Multi-scale analysis of habitat use during late summer for 0+ fishes in the River Garonne (France)

Abstract

Relationships between environmental variables and 0+fish in the upper River Garonne (France) were studied at different habitat scales during late August 1995. In total, 3911 0+ fish representing 21 species were sampled using point abundance sampling by electrofishing. Fish reproductive function of floodplain channels was evaluated using principal components analysis of 0+ fish distributions (in absence/presence), with distinction of the three main channel types (flowing, partially abandoned and abandoned channels). A descriptive model of microhabitat use and microhabitat profiles of 0+ fish was developed for the more frequently encountered species using canonical correspondence analysis and an electivity index combined with chi-square analysis. Water velocity, water depth and distance from the bank were the most important microhabitat variables, followed by bank gradient and bottom composition. Partially-abandoned channels provide conditions particularly suitable to 0+ fish, with submerged vegetation in these sidechannels serving many of the fishes as refuge and feeding areas. Similarities in microhabitat use were found with respect to 0+ juvenile fish in the Danube flood plain (Slovakia/Hungary), the upper River Rhône (France) and the River Great Ouse catchment (England).

Fish Community Structure in Temporary Lowland Flooded Grasslands

“…These latter non-indigenous species and nest guarder spawners are more tolerant and not dependent on water depth, but greatly prefer a dense vegetation cover (THIERO YATABARY, 1981;GRENOUILLET, PONT and OLIVIER, 2000). Ameiurus melas age > 1, which is dominant in the present study, is known to inhabit a wide range of ecosystems, from deep oxbows (COPP, 1989;GOZLAN et al, 1998;BERREBI-DIT-THOMAS, 1999) to shallow isolated ponds (THIERO YATABARY, 1981;DECLERCK et al, 2002). The high colonization capacity of exogenous species (BABER et al, 2002) may explain their adaptative success and importance in fish communities.…”

Diel dynamics of young and small fishes in a side-channel of the River Garonne, France, before and after a late-summer spate

“…Sampling was generally undertaken from a dingy, though some points were so shallow that sampling was undertaken by foot. The sampling technique is described in detail in Copp & Penáz (1988), Copp & Garner (1995) and Gozlan et al (1998).…”

“…For data analysis, fish relative density was calculated as the number of specimens captured per total surface area sampled (Copp 1989a, 1989b, Gozlan et al 1998, with chub Leuciscus cephalus classed as 'small', i.e. non-piscivorous (<100 mm SL), and potentially 'piscivorous' (≥100 mm SL) as per Mann (1976).…”

Otolith trace element and stable isotopic compositions differentiate fishes from the Middle Mississippi River, its tributaries, and floodplain lakes

“…Many riverine species are believed to require connectivity of large rivers and floodplain habitats for spawning and larval nursery (Bayley & Li, 1992;Gozlan et al, 1998;Nunn et al, 2007a), foraging (Nunn et al, 2007b), and winter refuge (Knights et al, 1995;Raibley et al, 1997). However, there are currently several hypotheses regarding the primary source habitat (floodplain lakes, tributaries, and river channel) for fishes in large, regulated rivers.…”