Migration patterns and home range of pike‐perch (Sander lucioperca,Linnaeus, 1758) in Dutch river systems

Pike‐perch (Sander lucioperca L. 1758) is one of the freshwater species caught by professional fishermen in the Netherlands. The species is also popular with sport fishermen. Little is known about its migration and rehabilitation in large river systems. The aim of the present study was to obtain data on the movements of pike‐perch in the Dutch large river systems and investigate when and how far individual fish swim up‐ or downstream. Seasonal migration was expected. The second objective was to gain information on how many fish pass the Haringvlietdam when migrating downstream during high discharge, and ending up in the North Sea. The third objective was to gain data on how many fish were caught by the fishermen. NEDAP TRAIL System® transponders were surgically implanted in 286 pike‐perch between June 2007 and October 2008. Marked fish could be detected via several detection stations in the river systems throughout the Netherlands and one in the River Rhine station in Germany. Sport fishermen were asked to inform the organization when a marked fish was caught. Data collected between June 2007 and April 2010 indicate a pike‐perch home range of 30–40 km, with some individuals migrating up to more than 200 km. A regional approach regarding fisheries management is necessary. No seasonal patterns were found. Swimming activity was highest during darkness. Results showed pike‐perch around the Haringvlietdam swimming in the saltwater area on the sea side of the dam, and returning to the freshwater Lake Haringvliet, indicating that the structure of the dam is used for feeding, but also that the fish will die if the dam is closed when fish are still outside.     

Dynamics of a Boreal Lake Ecosystem during a Long-Term Manipulation of Top Predators

We assessed the long-term (16 years) effects of introducing piscivores (northern pike) into a small, boreal lake (Lake 221, Experimental Lakes Area) containing abundant populations of two planktivorous fish species. After the introduction, pearl dace were extirpated and yellow perch abundance was greatly reduced. Daphnia species shifted from D. galeata mendota to larger bodied Daphnia catawba, but the total zooplankton biomass did not increase, nor did the biomass of large grazers such as Daphnia. Phytoplankton biomass decreased after the northern pike introduction, but increased when northern pike were partially removed from the lake. Phosphorus (P) excretion by fish was ∼0.18 mg P m⁻² d⁻¹ before pike addition, declined rapidly to approximately 0.03–0.10 as planktivorous perch and dace populations were reduced by pike, and increased back to premanipulation levels after the pike were partially removed and the perch population recovered. When perch were abundant, P excretion by fish supported about 30% of the P demand by primary producers, decreasing to 6–14% when pike were abundant. Changes in phytoplankton abundance in Lake 221 appear to be driven by changes in P cycling by yellow perch, whose abundance was controlled by the addition and removal of pike. These results confirm the role of nutrient cycling in mediating trophic cascades and are consistent with previous enclosure experiments conducted in the same lake.     

Faunistic groups of carpenter-moths (Lepidoptera, Cossidae) in the fauna of Russia

An arealogical review of carpenter-moths of the fauna of Russia is presented. Southern steppe western Palaearctic species (10); steppe, southern steppe, and Central Asian semidesert species (7); and nemoral eastern Palaearctic species (6) predominate. Endemics of the Russian fauna are 6 species: Acossus victor (Yakovlev, 2004) (southern Tuva); Cossus shmakovi Yakovlev, 2004 (Tuva, Khakassia); Deserticossus volgensis (Christoph, 1893) and D. sareptensis (Rothschild, 1912) (southern Volga River Basin), Phragmataecia pacifica Yakovlev, 2007 (Daghestan), and Meharia scythica D. Komarov et Zolotuhin, 2005 (southern Volga River Basin).     

American rotifer <Emphasis Type="Italic">Kellicottia bostoniensis</Emphasis> (Rousselet, 1908) (Rotifera: Brachionidae) in the Kama Reservoir (Kama River,Russia)

The American rotifer Kellicottia bostoniensis (Rousselet, 1908) was first recorded in the Kama Reservoir (Kama River, Middle Volga basin) in 2012. The species was found in over 70% of the samples; its maximum abundance was 2000 ind./m³. This alien species co-existed with closely related native species K. longispina (Kellicott). This is the easternmost location (56°–57° E) for K. bostoniensis in the Volga River basin and in Europe.     

Effects of temperature,pH, and heavy metals (copper,zinc) upon proteinase activities in digestive tract mucosa of typical and facultative piscivorous fish

Species-specific differences and effects of natural (temperature, pH) and anthropogenic (zinc, copper) factors upon activities of casein-and hemoglobinlytic proteinases have been studied in the gut mucosa in pike (Esox lucius), zander (Stizostedion lucioperca), burbot (Lota lota) and perch (Perca fluviatilis). It is revealed that the intestine mucosa proteinase activities differ considerably from those ones in the fish stomach mucosa and that studied factors affect these activities to different extents. The stomach mucosa proteinases are most tolerant to the effects of studied factors, which is especially true for pike. The least tolerant are the intestine caseinlytic proteinases (except for the enzymes in perch). The effects of temperature, pH, and heavy metals depend on fish species, factors’ combinations (mono-factor, bi-factor, or multi-factor action) and on factor variability.     

Walleye, Stizostedion vitreum, and northern pike, Esox lucius, populations in three Alberta lakes

Results are presented from a survey of walleye and northern pike in Ethel, Marie and Wolf Lakes, Alberta conducted May-September, 1983. Three types of experimental gill net were fished, mainly inshore. Northern pike were abundant in all three lakes but white sucker and yellow perch also were common. Walleye were caught in largest numbers in Wolf Lake. Age and growth of both walleye and northern pike were determined from examination of the opercular bones. The walleye in the three lakes were represented by a few strong year classes but there was no synchronism between the lakes. The strong 1975 year class in Ethel and Wolf Lakes may have been correlated with high spring precipitation and heavy run-off. Although there were dominant year classes in the northern pike populations (especially the 1979 year class) the variability was not so marked as in the walleye. There were no significant differences between length-at-age for year classes of walleye in Ethel and Marie or northern pike in all three lakes. In Wolf Lake the 1978 and 1979 year classes grew faster than in previous years. Walleye and northern pike growth was well described by the von Bertalanffy growth model. Females of both species grew to a greater ultimate length and had a longer lifespan than the males. Fecundity data are presented for walleye from Wolf Lake (log₁₀ absolute fecundity = 0.856 + 2.441 log₁₀ length) and northern pike from Marie Lake (log₁₀ absolute fecundity =?2.671+4.052 log₁₀ length). The stomach contents of both species were examined during May and June. The majority of walleye had empty stomachs. Walleye and northern pike in Ethel and Wolf Lakes fed on a variety of fish and invertebrate species but both fed mainly on fish (in particular whitefish) in Marie Lake. The similarity of diet suggests competition for prey species. A walleye yield to commercial fishermen of c. 0.69 kg ha^?1 year^?1 in Wolf Lake has made up 8% of the total catch. Since 1970/71 when mesh size of nets was increased, the yield has been reduced to c. 0.30 kg ha^?1 year^?1. Anglers remove an additional c. 0.48 kg ha^?1 year^?1 walleye from Wolf Lake. Northern pike yields to commercial fishermen have been c. 2.00 kg ha^?1 year^?1 in Wolf Lake. Ethel and Marie Lakes have yielded only poor catches of walleye and northern pike. A yield model was used to illustrate that faster-growing northern pike have higher potential yields than walleye. Walleye produce higher yields in Wolf Lake than in Marie Lake, the reverse being true for northern pike. It is suggested that northern pike could be cropped at a higher rate in Marie and Wolf Lakes with a possible improvement in walleye stocks.     

Ichthyofauna of the Lena River (Laptev Sea Basin): Modern composition and historical formation

The modern ichthyofauna of the Lena River includes 46 species and subspecies: 45 bony fishes and one lamprey. In the upper reaches, 24 species have been recorded, 38 in the middle reaches, 36 in the lower reaches, and 24 in the delta. Four of the seven species intentionally introduced into water bodies of the Lena River basin have successfully naturalized; the presence of the others is unconfirmed. All areas of the river are dominated by fishes of the orders Salmoniformes and Cypriniformes. The ranges of the Amur carp Cyprinus rubrofuscus, common bream Abramis brama, ide Leuciscus idus, roach Rutilus rutilus, pike Esox lucius, and perch Perca fluviatilis have expanded over the last few years. The causes and possible ways of the historical formation of the Lena River fish population are discussed in the light of data on the Pleistocene paleogeographical events and patterns of the distribution of species in the river and in adjacent basins.     

Vitamin losses during frozen storage of Liza aurata (Risso, 1810), Cyprinus carpio L. 1758, Clupeonella cultriventris caspia (Nordmann, 1840), Rutilus frisii kutum (Kamenskii, 1901) and Sander lucioperca (L., 1758)

The objective of this study was to determine the fat and water‐soluble vitamins contents (A, E, D, K, B₁, B₂, B₆, B₁₂, niacin, biotin, ascorbic, folic and pantethonic acids; in mg kg^?1 fresh weight) lost during frozen storage (?24°C) in time intervals of 0, 1, 2, 3 and 4 months. Studied species included: Liza aurata (golden grey mullet), Cyprinus carpio (common carp), Clupeonella cultriventris caspia (common kilka or sprat), Rutilus frisii kutum (Caspian kutum) and Sander lucioperca (pike perch). Results showed that A, D and K vitamin losses occurred in all samples during storage, but no statistically significant differences were observed. Vitamin E losses under frozen conditions were significant in common kilka, Caspian kutum and pike perch, however, not in golden grey mullet or common carp. A decrease in vitamin C was significant in all fish species, but there were no significant decreases in other water‐soluble vitamins (B₁, B₂, B₆, B₁₂, niacin, folic acid, pantothenic acid, biotin).     

Dynamics of potentially pathogenic microflora of the water and pike perch in the Volga Delta

On the basis of long-term (1995–2010 and 2013–2014) microbiological monitoring of water and pike perch in the various water areas of the Volga Delta, four dominant groups of bacteria from the family Enterobacteriaceae and genera Aeromonas, Flavobacterium, and Pseudomonas were identified. The results of studies on the species composition of water microflora and fish from natural populations and artificial breeding are summarized. The prevalence of potentially pathogenic microflora in the water and fish over the indicative ones has been shown. Water temperature influences the seasonal cycles of microorganisms and their pathogenicity factors, which determine their fast adaptation to living in different ecological niches.     

Genomic inbreeding and population structure of northern pike (Esox lucius) in Xinjiang,China

Northern pike (Esox lucius) was widely distributed in the high latitudes of the northern hemisphere. In China, northern pike was originally distributed only in the upper reaches of the Irtysh River in Xinjiang and has appeared in many water bodies outside the Irtysh River Basin in Northern Xinjiang. A total of four populations were collected from north to south in Xinjiang, including Irtysh River (RIR), Ulungu Lake (LUL), a small lake nearby Ulungu River (LJD), and Bosten Lake (LBO). We estimated population genomic parameters, performed gene flow analysis, and estimated the effective population size of each population. The proportion of individuals with high inbreeding coefficient (F ≥ 0.0625) accounted for 36.4% (44/121) of all sequenced individuals, approximately 4.5% (1/22) in LUL, 25.9% (7/27) in LBO, 42.9% (18/42) in RIR, and 60% (18/30) in LJD. RIR had the highest mean of genomic relatedness (coancestry coefficient = 0.025 ± 0.040, IBD = 0.036 ± 0.078). Gene flow results showed that the population spreading was from RIR into two branches, one was LBO, and the other continued to split into LUL and LJD, and migration signal from LBO to LUL was detected. Our results suggested that the extinction risk of northern pike was very low in Xinjiang of China, and the controlled capture fishery of northern pike could be developed reasonably.     

The genus Kepplerites Neumary et Uhlig (Kosmoceratidae,Ammonoidea) in the Bathonian-Callovian beds (Middle Jurassic) of the Russian Platform

The succession of early species of the genus Kepplerites is established in the Upper Bathonian-Lower Callovian beds of Central Russia and compared with the ammonoid succession of East Greenland and Western Europe. Late Bathonian members of the genus Kepplerites from the Middle Volga Region are generally similar, though not identical to those from Greenland, whereas the Early Callovian Kepplerites species and their immediate Bathonian ancestors are represented by species common to all three regions. The analysis of the ammonoid distribution suggests a connection between the East Greenland and Central Russian marine basins in the Early and Middle Bathonian and in the Early Callovian, and their short-term isolation in the Late Bathonian. A new species, Kepplerites (Kepplerites) aigii sp. nov., is described from the Upper Bathonian (keuppi Zone) of the Alatyr River basin (Middle Volga Region).     

Co-introduction of Dolicirroplectanum lacustre,a monogenean gill parasite of the invasive Nile perch Lates niloticus: intraspecific diversification and mitonuclear discordance in native versus introduced areas

The Nile perch (Lates niloticus) is a notorious invasive species. The introductions of Nile perch into several lakes and rivers in the Lake Victoria region led to the impoverishment of trophic food webs, particularly well documented in Lake Victoria. Additionally, its parasites were co-introduced, including Dolicirroplectanum lacustre (Monogenea, Diplectanidae). Dolicirroplectanum lacustre is the single monogenean gill parasite of latid fishes (Lates spp.) inhabiting several major African freshwater systems. We examined the intra-specific diversification of D. lacustre from Lates niloticus in Lake Albert, Uganda (native range) and Lake Victoria (introduced range) by assessing morphological and genetic differentiation, and microhabitat preference. We expected reduced morphological and genetic diversity for D. lacustre in Lake Victoria compared with Lake Albert, as a result of the historical introductions. We found that D. lacustre displayed high morphological variability within and between African freshwaters, with two morphotypes identified, as in former studies. The single shared morphotype between Lake Albert and Lake Victoria displayed similar levels of haplotype and nucleotide diversity between the lakes. Mitonuclear discordance within the morphotypes of D. lacustre indicates an incomplete reproductive barrier between the morphotypes. The diversification in the mitochondrial gene portion is directly linked with the morphotypes, while the nuclear gene portions indicate conspecificity. Based on our results, we reported reduced genetic and morphological diversity, potentially being a result of a founder effect in Lake Victoria.     

Predator odor recognition and antipredatory response in fish: does the prey know the predator diel rhythm?

We studied in a laboratory experiment using stream tanks if two percid prey fish, the perch (Perca fluviatilis) and the ruffe (Gymnocephalus cernuus), can recognize and respond to increased predation risk using odors of two piscivores, the pike (Esox lucius) and the burbot (Lota lota). Burbot is night-active most of the year but pike hunts predominantly visually whenever there is enough light. Perch is a common day-active prey of pike and dark-active ruffe that of burbot. We predicted that besides recognizing the predator odors, the prey species would respond more strongly to odors of the predator which share the same activity pattern. Both perch and ruffe clearly responded to both predator fish odors. They decreased movements and erected the spiny dorsal fins. Fin erection showed clearly the black warning ornamentation in the fin and thus erected fin may function besides as mechanical defense also as warning ornament for an approaching predator. No rapid escape movements were generally observed. Both perch and ruffe responded more strongly to pike odor than to burbot. There were no clear differences in response between day and night. In conclusion, we were able to verify clear predator odor recognition by both prey fish. Both perch and ruffe responded to both predator odors and it seemed that pike forms a stronger threat for both prey species. Despite of diel activity differences both perch and ruffe used the same antipredatory strategies, but the day-active perch seemed to have a more flexible antipredatory behavior by responding more strongly to burbot threat during the night when burbot is active.     

Environmental correlates of population variables of perch (<Emphasis Type="Italic">Perca fluviatilis</Emphasis>) in boreal lakes

We examined relationships among perch population variable parameters in two types of lakes, lakes with perch (P-lakes, n?=?15) and lakes with perch and roach (PR-lakes, n?=?10) using redundancy analysis (RDA) to relate population variables to environmental factors. Effects from environmental factors were tested for significance by means of permutation tests (Monte Carlo). Three factors, pH, altitude and fraction of roach (by number) in the gill net catches, explaining 47.9% of the variation, had significant effects on perch population variables. The significance of pH was improved by partialing out the effect of conductivity and roach. Similarly, the significance of altitude was improved by partialing out the effect of pH and roach, and the significance of roach was improved by partialing out the effect of pH and altitude. When the fraction of pike in the catch was included in the analysis, the effect of roach was not significant and vice-versa, as roach and pike fractions were correlated with each other. The effect of pike was significant when roach was not included, but the effect was not as strong as the effect of roach. A biplot was constructed by plotting population variables on the first and second RDA axis, with arrows showing five selected environmental factors. Growth of 3+ to 5+ perch was positively related to pH and altitude, perch catch per unit effort was negatively related to pH and altitude, and age specific perch weight was negatively related to fraction of roach. The relationship between growth of 2+ perch and pH was not as strong as the relationship between pH and the growth of older perch. Moreover, the growth of 2+ perch was negatively related to the fraction of roach, probably due to competition between young zooplankton feeding perch and roach.     

Early Devonian (Lochkovian) trilobites and brachiopods from the west Balkhash Region,Kazakhstan and their significance for regional terrane dynamics

A moderately diverse Early Devonian (Lochkovian) trilobite and brachiopod association has been recovered from the lower part of the volcano-sedimentary Shakshagaily Formation, exposed on the western side of Lake Balkhash in central Kazakhstan. Its discovery demonstrates the presence of Lower Devonian marine deposits in the region. The trilobite assemblage includes representatives of six genera: the dalmanitid Kasachstania alperovichi nov. sp. is the dominant taxon, with other components being Ananaspis?, Leonaspis?, Maurotarion, Trimerus (Edgillia), and Warburgella. Associated brachiopods include species of Glossoleptaena, Leptaena, Protolepstostrophia, Pseudostrophochonetes, and Resserella. Whilst a significant proportion of these taxa show distinct links with the contemporaneous trilobite and brachiopod faunas of the north Balkhash Region, the occurrence of Trimerus (Edgillia) aff. kinglakensis Gill, 1949 suggests a possible link with the Lochkovian trilobite fauna of the Australasian sector of Gondwana. The west Balkhash Region preserves an extensive record of late Silurian to Early Devonian island arc volcanism, slope-rise sedimentation and olistostrome formation, which has invariably been ignored in models favouring early amalgamation of the Kazakhstanian terranes into a single continent by the end of the Ordovician.     

Impact of Toxic Cyanobacterial Blooms on Eurasian Perch (Perca fluviatilis): Experimental Study and In Situ Observations in a Peri-Alpine Lake

Due to the importance of young-of-the-year (YOY) perch in the peri-alpine regions where they are consumed, the microcystin (MC) contamination of YOY perch was analysed both in field (Lake Bourget, France) and experimentally using force-feeding protocols with pure MCs. In-situ, schools of YOY perch present in the epilimnion of the lake were never found in direct contact with the P. rubescens blooms that were present in the metalimnion. However, MCs were detected in the muscles and liver of the fish and were thus assumed to reach YOY perch through dietary routes, particularly via the consumption of MC-containing Daphnia. Force-feeding experiment demonstrates the existence of MC detoxification/excretion processes and suggests that in situ, YOY perch could partly detoxify and excrete ingested MCs, thereby limiting the potential negative effects on perch populations under bloom conditions. However, because of chronic exposure these processes could not allow for the complete elimination of MCs. In both experimental and in situ studies, no histological change was observed in YOY perch, indicating that MC concentrations that occurred in Lake Bourget in 2009 were too low to cause histological damage prone to induce mortality. However, Deoxyribonucleic acid (DNA) damages were observed for both the high and low experimental MC doses, suggesting that similar effects could occur in situ and potentially result in perch population disturbance during cyanobacterial blooms. Our results indicate the presence of MCs in wild perch, the consumption of this species coming from Lake Bourget is not contested but more analyses are needed to quantify the risk.     

Genetic differentiation of sockeye salmon Oncorhynchus nerka (Walbaum, 1792) populations of eastern Kamchatka

The interpopulation differentiation of the sockeye salmon Oncorhynchus nerka (Walbaum) from the Olyutorskiy and Karaginskiy districts and from the Kamchatka River basin was examined based on the allelic variation at eight microsatellite loci (Ots107, Oki1a, Oki1b, One104, One109, OtsG68, OtsG85, and Oki6). The genetic diversity of samples from the northern rivers was lower, compared to samples from the Kamchatka River basin. Significant heterogeneity was found in the allele-frequency distribution at microsatellite loci of sockeye salmon from the investigated localities. The degree of genetic similarity of populations corresponded to their geographic closeness. The differences between population groups greatly exceeded the level of interpopulation differentiation. The analyzed samples formed four relatively separate groups: Lake Azabachye, Kamchatka River basin, Karaginskiy area (including the Navyrinvayam River in the south of the Olyutorskiy district), and northern Olyutorskiy area. The identification likelihood estimates of eastern Kamchatkan sockeye salmon in mixed aggregations at the level of population groups were fairly high (67.2–81.8%), greatly exceeding the accuracy of identification of individual populations.     

The population dynamics of pike,Esox lucius,and perch,Perca fluviatilis,in a simple predator-prey system

Synopsis The population dynamics and predator-prey relationship of pike, Esox lucius, and perch, Perca fluviatilis, were examined in simple fish communities in two adjacent shallow lakes, Lochs Kinord and Davan, Deeside, Scotland. Few perch survive to age 3 but Z is low for fish > 3 years and perch live up to 17 years. Population fecundity remained relatively high and constant in perch because of the multi-age spawning stock and the presence of older more fecund perch. Growth rates of perch in both lochs are relatively high as a consequence of low stock abundance. The N, B, and P of adult perch were unusually low. The age range of pike, and N, B, P, and growth were in the range of values reported elsewhere. There was little variation in the strength of pike year classes and the importance of cannibalism and low occurrence of alternative prey in the lochs suggest that the populations were self-regulating. Cannibalism by adults was responsible for most of mortality in perch larvae, and predation by pike and adult perch was responsible for the majority of juvenile losses. This conclusion is supported by the high biomass ratios of pike:juvenile perch of 1.0–30.8. While the number of adult fish was almost equal, the biomass of adult pike was 2–3 × that of perch in Kinord and 6 × in Davan. In L. Kinord, where year class strength was stable, high predation pressure from perch and pike reduced perch abundance rather than eliminated year classes. Perch year classes fluctuated in abundance in L. Davan and were eliminated in the first summer in two sampling years. The pike, and particularly the perch populations, have features characteristic of fish communities in unperturbed ecosystems: namely, a wide range of age classes, stability in biomass with variation dampened by longevity, and low production.     

Comparative analysis of variability of three mitochondrial genes of cytochrome oxidase complex (cox1, cox2, and cox3) in wild and domestic carp (Cyprinus carpio L.)

For the first time, we studied the polymorphism of three mitochondrial genes of the cytochrome oxidase complex (cox1, cox2, and cox3) in natural populations of wild carp living in the Volga, Amur, and Don River Basins, as well as in European Hungarian carp and two pedigree lines of Ropsha carp of domestic breeding. The highest level of nucleotide and haplotype diversity in the studied samples was detected for the cox1 gene (?? = 0.61, h = 100%). Two lines of the Ropsha carp (?? = 0.61, h = 100%) and the Far East population of Amur wild carp from Shershikh strait (Am: ?? = 0.20, h = 70%) were the most polymorphic for three genes. The second sample of Amur wild carp from the Amur River (Ac), as well as the samples of Volga and Don wild carp and Hungarian carp had lower values of variability. The presence of two main genealogical lines of the wild carp and carp was demonstrated based on the total sequence of three genes, as well as the corresponding amino acid sequences in the studied area. One of these lines (line I) is typical of the sample of Amur wild carp (Am) and three members of the Ropsha carp. Line II is developed by sequences of Volga, Don, and Amur wild carp (Ac), as well as European Hungarian carp and seven other members of the Ropsha carp. Three to four sublines, which differ in nucleotide and amino acid substitutions, were found within the lines. Possible reasons for the origin of genomic variability in wild carp, as well as in European and Russian breeds of carp, are discussed.     

A survey of the spawning of perch (Perca fluviatilis), pike (Esox lucius), and roach (Rutilus rutilus), using artificial spawning substrates in lakes

The development of spawning in perch, pike and roach in Lake Geneva has been studied by means of artificial spawning substrates, laid at different depths, from 1984 to 1993. In Lake Geneva, perch spawned in May. A rise of surface water temperature up to 14 °C stimulated spawning activity while bad weather (surface temperature at 10 °C) induced a spread of the spawning period over more than one month. The spawning period was delayed in years when the mean width of perch egg-ribbons was the largest; this corresponded to the biggest females. At the beginning of the spawning period (early in May), perch preferentially chose a depth of 4 m to spawn. In contrast, at the end of the spawning period, maximum spawning intensity was observed at a depth of 12 m. This phenomenon was more pronounced when water temperature rose above 14 °C in the top 4 m while it remained below 12 °C at a depth of 12 m. Pike spawned at the end of April and at the beginning of May in Lake Geneva. They preferred spruce branches among the different spawning substrates that we tested in Lake Vouglans. When the water temperature increased at the surface of Lake Geneva, pike preferred to lay their eggs on substrates set at 3 m depth where the temperature was cooler than in the surface layer (10.5 °C vs 14 °C). Roach spawned during the last two weeks of May or during the first two weeks of June in Lake Geneva, depending on water temperature. Spawning had generally been spread over a week, but a sudden decrease of water temperature could slow spawning intensity. Roach were able to lay their eggs on natural or synthetic substrates, located 0.5 m below the surface near the shore as well as, at a distance of several hundred metres from the shore. The survival of eggs was always above 90% for perch and roach and generally above 70% for pike.