Habitat Use of 0+ Fish Communities in Rivers of Lithuania

Abstract

A relationship between environmental variables and 0+ fish communities was investigated in inshore river zones and offshore zones in 21 different river of Lithuania. In 278 study sites, a total of 59,864 young-of-the-year fish from eight families and 31 species was caught using a fish dredge. In warmwater rivers, species diversity and density were higher than in the same-sized coldwater ones. Based on ANOVA results, 0+ fish density was mostly influenced by water limpidity, filamentous and attached algae, river zone, and average water yield. Less impact was made by shade, channel shape, current velocity, and shallow water zone width. Quantitative parameters of 0+ fish communities were principally determined by larger scale environmental variables. Qualitative parameters of the communities were conditioned by properties of a narrow living habitat. Environmental variables that are important to the abundance of 0+ fish food decide quantitative parameters of 0+ fish communities, whereas they are not so important to qualitative parameters of the communities.

Keywords:

• young-of-the-year fish
• river zones
• fish density
• ecological guilds
• ANOVA
• principal components analysis