References of "Nzau Matondo, Billy"
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See detailUsing intensive multiyear fish-pass monitoring to analyse seasonal upstream movement patterns of patrimonial holobiotic potomadromous fish species in a medium size river
Benitez, Jean-Philippe ULg; Nzau Matondo, Billy ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

Belgian rivers are fragmented by numerous obstacles which considerably limit the free access of fish to functional habitats. Fish-passes are major tools used to increase stream continuity and improve ... [more ▼]

Belgian rivers are fragmented by numerous obstacles which considerably limit the free access of fish to functional habitats. Fish-passes are major tools used to increase stream continuity and improve connectivity in the upstream direction. Using two modern multispecies fish-passes, this study aims to investigate multiyear abundance of holobiotic potamodromous fish and their seasonal movement patterns in relation with environmental factors. The fish passes were monitored continuously during 5 and 7 years and are located in two Belgian streams: the (19.3m³.s-1) and the Berwinne (1.9m³.s-1). Results revealed the presence of 20 different fish species, 14 species in the Berwinne and 19 species in the occurrence, salmonids and cyprinids species were predominant. A great interspecific and intraspecific variability in capture periodicity and in terms of stimulation by combination of factor environmental was observed. This study highlights the complexity and the omnipresence of holobiotic potamodromous fish movements at different life stages, in medium size river and brings new information on fish passes efficiency and use by these poorly known species. [less ▲]

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See detailArrival of european eel in Belgian Part of the Meuse: who and how are they?
Nzau Matondo, Billy ULg; Benitez, Jean-Philippe ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

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See detailA bit of quiet between the migrations: the resting life of the European eel during their freshwater growth phase in a small stream
Ovidio, Michaël ULg; Seredynski, Aurore ULg; Philippart, Jean-Claude ULg et al

in Aquatic Ecology (2013), 47

The movements and habitat use of resident yellow eels were studied in a stream stretch having both natural and minimum flow zones. N = 12 individuals (total length 505–802 mm) were surgically tagged with ... [more ▼]

The movements and habitat use of resident yellow eels were studied in a stream stretch having both natural and minimum flow zones. N = 12 individuals (total length 505–802 mm) were surgically tagged with radio transmitters and released at their capture sites. They were located using manual radio receivers during the daytime from 2 to 5 days/ week over periods ranging from 200 to 329 days, for a total of 1,098 positions. Eels showed home ranges ranging from 33 to 341 m (median value, 62 m), displayed strong fidelity to sites and demonstrated a great degree of plasticity in habitat use. Eels were slightly mobile throughout the year, but their movements were season and temperature dependent, with a maximum during the spring (mean water temperature, 12 C) and a minimum in winter (3 C). Stones and roots (utilization rate greater than 50 % of eels for more than 30 % of location days) were significantly the most frequently used habitats. Between the two flow zones, the natural flow was the most occupied, with a significantly higher proportion of resident eels(66.7 % of radio-tagged yellow eels) and longer occupation (81 % of location days) than the minimum flow zone with less suitable habitats. [less ▲]

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See detailSpawning behaviour and mating success in hybrids of silver bream (Blicca bjoerkna L.) and rudd (Scardinius erythrophthalmus L.) in an experimental environment
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

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 ▲]

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See detailEvaluation de la qualité biologique des rivières wallonnes sur base des indices biologiques poissons. Support technique aux inventaires 2012.
Rimbaud, Gilles ULg; Ovidio, Michaël ULg; Dierckx, Arnaud ULg et al

Report (2012)

Ce rapport a pour objectif l’évaluation de la qualité biologique des eaux de surface basée sur les indices biologiques « poissons » dans un certain nombre de cours d’eau de Wallonie. Il résulte d’une ... [more ▼]

Ce rapport a pour objectif l’évaluation de la qualité biologique des eaux de surface basée sur les indices biologiques « poissons » dans un certain nombre de cours d’eau de Wallonie. Il résulte d’une convention entre le Service public de Wallonie et l’Université de Liège. [less ▲]

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See detailA comparative study of sexual product quality in F1 hybrids of the bream Abramis brama X the silver bream Blicca bjoerkna
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

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 ▲]

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See detailReproductive performance in F1 hybrids of two phytophilous cyprinid fish, the silver bream (Blicca bjoerkna) x the rudd (Scardinius erythrophthalmusl
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

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 ▲]

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See detailEco-ethological characteristics of two natural hybrids of Abramis brama (L.) from the River Meuse basin
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Poncin, Pascal ULg et al

in Environmental Biotechnology (2010), 6(2),

Eco-ethology as expressed in migration patterns, abundance level, growth rates in river conditions, and reproductive behaviour in a controlled environment were investigated in natural common bream x roach ... [more ▼]

Eco-ethology as expressed in migration patterns, abundance level, growth rates in river conditions, and reproductive behaviour in a controlled environment were investigated in natural common bream x roach and common bream x silver bream hybrids. From 2001 to 2003, hybrids and parental species were captured in a fish pass trap at the Lixhe dam on the Belgian Meuse river during their reproductive migration. The fish pass was checked 3 days a week and the water temperature was recorded hourly. The results showed that hybrids were less frequent but they had migrated during the same period and in the same environmental conditions as the parental species. Scale readings showed that the growth of hybrids was intermediate to the two parent species growth. In reproductive experiments between hybrids under controlled conditions, the female hybrid mated with one to two hybrid males. In reproductive experiments with hybrids mixed with parental species males, the female hybrid mated with male hybrid and male roach or male silver bream, but not with the male common bream. The succession of spawning episodes in hybrids were those recognised in parental species. Aggressive and territorial acts were observed among the males of these hybrids in a territory including a spawning substrate. This study has proven that the natural hybrids are eco-ethologically viable. [less ▲]

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See detailEco-ethological aspects of two natural hybrids involving Abramis brama (L.), of the River Meuse basin (Belgium) and implications in ecosystem management.
Nzau Matondo, Billy ULg; Ovidio, Michaël ULg; Philippart, Jean-Claude ULg et al

Conference (2009, September)

Eco-ethology as expressed in migration patterns, hybridisation level, growth rates in river conditions, and reproductive behaviour in a controlled environment were investigated in natural common bream ... [more ▼]

Eco-ethology as expressed in migration patterns, hybridisation level, growth rates in river conditions, and reproductive behaviour in a controlled environment were investigated in natural common bream Abramis brama × roach Rutilus rutilus and common bream × silver bream Blicca bjoerkna hybrids. From 2001 to 2003, hybrids and parental species were captured in a fish pass trap at the Lixhe dam on the Belgian Meuse River during their reproductive migration. The fish pass was checked 3 days a week and the water temperature was recorded hourly. The results showed that these hybrids were less frequent but they had migrated during the same period and in the same environmental conditions as the parental species. Scale readings showed that the growth of hybrids was intermediate between the two parent species’ growth. In controlled environments, the female hybrid mated with one to two males, including male hybrids, in reproductive experiments between hybrids; they also mated with male hybrid and male roach or male silver bream, but without the male common bream in reproductive experiments with hybrids mixed with parental species males, in a succession of spawning episodes recognised in parental species. Aggressive and territorial acts were observed among the males of these hybrids in a territory including a spawning substrate. This study has proven that these natural hybrids are eco-ethologically viable. For the management of fish populations and aquatic environments, the hybridisation process can be considered an indicator of habitat degradation. This degradation can then be interrupted by preserving spawning sites, controlling the restocking and species introduction, restoring habitats, and preserving the obstruction of fish migration. [less ▲]

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