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Perch Perca Fluviatilis (perch + perca_fluviatili)
Selected AbstractsSpawning site selection by Eurasian perch (Perca fluviatilis L.) in relation to temperature and wave exposureECOLOGY OF FRESHWATER FISH, Issue 1 2009W. N. Probst Abstract,,, The selection of spawning depth by Eurasian perch Perca fluviatilis was investigated in an experiment using artificial substrata in Lake Constance during the spawning season of 2007. The experiment compared spawning behaviour at substrata between 0.5 and 15 m depth at two sites exposed to different regimes of ship-generated wave action. The total abundance of egg ribbons did not differ significantly between the two sites, but the preferred spawning depth was deeper at the wave exposed site (5 m) compared to the sheltered site (2 m). While water temperatures could not account for the observations, differences in wave exposure may explain the different spawning depth preferences. At both sites, large egg ribbons were generally found in deeper water, and large egg ribbons occurred more frequently at the sheltered site. Because the egg ribbons of perch are likely to have a size-dependent susceptibility to hydrodynamic stress, large females may be expected to select deeper spawning locations where the effects of surface waves are considerably attenuated. [source] Ontogenetic diet profiles and size-dependent diet partitioning of ruffe Gymnocephalus cernuus, perch Perca fluviatilis and pumpkinseed Lepomis gibbosus in Lake BalatonECOLOGY OF FRESHWATER FISH, Issue 3 2006E. Rezsu Abstract ,, Life-long diet ontogeny and size-dependent intra- and interspecific diet partitioning of the native ruffe and perch and the introduced pumpkinseed, were studied in Lake Balaton. Estimated intraspecific diet overlap was high in ruffe, whereas in perch and pumpkinseed only the neighbouring size groups exhibited a high diet similarity. Interspecific diet overlap among size groups of the three species was moderate and ,60% diet overlap occurred only in 13 size group pair variations out of the 429 analysed. The earliest developmental stages of the three species were planktivorous, whereas larger ruffe and some size groups of perch and pumpkinseed fed dominantly on chironomids. Adult perch and pumpkinseed consumed different littoral macroinvertebrates, while the largest perch were piscivorous. Although productivities of the two studied areas differ significantly, this had only little effect on the diet ontogeny and diet partitioning of the three species. Present results suggest that in Lake Balaton these three species effectively partition food resources throughout their life span. [source] Effect of wave exposure dynamics on gut content mass and growth of young-of-the-year fishes in the littoral zone of lakesJOURNAL OF FISH BIOLOGY, Issue 7 2010S. Stoll Total length, body mass and gut content mass of young-of-the-year (YOY) perch Perca fluviatilis, dace Leuciscus leuciscus and bleak Alburnus alburnus were recorded over the summer of 2006 at three littoral sites at Upper Lake Constance. In P. fluviatilis and L. leuciscus, gut content mass correlated positively with wave-induced energy flux (EF) of the respective site and sampling day, while no correlation of gut content mass with EF was found in A. alburnus. It was assumed that benthivorous P. fluviatilis and L. leuciscus profited from suspended or uncovered benthic food items generated by wave action at sites and periods with high EF. Alburnus alburnus, in contrast, feeding mainly on zooplankton in upper parts of the water column, could not profit from increased EF. In P. fluviatilis, increased gut content mass during periods of high EF resulted in higher growth rates. For L. leuciscus, no real growth rates in local fish populations could be determined, as individuals were less sedentary, and when increased growth occurred at sites during the periods of high EF, migration of fish levelled out the resulting size differences within few days. The results of this study show that dynamic habitat variables affect site profitability in the littoral zone of lakes, especially in benthivorous fishes. Therefore, dynamic habitat variables should be considered in addition to fixed habitat properties in analyses of habitat choice of fishes in the littoral zone of lakes. [source] Feeding efficiency of planktivorous perch Perca fluviatilis and roach Rutilus rutilus in varying turbidity: an individual-based approachJOURNAL OF FISH BIOLOGY, Issue 7 2010L. Nurminen The feeding rate of perch Perca fluviatilis showed high individual variation at low and moderate turbidities, when one individual had consumed more Daphnia pulex than any other fish, whereas no such variation in feeding efficiency was observed with roach Rutilus rutilus. There was a significant decrease in total consumption of D. pulex by P. fluviatilis with increasing turbidity, but no correlation was observed in the case of R. rutilus. The results suggest that the difference in the ontogeny of P. fluviatilis and R. rutilus may be detectable as behaviour-related species-specific trait differences in the early planktivorous feeding stage of the two common species. [source] Morphological variation of perch Perca fluviatilis in humic lakes: the effect of predator density, competition and prey abundanceJOURNAL OF FISH BIOLOGY, Issue 4 2010J. Kekäläinen Between and within-lake variations in morphology of perch Perca fluviatilis were studied in four humic lakes in eastern Finland. Perca fluviatilis were more streamlined and smaller headed in a lake with the highest abundance of cyprinids, but lowest abundance of predators (Lake Tuopanjärvi), indicating adaptation to planktivorous feeding and low predator density. Highest bodied fish were found from a lake with the lowest cyprinid but highest predator abundance (Lake Koppelojärvi), which conversely indicates adaptation to more effective predator avoidance. Furthermore, the length of the paired fins was longest in Lake Kinnasjärvi and Lake Tuopanjärvi, where the abundance of benthic macroinvertebrates was lowest, suggesting selection for more effective benthivory. Clear morphological differences of P. fluviatilis between habitats were found only in Lake Kinnasjärvi, whereas in Lake Koppelojärvi and Lake Tuopanjärvi only the length of the paired fins differed and in Lake Harkkojärvi no differences were found. Taken together, these results suggest that inter and intrapopulation morphological differences are probably highly dependent on different biotic factors (i.e. predation risk, resource availability and competition). Spatial and temporal variations in these factors may have a great effect on body morphology of P. fluviatilis. [source] Habitat-choice interactions between pike predators and perch prey depend on water transparencyJOURNAL OF FISH BIOLOGY, Issue 1 2007C. Skov A mesocosm experiment indicated that water transparency influenced antipredator behaviour in young-of-the-year perch Perca fluviatilis, which partly contradicts another study by showing that high transparency decreases rather than increases perch antipredatory use of vegetated habitats when predators are also free to choose habitat. The present study emphasizes the importance of simultaneously considering both prey and predator habitat-choice behaviours when evaluating predator,prey interactions in relation to water visibility [source] The effect of temperature on mortality in small perch marked with coded wire tagsJOURNAL OF FISH BIOLOGY, Issue 4 2006H. Dörner Mortality of small (60,100 mm total length) perch Perca fluviatilis after marking with coded wire tags in relation to water temperature (6·9, 14·2, 17·8 and 22·6° C) was experimentally tested and exclusively occurred within the first day of the experiments. Moreover, mortality rates were generally low with a maximum of 4%. No increased mortality at higher water temperatures was observed. [source] Correlations between type-indicator fish species and lake productivity in German lowland lakesJOURNAL OF FISH BIOLOGY, Issue 4 2006X.-F. Garcia Morphotypes for 67 lakes in the German lowlands were derived, based on maximum depth and mixis type. A threshold of 11 m maximum depth was identified to be the best level to discriminate shallow from deep lake morphotypes. The fish communities in these two morphotypes were significantly different. Indicator species analyses based on fish biomasses found vendace Coregonus albula in deep lakes and ruffe Gymnocephalus cernuus, bream Abramis brama, white bream Abramis bjoerkna, roach Rutilus rutilus, pikeperch Sander lucioperca and small perch Perca fluviatilis in shallow lakes to be the most representative species of their communities. Lake productivity was closely related to biomass and in part abundance of the type-indicator species, with vendace declining with increasing chlorophyll a concentration in the deep lakes, whereas biomass of pikeperch, bream, white bream and ruffe increased and biomass of small perch decreased with increasing chlorophyll a. These results indicate that assessment of ecological integrity of lakes by their fish fauna is generally possible, if lakes are initially separated according to a depth-related morphotype before the assessment, and if eutrophication is considered to be the main anthropogenic degradation. [source] Growth in length and in body depth in young-of-the-year perch with different predation riskJOURNAL OF FISH BIOLOGY, Issue 3 2004C. Magnhagen Body shape of young-of-the-year (YOY) perch Perca fluviatilis, and number and size of potential predators (perch and pike Esox lucius) were compared across five lakes in northern Sweden. Body depth and dorsal fin ray length of YOY perch differed between lakes, with high relative body depth and long dorsal fin rays found in the lakes where the number of large piscivores was the highest. The most slender fish were found in the lake where the perch population had the smallest individuals and pike occurred in very low numbers. The average body mass in YOY perch from the two lakes with highest and lowest body depth, respectively, were the same, which indicates a difference between lakes in the relation between growth in length and in depth. Both body depth and fin ray length were correlated with predation risk by pike. Fin ray length was also correlated with number of piscivorous perch. Selection for different body shapes can be caused by different biotic and abiotic factors, singly or in combination, and the results from this study indicates that predation risk is one of these factors affecting body depth and fin ray length in perch. [source] The effects of thermal effluent exposure on the gametogenesis of female fishJOURNAL OF FISH BIOLOGY, Issue 1 2000D. Luk High temperature in Swedish and Lithuanian thermal effluent areas influenced gametogenesis of female perch Perca fluviatilis, roach Rutilus rutilus and pike Esox lucius negatively, indicating reduced reproductive capacity. Oocyte atresia started during vitellogenesis in autumn, and was often followed by asynchronous egg cell development. Among other anomalies, multi-nucleus oocytes and hermaphroditism were observed. No significant impact was seen in silver bream Blicca bjoerkna. Ruffe Gymnocephalus cernuus reacted by a tendency to produce an additional mature oocyte generation during the spawning period. Ovaries in roach from coastal areas were often infected by a microsporidian parasite Pleistophora mirandellae, causing severe damage to the gonad. Parasites were also detected in pike, but neither in perch nor in lake populations of roach. Fish living in open coastal environments did not avoid impact by moving out of the heated areas. There seems to be a conflict in some temperate fish between temperature preference behaviour and safeguarding normal reproduction. [source] Activities of glucose phosphorylation, glucose-6-phosphatase and lipogenic enzymes in the liver of perch, Perca fluviatilis, after different dietary treatmentAQUACULTURE RESEARCH, Issue 2001B Borrebaek Abstract Glucose phosphorylation was increased and the activity of glucose-6-phosphatase was decreased in the liver of perch Perca fluviatilis after feeding previously fasted fish with a high protein/low carbohydrate diet as well as with a diet containing 23% carbohydrate. Activity of the low affinity hexokinase IV (or D), also called glucokinase (GK), was not observed in the liver of perch on the natural diet, fasted perch or perch after feeding with the high protein/low-carbohydrate diet (< 0.2% CHO). How ever, hepatic GK-activity appeared after feeding with the carbohydrate containing diet. By contrast, the activity of hepatic high affinity hexokinase (HK), which was very low in fasted fish, was strongly increased after feeding with the low-carbohydrate as well as the carbohydrate-containing diet. Apparently, HK rather than GK is the hexokinase isoenzyme that is consistently regulated inversely to glucose-6-phosphatase. Activities of the lipogenic enzymes glucose-6-phosphate dehydrogenase, ATP-citrate lyase and malic enzyme were increased by feeding, particularly with the high protein/low carbohydrate diet. Very high levels of hepatic glycogen were observed after both diets. The results are in accordance with the hypothesis that the hepatic high affinity isoenzyme (HK) has a particular anabolic role. [source] | ||||||||||