Home About us Contact
|
Home About us Contact | ||
|
|
||
Silver Bream (silver + bream)
Selected AbstractsRole of habitat degradation in determining fish distribution and abundance along the lowland Warta River, PolandJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007A. Kruk Summary The distribution and abundance of fish collected in 1996,1998 are compared in three river sections X, Y and Z in the 808-km-long Warta River, Poland. The upper section, X, was least human-modified, the middle section, Y, was the most polluted by industry and regulated, and the downstream section, Z, was moderately disturbed. The differences between X and Y in concentrations of dissolved oxygen, volatile phenols and nitrite nitrogen, and in the index of availability of hiding places, were highly significant because these parameters were several times worse in the Y section; in the Z section they assumed intermediate values. Although the abundance of certain fish species was changing along the downstream river gradient (i.e. differed the most between X and Z), both the Kohonen artificial neural network (SOM) and assemblage indices showed the biggest differences between X and Y, thus confirming the crucial role of the degradation of aquatic environment in shaping fish assemblages. The latter result ensued from the reaction of the rheophilic burbot, stone loach, gudgeon, chub and dace, which were most abundant in X, almost absent in Y and reoccurring in Z (although less numerous when compared with X). The opposite was recorded for mud loach, tench, ide and silver bream, which were most abundant in the degraded section Y, probably because of weak competition with the almost-absent rheophils. The abundance of two generalists, roach and pike, was similar in all three sections, i.e. changed neither along the downstream nor in the degradation gradient. [source] An in situ estimate of food consumption of five cyprinid species in Lake BalatonJOURNAL OF FISH BIOLOGY, Issue 5 2002A. Specziár Daily rations of five cyprinid species, bream Abramis brama, silver bream Blicca bjoerkna, roach Rutilus rutilus, gibel Carassius auratus gibelio and carp Cyprinus carpio, in Lake Balaton, a large shallow lake, estimated by the Eggers model differed from that of the Elliott , Persson model by only , 4.3 to +7.3% (the differences were insignificant). Daily rations varied within the range of 0.23,0.69 in bream, 0.55,3.61 in silver bream, 0.69,4.65 in roach, 0.38,3.16 in gibel and 0.50,9.74 g dry 100 g wet fish mass,1 day ,1 in carp at temperatures ranging from 8.7,25.8% C. Daily ration was related exponentially with temperature in silver bream, roach, gibel and carp. For bream, a significant relationship was obtained only when a daily ration value was excluded from the analysis. Annual rations were assessed using the relationships between the daily ration estimates from the Elliott,Persson model and water temperature, and the long-term averages of the monthly water temperature data. From these estimates the bream population consumed 104%, silver bream 424%, roach 487%, gibel 363% and carp 913% dry mass of food of its wet biomass annually. [source] Nutritional regulation of intestine morphology in larval cyprinid fish, silver bream (Vimba vimba)AQUACULTURE RESEARCH, Issue 12 2008Teresa Ostaszewska Abstract The present study includes the evaluation of morphological changes in the digestive tract of larval, stomachless fish silver bream (Vimba vimba) fed with various diets , live Artemia nauplii, commercial feed Aglo Norse (NOR) and semi-purified formulated diets: casein,gelatin (CG), dipeptide-protein (50P), dipeptide (100P), no-arginine dipeptide diet (100Pw/oArg) and a free amino acid (FAA) mixture diet. The supranuclear area of enterocytes in the posterior intestine contained enlarged absorptive vacuoles in the FAA, 100P and 100Pw/oArg groups, compared with the remaining groups. Hepatocytes' cytoplasm in fish fed with FAA, 100P and 100Pw/oArg contained mainly glycogen, and no lipid vacuoles were found. Fish fed with 100Pw/oArg showed the lowest hepatocyte surface areas while in those fed with 50P, the largest nuclei diameters were observed. Fish fed with Artemia, NOR and CG diets showed significantly (P<0.05) higher number of proliferating cells compared with the remaining groups. Chromogranin A staining showed endocrine-immunoreactive cells (CgA-IR) in the taste buds in the oral cavity and in the enterocytes' supranuclear areas of the anterior and posterior intestine. We conclude that the growth rate and histological examination of the digestive tract in the 50P group of silver bream showed no nutritional deficiency. [source] | ||||||||||