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Nikolova L.,Institute of Fisheries and Aquaculture
Bulgarian Journal of Agricultural Science | Year: 2013

The study was conducted in two consecutive years in the Fisheries and Aquaculture Institute - Plovdiv. For the needs of ecologo- and bio-friendly fish farming, the impact of some factors on the growth of carp fish reared in polyculture, based on a natural nutritive basis, have been investigated. Rearing in autochthonous polyculture led to satisfactorily fish growth. The polyculture structure is a significant source of common carp growth variation, as the impact decreases when taking into account intense vegetation in the pond, and increases when taking into account the size of the pond. Common carp had better growth in one-year polyculture. The polyculture structure had no impact on bighead carp growth. One-year old grass carp grew more intensively compared to two-year old grass carp. Fertilization is a significant source for growth variation, but the impact is specific for the different species. Positive effect of the factor is established only for bighead carp. Significant sources for growth variation in all studied species are pond size and macrophytes density level.

A comparative slaughtering analysis has been carried out at the Institute of Fisheries and Aquaculture, Bulgaria upon two-summer old silver carp, reared in polyculture (H. molitrix 300 p-ces.ha-1 and C. carpio - 2000 p-ces.ha-1) under the conditions of integrated with ducks (Peking ducks and mule ducks) and non-integrated technologies. The fish in all experimental ponds have grown well and no considerable difference has been observed between the separate variants as regards the final live weight. The integration has exercised a positive (F=4.182; P<0.005) effect upon the slaughtering output, however, this effect has not been preserved as regards the relative fillet share within the fish carcass (F=0.096; P<0.05).

An investigation upon the daily dynamics of the separate elements of mule ducks behavior has been carried out at the Institute of Fisheries and Acuaculture Plovdiv, Bulgaria, applying the schedule of feeding with full-ration factory-made mixtures, at conditions of integrated fish-ducks technology. Ducks used to enter the water for a short time, and the time for swimming reported has been 9.63 min.h1 while the time spent at rest in the water has not surpassed 2.5 min.h-1. Age differences concerning behavior have been observed. With the advance of the fattening period, in general, the motion activity has decreased, ducks have reacted weaker to forage supply, and the forages have been consumed more actively during the morning hours. The tested technology has ensured good rearing conditions of mule ducks, however, the influence of ducks upon fishpond ecosystem was minimal.

Belabed B.-E.,Annaba University | Laffray X.,University of Franche Comte | Dhib A.,Institute National Des Science Et Technologies Of La Mer Instm | Fertouna-Belakhal M.,Institute of Fisheries and Aquaculture | And 2 more authors.
Marine Pollution Bulletin | Year: 2013

This paper presents the results of a seasonal survey of heavy metals accumulated in sediments and in the soft parts of the body of the mussel Perna perna at four stations in the Gulf of Annaba (Algeria). Pooled soft tissues from 10 mussels representing the entire range of sizes were digested in nitric acid. Statistical analysis reveals a significant seasonal effect on all the measured metals, the highest values being recorded in winter. With the exception of Cr, the levels for all metals were significantly higher in the east, at the outlet of the Seybouse River, than at all other monitoring stations. The study also shows that north-western waters are subject to a significantly lower degree of heavy metal pollution than elsewhere in the gulf. Levels were nevertheless within the limits of public health standards. The results confirm the usefulness of P. perna as a bioindicator for heavy metal pollution. © 2013 Elsevier Ltd.

Nikolova L.,Institute of Fisheries and Aquaculture
Journal of Environmental Protection and Ecology | Year: 2012

Loading of fishponds with organic matter in integrated rearing offish and ducks of the Peking breed and mule ducks was studied at the Institute of Fisheries and Aquaculture - Plovdiv. The stocking density of ducklings was 340 pes ha-1 The coefficient of loading (M) was used for establishing the pond loading: Mathmatical Equation Repersented where N is the mean number of ducks in the rotation; t - rotation length in days; W-average live weight of the ducks for the growing period, kg; 96 g - the amount of the manure released for a day by 1 duck per kg of live weight; P - pond surface area, ha; r- relative stay of the ducks in water out of the active time of days. It was established that using ducks of different genotypes had a significant effect (P<0.05) on the levels of the organic matter accumulated in the pond. The ducks of the Peking breed gained in weight more intensively and in 3 out of the 4 periods of study they had a higher live weight than the mule ducks. However, the time the ducks spent in water played a significant role for pond loading. In the period of study the Peking ducks spent in water 2 times more time compared to the mule ducks. That caused the release of twice bigger amount of manure in the fishpond.

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