References of "Poncin, Pascal"
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See detailBrown trout fry move inshore at night: a choice of water depth or velocity?
Bardonnet, A.; Poncin, Pascal ULg; Roussel, J. M.

in Ecology of Freshwater Fish (2006), 15(3), 309-314

The instream positions of brown trout fry differ between daylight and darkness. According to field and laboratory observations, recently emerged 0+ brown trout use shallow and slow-flowing areas close to ... [more ▼]

The instream positions of brown trout fry differ between daylight and darkness. According to field and laboratory observations, recently emerged 0+ brown trout use shallow and slow-flowing areas close to the bank at night and tend to move off-shore during daylight. In laboratory channels, we tested whether the use of habitats close to the river bank could be attributed to a choice of either water depth or velocity. In two complementary experiments, emerging brown trout alevins were given the choice of using shallow-slow or deep-swift habitats (experiment 1), and deep-slow or shallow-swift habitats (experiment 2). At night, a persistent preference for the shallow habitats was displayed, regardless of velocity. It was concluded that swim-up brown trout fry respond to shallowness rather than ambient low water velocity when selecting habitats close to the bank at night. The behavioural significance of this result and implications for river management are discussed. [less ▲]

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See detailExperimental evidences of a structural and dynamical transition in fish school
Becco, Christophe ULg; Vandewalle, Nicolas ULg; Delcourt, Johann ULg et al

in Physica A: Statistical Mechanics and its Applications (2006), 367

We have developed a video tracking system in order to determine all the trajectories of young fish (Oreochromis niloticus L.) within a school. Both individual and collective behaviours have been studied ... [more ▼]

We have developed a video tracking system in order to determine all the trajectories of young fish (Oreochromis niloticus L.) within a school. Both individual and collective behaviours have been studied as a function of the number of fish per unit area. By studying distributions of distances between fish and distributions of relative orientations, structural effects and cooperative motions have been evidenced. Signatures of a phase transition have been found, as predicted by some numerical models. This work opens new perspectives in the study of collective phenomena in biological systems since it is the first time that such measurements are possible. [less ▲]

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See detailComparing the EthoVision 2.3 system and a new computerized multitracking prototype system to measure the swimming behavior in fry fish
Delcourt, Johann ULg; Becco, Christophe ULg; Ylieff, Marc ULg et al

in Behavior Research Methods (2006), 38

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The ... [more ▼]

Coming from the framework of unmarked fry tracking, we compared the capacities, advantages, and disadvantages of two recent video tracking systems: EthoVision 2.3 and a new prototype of multitracking. The EthoVision system has proved to be impressive for tracking a fry using the detection by gray scaling. Detection by subtraction has given less accurate results. Our video multitracking system is able to detect and track more than 100 unmarked fish by gray scaling technique. It permits an analysis at the group level as well as at the individual level. The multitracking program is able to attribute a number to each fish and to follow each one for the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fish cross each other. This is possible thanks to the theoretical estimation of the trajectory of each fish, which can be compared with the real trajectory (analysis with feedback). However, the period of the track is limited for our system (about 1 min), whereas EthoVision is able to track for numerous hours. In spite of these limitations, these two systems allow an almost continuous automatic sampling of the movement behaviors during the track. [less ▲]

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See detailFacteurs influençant l'efficacité des repeuplements. In: Vers une nouvelle politique des rempoissonnements.
Rollin, X.; Poncin, Pascal ULg

in Vers une nouvelle politique de rempoissonnement (2006)

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See detailFactors affecting black grouse numbers : an overview of the part of predators. European conference, black grouse endangered species,
Loneux, Michèle ULg; Kolb, Karl-Heinz; Ruwet, Jean-Claude et al

in PLUMMER, Ron (Ed.) European Conference 'Cynhadledd Ceiliog Y Rhos' Black Grouse Endangered Species (2005, December)

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See detailCourtship behavior in the Alpine newt Triturus alpestris at two different densities of males
Denoël, Mathieu ULg; Hector, Marie-Pierre; Poncin, Pascal ULg

in Herpetologica (2005), 61(4), 373-379

The aim of this laboratory experiment was to examine courtship behavior and reproductive success under two different perceived male densities ill the Alpine newt (Triturus alpestris). Male behavioral ... [more ▼]

The aim of this laboratory experiment was to examine courtship behavior and reproductive success under two different perceived male densities ill the Alpine newt (Triturus alpestris). Male behavioral patterns were similar at unbiased and male-biased operational sex ratios (OSR). Although the exhibition of hiring behaviors is risky in the presence of other males, no difference in the frequencies of displays was found at the two male, densities. Similarly, the responsiveness of females towards males and the Success rate of the encounters (i.e. spermatophore transfer) were not explained by file OSR. Our results show that courting Alphine newts do not change their courtship patterns when other males are present and do not interact directly. However they are not necessarily opposed to those of previous experiments showing sexual interference awl ,female aversion in male-biased OSR with possibility of interactions. These observations suggest that the evolution of courtship behavior may not be driven by the risk of sexual interference with other males prior to potential physical contact and that the benefits of breeding regardless of OSR can overcome the risk of Competition at male-biased OSR. [less ▲]

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See detailImpact implantation of a transmitter on Sarpa salpa behaviour: study with a computerized video tracking system
Jadot, Catherine; Donnay, Annick ULg; Ylieff, Marc ULg et al

in Journal of Fish Biology (2005), 67(2), 589-595

Two transmitter masses (2 and 6% of the fish's mass) were selected to examine the interference of tags with the behaviour of Sarpa salpa using a computerized video tracking system based on digital imaging ... [more ▼]

Two transmitter masses (2 and 6% of the fish's mass) were selected to examine the interference of tags with the behaviour of Sarpa salpa using a computerized video tracking system based on digital imaging techniques. The study demonstrated that light transmitters had no effect on the behavioural variables studied, and a substantial bias in behaviour is introduced if heavier (6%) tags are used. (c) 2005 The Fisheries Society of the British Isles. [less ▲]

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See detailEffect of water temperature on the courtship behavior of the Alpine newt Triturus alpestris
Denoël, Mathieu ULg; Mathieu, Maryève; Poncin, Pascal ULg

in Behavioral Ecology and Sociobiology (2005), 58(2), 121-127

Temperature is expected to have an effect on the behavioral patterns of all organisms, especially ectotherms. However, although several studies focused on the effect of temperature on acoustic displays in ... [more ▼]

Temperature is expected to have an effect on the behavioral patterns of all organisms, especially ectotherms. However, although several studies focused on the effect of temperature on acoustic displays in both insects and anurans, almost nothing is known about how environmental temperature may affect ectotherm visual courtship displays and sexual performance. The purpose of this study was to determine the effect of environmental temperature on the sexual behavior of Alpine newts (Triturus alpestris). We subjected T. alpestris to two different temperatures in controlled laboratory conditions. Temperature had a major effect on both male and female behaviors: at low temperature, the frequencies of several displays, including tail-raising during sperm deposition, are lowered. This variation is caused indirectly by temperature because it is due to female responsiveness, which is temperature-dependent. However, the fanning movement of the male's tail during its main courtship display is independent of female behavior: at lower temperatures, the tail beats at a lower rate, but for a longer time. The similar reproductive success (i.e. sperm transfer) at the two temperature ranges indicates that breeding in cold water is not costly but instead allows males and females to mate early in the season. This is particularly adaptive because, in many habitats, the reproductive period is shortened by drying or freezing conditions, which may impair survival of branchiate offspring. This study also demonstrates the necessity of considering environmental parameters when modeling optimality and characteristics of ectotherm behaviors. [less ▲]

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See detailFactors affecting black grouse numbers : an overview of the part of predators.
Loneux, Michèle ULg; Kolb, K.; Ruwet, Jean-Claude et al

Conference (2005)

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See detailThe spawning behaviour of the endangered freshwater fish Ladigesocypris ghigii (Gianferrari, 1927)
Poncin, Pascal ULg; Stoumboudi, M. T.; Gervalle, L. et al

in Journal of Applied Ichthyology (2005), 21(3), 225-228

Ladigesocypris ghigii (Gianferrari, 1927), commonly called gizani, is an endangered freshwater fish endemic to the Greek island of Rhodes. The spawning behaviour of gizani was studied in aquaria, to ... [more ▼]

Ladigesocypris ghigii (Gianferrari, 1927), commonly called gizani, is an endangered freshwater fish endemic to the Greek island of Rhodes. The spawning behaviour of gizani was studied in aquaria, to develop an artificial breeding technique for this endangered species. Spawning in captivity was recorded over 41 spawning days between 15 February and 14 July 2001, under constant temperature (18 or 21 degrees C) and photoperiod 14L/10D. The number of spawning acts in a day was 82 +/- 28. No aggressiveness and no territoriality were developed. The mating system of the fish was polygamous, with females spawning more than once. In captivity, eggs are laid either on aquatic plants or on gravel, while in nature fish spawn mainly on algae and plants. The latter suggests that, as far as breeding substrate is concerned, gizani is an opportunistic species using different substrates when necessary. [less ▲]

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See detailMorphological changes of the nucleolus during oogenesis in oviparous teleost fish, Barbus barbus (L.).
Thiry, Marc ULg; Poncin, Pascal ULg

in Journal of Structural Biology (2005), 152(1), 1-13

In fishes, like in amphibians, it is well established that variations in rRNA activity occur during oogenesis. Contrary to amphibians, however, little is known about the ultrastructural changes of the ... [more ▼]

In fishes, like in amphibians, it is well established that variations in rRNA activity occur during oogenesis. Contrary to amphibians, however, little is known about the ultrastructural changes of the nucleolus during fish oogenesis. Evolution of the nucleolus has been followed during oogenesis in the teleost fish Barbus barbus (L.) using light and transmission electron microscopies. We show that the behaviour of the nucleolus during B. barbus oogenesis resembles that reported in amphibians but also presents several peculiarities. The most striking feature is the marked vacuolization of nucleoli occurs at the beginning of the growth during previtellogenesis. The results obtained by means of the in situ terminal deoxynucleotidyl transferase-immunogold method for detecting DNA seem further to indicate that the chromatin cap becomes integrated into developing nucleoli during previtellogenesis and then segregate at the periphery of nucleoli at the end of glycoproteinic vitellogenesis. Our study also shows that the nucleoli of germ cells, like that of follicle cells, are devoid of fibrillar centre but comprise a fibrillar and a granular component whatever the oogenetic stage. Ultrastructural detection of DNA and nucleolar proteins (AgNOR proteins, fibrillarin, and pp135) supports further the view that the Barbus nucleolus is a bipartite structure. [less ▲]

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See detailA new automatic video multitracking system able to follow a large school
Delcourt, Johann ULg; Becco, Christophe ULg; Vandewalle, Nicolas ULg et al

in Noldus, L.P.P.J.; Grieco, F.; Loijens, L. W. S. (Eds.) et al Proceedings of Measuring Behavior 2005 (2005)

The study of shoaling behaviours is tackled by scientists by three approaches: the field, laboratory and computer modelling approach. The field studies are complicated and permit rarely an analysis of ... [more ▼]

The study of shoaling behaviours is tackled by scientists by three approaches: the field, laboratory and computer modelling approach. The field studies are complicated and permit rarely an analysis of individual positions. The third approach, consisting of development of mathematic models, is artificial. It requires a comparison with empiric results to validate and to determine the explications’ degree of each model. Thanks to the developments of digital imaging techniques, the laboratory studies on fish are able to measure the behavioural parameters with precision, impossible to realize with manual recording. Multitracking systems are rare and of recent development. These are insufficient to study the real size of shoals, often composed of hundreds of .shes. We have developed a new system of multitracking thanks to collaboration with the G.R.A.S.P. The G.R.A.S.P. has before realised other multitracking systems to follow some hundreds physical objects. Our video multitracking system is able to detect and to track more than a hundred unmarked fishes by gray scaling technique during some minutes. It permits an analysis as well at the group level as at the individual level. The multitraking program is able to attribute a number at each fish and to follow each one during the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fishes cross each other. It is possible thanks to the theoretical estimation of trajectory of each fish, compared with the real trajectory (analysis with feedback). The human eye is always necessary to detect the errors in identification but reediting is possible. However, if the fishes don’t move too rapidly, a rate of 25 images /s gives very good results, without too much visual expertise from the experimenter. If the fishes are too fast (i.e. escape response), it is better to use a high speed camera. [less ▲]

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See detailPréface
Poncin, Pascal ULg

in Philippart, Jean-Claude (Ed.) « Le voyage périlleux des poissons grands migrateurs dans la Meuse » (2005)

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See detailCourtship behaviour at low and high water temperatures in the Alpine newt
Denoël, Mathieu ULg; Mathieu, Maryève; Poncin, Pascal ULg

Poster (2005)

Environmental factors are known to have a major effect on behavioral patterns of organisms. Among these factors, temperature particularly affects ectotherms. However, although many studies focused on ... [more ▼]

Environmental factors are known to have a major effect on behavioral patterns of organisms. Among these factors, temperature particularly affects ectotherms. However, although many studies focused on acoustic communication, the effect of environmental temperature on visual courtship displays and sexual performance has been little explored. The aim of this work was to determine the effect of temperature on the sexual behaviour of the Alpine newt Triturus alpestris in controlled laboratory conditions. Temperature had a major effect on the two sexes: at low temperatures, the frequencies of several displays, including sperm deposition, is lowered. This variation is in fact caused by the female responsiveness, which is temperature-dependent. However, some other behaviours, such as the fanning movement of the male’s tail (i.e., the main courtship display) are directly dependent on temperature: at lower temperatures, the tail beats at a lower rate but for a longer time. The similar reproductive success at the two temperatures indicates that breeding in cold water is not necessarily costly. It allows males and females to mate early in the season. This is particularly adaptive because, in many habitats, the reproductive period is shortened by drying or freezing conditions which may impair survival of branchiate offspring. [less ▲]

Detailed reference viewed: 32 (0 ULg)