Video multitracking of fish behaviour: a review and future perspectives

in Fish & Fisheries (2013), 14(2), 186-204

With the development of digital imaging techniques over the last decade, there are now new opportunities to study complex behavioural patterns in fish (e.g. schooling behaviour) and to track a very large ... [more ▼]

With the development of digital imaging techniques over the last decade, there are now new opportunities to study complex behavioural patterns in fish (e.g. schooling behaviour) and to track a very large number of individuals. These new technologies and methods provide valuable information to fundamental and applied science disciplines such as ethology, animal sociology, animal psychology, veterinary sciences, animal welfare sciences, statistical physics, pharmacology, as well as neuro- and ecotoxicology. This paper presents a review of fish video multitracking techniques. It describes the possibilities of tracking individuals and groups at different scales, but also outlines the advantages and limitations of the detection methods. The problem of occlusions, during which errors of individual identifications are very frequent, is underlined. This paper summarises different approaches to improving the quality of individual identification, notably by the development of three-dimensional tracking, image analysis and probabilistic applications. Finally, implications for fish research and future directions are presented. [less ▲]

Spawning behaviour and mating success in hybrids of silver bream (Blicca bjoerkna L.) and rudd (Scardinius erythrophthalmus L.) in an experimental environment

in Animal Biology (2013), 63

The egg-release, mating, courting and aggressive acts for the spawning behaviour as well as the survival rates after spawning at stages of eyed embryos, viable hatchlings, and larvae to dry food ... [more ▼]

The egg-release, mating, courting and aggressive acts for the spawning behaviour as well as the survival rates after spawning at stages of eyed embryos, viable hatchlings, and larvae to dry food consumption for the mating success were studied in cultured silver bream Blicca bjoerkna × rudd Scardinius erythrophthalmus hybrids at their first sexual maturity. Experiments were conducted in experimental environments simulating natural reproductive conditions of the parental species. Spawning behaviour was analysed over 1 day from 8.00 to 18.00 hours using a remote-controlled video. Mating success was assessed from eggs and hatched embryos collected on the spawning ground. The results showed that these hybrids exhibited all the reproductive behaviours of the parental species with significantly more courtship than mating. Each egg-release act was accompanied by mating behaviour, involving all the experimental males. A surprising aggressive behaviour was observed in one male which attacked all other experimental fish. Successful mating resulted in the presence of fertilized eggs, the production of hatched embryos in experiments, and the survival of larvae at the dry food consumption stage. However, the low viable hatchling rate observed could indicate a very low chance of survival for these hybrids in rivers in which the occurrence of post-F1 individuals may be more possible by backcrossing. [less ▲]

A comparative study of sexual product quality in F1 hybrids of the bream Abramis brama X the silver bream Blicca bjoerkna

in Fisheries Science (2012), 78

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured ... [more ▼]

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured Abramis brama 9 Blicca bjoerkna F1 hybrids and compared with the parental species at their first sexual maturity. Females ovulated under environmental conditions, and their eggs were weighed, counted and measured. Semen of males was macroscopically examined and spermatozoa counted using a hemocytometer. Results revealed that hybridization affected the quality of female and male gametes but with an overlap between hybrids and parents. The gonadosomatic index and fecundity were significantly lower than those of parental species. Egg sizes in hybrids showed a parental effect but to the benefit of hybrids. Semen of hybrids was more diluted which was classified into two groups: the white semen overlapping slightly with parents and the aqueous without any overlap with parents. Overlapped areas between hybrids and parents in term of quality of sexual products could translate that females and males of these hybrids have the biological capacity to produce high quality gametes and thus, a greater chance to produce F2 and backcross generations in rivers. [less ▲]

Video multitracking to study the fish behaviour

Conference (2012, July 07)

With the development of digital imaging techniques over the last decade, there are now new opportunities to study complex behavioural patterns and rhythms in fish (from individual to collective group) and ... [more ▼]

With the development of digital imaging techniques over the last decade, there are now new opportunities to study complex behavioural patterns and rhythms in fish (from individual to collective group) and to track a very large number of individuals. These new technologies and methods provide valuable information to fundamental and applied science disciplines such as ethology, animal sociology, animal psychology, veterinary sciences, animal welfare sciences, statistical physics, pharmacology, as well as neuro- and ecotoxicology. Specifically in situations where a large number of individuals are involved, the use of video tracking data is essential, as manual analyses would be complicated, time-consuming and sometimes even impossible. Today, multitracking allows us to observe directly the behaviours of groups, and to determine the real interaction rules by sampling data collected in nature or in the laboratory, without any a posteriori rules as it was and is frequently the case in computer simulation of collective behaviours. With these technologies, the quantitative measures of collective behaviours is now easily accessible, and allow to define social behaviours with more accuracy than just qualitative criteria as is always the case for instance with the definition of shoaling and schooling behaviours. Firstly will be introduced a review of fish video multitracking techniques. This review describes the possibilities of tracking individuals and groups at different scales, but also outlines the advantages and limitations of the different detection methods. The problem of occlusions, during which errors of individual identifications are very frequent, will be discuss. Secondly, our recent contribution in colour-based multitracking will be introduced, notably the new application of fluorescent VIE (Visible Implant Elastomer) tags in automatic tracking technology to study the behaviour of transparent animals like glass eels (Anguilla anguilla) in dim light or in darkness. The method makes it possible to measure the activity (notably distance and speed) of four individuals as a function of tidal and nycthemeral rhythms in the same flume (circular aquarium simulating the river or estuarine conditions) across a wide time scale (from seconds to weeks) in the context of migration in estuary. [less ▲]

Reproductive performance in F1 hybrids of two phytophilous cyprinid fish, the silver bream (Blicca bjoerkna) x the rudd (Scardinius erythrophthalmusl

in Program and Abstracts of the XIV European Congress of Ichthyology (2012, June)

Reproductive performance including the spawning behaviour and quality of gametes in cultured F1 hybrids of two phytophilous cyprinid fish species, the silver bream Blicca bioerkno x rudd Scardinius ... [more ▼]

Reproductive performance including the spawning behaviour and quality of gametes in cultured F1 hybrids of two phytophilous cyprinid fish species, the silver bream Blicca bioerkno x rudd Scardinius erythrophtalmus was investigated in this study at their first sexual maturity. The spawning behaviour was studied in terms of egg release, courting and mating acts under reproductive conditions between hybrids or mixed with the silver bream males. Behavioural experiments were conducted in experimental environments simulating natural reproductive conditions of the species using the spawning ground, high temperature, mixing of sex, natural photoperiod and no hormonal injections. The quality of gametes was evaluated by analysing egg production, sperm density, and F2 and backcross offsprings. For the egg production, the gonadosomatic index, absolute fecundity and egg diameters were analysed at spawning. sperm density was estimated by counting spermatozoa in a hemocytometer. F2 and backcross offsprings were produced from eggs of the female hybrid fertilised with the sperm of a corresponding hybrid male and a male silver bream. The results revealed that these hybrids exhibited all the reproductive behaviours of the parental species with an intense courting activity. Each egg-release act was accompanied by mating activity, involving simultaneously and successively all the experimental males, hybrids and silver bream, resulting in fertilised eggs. The quality of female sexual products was close to that found in parental species. However, the male sexual products were found more diluted, and F2 generations produced with a significantly lower hatching rate than backcrosses. This study has proven that these FL hybrids have the capacity to exhibit all the reproductive behaviour as observed in the wild population of parental species. These hybrids are fertile and thus biologically viable. ln rivers, their backcrossed offsprings have a greater chance of occurring than F2 progeny. [less ▲]

Développement postembryonnaire du squelette céphalique en relation avec les changements morphologiques externes chez Labeo parvus (Ostariophysi, Cyprinidae)

in Cybium (2012), 36(2), 383-396

La pêche aux nasses dans le delta du fleuve Ouémé, Bénin : implications pour une gestion rationnelle des ressources halieutiques

Poster (2012)

Successful artificial reproduction of the African carp : Labeo parvus Boulenger, 1902 (Pisces : Cyprinidae)

in International Journal of Fisheries and Aquaculture [=IJFA] (2011), 3(3), 35-40

Essai d’estimation des dommages piscicoles engendrés par les prises d’eau industrielles et les turbines hydroélectriques dans les cours d’eau de la Province de Liège. Partie C. Le cours principal de l’Amblève non navigable.

Report (2011)

Ce rapport à la Commission provinciale de Liège du Fonds piscicole de Wallonie est un dossier bibliographique qui analyse l’impact sur les populations de poissons des centrales hydroélectriques (CHE ... [more ▼]

Ce rapport à la Commission provinciale de Liège du Fonds piscicole de Wallonie est un dossier bibliographique qui analyse l’impact sur les populations de poissons des centrales hydroélectriques (CHE) installées sur le cours principal de l’Amblève non navigable. Il s’agit d’un grand cours d’eau (module du débit : 20 m3/s dans le cours inférieur à Martinrive-Aywaille) constitué de zones à ombre et à truite qui abritent une importante biodiversité piscicole dont notamment des poissons migrateurs amphihalins comme l’anguille européenne, la truite de mer et le saumon atlantique en cours de réintroduction en Wallonie.L’évaluation des impacts piscicoles des CHE se limite à une approche très préliminaire consistant à apprécier de manière théorique (par rapport à des modèles élaborés en France) les ordres de grandeur des entraînements vers les turbines et des mortalités des populations migratrices (surtout les anguilles argentées et les smolts de Salmonidés) attendues sur les différents sites, compte tenu des caractéristiques connues des prises d’eau (grilles), des turbines (Kaplan, Francis, Banki ; grandeur des roues, vitesse de rotation, débit turbiné), de la taille des poissons et des possibilités de dévalaison par une voie autre (déversoir de barrage, exutoire de dévalaison) que le passage dans les turbines. Partant de ces premiers résultats, le rapport détaille les actions à entreprendre sur chaque site hydroélectrique pour le rendre moins pénalisant pour les poissons migrateurs en dévalaison et dans certain cas, en montaison comme à la cascade de Coo. Il propose aussi quelques recommandations générales applicables à l’évaluation objective de l’impact piscicole de tout site hydroélectrique et à l’atténuation de cet impact. Ainsi, en matière biologique et piscicole, il apparait prioritaire de mettre en place des programmes d’études permettant : i) de caractériser qualitativement (taille des poissons et périodicité des mouvements) et surtout quantitativement (effectifs numériques et biomasse) les migrations de dévalaison des principales espèces cibles dans les cours d’eau concernés des zones à ombre et à truite et ii) d’estimer les mortalités réelles des poissons dans les différents types d’installation de production d’hydroélectricité. [less ▲]

Evaluating radical conservation futures: strategies for assessing the potential for Eurasian lynx in the Benelux countries

Poster (2011, July 08)

Tolerance of anthropic environment has allowed large carnivores to recolonize and to be reintroduced within Europe in the last forty years. This indicates that, even in areas where the return of large ... [more ▼]

Tolerance of anthropic environment has allowed large carnivores to recolonize and to be reintroduced within Europe in the last forty years. This indicates that, even in areas where the return of large carnivores seems unlikely, their presence and establishment is possible, even in highly modified environments. In the current context of the return of large carnivores in Europe, there is a need for scientific conservation tools to assess the full potential and consequences of the return of large carnivores in Europe, and in particular to evaluate potential impact on game and livestock. Today, the return of the Eurasian Lynx (Lynx lynx) in areas where it has been absent for long periods is becoming increasingly probable, and this requires further investigations. Three main lines of research will be particularly important: the use of habitat by Eurasian Lynx, the effect of habitat on predation behavior, and potential sources of conflict with human populations. The research project will address fine scale habitat use, the effect of prey‘s spatial variation on Lynx predation behavior, the use of different statistical methods to estimate Lynx‘s viability in various habitats and landscape, and a review of current conflicts throughout Europe. Results should allow better understanding of the Lynx redeployment potentials in lowland Western Europe [less ▲]