The effect of depth, distance from dam and habitat on spatial distribution of fish in an artificial reservoir

Abstract

– Spatial distribution of the fish community in the deep canyon‐shaped Římov Reservoir, Czech Republic, was studied using overnight gillnetting fishing in 1999–2007. Effects of depth, distance from the dam to the tributary and habitat type (benthic and pelagic) on fish community structure, catch per unit of effort (CPUE), biomass per unit of effort (BPUE) and average weight were tested. Fish were recorded in all sampled depths and parts of the reservoir. Redundancy analysis revealed that effects of three environmental variables were significant and most variability was explained by depth, then by distance from the dam and habitat type. CPUE and BPUE of all species decreased with depth and responses of individual species to depth were similar for juvenile and adult fish. Number of species, CPUE and BPUE of all species except perch increased heading towards the tributary and peaked close to or at the tributary part of the reservoir. Responses of juvenile fish to distance from the dam differed from that of adult fish. Structure of fish community differed in benthic and pelagic habitats with species preferably occupying epipelagic (bleak, asp, rudd and juvenile bleak, roach and bream) or littoral waters (perch, pikeperch, ruffe, roach, bream and juvenile percids). This study showed that fish distribution in the reservoir followed distinct patterns, which were probably shaped by a combination of physiological constraints plus trade‐off between food resources and competition.

Influence of limnological zones on the spatial distribution of fish assemblages in three Brazilian reservoirs

“…The Três Marias riverine zone had greater total abundance of fishes than its lacustrine zone, which has been reported in other reservoir studies (Britto and Carvalho, 2006;Juza et al, 2009 (Fernando and Holčík, 1991;Sanches et al, 2014). Furthermore, the greater density of fishes in the riverine zone may reflect greater availability of resources there, compared with the lacustrine zone (Lind et al, 1993).…”

Spatial variations in fish assemblage structure in a southeastern Brazilian reservoir

“…The nonrandom pattern in total abundance and the greater abundance of some species in sites that were distant from the dam are consistent with the expectation that the dam alters several characteristics of fish assemblages along the river-reservoir axis (Prchalová et al, 2009;Terra et al, 2010). Irz et al (2002) suggested that the processes that determine the fish distribution in reservoirs are a combination of what occurs in lakes and rivers, partly influenced by river continuity, and partly the result of the confinement of species in reservoirs.…”

Pelagic underyearling communities in a canyon-shaped reservoir in late summer

“…These longitudinal enviromental gradients influence the horizontal distributions of phytoplankton (Fernández-Rosado et al 1994;Hejzlar & Vyhnálek 1998), zooplankton (Seďa & Devetter 2000;Fernández-Rosado & Lucena 2001) and, consequently, fish (Oliveira et al 2004;Vašek et al 2006;Čech et al 2007a;Čech et al 2007b;Prchalová et al 2009) within the pelagic zone of deep valley reservoirs. Beside the horizontal spatial heterogeneity, the pelagic environment also varies vertically in deep reservoirs, especially in those which have relatively long retention times enabling the development of thermal stratification.…”