were recorded as most heavily dependent on microhabitat variables, whereas roach, chub and perch were found to be most susceptible to the impact of mesohabitat variables, and minnow – to that of the macrohabitat ones. For bitterling both micro and macrohabitat variables were nearly equal in importance, while bleak and riffle minnow were proved to be most dependent on meso and macrohabitat variables.

Keywords:

• young of the year fish
• ANOVA
• fish density
• species richness
• river temperature conditions