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1.
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.  相似文献   

2.
Abstract – Structural complexity offered by submerged macrophytes was shown to have fundamental effects on interactions between fish and their prey. However, less information is available for littoral reed (Phragmites spp.) stands. A previous field study found juvenile roach and perch to coexist within the reed stands. It was suggested that reed serves mainly as refuge against littoral piscivores, such that coexistence of perch and roach in the reed was externally forced. Several hypotheses were raised to explain why roach nevertheless showed good growth performance. Three of the hypotheses were tested experimentally. In particular, we were interested in how the confinement of fish to one of the reed or open water habitats alters feeding and growth patterns of juvenile age‐1 perch and roach. Fish were stocked separately into littoral enclosures for a 3‐week period in densities which had been found in the surrounding lake. Development of zooplankton and macroinvertebrate biomasses was observed by sampling the enclosures three times over the experimental period. Individual consumption of prey groups by the fish was calculated with a bioenergetics model, and was compared with prey group biomass in the enclosure treatments. The confinement of fish to one littoral habitat had clear effects on diet composition and growth rates. Roach fed less zooplankton and partially switched to macroinvertebrates in the reed enclosures when compared with the open water treatments, and consequently their growth rates were lower in the reed. Perch preferred macroinvertebrates in both habitats, without any difference in growth rates between the habitats. Effects of fish predation on both zooplankton and macroinvertebrate biomass were low in open water and reed enclosures. Daily consumption rates were only in a few cases higher than 40% of the available biomass of the respective prey group, but mainly were below 10% of available biomass. Therefore, we argue that both the diel horizontal migrations of roach and the relatively low consumption rate of fish when compared with the available resource biomass allow the coexistence of juvenile roach and perch in littoral reed stands.  相似文献   

3.
Abstract – Complex interactions between fish predators and their prey have been found in structurally complex habitats built by submerged macrophytes. In contrast, the role of comparably structured littoral reed stands in shaping biotic interactions has not been investigated. We hypothesised that reed stands may be a valuable feeding habitat for juvenile fish, and that perch and roach may segregate along the spatial and dietary niche dimensions between reed and open water habitats. In contrast, the protection effect of reed against predators was assumed to be rather low because of the lower plant volume infested in reed when compared with submerged macrophytes. We analysed biomass and growth of juvenile (age 0 and age 1) perch and roach in littoral reed habitats and in open water habitats in front of the reed in the shallow Lake Müggelsee over 4 months in 2000. Sampling was conducted by point-abundance electrofishing over the full diel cycle (day, dusk, night, dawn). Zooplankton and benthos biomasses were determined in both habitats as well, and habitat-specific diet of fish was assessed during day and night. Roach were more frequent than perch in both habitats. Food of roach included a higher proportion of zooplankton, whereas perch fed more on macroinvertebrates. Overall, diet overlap between the fish groups was high. Diel distribution of fish did not follow the expectations of habitat segregation between perch and roach. Instead, the function of reed as refuge habitat against littoral piscivores (mainly birds) may have caused the strong daytime preference for reed in almost all fish groups, which was partly upset by roach at night. The higher behavioural plasticity of roach may explain their good performance even under the conditions of high structural complexity.  相似文献   

4.
Abstract – The horizontal distribution of fish in lakes varies with species, age, predation risk, vegetation coverage and water clarity. Although sporadic data are available for specific lakes, little is known about how habitat distribution generally changes along a gradient in nutrients and clarity. Here we analyse littoral and pelagic fish catch data for 34 Danish lakes (covering 94 lake years) with contrasting total phosphorus (TP) concentrations and mean depth levels (but mainly eutrophic and shallow). Electrofishing was conducted during day along the shore or along the edge of the reed belt if such existed. Gill nets were set overnight for 18 h in open water. We calculated a littoral proportion as: LITPRO = (100 × number caught by electrofishing in the near‐shore area)/(number caught by electrofishing in the near‐shore area and nets in the open water). At all summer TP concentrations LITPRO was high for several ‘littoral’ species such as gudgeon (Gobio gobio), rudd (Scardinius erythrophtalmus) and pike (Esox lucius) and low for more typical pelagic species like pikeperch (Sander lucioperca), ruffe (Gymnocephalus cernuus) and smelt (Osmerus eperlanus). However, for many of these species including the dominant roach (Rutilus rutilus) and perch (Perca fluviatilis) LITPRO increased with TP or lake water chlorophyll a (CHLA) for fish >10 cm, suggesting a more littoral distribution with increasing turbidity. Exceptions are pikeperch and bream (Abramis brama). For bream, LITPRO increased significantly with mean lake depth only. For fish ≤10 cm LITPRO showed only a weak relationship to TP, CHLA or depth. In accordance with the TP‐dependent distribution, major changes occurred in the fish community structure during the monitoring period following nutrient loading reduction. A comparison of LITPRO from the first part of the monitoring period (1989–1993) with a subsequent period (1997–2003) for four abundant species showed a significant decline in LITPRO over time for large‐ and small‐sized roach and perch and large rudd. This suggests a fast response in fish distribution to improved water quality. It further demonstrates that fish monitoring in lakes should cover both littoral and pelagic habitats to describe the recovery process.  相似文献   

5.
We studied the relationships between the planktonic food base and feeding patterns of juvenile mid-summer/early autumn Eurasian perch Perca fluviatilis L., a common predatory freshwater fish in large parts of Europe and Asia. The feeding of 0+ perch was studied during summer and autumn in littoral habitats of seven lakes with different environmental conditions – four Latvian (Auciema, Riebinu, Vārzgūnes, Laukezers) and three Estonian (Kaiavere, Prossa and Akste) lakes. Simultaneously, the abundance, biomass and structure of zooplankton communities were examined. We focused on the littoral areas because many studies in lakes suggest that littoral habitats are particularly important for 0+ fish growth and survival. We were interested in the question: can the diet and growth of 0+ perch be explained by zooplankton community structure? We also presumed that if the amount of zooplankton is low, more benthic invertebrates will be consumed by 0+ perch. Opposite to expectations, we found that zooplankton always counted for over 90% of diet biomass in perch. There were also clear correlations between the zooplankton biomass in a given lake, the zooplankton biomass in 0+ perch stomachs, and the fish growth rate. The study also suggested that nutrient enrichment can positively impact the 0+ perch feeding conditions in lakes.  相似文献   

6.
Abstract Diel changes in littoral fish assemblage were studied in four reservoirs in the Czech Republic (Central Europe). The sampling was performed by beach seining in an unstructured littoral zone. Perch, Perca fluviatilis L., roach, Rutilus rutilus (L.), bream, Abramis brama (L.), carp, Cyprinus carpio L., ruffe, Gymnocephalus cernua (L.), pikeperch, Sander lucioperca (L.), eel, Anguilla anguilla (L.) and A. brama × R. rutilus hybrids exhibited higher densities at night. Only bleak, Alburnus alburnus (L.) exhibited higher densities during the day. The number of species was higher in night hauls, and mean body size of roach and bleak was also higher at night. Diel changes in fish densities resulted in the change in species composition between day and night. The study has implication for the sampling design to assess littoral fish assemblages using beach seine netting and recommends night sampling for a representative assessment or sampling during both diel periods for a robust assessment.  相似文献   

7.
The diversity of predatory species plays a key role in ecosystem functioning but our understanding of the mechanisms underlying their coexistence is limited, particularly in freshwater ecosystems. Northern pike Esox lucius, European perch Perca fluviatilis and pikeperch Sander lucioperca are three widespread predatory species in European lakes, where they often coexist. As potential competitors, we hypothesised that partitioning habitat is a determinant of species coexistence. This was tested by quantifying the variability of their habitat use in tracking adult individuals in the Bariousses reservoir (France, 86.6 ha, mean depth 7.1 m). Specifically, we investigated their distribution along the littoral–pelagic and depth axes along the daily cycle and across seasons. From littoral to pelagic waters were first found pike, then perch and finally pikeperch. Pike was the closest to the surface while pikeperch was the deepest. This general pattern was, however, variable across seasons with the three species located in the upper layer in summer during reservoir stratification. Individuals were more evenly distributed along the littoral–pelagic axis and closer to the bottom when water was mixing (autumn, winter). In summer, perch used more intensively in the pelagic zone during the daytime. Other species did not show any diel change of habitats. Our results highlighted that species coexistence is associated with habitat partitioning among these three predators, with perch showing a more variable behaviour regarding habitat characteristics. Now more than ever, in the context of global change which modifies habitats, it is of crucial importance to understand the coexistence mechanisms of species that shape ecosystems.  相似文献   

8.
The Pilica River has warmed at a rate of 0.06°C per year since 1969, threatening the ecological services provided by the Sulejów Reservoir. Gillnet sampling revealed that the reservoir is inhabited by a cyprinid‐dominated fish assemblage with roach, Rutilus rutilus (L.) (42% of the total biomass), the dominant species. However, the interest of the anglers was primarily focused on common bream, Abramis brama (L.) (almost 65% of the catch), as revealed by the catch statistics (2004–2014). No direct evidence was found that the temperature increase had an influence on the recreational fishery or fish assemblage structure. On the other hand, changes in the fish assemblage that were reflected in angler catch composition were observed. A decrease in the catch of common bream in gillnets was accompanied by a shift in angler choices towards roach and other fish species. The sustainability of recreational fisheries is more likely to be influenced by changes in the economic status of society, water quality (toxic cyanobacteria blooms) and water management practices in Poland. The question arises about which species will dominate in the impoundment in the future if the warming trend continues and common carp, Cyprinus carpio L., stocking is maintained.  相似文献   

9.
Abstract  Logistic curves of the average growth in length were elaborated for young-of-the-year perch, Perca fluviatilis L., zander. Stizostedion lucioperca (L.), ruffe, Gymnocephalus cernua (L.), bream, Abramis brama (L.), and roach, Rutilus rutilus (L.), using data from 62 localities. Mean relative deviation from this average growth (MRDAG) is proposed as a simple and reliable indicator of growth rate. The MRDAG for perch, zander, bream and roach showed a significant negative linear relationship with the geographical latitude.  相似文献   

10.
Abstract – We compared fish microhabitat use patterns in the littoral zone of a lake using a new direct method (point abundance sampling by scuba, PASS) and the widely used point abundance sampling by electrofishing technique (PASE). We collected microhabitat data for age 0+ roach ( Rutilus rutilus L.), perch ( Perca fluviatilis L.), and pike ( Esox lucius L.). The two methods yielded different results for fish assemblage structure and microhabitat patterns. Using PASE, fish were mainly found in "shelter habitats" such as shallow waters and dense vegetation. It is likely that this behavior is caused by the disturbance of the observer stamping around. Using PASS, fish escapement behavior was rarely observed. Therefore, we concluded that this direct and nondestructive sampling technique can be used to provide an accurate microhabitat estimation of a fish community and is assumed to be more suitable than PASE for fish habitat studies.  相似文献   

11.
Abstract The effects of perch, Perca fluviatilis L., and bronze bream, Abramis brama (L.), predation on the production of insects emerging at the water surface and the autumn biomass of benthic macro-invertebrates were assessed in a series of experimental ponds. The study attempted to discover whether fish affect food availability for diving and dabbling ducks in freshwater habitats. Ten ponds (bisected by fine netting) were used for the study: one was left totally fish-free, whilst one half of each of three groups of three ponds was stocked with either perch, bream or perch plus bream. The relative abundance of emerging insects (mainly Chironomidae) was significantly reduced in two perch ponds, two perch + bream ponds and two bream ponds. The autumn standing crops of benthic macroinvertebrates were significantly reduced in one perch pond, three bream ponds and one perch plus bream pond. These results support findings of a contemporaneous large bio-manipulation experiment carried out in two adjacent lakes. During the biomanipulation studies, aquatic invertebrate standing stocks greatly increased after the removal of fish and decreased following restocking.  相似文献   

12.
Abstract –  Eurasian ruffe are invading habitats in the North American Great Lakes watershed occupied by commercially important native yellow perch. We conducted laboratory experiments to evaluate potential overlap in habitat (macrophytes, mud, cobble) and food (benthic invertebrates) use. Ruffe and yellow perch both preferred macrophytes > cobble > mud in the light, but only ruffe increased their use of mud in the dark. Neither fish density nor food availability affected habitat preferences, and competition for habitat was not evident. For both species, feeding rates were marginally lower in macrophytes but did not differ between species. Our experiments suggest that if ruffe and yellow perch share a habitat (e.g., during invasion or because of predation risk), competition for space will be weak or absent. However, within a shared habitat, competition for food may occur when food is limiting because neither species has a clear advantage in its ability to consume invertebrates in any habitat.  相似文献   

13.
Understanding the forces that drive habitat selection of species in communities is important in both ecology and evolution. In nature, species face variation in competition, predation and physical characters among habitats. Vendace (Coregonus albula (L.)) is a specialised zooplanktivorous fish predominantly using deeper water in lakes during summer, while roach (Rutilus rutilus (L.)) uses mainly the shallow littoral zone as well as the upper layer of the pelagic zone. To understand mechanisms behind habitat use of these species, I first conducted a predation experiment to investigate their sensitivity to predation by perch (Perca fluviatilis L.). Second, I performed a foraging experiment using different temperature and light treatments. I then used metabolic calculations to estimate energetic costs when foraging. I found no difference between species regarding sensitivity to predation. Vendace was the most efficient forager on zooplankton but also swam faster spending more energy compared to roach. Roach had a comparatively high metabolic rate in the lowest temperature, where their foraging efficiency was lowest. The energy gain ratio at 6°C was highest for vendace, while it was lowest for roach. In the highest temperature (18°C) and the lowest light level (1 lux), both species were similar in their energy gain ratio. The relative energy gain ratio provides a mechanism to explain habitat distribution for the two species. An increased understanding of the role of metabolism in combination with biotic interactions and habitat use may help to foresee effects of environmental change for different species.  相似文献   

14.
Abstract Two rehabilitation projects were compared to determine their feasibility for successfully improving habitat for fish in urban waters. The first re‐meandering project involved channel reconstruction in the Müggelspree upstream of Berlin to create an aesthetically pleasing, stable, meandering channel. The second project addressed a typical habitat bottleneck for fish found in urban waterways; that of nursery habitats lost due to river engineering works. Rehabilitated and control sites were sampled before and after in the Müggelspree and once in the urban Spree River. A total of 30 303 fish belonging to 27 species were collected. The fish assemblage was dominated by generalist species with 81% roach, Rutilus rutilus (L.), and perch, Perca fluviatilis L. Species diversity did not improve in either the rural or urban stretch. In the Müggelspree, the loss of riverine habitats was mirrored by significant declines in the densities of chub, Leuciscus cephalus (L.), ide, Leuciscus idus (L.), gudgeon, Gobio gobio (L.), rheophilic and lithophilic species. By contrast, densities of rheophilic species around the artificial structures created in the urban Spree River, although the main effect was an overwhelming increase in roach and perch. The results suggest that if underlying bottlenecks can be identified, artificial structures can provide functional fish habitat that replaces the natural equivalent in urban river stretches. Consequently, even the most heavily degraded waters provide opportunities to improve fish diversity and fisheries using artificial habitat structures.  相似文献   

15.
Abstract  The inshore fish community of the Římov Reservoir in the Czech Republic was evaluated over 21 years using shore seining at night. The development of the fish community was divided into two separate phases: a highly dynamic and unstable phase dominated by perch, Perca fluviatilis L., was replaced by an extremely stable cyprinid phase dominated by roach, Rutilus rutilus (L.), and bream, Abramis brama (L.). The abundance of both these species oscillated during the cyprinid phase, but with decreasing amplitude. The proportion of piscivorous fish species such as asp, Aspius aspius (L.), pike, Esox lucius L., and pikeperch, Sander lucioperca (L.), increased slightly with time but remained low. The biomass of large Cladocera was negatively correlated with fish biomass only during the perch phase. The Shannon–Weaver index of diversity increased during the fish community succession, mainly because of greater evenness amongst the species.  相似文献   

16.
Abstract –  The aim of this study was to test assumptions about the interaction of perch ( Perca fluviatilis L.) and roach ( Rutilus rutilus L.) concerning their food and habitat use in a deep and mesotrophic reservoir. From 1998 to 2001 the fish were caught with gillnets to perform diet analyses. Additionally, vertical gillnets were set to study vertical spatial distribution of both species. The results indicate that in a large and deep reservoir perch and roach are able to avoid competition by separating their niches first in the spatial dimension and then in the dimension of food utilisation. These separations result in low inter- and intraspecific competition of both species. We conclude that these niche separations can widen the juvenile competitive bottleneck to such an extent that the perch are not forced to compete with their older conspecifics during their first year of life, enabling perch to become large and consequently piscivorous.  相似文献   

17.
Abstract – Although introductions of prey species have the potential to significantly alter habitat use by top predatory fish, this aspect has rarely been directly quantified. Introduction of yellow perch (Perca flavescens), a littoral–pelagic prey species, to a small boreal lake previously dominated by littoral cyprinids provided a unique opportunity to examine how a change in forage base influenced habitat use by the sole top predator, lake trout (Salvelinus namaycush). We monitored lake trout pelagic and spatial distribution using acoustic telemetry before (2001) and after (2008) the introduction of perch to determine whether habitat use reflected a deeper, offshore prey community. After accounting for differences in water temperature and dissolved oxygen concentrations between years and the inclusion of a control lake, our data suggest that lake trout habitat use changed after the introduction of yellow perch. Lake trout, on average, were 1.4 m deeper (P < 0.01), reduced their use of littoral habitat by 55% (P = 0.03) and experienced a 71% decrease in home range size (P < 0.01), consistent with a greater offshore habitat overlap between predator and prey after the introduction of yellow perch. This study illustrates how introduced prey species may have a significant influence on habitat use by top predatory fish, while also showing the importance of using direct measurements to quantify behavioural changes.  相似文献   

18.
护堤、桥梁、大坝等涉水工程的兴建会对鱼类栖息地产生影响,了解鱼类幼鱼生境偏好可为鱼类栖息地的保护和修复提供理论依据。本文选取6种长江经济鱼类幼鱼,鳙(Hypophthalmichthys nobilis)、翘嘴鲌(Chanodichthys erythropterus)、青鱼(Mylopharyngodon piceus)、团头鲂(Megalobrama amblycephala)、鲫(Carassius auratus auratus)、黄颡鱼(Pelteobagrus fulvidraco)进行了生境偏好选择模拟试验。结果表明:这6种鱼在各个组合生境中对沙生境均没有显著偏好(P>0.05);黄颡鱼在各个组合生境中均对岩石生境有明显偏好(P<0.05);鳙、翘嘴鲌、青鱼、团头鲂在各个组合生境中对沉水植物生境均有显著偏好(P<0.05)。生境修复的方案要根据环境条件和目标物种来确定,使用多种组合生境,可以为更多鱼类提供适宜的栖息生境。  相似文献   

19.
  • 1. This study was conducted to determine whether there were significant differences in the species richness and community composition of fish assemblages in coastal nearshore habitats with differing compositions of supralittoral vegetation.
  • 2. We sampled fish assemblages and conducted supralittoral vegetation surveys at 27 beaches on the west coast of Vancouver Island, British Columbia. Thirteen of the beaches had supralittoral vegetation characteristic of old‐growth coastal forests and 14 had been previously subjected to logging or other disturbances.
  • 3. Physical features (e.g. substrate, salinity, etc.) were recorded at each beach to determine whether there were significant associations between supralittoral vegetation and beach characteristics as well as between beach characteristics and fish assemblages.
  • 4. Across all 27 beaches, 1832 individuals of 31 species of nearshore fish were collected, primarily juvenile cottids and salmonids. Mean species richness did not differ between beaches with old‐growth versus secondary‐growth supralittoral vegetation; however, a higher cumulative number of species was found at beaches with old‐growth supralittoral vegetation.
  • 5. Canonical Correspondence Analysis (CCA) showed that beach characteristics and supralittoral vegetation were not significantly associated. Separate CCA for fish associations with beach characteristics and fish associations with supralittoral vegetation explained ～55% of the variance in fish assemblage composition, suggesting that fish assemblage composition is significantly affected by substrate, submerged vegetation, and physico‐chemical conditions as well as by the community composition of vegetation in adjacent supralittoral habitats.
  • 6. Specifically, we found associations between supralittoral vegetation and penpoint gunnels (Apodichthys flavidus Girard), tidepool sculpins (Oligocottus maculosus Girard), Pacific staghorn sculpins (Leptocottus armatus Girard), arrow gobies (Clevelandia ios Jordan and Gilbert), shiner perch (Cymatogaster aggregata Gibbons) and kelp perch (Brachyistius frenatus Gill). Juvenile chum (Oncorhynchus keta Walbaum) and coho (Oncorhynchus kisutch Walbaum) salmon were strongly associated with supralittoral vegetation characteristic of mature coastal forests such as mosses and western red cedar (Thuja plicata) suggesting that some nearshore fish species may be affected by processes originating in terrestrial ecosystems.
  • 7. Our results suggest that some nearshore fish species may be affected by removal of supralittoral vegetation.
Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

20.
Horppila J, Olin M, Vinni M, Estlander S, Nurminen L, Rask M, Ruuhijärvi J, Lehtonen H. Perch production in forest lakes: the contribution of abiotic and biotic factors.
Ecology of Freshwater Fish 2010: 19: 257–266. © 2010 John Wiley & Sons A/S Abstract – The biomass, growth and production of perch (Perca fluviatilis (L.)) in five humic forest lakes in southern Finland were estimated and the abiotic and biotic factors contributing to the between‐lake differences were explored. The average perch biomass in the study lakes varied from 13.1 to 45.6 kg·ha?1 and annual production from 6.0 to 16.5 kg·ha?1. The highest biomass and production were found in Lake Majajärvi with highest water colour and nutrient concentration. Variability in fish density rather than in individual growth rate seemed to be the main factor behind the between‐lake differences in perch production. No dependence of perch production on water transparency was found, because transparency had a stronger effect on individual growth than on fish density. The length increment of perch in their second year increased significantly with water transparency but at older ages no such dependence was found. At age of 4 years, the growth rate of perch decreased with perch density, indicating intraspecific competition for benthic food resources. At age of 7 years, the growth rate increased with increasing roach (Rutilus rutilus (L.)) abundance, suggesting that roach served as a resource for piscivorous perch. The effects of predatory top‐down control on perch populations were probably obscured due to the variable size and water quality of the study lakes.  相似文献   

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