Annual development cycle of gonads of bream (Abramis brama L. 1758) females from the lower Oder River sections influenced differently by the heated effluents from a power station

2015 ◽  
Vol 31 ◽  
pp. 41-48 ◽  
Author(s):  
J. Domagała ◽  
L. Kirczuk ◽  
M. Pilecka-Rapacz
1979 ◽  
Vol 36 (8) ◽  
pp. 883-890 ◽  
Author(s):  
Per-Edvin Persson

The study area was a shallow, extremely eutrophic, somewhat brackish water bay on the south coast of Finland. Muddy odor in bream (Abramis brama) was significantly correlated with the amount of the blue-green alga Oscillatoria agardhii occurring in the phytoplankton. Cultures dominated by this alga contained the muddy odor compound geosmin. The high concentrations of O. agardhii in the study area were caused by several interacting factors, of which the high nutrient concentration and the temperature of the water seemed to be especially important. Odoriferous actinomycetes isolated from the water produced the muddy odor compounds geosmin and 2-methylisoborneol, but there seemed to be a lag time of several weeks between maximal concentrations of actinomycetes and development of off-flavors in the fish. Key words: geosmin, 2-methylisoborneol, Oscillatoria agardhii, actinomycetes, flavor, fish, eutrophication


2009 ◽  
Vol 59 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Michaël Ovidio ◽  
Jean-Claude Philippart ◽  
Billy Nzau Matondo ◽  
Pascal Poncin

AbstractThe egg release–mating comparison, heterospecific matings and mating success under two hybridization conditions – (i) mixing one sex per species and (ii) mixing both sexes from each species – were investigated to determine whether silver bream Blicca bjoerkna and common bream Abramis brama can hybridize in nature.The results revealed that non-matings in hybridization experiments of silver bream females × common bream males can be explained by territorial and aggressiveness activities observed in common bream. In common bream females × silver bream males, heterospecific matings were observed but their numbers were significantly lower than the spawning numbers, and in this experiment, a female mated with one to four heterospecific males. In mixing both sexes from both species, similar spawning – mating numbers were observed but heterospecific matings accounted for only 27% of the total matings, with 24% accounting for heterospecific matings between common bream females and silver bream males, directly or by opportunism. Mating success was characterized by the occurrence of fertilized eggs after matings.Natural hybridization occurred preferentially between common bream females and silver bream males.


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