Do diel variations in stream fish assemblages depend on spatial positioning of the sampling sites and seasons?

Abstract

The effect of diel period (i.e. day vs night) and its dependence on the spatial position of the sampling site were evaluated on the assessment of fish assemblage attributes in a wadeable lowland stream (Hajagos stream, Hungary). Species richness, composition and abundance data of two 150 m long reaches, one situated directly at the tributary mouth and one 6 km upstream were compared using three pass removal by electrofishing in three seasons (summer, autumn and spring) to test the effect of spatial position on day and night patterns. No differences in any assemblage level variables were found between day and night. Although fish assemblages showed large temporal variations, spatial position of the sampling site had the most influential effect on fish assemblage attributes compared with seasonal and/ or day night patterns. Consequently, the diel period had rather negligible effect in the studied stream. Daytime electrofishing data seems to be highly representative for the accurate assessment of fish assemblages in relatively small (less than 5 m wide) wadeable streams and maybe used reliably for any model of community organization (e.g. food web studies).

Temporal dynamics of freshwater fish assemblages, their background and methods of quantifications—A synthesis

“…Assemblage variability is, however, frequently identifiable at even shorter time periods, such as monthly, weekly, daily and within‐day basis (e.g. Czeglédi et al., 2016; Olin & Malinen, 2003). Although this variability at such short time intervals can be caused by sampling bias (i.e.…”

Relative importance of meso‐ and microhabitat features in the within‐reach spatial distribution of size‐structured fish assemblages in small streams

“…Moreover, location in the stream network (e.g. distance from the stream source) can also influence the diel dynamics of habitat use (Czeglédi et al, 2016; Janáč & Jurajda, 2011).…”

“…Drift feeder water-column species can feed in fast-flowing and rest in slowflowing habitat patches, with a low predation risk (Grossman, 2014;Grossman et al, 2002). Therefore, we hypothesise that within-day temporal patterns will primarily manifest at longer (24 h) observational extents in streams that have hydro-geomorphological and from the stream source) can also influence the diel dynamics of habitat use (Czeglédi et al, 2016;Janáč & Jurajda, 2011).…”

Diel changeover of fish assemblages in shallow sandy habitats of lowland rivers of different sizes

“…Diel changeovers of fish assemblages in shallow riverine habitats are observed worldwide (e.g., Copp andJurajda, 1993, 1999;Arrington and Winemiller, 2003;Baumgartner et al, 2008;Ko sčo et al, 2008;Copp, 2010;Roach and Winemiller, 2011;Janáč and Jurajda, 2013) and studies that document no differences between day and night assemblages are scarce (Czeglédi et al, 2016). This is why diel changeover is presumed to be of adaptive significance (Gliwicz and Jachner, 1992;Roach and Winemiller, 2011).…”