References of "Faucher, Karine"
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See detailPerception sensorielle et comportement chez la truite arc-en-ciel
Faucher, Karine ULg; Millot, Sandie ULg; Lefrançois, Christel et al

in Jalabert, Bernard; Fostier, Alexis (Eds.) La truite arc-en-ciel: De la biologie à l’élevage (2010)

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See detailFish lateral system is required for accurate control of shoaling behaviour
Faucher, Karine ULg; Parmentier, Eric ULg; Becco, Christophe ULg et al

Conference (2010)

In teleost fishes, the lateral system is assumed to contribute, among other roles, to maintaining schooling behaviour. Sight is also assumed to play a role in schooling, as fish with a cut lateral line do ... [more ▼]

In teleost fishes, the lateral system is assumed to contribute, among other roles, to maintaining schooling behaviour. Sight is also assumed to play a role in schooling, as fish with a cut lateral line do not stop schooling unless they are also blinded. This conclusion, however, was based on experiments where only the trunk lateral line was inactivated, leaving the head lateral system intact. Here the aim was to test how inactivation of the whole lateral system affects the fish shoaling behaviour. Groups of firehead tetras, Hemigrammus bleheri, were video-recorded before and after inactivation of their whole lateral system with aminoglycoside antibiotics (and also in sham-treated specimens). Shoaling behaviour was characterized by: nearest distance to the first, second, and third neighbour, shoal radius, shoal order parameter, and the number of collisions between individuals. SEM observations showed damage to most superficial neuromasts as a result of antibiotic treatment. Importantly, the antibiotic-treated fish proved unable to maintain a shoal. After the end of the treatment, however, they recovered both a normal tissue morphology and normal shoaling behaviour within about a month. The lateral system is thus more crucial to shoaling behaviour than previously believed. [less ▲]

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See detailFish lateral system is required for accurate control of shoaling behaviour
Faucher, Karine ULg; Parmentier, Eric ULg; Becco, Christophe ULg et al

in Animal Behaviour (2010), 79

In teleost fishes, the lateral system is assumed to contribute, among other roles, to maintaining schooling behaviour. Sight is also assumed to play a role in schooling, as fish with a cut lateral line do ... [more ▼]

In teleost fishes, the lateral system is assumed to contribute, among other roles, to maintaining schooling behaviour. Sight is also assumed to play a role in schooling, as fish with a cut lateral line do not stop schooling unless they are also blinded. This conclusion, however, is based on experiments where only the trunk lateral line was inactivated, leaving the head lateral system intact. We investigated how inactivation of the whole lateral system affects fish shoaling behaviour. Groups of firehead tetras, Hemigrammus bleheri, were videorecorded before and after inactivation of their whole lateral system with aminoglycoside antibiotics (and also in sham-treated specimens). Shoaling behaviour was characterized by nearest distance to the first, second and third neighbours, shoal radius, shoal order parameter and the number of collisions between individuals. Scanning electron microscope observations showed damage to most superficial neuromasts as a result of antibiotic treatment. Importantly, the antibiotic-treated fish proved unable to maintain a shoal. After the end of the treatment, however, they recovered both a normal tissue morphology and normal shoaling behaviour within about a month. The lateral system is thus more crucial to shoaling behaviour than previously believed. [less ▲]

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See detailDamage and functional recovery of the Atlantic cod (Gadus morhua) inner ear hair cells following local injection of gentamicin
Faucher, Karine ULg; Aas-Hansen, Øyvind; Damsgård, Borge et al

in International Journal of Audiology (2009), 48(7), 456-464

This study addresses the ultrastructural and functional damage and subsequent recovery of the inner ear in the Atlantic cod following intrasaccular gentamicin injection. Inner ear damage was assessed ... [more ▼]

This study addresses the ultrastructural and functional damage and subsequent recovery of the inner ear in the Atlantic cod following intrasaccular gentamicin injection. Inner ear damage was assessed using SEM and measurements of AEP following 250-Hz pure-tone stimuli. Data from gentamicin-treated fish were compared with control (no injection) and sham (injection of saline) fish. Control fish had normal response thresholds associated with welldeveloped hair cell bundles in their macula sacculi. Sham fish had higher response thresholds compared with control fish during the first week post-intervention, but response thresholds were subsequently normal. Treated fish displayed significant inner ear damage associated with an increased average AEP threshold on the third day following treatment. Thereafter, inner ear tissue displayed signs of progressive regeneration until it was comparable to controls from the 14th day. Response thresholds were similar to those of control fish from the 17th day following treatment. These observations suggest that the macula sacculi of Atlantic cod can regenerate towards a near-complete functional and ultrastructural recovery within 17-21 days following ototoxic gentamicin treatment. [less ▲]

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See detailIntrasaccular injection of aminoglycosides: a novel method for temporary damaging fish inner ear hair cells
Faucher, Karine ULg; Aas-Hansen, Øyvind; Damsgard, Borge et al

Poster (2008, October)

Fish models are increasingly being used for hearing research investigations. Aminoglycoside antibiotics that are used for damaging the inner ear hair cells can have systemic side effects leading to death ... [more ▼]

Fish models are increasingly being used for hearing research investigations. Aminoglycoside antibiotics that are used for damaging the inner ear hair cells can have systemic side effects leading to death of study animals. This study aimed to compare two methods: i) systemic (intravenous) and ii) local (intrasaccular) gentamicin administration for induction of inner ear hair cell damage in the Atlantic cod, Gadus morhua (L.). Hair cell damage was assessed using scanning electron microscopy; hair cell density, prevalence of immature hair cells and kinocilia length were measured. Gentamicin-treated fish were compared with control and sham fish. Intravenous gentamicin led to dose-dependent mortality caused by nephrotoxicity. The only visible effect after treatment was more immature hair cells and shorter kinocilia, the effect on hair cell density was equivocal. Following intrasaccular gentamicin treatment, fish mortality was negligible, and hair cells were damaged regardless of dose. Here, we observed decreased hair cell density, high prevalence of immature hair cells, and significantly shortened kinocilia. Conclusion: intrasaccular injection is preferable to intravenous injection of gentamicin for the study of ototoxicity in the Atlantic cod. [less ▲]

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See detailImpact of chronic cadmium exposure at environmental dose on escape behaviour in sea bass (Dicentrarchus labrax L.; Teleostei, Moronidae).
Faucher, Karine ULg; Fichet, Denis; Miramand, Pierre et al

in Environmental Pollution (2008), 151(1), 148-57

The effect of chronic exposure to a low concentration (0.5 microg l(-1)) of cadmium ions was investigated on escape behaviour of sea bass, Dicentrarchus labrax, using video analysis. Observations were ... [more ▼]

The effect of chronic exposure to a low concentration (0.5 microg l(-1)) of cadmium ions was investigated on escape behaviour of sea bass, Dicentrarchus labrax, using video analysis. Observations were also performed on the microanatomy of lateral system neuromasts. When fish were exposed for 4h per day over 8 days to the cadmium ions, most of both types of neuromasts observed remained intact. However, some of them presented damaged sensory maculae. Whereas before cadmium exposure, fish responded positively to nearly all the lateral system stimulations, after exposure they decreased by about 10% their positive responses to stimulations. From the 15th day after the beginning of cadmium exposure, neuromasts presented progressively less damage, cadmium accumulation in gills and scales decreased significantly and fish escape behaviour had recovered. This study presents a new concept in ecotoxicology: using behavioural change to reveal the effects of pollution levels, scarcely detectable by currently used techniques (physiological responses). [less ▲]

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See detailEffects of systemic versus local gentamicin on the inner ear in the Atlantic cod, Gadus morhua (L.), relevance for fish hearing investigations.
Faucher, Karine ULg; Aas-Hansen, Øyvind; Damsgard, B. et al

in Hearing Research (2008), 240(1-2), 12-21

Fish models are increasingly being used for hearing research investigations. Aminoglycoside antibiotics that are used for damaging the inner ear hair cells can have systemic side effects leading to death ... [more ▼]

Fish models are increasingly being used for hearing research investigations. Aminoglycoside antibiotics that are used for damaging the inner ear hair cells can have systemic side effects leading to death of study animals. This study aimed to compare two methods: (i) systemic (intravenous) and (ii) local (intrasaccular) gentamicin administration for induction of inner ear hair cell damage in the Atlantic cod, Gadus morhua (L.). Hair cell damage was assessed using scanning electron microscopy; hair cell density, prevalence of immature hair cells and kinocilia length were measured. Gentamicin-treated fish were compared with control and sham fish. Intravenous gentamicin led to dose-dependent mortality caused by nephrotoxicity. The only visible effect after treatment was more immature hair cells and shorter kinocilia, the effect on hair cell density was equivocal. Following intrasaccular gentamicin treatment, fish mortality was negligible, and hair cells were damaged regardless of dose. Here, we observed decreased hair cell density, high prevalence of immature hair cells, and significantly shortened kinocilia. Conclusion: intrasaccular injection is preferable to intravenous injection of gentamicin for the study of ototoxicity in the Atlantic cod. [less ▲]

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See detailAssessment of sea bass swimming activity and preferential space use in sea cages using acoustic telemetry and archival tags
Faucher, Karine ULg; Millot, Sandie ULg; Struski, Caroline et al

Poster (2007, June)

Swimming activity rhythms and levels as well as space occupation by sea bass, Dicentrarchus labrax, in a sea cage (6.5 x 6.5 x 8 m, ca. 25000 fish of 400 g stocked at 30 kg m-3) were recorded using ... [more ▼]

Swimming activity rhythms and levels as well as space occupation by sea bass, Dicentrarchus labrax, in a sea cage (6.5 x 6.5 x 8 m, ca. 25000 fish of 400 g stocked at 30 kg m-3) were recorded using acoustic telemetry (9 fish, IBDT Sonotronics) and archival tags (11, DSTs STAR ODDI). Acoustic tracking was realized over a 13 days period and successful for 3 individuals (one fix every 2 min on average). For archival tags, only 4 tags were retrieved and 3 had been recording swimming depth and temperature for 9 mo (Nov 05-June 06). Telemetry results showed an even day/night swimming activity levels in November with fish staying in close association with the bottom. Archival tags recordings revealed a preferential distribution in the water column between mid-water and bottom of the net cage in winter, over the whole water column in spring and near the surface zone in early-summer. In addition, on a 24 hrs period basis, sea bass presented a vertical movement rhythm: they swam closer to the surface during the day, specially around feeding events, and near the bottom at night. That vertical movement was pronounced during winter, faded during spring and almost disappeared in summer. [less ▲]

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See detailAminoglycoside antibiotics and the sensory hair cells of inner ear and lateral line system in the Atlantic cod, Gadus morhua: effects on fish hearing threshold
Faucher, Karine ULg; Aas-Hansen, Øyvind; Damsgard, Borge et al

Poster (2007, April)

The aims of the present study were to investigate: a) the potential involvement of the fish lateral line system in hearing at 250 Hz and b) the possible regeneration of the inner ear hair cells in the ... [more ▼]

The aims of the present study were to investigate: a) the potential involvement of the fish lateral line system in hearing at 250 Hz and b) the possible regeneration of the inner ear hair cells in the Atlantic cod (Gadus morhua). The inner ear and lateral line system of the Atlantic cod were inactivated using ototoxic aminoglycoside antibiotics by injection (gentamicin) or bath (gentamicin and streptomycin), respectively. Hearing thresholds were measured in the fish using the Auditory Brainstem Response (ABR) technique at 10, respectively 17 - 20 days following antibiotic treatment. Results were compared between groups of individuals i) with inner ear damage, ii) with lateral line system altered, iii) placebo (immersion in fresh sea water) and iv) control. The sound stimuli applied were series of 2000 five-cycle (2-1-2) 250 Hz tone bursts delivered using a Brüel & Kjær (Nærum, Denmark) loudspeaker. ABRs were measured using a filter set at 30-3000 Hz, a gain of 100 000 and visual interpretation using the Bio-Logic AEP software. Sound stimulus level was reduced until threshold was attained. To check the tissue status of the inner ear and lateral line system, hair cells from sensory maculae were visualized using scanning electron microscope (SEM). Ten days after treatment, hearing thresholds of placebo and lateral line damaged cods did not differ from controls fish (p = 0.387 and p = 0.095, respectively), whereas the fish that received intravenous gentamicin injection had significantly elevated hearing thresholds compared to controls (p < 0.0001). SEM analyses further demonstrated that, 10 days following antibiotic treatment, cod inner ear hair cells were damaged, as well as lateral line hair cells and more particularly in the case of canal neuromasts. There was no hearing effect or microscopic tissue damage in untreated fish. From the 17th day after treatment, ABR measurements showed that some of the gentamicin treated fish had regained hearing thresholds comparable to the control cods (p = 0.535), and this was associated with an apparent regeneration of hair cells in the sensory maculae of their inner ear. This study indicates a capacity for inner ear hair cell regeneration in Atlantic cod, and illustrates the advantages of the ABR-method for investigation of fish hearing after intervention on the inner ear, and during the hair cell regeneration process. The present work further suggests that the lateral line system is not involved in cod hearing at 250 Hz. [less ▲]

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See detailImpact d'une exposition aiguë au cadmium sur les neuromastes du système latéral troncal et conséquences sur le comportement de fuite "C-Start" du bar (Dicentrarchus labrax L., Téléostéen, Moronidae)
Faucher, Karine ULg; Fichet, Denis; Miramand, Pierre et al

Conference (2006, March)

Les réponses comportementales du bar, Dicentrarchus labrax, ont été examinées après exposition aux ions cadmium en conditions contrôlées de laboratoire. Le but de cette étude était de découvrir si les ... [more ▼]

Les réponses comportementales du bar, Dicentrarchus labrax, ont été examinées après exposition aux ions cadmium en conditions contrôlées de laboratoire. Le but de cette étude était de découvrir si les ions cadmium étaient capables d’inactiver les neuromastes du système latéral du poisson et de déterminer les conséquences comportementales d’un tel blocage sensoriel chez des poissons soumis à des dangers artificiels. Pour cela, le comportement de fuite des poissons en réponse à un jet d’eau artificiel a été enregistré grâce à une caméra vidéo analogique (25 images.s-1) avant et après l’exposition au cadmium. Le protocole expérimental a été testé sur des poissons dont le système latéral avait été artificiellement endommagé par des antibiotiques (gentamicine et streptomycine). Les contrôles histologiques réalisés en microscopie électronique à balayage ont montré que le traitement antibiotique avait détruit les neuromastes du système latéral. En parallèle, ces poissons ne répondaient plus aux stimulations engendrées par le jet d’eau après un tel traitement. Le comportement de fuite des poissons a ensuite été enregistré avant puis après une exposition au cadmium à deux concentrations différentes. Lorsque les bars ont été exposés à la première concentration testée (0.5 µg.l-1, ce qui représente la concentration maximale rencontrée dans des estuaires contaminés), aucune altération des tissus des neuromastes n’a été observée. De plus, avant l’exposition au cadmium, les poissons répondaient de manière positive à 98.41 ± 4.95 % (n = 42) des stimulations de leur système latéral (réponse de fuite face au jet d’eau). Après l’exposition au cadmium, aucune modification comportementale n’a été détectée : les poissons répondaient positivement à 95.16 ± 9.79 % (n = 41) des stimulations ( ² = 2.464, p = 0.116). Au contraire, la concentration la plus élevée de cadmium testée (5 µg.l-1, ce qui représente 10 fois la concentration rencontrée dans les estuaires fortement pollués) a entraîné de sévères dommages au niveau des tissus des neuromastes. Juste après une telle exposition au cadmium, les poissons présentaient seulement 41.67 ± 35.36 % (n = 2) de réponses positives aux stimulations de leur système latéral, alors qu’ils répondaient positivement à 95.93 ± 9.10 % (n = 41) des stimulations en conditions témoins ( ² = 24.562, p < 0.0001). Les neuromastes de leur système latéral ont semblé se régénérer au bout d’environ un mois après l’exposition au cadmium. Associée à cette régénération, à partir du 21ème jour suivant l’exposition au cadmium, leur comportement de fuite s’est restauré et n’était plus significativement différent de celui enregistré en conditions témoins (86.74 ± 20.82 %, n = 11, ² = 2.876, p = 0.090). Cette étude montre que si la concentration de cadmium de 5 µg.l-1 est capable d’endommager les neuromastes du système latéral et de provoquer des altérations comportementales chez les poissons, les bars exposés à 0.5 µg.l-1 de cadmium ne présentent ni dommage tissualaire de leurs neuromastes, ni modification comportementale. [less ▲]

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See detailLe système latéral, organe sensoriel majeur, n'intervient pas dans le comportement alimentaire nocturne du bar
Faucher, Karine ULg; Lagardère, Jean-Paul

in Aquaculture Recherche (2006), 199

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See detailNo efficiency of the lateral system on nocturnal feeding in the European sea bass (Dicentrarchus labrax L.)
Faucher, Karine ULg; Dutto, Gilbert; Covès, Denis et al

in Aquaculture (2006), 252(2-4), 462-475

In order to evaluate the effect and consequence of lateral system inactivation on fish nocturnal feeding, the differential growth of groups of European sea bass maintained in different rearing conditions ... [more ▼]

In order to evaluate the effect and consequence of lateral system inactivation on fish nocturnal feeding, the differential growth of groups of European sea bass maintained in different rearing conditions were compared. Whereas some fish with intact lateral system (placebo fish) were placed under a photoperiod of 12-L: 12-D, other placebo fish were kept in the dark. In the same way, fish deprived of lateral system by section of their lateral system nerves and antibiotic treatment were placed under a photoperiod of 12-L :12-D and the others in the dark. For each of these four rearing conditions, two sets of experiment were realized. Percent mortality, feed rhythm, averaged daily feed demand, specific growth rate and feed efficiency were compared among these four groups of fish. After four months of experiment, results revealed that, under a photoperiod of 12-L: 12-D, fish showed a diurnal feed rhythm whereas no rhythm appeared in fish kept in the dark. In addition, as reported by other authors, the average daily feed demand, the quantity of ingested food and specific growth rate were greater in fish maintained under a photoperiod of 12-L :12-D than those kept in the dark. The fish lateral system inactivation did not affect mortality, feed intake, specific growth rate or feed efficiency. These results demonstrated that lateral system is not the major sensory organ leading to European sea bass nocturnal feeding; chemoreception system undoubtedly taking over. If the olfactory system explains equal feed intake between placebo and treated fish, the greater specific growth rate in treated than in placebo fish indicates the action of another mechanism, such as a "booster effect" of antibiotics used for lateral system inactivation on fish. [less ▲]

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See detailImpact of acute cadmium exposure on the trunk lateral line neuromasts and consequences on the "C-start" response behaviour of the sea bass (Dicentrarchus labrax L.; Teleostei, Moronidae).
Faucher, Karine ULg; Fichet, Denis; Miramand, Pierre et al

in Aquatic Toxicology (2006), 76(3-4), 278-94

Behavioural responses of sea bass Dicentrarchus labrax were investigated after exposure to cadmium ions in laboratory-controlled conditions. The aim of this study was to discover whether environmental ... [more ▼]

Behavioural responses of sea bass Dicentrarchus labrax were investigated after exposure to cadmium ions in laboratory-controlled conditions. The aim of this study was to discover whether environmental exposure to cadmium ions inactivates fish lateral line system neuromasts, and to determine the behavioural consequences of such a sensory blockage. For this, fish escape behaviour in response to an artificial water jet was recorded using a 25-frames s(-1) analog video camera before and after cadmium exposure. Experimental set up was tested with fish whose lateral line system was artificially inactivated by antibiotics (gentamicin and streptomycin). Histological analyses with scanning electron microscopy showed antibiotic treatment destroyed lateral line system neuromasts. In addition, these fish did not respond to stimulations provoked by the water jet after antibiotic treatment. Fish escape behaviour was then recorded before and after cadmium exposure at two different concentrations. When fish were exposed to the first concentration of cadmium tested (0.5 microg l(-1), which represents the maximal cadmium concentration encountered in contaminated estuaries), no alteration in neuromast tissue was observed. In addition, before cadmium exposure, fish responded positively in 98.41 +/- 4.95% of lateral line system stimulations (escape behaviour in response to the water jet). After cadmium exposure, no behavioural modification could be detected: the fish responded positively in 95.16 +/- 9.79% of stimulations (chi(2) = 2.464, p = 0.116). In contrast, the high cadmium concentration used (5 microg l(-1), which represents 10 times the concentration occurring in highly polluted estuarine areas) involved severe neuromast tissue damage. Just after such cadmium exposure, fish showed only 41.67 +/- 35.36% of positive responses to their lateral line system stimulations, while they responded positively in 95.93 +/- 9.10% of stimulations under control conditions (chi(2) = 24.562, p < 0.0001). Their lateral line system neuromasts seemed to regenerate about 1 month after cadmium exposure. Associated with this regeneration, from the 21st day after cadmium exposure, their escape behaviour had recovered and was not significantly different from that recorded under control conditions (86.74 +/- 20.82%, chi(2) = 2.876, p = 0.090). This study shows that although 5 microg l(-1) cadmium is able to damage lateral line system neuromasts and causes fish behavioural alterations, fish exposed to 0.5 microg l(-1) cadmium displayed neither tissue neuromast nor behavioural modification. [less ▲]

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See detailEt la pollution marine?
Faucher, Karine ULg; Lepage, Caroline

Article for general public (2005)

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See detailRésumé de thèse - Le système latéral du bar, Dicentrarchus labrax, et les conséquences d'un dysfonctionnement sur son comportement: action potentielle des ions métalliques
Faucher, Karine ULg

in Cybium (2005), 29(2), 118

Le système latéral est un organe sensoriel présent chez les poissons et utilisé pour l'identification et la localisation d'obstacles, la détection des objets en mouvement (proies, prédateurs, nage en banc ... [more ▼]

Le système latéral est un organe sensoriel présent chez les poissons et utilisé pour l'identification et la localisation d'obstacles, la détection des objets en mouvement (proies, prédateurs, nage en banc, parade sexuelle) et la rhéotaxie. L'intégrité morphologique et fonctionnelle de ce système sensoriel apparaît donc comme un élément indispensable à la présence et à la survie d'un poisson dans un écosystème. Or, de part sa localisation à l'interface entre l'animal et le milieu, et par le fait qu'il fonctionne via des flux d'ions, cet organe sensoriel pourrait être la cible d'une pollution d'origine naturelle ou anthropique. Le but de cette étude était d'examiner l'impact d'une pollution métallique du milieu (et en particulier de l'ion cadmium) sur l'état tissulaire et fonctionnel du système latéral du bar, Dicentrarchus labrax (L.), puis d'observer les conséquences comportementales induites sur des groupes d'individus évoluant dans des conditions contrôlées de laboratoire. Une étude préliminaire des caractéristiques morphologiques et de la distribution spatiale des neuromastes composant le système latéral du bar a révélé la présence de deux types de neuromastes (superficiels et canaux) répartis sur la tête, le tronc et la queue. Le gradient décroissant de capacité sensorielle, mis en évidence de l'extrémité rostrale à l'extrémité caudale de la ligne latérale troncale du bar, est très original et pourrait jouer un rôle dans le fonctionnement du système latéral. L'axe de sensibilité majeure des deux types de neuromastes du système latéral troncal s’aligne selon l'axe longitudinal du poisson, ce qui lui confère une sensibilité accrue aux stimuli appliqués le long de son corps. L'inactivation artificielle du système latéral du poisson entraîne une réduction de son exploration verticale de l'habitat. Par contre, aucun effet sur sa prise alimentaire nocturne n’est constaté lorsque cette prise est constituée de proies inertes ; un système de compensation sensorielle orienté sur le système olfactif se mettant en place très rapidement. Les conséquences comportementales d'une exposition aiguë du bar à l'ion métallique cadmium ont ensuite été examinées. Le cadmium à forte concentration dans l'eau de mer (5 µg.l-1) a un effet inhibiteur sur la réponse de fuite des poissons face à un danger. Cet effet comportemental s'accompagne de la destruction des deux types de neuromastes composant le système latéral. Après 21 jours, on constate une régénération des tissus des neuromastes, ainsi qu'une restauration du comportement de fuite des poissons. Par contre, lors de l'exposition aiguë au cadmium à la concentration rencontrée en milieu naturel contaminé (0,5 µg.l-1), le comportement de fuite du poisson n'est pas modifié et les tissus des neuromastes demeurent intacts. Cependant, les stimuli appliqués lors de cette étude pour simuler un danger étant relativement forts, on peut se demander si après une exposition aiguë au cadmium à 0,5 µg.l-1, le bar serait toujours capable de détecter le mouvement ténu d'une proie vivante mobile. Ce travail mériterait d'être poursuivi par des études visant à déterminer la concentration seuil de cadmium responsable de dommages tissulaires au niveau des neuromastes et celle causant des désordres comportementaux. Il serait également intéressant d'examiner l'effet synergique des ions métalliques présents dans le milieu naturel (cadmium, cobalt, cuivre, mercure, nickel, plomb, zinc, etc.…) sur le système latéral et le comportement du bar. [less ▲]

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See detailQuantitative aspects of the spatial distribution and morphological characteristics of the sea bass (Dicentrarchus labrax L.; Teleostei, Serranidae) trunk lateral line neuromasts.
Faucher, Karine ULg; Lagardère, Jean-Paul; Aubert, Anne

in Brain, Behavior & Evolution (2005), 65(4), 231-43

The results presented herein report quantitative data relative to the distribution and morphological characteristics of both types of neuromasts encountered on the trunk lateral line of the sea bass ... [more ▼]

The results presented herein report quantitative data relative to the distribution and morphological characteristics of both types of neuromasts encountered on the trunk lateral line of the sea bass (Dicentrarchus labrax, L.). These data were obtained from scanning electron micrographs. They indicate that, as expected, each modified scale of the sea bass possessed a single canal neuromast with long axis oriented parallel to the fish's long axis. In contrast to several fish species, two thirds of superficial neuromasts observed herein were oriented perpendicular to the fish's long axis. However, whatever the main orientation of superficial neuromasts, two thirds of their hair bundles were oriented parallel to the long axis of the animal with approximately half of them in the direction of the head. Similar ratios were observed for canal neuromasts whatever the area of the maculae: central or peripheral. For both types of neuromasts it was not possible to clearly distinguish a paired organization of hair bundles with opposing polarities. Superficial neuromasts on each trunk canal scale were located on either the dorsal or ventral side of the canal and appeared to be distributed along the trunk lateral line with a higher probability to be encountered closer to the operculum. The frequency of presence and the average number of superficial neuromasts per scale increased with fish size. We observed a size gradient for canal neuromasts between the operculum and caudal peduncle. This gradation was correlated with a reduction of the width of the central area of the canal segment. Canal neuromasts were always localized in the larger portions of the canal segments. Taken together, these results point out some specific features associated with the sea bass trunk lateral line. With the previous report, they establish the first full description of the trunk lateral line of sea bass and will be useful for upcoming experiments regarding the function of the two types of neuromasts. [less ▲]

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See detailSpatial distribution and morphological characteristics of the trunk lateral line neuromasts of the sea bass (Dicentrarchus labrax, L.; Teleostei, Serranidae).
Faucher, Karine ULg; Aubert, Anne; Lagardère, Jean-Paul

in Brain, Behavior & Evolution (2003), 62(4), 223-32

The morphology and spatial distribution of the different types of neuromasts encountered on the trunk lateral line of the sea bass (Dicentrarchus labrax) were examined using scanning electron microscopy ... [more ▼]

The morphology and spatial distribution of the different types of neuromasts encountered on the trunk lateral line of the sea bass (Dicentrarchus labrax) were examined using scanning electron microscopy. The sea bass trunk lateral line exhibits a complete straight pattern. In their basic features, the two types of neuromasts present, canal and superficial, resemble what has been described in other fishes. They are similar in their general cellular organization but differ in sizes, and shapes, as well as in the densities and lengths of their hair bundles. However, the sea bass trunk lateral line distinguishes itself in several ways. For instance, the pores of the canal segments are partially obstructed due to the overlap of scales throughout the trunk. Moreover, based on the density and length of the hair bundles, two distinct areas, central and peripheral, could be distinguished within the maculae of canal neuromasts. Their cupulae are also peculiar as they possess two wing-like extensions and that their central core appears to be organized in layers instead of columns. In addition, the superficial neuromasts, up to 6 per scale, are either round or elliptical and seem to be distributed serendipitously. Finally, within the maculae of both types of neuromasts, a significant number of hair bundles do not follow the two-directional polarity pattern usually described. Although some hypotheses are proposed, the influence of these characteristics in terms of signal encoding and fish behavior is yet to be understood. [less ▲]

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