Distribution patterns of fishes in a canyon‐shaped reservoir

Abstract

and 2005, an extensive study of the fish community was carried out in the largest water supply reservoir in the Czech Republic and Central Europe, the canyon-shaped Ž elivka Reservoir, using a fleet of Nordic multimesh gillnets. Fishes were sampled at eight locations along the longitudinal profile of the reservoir and at five benthic depth layers covering depths from the surface down to 18 m (benthic gillnet 1Á5 m high), and at three pelagic depth layers down to the depth of 5 m above the bottom (pelagic gillnets 4Á5 m high). Catches of both juvenile (age 0þ year) and adult (fishes >1 year) fishes were highest in the upper layers of the water column (i.e. in the epilimnion down to 5 m, and down to 10 m in the benthic habitats). Along the tributary-dam axis in the pelagic habitats, both juvenile and adult fishes preferred the upper part of the reservoir, where the maximum number of species and also the greatest abundance of zooplankton were found. In the benthic habitats, fishes selected location according to factors other than trophic status. More juvenile fishes were recorded in the benthic habitats than in the pelagic habitats. Depth had the largest explanatory power for predicting fish community composition, followed by the affiliation with benthic and pelagic habitats, and location on the longitudinal axis of the reservoir. The fish community was represented mainly by cyprinids and consisted of two distinct groups of species, with bleak Alburnus alburnus, rudd Scardinius erythrophthalmus and asp Aspius aspius dominating the offshore group while perch Perca fluviatilis and ruffe Gymnocephalus cernuus were affiliated with the inshore group of the adult fish community. Roach Rutilus rutilus, bream Abramis brama and pikeperch Sander lucioperca occurred in important proportions in both the inshore and the offshore zones. All species, with the exceptions of adult perch (1þ year and older), 0þ year perch and 0þ year roach, preferred the most eutrophic tributary part of the reservoir. The fish community was relatively stable between the 2 years sampled.

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

“…In artificially destratified, deep reservoirs fish inhabited the whole volume (Prchalová et al 2006). In the sharply stratified Římov Reservoir the highest fry density was usually observed in the surface layer as has also been observed for adult fish in other stratified lakes and reservoirs Järvalt et al 2005;Kahl & Radke 2006;Prchalová et al 2008).…”

Temporal variation in juvenile fish communities of Kaunas reservoir littoral zone, Lithuania

“…It was observed that, depending on a studied period, the inshore community was dominated by three fish species. The dominance of only a few highly abundant species was also observed by others investigators [11,32,52,56,65]. Decrease in the dominance of pikeperch was quite obvious (the average of its relative abundance dropped to 0.4% in period III compared to period I).…”

Ecological assessment of a southeastern Brazil reservoir

“…In contrast, several studies observed associations between abiotic variables and the distribution of the ichthyofauna in this type of environment (Oliveira et al 2005, Prchalová et al 2008. Some environmental variables are particularly associated with fish assemblages, such as depth (Prchalová et al 2008), availability of littoral zone food and shelter (Vidotto & Carvalho 2007), presence of aquatic vegetation (Pelicice et al 2005, Abes & Agostinho 2001, dissolved oxygen, temperature, pH, (Castro et al 2003, Araú jo et al 2009), transparency (Petry et al 2003) and conductivity (Rodríguez & Lewis 1997). Distribution and abundance patterns of fish species in reservoirs can also be affected by other physical habitat attributes, such as type and size of substrate, presence of macrophytes or submerged vegetation, and type and integrity of riparian vegetation (Kaufmann et al 2014).…”

“…Silva et al (2006) related low correlations between fish abundance and limnological characteristics to a low susceptibility of fish to alterations in limnological characteristics. In contrast, several studies observed associations between abiotic variables and the distribution of the ichthyofauna in this type of environment (Oliveira et al 2005, Prchalová et al 2008. Some environmental variables are particularly associated with fish assemblages, such as depth (Prchalová et al 2008), availability of littoral zone food and shelter (Vidotto & Carvalho 2007), presence of aquatic vegetation (Pelicice et al 2005, Abes & Agostinho 2001, dissolved oxygen, temperature, pH, (Castro et al 2003, Araú jo et al 2009), transparency (Petry et al 2003) and conductivity (Rodríguez & Lewis 1997).…”