Domestication et comportement chez les poissons téléostéens

National audienceOne of the major objective of domestication is the selection of lines with low aggressiveness and a high growth potential. Analyses of domesticated animals traits often illustrate numerous changes in behaviour due to rearing environment. However there are few reports of these changes in fish. In the present paper, we first describe how behaviour is affected by rearing and then discuss how sensory organs and behavioural abilities are modified during development under breeding conditions. Rearing conditions modify feeding behaviour particularly because food distribution do not necessary follow biological rhythm and food is often available in larger amount compared to wild-type situations. In particular food distribution mode may favour aggressiveness. Rearing conditions (stream, fish density...) are also susceptible to modify spatial distribution of fish and relationship between fish in their closed environment. In particular, fish often reduce their inter-individual distances which may also have detrimental influences on their aggressiveness. Several behavioural abilities seem to be affected by development in breeding conditions and this appears to be related to modification of sensory organs. This includes modification of the lateral line system, eye and smell. These modifications are often associated to a lowering of watchfulness threshold which in turn modifies behaviour and particularly escape responses from potential predators. A modification of chromatic adaptation has also been shown for flat fishes. In conclusion, the analysis of behavioural modifications is of utmost importance to identify indicators of domestication progress which must be taken into account to guarantee cultured fish welfare and thus rearing sustainability.Un des principaux objectifs de la domestication est de sélectionner des lignées à haut potentiel de croissance et à faible agressivité. L’étude des caractéristiques des animaux domestiqués montre souvent de nombreux changements comportementaux dus aux conditions d’élevage, mais très peu de données sont disponibles chez les poissons. Cet article décrit d’abord comment la mise en élevage affecte certains comportements, notamment alimentaires et natatoires, puis présente les modifications, au cours du développement, des organes sensoriels et des aptitudes comportementales. Concernant le comportement alimentaire, les modifications sont principalement dues au fait que la distribution d’aliment ne correspond pas nécessairement au rythme biologique des poissons et que la quantité d’aliment disponible est souvent bien supérieure en élevage comparé au milieu naturel. Le mode de distribution peut également influencer l’agressivité. Les conditions d’élevage (courant, densité animale …) peuvent avoir des conséquences sur l’agressivité des poissons, en modifiant leur répartition spatiale, avec en particulier une réduction de la distance interindividuelle. Le développement des poissons en milieu d’élevage semble affecter certaines aptitudes comportementales en relation avec des modifications de leurs organes sensoriels (yeux, ligne latérale et odorat). Ces modifications sont généralement associées à une diminution de la vigilance avec notamment des conséquences sur la capacité à échapper aux prédateurs potentiels. Chez les poissons plats, le maintien en élevage modifie également l’adaptation chromatique. En conclusion, l’analyse des modifications comportementales induites par la domestication est un outil nécessaire pour identifier les facteurs à prendre en compte afin d’identifier la mise en place du processus de domestication, de garantir le bien-être des poissons et ainsi la durabilité du système d’élevage

Allis shad (Alosa alosa) exhibit an intensity-graded behavioral response when exposed to ultrasound

[Departement_IRSTEA]MA [TR1_IRSTEA]QSA / DYMECOInternational audienceMost fish cannot hear frequencies above 3 kHz, but a few species belonging to the subfamily Alosinae (family Clupeidae) can detect intense ultrasound. The response of adult specimens of the European allis shad (Alosa alosa) to sinusoidal ultrasonic pulses at 70 and 120 kHz is tested. The fish showed an intensity-graded response to the ultrasonic pulses with a response threshold between 161 and 167 dB re 1 µPa (pp) for both frequencies. These response thresholds are similar to thresholds derived from juvenile American shad (Alosa sapidissima) in previous studies, supporting the suggestion that these members of Alosinae have evolved a dedicated ultrasound detector adapted to detect and respond to approaching echolocating toothed whales

Allis shad (Alosa alosa) exhibit an intensity-graded behavioral response when exposed to ultrasound

[Departement_IRSTEA]MA [TR1_IRSTEA]QSA / DYMECOInternational audienceMost fish cannot hear frequencies above 3 kHz, but a few species belonging to the subfamily Alosinae (family Clupeidae) can detect intense ultrasound. The response of adult specimens of the European allis shad (Alosa alosa) to sinusoidal ultrasonic pulses at 70 and 120 kHz is tested. The fish showed an intensity-graded response to the ultrasonic pulses with a response threshold between 161 and 167 dB re 1 µPa (pp) for both frequencies. These response thresholds are similar to thresholds derived from juvenile American shad (Alosa sapidissima) in previous studies, supporting the suggestion that these members of Alosinae have evolved a dedicated ultrasound detector adapted to detect and respond to approaching echolocating toothed whales

Methodologies for investigating diadromous fish movements: conventional, PIT, acoustic and radio tagging and tracking: chapter 12

International audienceMethods to study the migratory behaviourr of fish can be divided in two categories: capture-dependent (based on sampling marked or unmarked fish) and capture-independent methods, such as visual or video observation, resistivity fish counters or hydroacoustics. In this chapter we focus only on capture-dependent methods using marked fish

Methodologies for investigating diadromous fish movements: conventional, PIT, acoustic and radio tagging and tracking: chapter 12

International audienceMethods to study the migratory behaviourr of fish can be divided in two categories: capture-dependent (based on sampling marked or unmarked fish) and capture-independent methods, such as visual or video observation, resistivity fish counters or hydroacoustics. In this chapter we focus only on capture-dependent methods using marked fish

Upstream migration and reproductive patterns of a population of allis shad in a small river (L’Aulne, Brittany, France)

 The characteristics and activity of adult allis shad [Alosa alosa (L.)] were analysed during the last part of their upstream migration in the L'Aulne, a small river in Brittany, and during reproduction on a unique spawning ground downstream of an insurmountable dam. The age of the spawners ranged from three to seven years, females being larger and older than males. Population-level migration and reproduction were studied by counting the number of migrating fish, by estimating the sex ratio, and by counting the number of nocturnal spawning acts for three consecutive years starting in 2000. The influence of the environment, especially water temperature and discharge, was highlighted: temperature during migration may supplant the influence of water flow, although high flow could allow passage over the dam. Such factors partly explain the annual pattern of migration and reproduction during the spawning season. The study showed that the biological features and characteristics of this population of allis shad in a small river were similar to those of western Atlantic stocks in large river

Analyse à long terme des demandes alimentaires d'une population de bar (Dicentrarchus labrax) en situation d'auto-nourrissage : incidence de l'activité manipulatrice individuelle sur l'alimentation du groupe

National audienc

An assessment of the upstream migration and reproductive behaviour of allis shad (Alosa alosa L.) using acoustic tracking

 We provide a detailed description of the migratory and reproductive behaviour of allis shad (Alosa alosa L.), a species that is in decline in Europe. Adult swimming behaviour during the last part of upstream migration and on a spawning ground downstream of an insurmountable dam was studied in detail and its main features identified, “characterized” in this context. Mobile telemetry and a fixed telemetry system were used to record fish positions and to monitor 23 acoustically tagged individuals (17 females and six males) during the 2001 and 2002 reproductive seasons. Allis shad showed considerable exploratory behaviour, and a rest area was observed 1.5 km downstream of the spawning ground. Thirteen individuals were observed on the spawning area, though both males and females spent most of their time (70–99%) away from it. Male and female residency times on the spawning area were, respectively, 1–11 days and 1–7 days, and females were observed during both day and night on the spawning ground. In 2002, an analysis of the 3D swimming behaviour on the spawning ground of six individuals allowed us to estimate the number of spawning events per fish. Males participated in more spawning acts (up to 60) than females (0–2

Feed demand behavior in sea bass juveniles : effects on individual specific growth rate variation and health (inter-individual and inter-group variation)

International audienceFeeding motivation is one major indicator of fish welfare and an investigation on the link between feed demand, growth and physiological variables in sea bass juveniles was developed. A computerized on-demand feeding system coupled with a PIT tag monitoring device was used to continuously record for 219 days the triggering activity of 150 individuals (initial average body weight 131.6 +/- 1.80 g and coefficient of variation 16.8%). Each group was held in 400 1 tanks at 22.2 +/- 1.5 degrees C and light regime was 16:8 LD. In all the tanks, 89% of the fish actuated the trigger, but only two or three fish accounted for 45% of the total triggering activity. These few high-triggering individuals had a transient higher growth i.e. at the time an individual was the high-triggering fish in the tank, its Specific Growth Rate (SGR) increased and was higher than that of the other fish. However, high-triggering fish did not exhibit a higher initial and final body weight nor a higher average SGR than low- and zero-triggering fish. Fish of different triggering categories did not show differences in physiological variables (muscle composition, blood and tissues biochemistry). This study also revealed that when an imbalance between apparent daily feed tank consumption and feed demand was observed (i.e. wastage), it was mostly due to an increasing demand rather than a decreasing consumption; such wastage could often be linked to particular stressors (measuring day, population sampling or social interactions) and therefore, feeding motivation disturbances could be a relevant operational fish welfare indicator. (C) 2007 Elsevier B.V. All rights reserved