European Perch Perca Fluviatilis Research Articles

Field testing a novel high residence positioning system for monitoring the fine-scale movements of aquatic organisms.

Acoustic telemetry is an important tool for studying the behaviour of aquatic organisms in the wild.VEMCO high residence (HR) tags and receivers are a recent introduction in the field of acoustic telemetry and can be paired with existing algorithms (e.g. VEMCO positioning system [VPS]) to obtain high‐resolution two‐dimensional positioning data.Here, we present results of the first documented field test of a VPS composed of HR receivers (hereafter, HR‐VPS). We performed a series of stationary and moving trials with HR tags (mean HR transmission period = 1.5 s) to evaluate the precision, accuracy and temporal capabilities of this positioning technology. In addition, we present a sample of data obtained for five European perch Perca fluviatilis implanted with HR tags (mean HR transmission period = 4 s) to illustrate how this technology can estimate the fine‐scale behaviour of aquatic animals.Accuracy and precision estimates (median [5th–95th percentile]) of HR‐VPS positions for all stationary trials were 5.6 m (4.2–10.8 m) and 0.1 m (0.02–0.07 m), respectively, and depended on the location of tags within the receiver array. In moving tests, tracks generated by HR‐VPS closely mimicked those produced by a handheld GPS held over the tag, but these differed in location by an average of ≈9 m.We found that estimates of animal speed and distance travelled for perch declined when positional data for acoustically tagged perch were thinned to mimic longer transmission periods. These data also revealed a trade‐off between capturing real nonlinear animal movements and the inclusion of positioning error.Our results suggested that HR‐VPS can provide more representative estimates of movement metrics and offer an advancement for studying fine‐scale movements of aquatic organisms, but high‐precision survey techniques may be needed to test these systems.

Sex and size matters: Selection on personality in natural prey-predator interactions

Optimal life-history strategies are currently considered to be a major driving force for the maintenance of animal personalities. In this experimental study we tested whether naturally occurring predation causes personality-dependent mortality of a marine isopod (Idotea balthica), which could maintain personality variation in nature. Moreover, as isopods are known to have sex-differences in behaviour, we were interested in whether personality-dependent predation was sex-specific. We also hypothesised that predation pressure among personality types could vary according to habitat type, as it has been shown in correlative studies that habitat may influence personality variation. We used natural predator (European perch Perca fluviatilis) of I. balthica and studied relative mortality of males and females with a different personality types in laboratory settings with two different habitats. We found that survival in males was lower than in females for high active individuals. Moreover, survival under predation was linked to body size differently in females and males. This, however, depended on personality class as larger size was advantageous for low-active males and middle- and high-active females. Conversely, smaller size was advantageous for low-active females and middle-active males. Size did not affect survival in high-active males. Our results suggest that predation can encourage life-history differences between sexes leading to different optimal life-history strategies and also maintains consistent activity for both sexes.

Environmental heterogeneity associated with European perch (Perca fluviatilis) predation on invasive round goby (Neogobius melanostomus)

Spatiotemporal environmental variation affects fish feeding behaviour and capacity for piscivorous control of prey populations, which is important for management when prey include invasive species causing ecosystem impacts. We assessed gut-contents of an important piscivore (European perch Perca fluviatilis) over two years, and analysed variables affecting initiation and amounts of feeding, focusing on an important invasive prey species, round goby (Neogobius melanostomus). We show that predation is primarily controlled by variation of physical and habitat characteristics surrounding perch. Fish prey began being incorporated in diets of perch that were >150 mm, with temperature conditions controlling initiation of their feeding. Total amounts of fish in perch diets, and amounts of round goby individually, were strongly affected by macrophyte cover; seldom were fish present in perch stomachs when macrophyte cover was >40%. Environmental densities of round goby were related to multivariate diet composition in ways that suggest predation of some native species may be relaxed in areas of dense round goby populations. There was evidence that perch predation is unlikely to limit populations of the invader, as there was only a weak relationship between round goby densities and amounts in gut contents. The results have ecosystem management implications, because some variables found to be important could be manipulated to control round goby or other similar invaders e.g. fisheries management of native piscivore stock-density and body-size, or modification of benthic environment structure.

Size-dependent foraging niches of European Perch Perca fluviatilis (Linnaeus, 1758) and North American Yellow Perch Perca flavescens (Mitchill, 1814)

Body size of consumer species is a fundamental trait that influences the trophic ecology of individuals and their contribution to the functioning of freshwater ecosystems. However, the relationship between body size and trophic ecology can be highly variable both within and between closely-related and similarly-sized species. In this study we compared the intra- and interspecific relationship between body size and trophic position for North American Yellow Perch Perca flavescens and European Perch Perca fluviatilis, which share similarities in morphology, life history traits and trophic requirements. We used stable isotope ratios (δ15N and δ13C) to characterize differences in size-dependency of trophic position and to trace consumer foraging history of Yellow Perch in lakes in the Northwestern United States and European Perch in lakes in Germany. The trophic position and stable isotope ratios of Yellow Perch and European Perch steadily increased with total body length, but European Perch were consistently feeding at higher trophic positions than Yellow Perch at a given length. European Perch occupied considerably higher trophic positions (mean trophic position = 3.9) than Yellow Perch (mean trophic position = 2.8). Large European Perch were increasingly piscivorous, whereas large Yellow Perch were more opportunistic and omnivorous predators of invertebrate prey. Overall, the trophic position among individual Yellow Perch varied more strongly than in European Perch. We conclude that both species similarly increase in trophic position with size, but the specific size-dependency of both trophic position and resource use varies with taxonomy and local ecological conditions. Thus, body size as a sole measure of trophic position should be considered cautiously when generalizing across populations and species.

МОРФОЛОГИЧЕСКИЕ ОСОБЕННОСТИ КРОВЯНЫХ КЛЕТОК ЕВРОПЕЙСКОГО ОКУНЯ (PERCA FLUVIATILIS) В ИСКУССТВЕННЫХ УСЛОВИЯХ

The article deals with basic morphological hematological characteristics of the three-year-old European perch ( Perca fluviatilis ) living in artificial conditions (1 m3 water tank). In the research there were used biological, histological and statistical methods. Erythrogramswerecalculated for 1000 erythrocytes; leukograms - for 200 leukocytes. In all samples taken in different periods (spring, summer, autumn, winter) there were registered different stages of erythrocyte development (erythroblasts, oxyphilic normoblasts, polychromatophilic normoblasts). Erythropoiesis activity in tested species was registered in spring (1.89%), in oxyphilic normoblasts (40.8%) in early autumn, when oxygen concentration in the water tank lowered due to high water temperature. In the course of testing in all samples there were registered certain morphological changes in the cells of erythrocyte series, such as poikilocytosis, displacement of the nucleus to the cell periphery, schistocytosis, non-nuclear cells, anisocytosis, oligochromasia, deformation of the nucleus. Poikilocytosis occurred most often. There were found piriform, falciform, rhomboid, polyhedral shaped cells; erythrocytes with outgrowths specific for erythropoiesis suppression were scares. Representatives of the leukocytes were lymphocytes, monocytes and a small number of precursor cells of granulocytes (myelocytes, promyelocytes). The predominant component of leukocyte form perch were represented by lymphocytes. Eosinophil and basophil cells in blood films were little. The number of thrombocytes for 1000 erythrocytes (0.92-1.59 depending on the season) testify sound state of fish species.

Methodological issues affecting the study of fish parasites. III. Effect of fish preservation method.

The aim of this study was to evaluate the influence of preservation method on the results of parasite community studies. Two host species, European perch Perca fluviatilis and European bitterling Rhodeus amarus, were examined for parasites after having been subjected to 4 different storage treatments: freezing, preservation in 4% formaldehyde or 70% ethanol and transportation of live (fresh) fish as a control. Preservation prior to dissection resulted in a loss of information, leading to incomplete quantitative data (all preservation treatments), qualitative data (ethanol and formaldehyde preservation) and a lowered ability to determine parasites to species level based on morphology compared to dissecting fresh fish. Of the more abundant taxa, only crustaceans and acanthocephalans provided relatively even results between treatments. We conclude that preservation media, such as ethanol or formaldehyde, significantly affects the ability to obtain precise parasite community data; hence, we recommend the use of freshly sacrificed fish for parasite community studies whenever possible. Alternatively, freezing may prove acceptable for evaluating parasite community taxonomic composition.

Feeding ecology and prey selection of European perch, Perca fluviatilis inhabiting a eutrophic lake in northern Turkey

ABSTRACTFeeding habits and prey selection of European perch (Perca fluviatilis) were examined in Lake Ladik between November 2009 and October 2010. Stomach contents of 308 individuals ranging in size from 73 to 275 mm total length were analyzed and 55.2% were empty. The fullness index indicated that feeding intensity of this species was the highest in summer and the lowest in winter. European perch feeds on prey fish and macroinvertebrates. The most important food items were Scardinius erythrophthalmus and Perca fluviatilis, followed by chironomidae larvae. Diet composition and feeding habits varied seasonally and ontogenetically. Macroinvertebrates were only consumed by small individuals, while prey fishes were only eaten by large individuals. S. erythrophthalmus, P. fluviatilis, and Blicca bjoerkna were positively selected but their selection indexes were not statistically significant (p > 0.05). This prey selection is important for combating eutrophication. Abramis brama constitute 24.03% of all fish species in this lake; however, it was a negatively selected prey item (Va = −0.198, χ2 = 7.86, p < 0.05). Esox lucius, Squalius cephalus, Chondrostoma regium, and Carassius gibelio inhabiting this lake were not preferred by European perch. Cannibalism rate was 12.3%.

The first record in Central Europe of the alien invasive rotan, Perccottus glenii, in the diet of the European perch Perca fluviatilis

The first record in Central Europe of the alien invasive rotan, Perccottus glenii, in the diet of the European perch Perca fluviatilis

Warming alters the body shape of European perch Perca fluviatilis.

The consequences of elevated temperature on body shape were investigated by comparing European perch Perca fluviatilis from the Forsmark area of the Baltic Sea to P. fluviatilis from a nearby Biotest enclosure. The Biotest is a man-made enclosure within the Baltic Sea that has received warm water from a nuclear power plant since 1980, resulting in temperatures that are elevated 5-10 °C relative to the surrounding Baltic Sea. Sampled fish ranged from young-of-the-year to 14 years. Geometric morphometrics and multivariate statistical analysis revealed significant morphological differences between individuals of P. fluviatilis from these two habitats. Most importantly, relative shape changed with size, with small individuals of P. fluviatilis from Biotest being characterized by a deeper body shape and a larger caudal peduncle than the smaller Baltic individuals. In large specimens, smaller differences were found with Biotest individuals being more slender than Baltic individuals. These results show that, in order to have a full understanding of the biological effects of elevated temperatures, studies that cover the entire size range of organisms will be important. Apart from the direct influence of temperature on growth rate and body shape, other ecological factors affected by temperature are discussed as possible contributors to the observed differences between the two populations.

Non-fish prey in the diet of an exclusive fish-eater: the Common Kingfisher Alcedo atthis

Capsule Non-fish prey constitutes an important component of the diet of many fish-eating birds.Aims In the present study, the role of non-fish prey in the diet of the Common Kingfisher Alcedo atthis was evaluated.Methods The species and size spectrum of prey in the diet was studied at 15 nest sites on 6 trout streams, 1 river and 1 reservoir in the Czech Republic, using the analysis of the nest sediment.Results 16 933 individual prey items were identified (99.93% fish and 0.07% non-fish prey). European Perch Perca fluviatilis, Roach Rutilus rutilus and Bleak Alburnus alburnus dominated the diets on the reservoir; Gudgeon Gobio gobio, European Chub Squalius cephalus and Roach those on the river; and Gudgeon, European Chub, Bullhead Cottus gobio, Roach, Bleak and Brown Trout Salmo trutta m. fario those in the trout streams. The sizes of their fish prey ranged from 16 to 134 mm in total length (LT) with an average size of 66 mm. The remains of non-fish prey were detected in only 5 of 30 nest sediments. The non-fish prey were mostly composed of large aquatic insect larvae: dragonflies Anax sp. and Aeshna sp., Common Club-tail Gomphus vulgatissimus and Great Diving Beetle Dytiscus marginalis. Kingfishers also took Spiny-cheek Crayfish Orconectes limosus, Newt Triturus sp. and a Lizard Lacerta sp. The estimated sizes of the non-fish prey ranged from 30 to 90 mm.Conclusion The catch of non-fish prey appears to be accidental, and is more likely a result of target misinterpretation (fish-like body and fish-like movement) than a Kingfisher regularly switching to prey other than fish. The unique finding of a Lizard is the first record of an amniotic vertebrate in the diet of Common Kingfisher.

Rapid evolution of parasite resistance in a warmer environment: insights from a large scale field experiment.

Global climate change is expected to have major effects on host-parasite dynamics, with potentially enormous consequences for entire ecosystems. To develop an accurate prognostic framework, theoretical models must be supported by empirical research. We investigated potential changes in host-parasite dynamics between a fish parasite, the eyefluke Diplostomum baeri, and an intermediate host, the European perch Perca fluviatilis, in a large-scale semi-enclosed area in the Baltic Sea, the Biotest Lake, which since 1980 receives heated water from a nuclear power plant. Two sample screenings, in two consecutive years, showed that fish from the warmer Biotest Lake were now less parasitized than fish from the Baltic Sea. These results are contrasting previous screenings performed six years after the temperature change, which showed the inverse situation. An experimental infection, by which perch from both populations were exposed to D. baeri from the Baltic Sea, revealed that perch from the Baltic Sea were successfully infected, while Biotest fish were not. These findings suggest that the elevated temperature may have resulted, among other outcomes, in an extremely rapid evolutionary change through which fish from the experimental Biotest Lake have gained resistance to the parasite. Our results confirm the need to account for both rapid evolutionary adaptation and biotic interactions in predictive models, and highlight the importance of empirical research in order to validate future projections.

Genetically distinct colour morphs of European perch Perca fluviatilis in Lake Constance differ in susceptibility to macroparasites.

The unusual yellow-finned morph of European perch Perca fluviatilis found in Lake Constance suffers more severely from macroparasite infections, including the tapeworm Triaenophorus nodulosus and the gill worm Ancyrocephalus percae, than conspecifics elsewhere. Microsatellite analysis of yellow-finned P. fluviatilis and red-finned variant recently discovered in Lake Constance revealed significant genetic differentiation. Red-finned P. fluviatilis and fish with mixed fin colour, suggested backcrosses between red and yellow-finned colour morphs, exhibit better resilience to parasite infection, suggesting that the inability of the yellow-finned morph to reject macroparasites may have a genetic basis.

Biological plasticity of non-native European perch (Perca fluviatilis) populations and the implications for management in northern New Zealand

Size and age structure, longevity, growth, and reproductive activity of European perch (Perca fluviatilis) were studied at Lake Wainamu in March 2012 and 2013 as part of an introduced species eradication programme. Size and age structure of P. fluviatilis were dominated by smaller and younger individuals, while maximum age was estimated at 6 and 5 years for both years, respectively. Initial growth by the end of first year was faster when compared with selected studies in Europe, but size-at-equivalent age thereafter was smaller at Lake Wainamu. Oocyte atresia, asynchronous gonad development and vitellogenic oocytes were prevalent in ovaries at time of sampling in later summer, which warrant further investigation of P. fluviatilis as an iteroparous spring-spawning species in northern New Zealand. Our findings imply that the population dynamics of P. fluviatilis are highly plastic and may be influenced by local biogeographical factors. This has strong implications for the management of P. fluviatilis in New Zealand freshwater systems.

Effect of pH on the activity of proteinases in intestinal mucosa, chyme, and microbiota of fish from the Cuciurgan reservoir

Proteolytic activities of the intestinal mucosa, chyme, and enteral microbiota have been studied in a wide range of pH values in five fish species from the Cuciurgan reservoir (Moldova). Differences in pH dependence of the intestinal proteinase activity of fish are determined by their feeding type. The maximum activity of proteinases is found in the pumpkinseed Lepomis gibbosus. The minimum activity of proteinases has been demonstrated by the zander Zander lucioperca. The pH optimum of the mucosa and chyme in all fish species (except for the European perch Perca fluviatilis) is 10. The pH optimum of the intestinal microflora varies from 6.0 (in the common carp Cyprinus carpio) to 10 (in the crucian carp Carassius carassius), whereas that in the perch from the Cuciurgan and Rybinsk reservoirs is 7. The majority of fish species, mostly Zander lucioperca and Lepomis gibbosus, are characterized by high proteniase activity of the microbiota, in the pH ranging from 6 to 9. It is assumed that proteinases in the enteral microbiota of fish are able to make up for the relatively low activity of those synthesized by their digestive system in the range of low pH values.

On the problem of ecological groups formation in European perch Perca fluviatilis populations

Simulation model of the intraseasonal growth dynamics of young-of-the-year European perch Perca fluviatilis has been developed and studied. The model has been constructed based on the principles of bioenergetics and covers all the main physiological utilization processes of energy that come with food, including somatic growth, expenses on metabolism, and partial loss of energy with egestion and excretion. It is assumed that there are two space-separated biotopes called “inshore” and “pelagial” with different feeding conditions. Fish move from inshore to pelagial as the amount of food in the inshore biotope gets lower, provided that the actual ration is reduced down to the predetermined threshold level. It is demonstrated that the combined distribution of fish specimens belonging to one generation according to weight by the end of their growth period mainly depends on the intensity of exchange process between the biotopes. The ratio between the abundance values of young fish localized in different biotopes is determined by the threshold ration level, which motivates fish to move, as well as the duration of spawning, and, accordingly, length of hatching period.

Marine spawning sites of perch Perca fluviatilis revealed by oviduct-inserted acoustic transmitters

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 19:201-206 (2013) - DOI: https://doi.org/10.3354/ab00529 Marine spawning sites of perch Perca fluviatilis revealed by oviduct-inserted acoustic transmitters Mikkel Skovrind1, Emil A. F. Christensen1,*, Henrik Carl1, Lene Jacobsen2, Peter R. Møller1 1University of Copenhagen, Natural History Museum of Denmark, Universitetsparken 15, 2100 Copenhagen, Denmark 2DTU Aqua, Technical University of Denmark National Institute of Aquatic Resources, Section for Freshwater Fisheries Ecology, Vejlsøvej 39, 8600 Silkeborg, Denmark *Corresponding author. Email: mts447@alumni.ku.dk ABSTRACT: In the 1970s, a flood-protection system dramatically changed a large part of the coastal environment of Køge Bugt, a bay in the western Baltic Sea, from open coast to a brackish lagoon habitat. An anadromous stock of European perch Perca fluviatilis seems to have benefitted from this change, but details about their spawning behavior remain unknown. We used oviduct-inserted acoustic transmitters to reveal the pre-spawning behavior and spawning sites of this population. Thirteen female perch were caught in the lower stream basin of St. Vejle Å, and were tagged with acoustic transmitters inserted through the oviduct. The fish were tracked from March 2 to May 24, 2012 with both passive and active telemetry systems. The pre-spawning behavior involved short trips between the stream and adjacent lagoons. Twelve of the 13 transmitters (92%) were expulsed during spawning, providing for the first time a strong proof of concept of oviduct-inserted acoustic transmitters in brackish and marine fish spawning studies. The transmitter expulsions were validated using an egg map, which was based on visual observations of perch egg-strands, and 11 of the 12 expulsed transmitters (92%) were located in areas with eggs. Many fish spawned in the brackish water with salinities up to 9.6 PSU. These salinities are higher than those previously observed for European perch spawning in the wild, and call for further investigations of salinity tolerance in perch eggs. KEY WORDS: Acoustic telemetry · Oviduct · European perch · Salinity · Spawning · Brackish water Full text in pdf format NextCite this article as: Skovrind M, Christensen EAF, Carl H, Jacobsen L, Møller PR (2013) Marine spawning sites of perch Perca fluviatilis revealed by oviduct-inserted acoustic transmitters. Aquat Biol 19:201-206. https://doi.org/10.3354/ab00529 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 19, No. 3. Online publication date: October 24, 2013 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2013 Inter-Research.

Biotic and abiotic effects on cohort size distributions in fish

Intraspecific variation in body size is common in animals and plants. Body size affects trophic interactions like foraging ability and vulnerability to predation, which in turn affect individual fitness as well as population stability and extinction risk. Experimental and theoretical work has shown that the size distribution of individuals within cohorts is strongly influenced by intraspecific competition for resources, often leading to skewed frequency distributions. However, little is known about the effects of environmental factors such as climate and eutrophication on the cohort size‐structure of natural populations. We use a long‐term time series of scientific monitoring of a freshwater fish (European perch Perca fluviatilis) to investigate the effects of density dependence, predation, nutrient availability, climate and the timing of spawning on the cohort size distributions. We find that the mean length of the fish is best predicted by the extrinsic factors phosphorus concentration and summer temperature, and the densities of the different age‐classes, whereas the skewness of the length distribution is best predicted by phosphorus concentration, summer temperature, abundance of small fish, and the timing of spawning. Higher nutrient levels, temperatures and densities of small fish increase food availability and thus reduce competition, which is reflected in increased mean length and decreased skewness. The timing of spawning affects skewness presumably through changes in the initial size variation of the cohort and the length of the first growth season. Our results indicate that higher temperatures increase the mean length and decrease skewness due to the concurrent eutrophication of the lake. The study thereby highlights the potential impact of human‐induced environmental change on the size structure of fish populations. More studies are needed to understand better the complex mechanisms through which these factors alter the intensity of intraspecific competition in fish communities.

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

Abstract The aim of this study was to assess juvenile fish communities in terms of species composition, fish diversity and density in the littoral zone of the Kaunas reservoir before (in 1989–1990, period I) and after (in 1999–2000, period II, and in 2006–2007, period III) launching the Kruonis hydroelectric pumped plant (Kruonis HPP). During the whole research period, 20 fish species were caught. According to the frequency of occurrence, the three-spined stickleback Gasterosteus aculeatus, European perch Perca fluviatilis and roach Rutilus rutilus were regarded as constant species in all investigated periods. Significant differences were established in juvenile fish community density between period I and periods II and III, whereas species richness (S) and species diversity indices (H′, J′) did not change significantly. The density of the shoreline community in period III was more than two times lower than in period I, probably due to higher fluctuations in water level of the reservoir, resulting from the Kruonis HPP operation.

Biomonitoring of polychlorinated biphenyls (PCBs) in heavily polluted aquatic environment in different fish species

The distribution and concentrations of polychlorinated biphenyls (PCBs) were determined in fish species (European perch Perca fluviatilis, northern pike Esox lucius, pike perch Sander lucioperca, wels catfish Silirus glanus, common carp Cyprinus carpio, European eel Anguilla anguilla, freshwater bream Abramis brama, goldfish Carassius auratus, and roach Rutilus rutilus) in a heavily polluted water reservoir Zemplínska šírava (Slovakia). The study performed at two different time points 5 years apart (2004 and 2009) revealed serious PCB contamination of fish muscle tissue and significant interspecies as well as tissue-specific differences in PCB uptake by fish. Total PCBs broadly correlated with the trophic position of individual fish species within a food chain (P < 0.01). The concentrations were particularly high in predatory fish species, perch, pike, and pike perch (108.0, 90.1, and 113.0 mg kg(-1) lipid wt, respectively), but comparable PCB values were also found in non-predatory detrivorous freshwater bream (128.0 mg kg(-1) lipid wt). The lowest PCB values were surprisingly assessed in European eel (17.1 mg kg(-1) lipid wt). Tissue analysis showed the highest storage capacity of the liver (hepatopancreas in cyprinids) with maximum concentrations recorded found in northern pike (214.0 mg kg(-1) lipid wt) and freshwater bream (163.0 mg kg(-1) lipid wt). Negative correlations, mostly not significant, between the total PCB concentrations and fish weight were observed (P > 0.05). The study has shown that the kind of fish, its feeding habit, and specific conditions of the habitat are mutually interrelated factors that are responsible for significant variations in fish body burdens. A tendency to PCB biomagnification was also proved in some fish species of this water reservoir.

Evaluation of food web and fish dietary niches in oligotrophic Lake Annecy by gut content and stable isotope analysis

Gut content analysis (GCA), stable isotopes analysis (SIA), and the multiple sources MixSIR mixing model were used to evaluate the dietary niches of 5 important species in Lake Annecy fisheries. Observations on gut content data revealed a variety of feeding habits, with some potential diet overlap between European whitefish (Coregonous lavaretus), Arctic char (Salvelinus alpinus), and Eurasian perch (Perca fluviatilis) during the winter and spring. However, food resources seemed to be partitioned among the Lake Annecy fish community during summer growth period, possibly limiting competitive interactions. Ten years of SIA data were used to evaluate food web dynamics. Values of δ15N indicated very low interspecies variability, whereas δ13C revealed the differences between fish species; pelagic species were δ13C depleted, while littoral species were δ13C enriched. The results demonstrated that Arctic char have a separate sustainable dietary niche and lower predation mortality. Stocking Arctic char to enhance populations might not have an impact on other fish populations. We found that the natural dietary variability can be misinterpreted when using GCA only. Our findings highlight the importance of combining both GCA and SIA to explore the trophic relationships between predators and prey, especially in Lake Annecy having spatial and seasonal variations in prey isotopic signatures. Results from these studies on food web dynamics could have implications in fisheries management decisions and development of trophic models.