Modelling the habitat preferences of preadult and adult fishes on the shoreline of the large, lowland Elbe River

Abstract

Summary From the years 1997 to 2000, fish assemblages from 15 groyne fields and training walls (a current guiding dyke, protecting the groyne field) of the Middle Elbe River (Germany) were examined by electrofishing. The aim of the study was to detect abiotic environmental key variables which determine preadult and adult fish assemblage in typical riverbank structures using multivariate ordination techniques (canonical correspondence analysis) and univariate methods (logistic regression analysis). Habitat preferences of preadult and adult stages of selected fish species were also estimated. Fish sampling was carried out at 190 river stretches; a further 1615 samples were taken by the point‐abundance sampling method. In total, 21 732 preadult and adult individuals belonging to 30 fish species were caught; perch, eel, ide, roach, chub, gudgeon, bleak and white bream were the most frequent. Eurytopic species clearly dominated the fish assemblage with 72% total abundance, followed by rheophilic species (26%). Limnophilic fish species (rudd, crucian carp, stickleback and tench) were relatively rare (2% of total abundance), with frequencies of occurrence between 1 and 10%. The highest species diversities were estimated in structurally diverse training walls and groyne fields with defective groynes, whereas low species diversity was found to occur in poorly structured, strongly silted groyne fields with intact groynes. Additionally, typical seasonal and annual changes of the fish assemblage were observed. From the mesoscalic point of view, the structure of the preadult and adult fish assemblage was affected by both spatial (type of groyne field, river stretch) and temporal factors (year, season). Regarding the microhabitat, hydromorphological parameters (slope, current velocity, water level, predominant and secondary substrate) followed by physicochemical water values [dissolved oxygen (DO), temperature and pH‐value] are of significance for the structure of the fish community. Furthermore, hiding places (shelter) are of subordinate but significant importance for the fish assemblage in the poorly structured main channel of the Elbe River. Importance of hydromorphological factors on the microhabitat scale was confirmed by multiple logistic regression in 12 of 14 preference models, conducted for different ontogenetic stages of roach, bream, white bream, bleak, ide, chub, gudgeon, asp, perch and eel. Habitat preferences of adult bleak and preadult roach were first determined by physicochemical water values and seasonal influences. Univariate models were generated to describe specific habitat preferences of different species and age‐stages regarding the most important environmental variables (depth, velocity, predominant substrate, slope and shelter). Intraspecific differences were noticed between preadult and adult chub regarding preferences for water velocity, or between preadult and adult perch concerning slope of shore. Interspecific differences were observed, e.g. between adult roach and white bream, with regard to the ...

A review of statistical methods for the evaluation of aquatic habitat suitability for instream flow assessment

“…CCA has been widely used for analysis of multiple aquatic species: for different fish species (e.g. Fladung et al, 2003;Godinho et al, 2000;Grift et al, 2003;Ostrand and Wilde, 2002;Taylor, 2000;Toepfer et al, 1998;Watkins et al, 1997), for microinvertebrate species (Cortes et al, 2002;Miserendino, 2001;Ruse and Davison, 2000), and macrophyte vegetation along rivers (Bernez et al, 2004). In these studies CCA determines which physical habitat variables influence spatial and temporal abundance of aquatic biota.…”

“…The model estimates the probability of a positive response occurring given a set of explanatory variables (Agresti, 1996;Jongman et al, 1995). Based on the presence-absence data, a response curve of a species describes the probability of the species being present, p, as a function of environmental variables (Fladung et al, 2003). The response variable is transformed by the logit link function (Agresti, 1996), which transforms bounded probabilities (between 0 and 1) to unbounded values:…”

Structure of 0+ juvenile fish assemblages in the modified upper stretch of the River Elbe, Czech Republic

“…According to some studies (e.g. IKSE-MKOL, 1994;Fladung et al, 2003), phytophilic and phyto-lithophilic fish species spawn preferentially in off-channel water bodies (i.e. backwaters) and fish species such as roach, perch, white bream, and common bream use these areas for spawning and recruitment development.…”

“…Havelková et al, 2008;Baborowski et al, 2011;Chalupová et al, 2012). Few studies, however, have monitored fish populations in the Elbe from an ecological point of view, and most of these have taken place along either the German stretch (Fladung et al, 2003;Oesmann, 2003) or in the Elbe estuary (Thiel et al, 1995(Thiel et al, , 2003. Indeed, few studies are available on the fish community in general, despite the Elbe being one of the most important rivers in the Czech Republic.…”

Point Sampling by Boat Electrofishing: A Test of the Effort Required to Assess Fish Communities

“…Several electrofishing techniques exist for sampling shallow waters, each of which is suited to particular objectives. Point abundance sampling by electrofishing (PASE; Nelva et al 1979) is used to determine fish densities, to examine population structure, and to study the habitat preferences of fishes (e.g., Fladung et al 2003). For PASE, a site is approached quietly and the anode (along with a dip net beneath it) is swiftly immersed for 1 to 5 s. The anode and net are then lifted, capturing any fishes stunned above the net (Copp et al 1994).…”