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An important stage in artificial reproduction in fish of the families Acipenseridae and Cyprinidae is the elimination of adhesiveness of egg process. International studies recommended a variety of substances used against adhesiveness of eggs but do not differentiate the major advantages and disadvantages of their use. The present experiment aimed to determine the effects of de-adhesion with mineral silt, talcum and tannin. The final results regarding the effect of the substances used for deadhesion on embryogenesis were determined by qualitative assessments, and the fungal infestation was quantitatively quantified by the percentages of fish eggs infested with Saprolegnia sp. in relation to the fertilization percentages. The present work emphasizes that the use of tannin for de-adhesion of fish eggs (B3) not only provides medium-good transparency in embryogenesis, but also reduces the risk of fungal infestation by 12.55% compared to de-adhesion with silt (B1), 13,56% with talcum (B2), with comparable fertilization percentages of 87% in B1, 86.9% in B2 and 89.4% in B3, which recommends it for deadhesing of eggs and reducing fungal attacks in aquaculture. [ABSTRACT FROM AUTHOR]

The experiment aimed to evaluate the plasticity of juvenile Russian sturgeon (Acipenser gueldenstaedtii, J. F. Brandt & Ratzeburg, 1833) reared in a floating cage located on a pond. The biological material was 1400 juvenile Russian sturgeon with a mean weight of 9 g/fish and 40 days of age. The intensive rearing system was a 5x5x3 m floating cage in a pond. The fish were fed NUTRA MP-L extruded feed containing 52% crude protein and 20% fat three times a day. The experimental results showed a 64% survival of Russian sturgeon juveniles and the evaluation of productive bioindicators demonstrates high technological plasticity at 50% of the tested group. From the analysis of rearing conditions (environmental and technological), it was concluded that Russian sturgeon juveniles show a certain degree of plasticity depending on the adaptability of the Russian sturgeon to the different environmental conditions which depend principally on the anatomy and physiology of the species Acipenser gueldenstaedtii. [ABSTRACT FROM AUTHOR]

This study aims to contribute to the identification of the ichthyofauna structure for the most important fish species in the Danube River, sector km 1047-1071 by quantifying the data obtained during 2021 through scientific fishing, compared to the studies carried out in 2020. The purpose of this work is also to analyze the influence of environmental factors on catches and the structure of the ichthyofauna. Compared to 2020, the appearance of the species Hypophthalmichthys molitrix (Valenciennes, 1844) in catches and changes in the ratios between catches per species and fishing seasons can be noted. Both temperature and water level showed variations in correlation with total catches. Water levels and flows show a direct correlation with both the number of specimens caught and the catches. [ABSTRACT FROM AUTHOR]

The importance of feeding live food in the first stages of fish life is crucial, because the organism is not fully developed, the accessory glands and the enzymatic equipment of the digestive tract are also insufficiently developed. Natural food brings a supply of vitamins, enzymes, and hormones with a major role in the process of digestion and absorption of the food, very important in the ontogenetic development and in increasing the immunity of fish in the larval and postlarval stages. Internationally, over the years, numerous studies have been carried out on the feeding of fish with Artemia, but the present study aims to optimize the process of feeding Artemia nauplii to freshwater fish reared in a recirculating system. This brine shrimp can survive a limited amount of time in fresh water, after which it rapidly decomposes and, due to its high protein content, becomes a water pollutant for the recirculating system. From the point of view of the costs for cyst decapsulating and the energy costs for hatching, they are too costly to afford feeding "ad libitum" with nauplii the fish larvae. The use of the minimum amount of live Artemia nauplii depends on the resistance of the nauplii in fresh water, expressed in a maximum time interval of 3.5 hours, after which vital activity and very low survival are recorded. The optimal Artemia nauplii feeding requirement of starry sturgeon with an average weight of 0.26±0.15 g and an average length of 3.78±0.8 cm is about 2.26% B.W. representing a maximum of 4.5 g wet mass of nauplii administered per 1,000 of larvae daily. [ABSTRACT FROM AUTHOR]

The salmonids represent a valuable food source for humans, thanks to a high nutritional value and digestibility. In recent times, the authorities are preoccupied with insuring the health and wellbeing of the consumers, by obtaining high quality, healthy and safe aquaculture products. The aim of this paper is health status monitoring for rainbow trout (Oncorhynchus mykiss), during the disease caused by Yersinia rukeri, quantified through the biochemical composition of the meat. Yersiniosis is a illness that leads to significant economical losses in aquaculture industry. The biological material – rainbow trout Oncorhynchus mykiss – was monitored monthly for 7 months. The biochemical analysis of trout meat was realized at the moment of identification of pathogenic bacterium Yersinia rukeri through microbiological methods, after 15 days following a 10 day treatment with antibiotics. The experiment demonstrated that the disease state compromises growth performance and nutritional value of the infected biological material. However, the results indicated that after a 15 day period following the treatment, the maintenance status of rainbow trout will get better, without recovering the weight loss determined by the disease. [ABSTRACT FROM AUTHOR]

Pontic shad is one of the most important species for industrial fishing and one of the most appreciated fish given its organoleptic qualities, having a particularly fine meat taste and a high percentage of fat. The purpose of this paper is to assess the condition of Pontic shad flocks that arrived in the breeding areas in 2020. The morphometric characteristics, the sex ratio, the age and the growth parameters for the Pontic shad from the Smârdan - Gropeni area, Brăila county were studied. A number of 50 specimens of Pontic shad were examined during April-May 2020. The sex ratio in the analysed group was 56% females and 44% males. The smallest males were 2 years old, measured 26 cm and weighed 150 g, while the largest specimens were 3 years old with a total length of 33 cm and a weight of 275 g. The average length of the males was 30.214 ± 1.608 cm and the average weight was 215.952 ± 35.410 g. The smallest females measured 30 cm, weighed 220 g and were 2 years old and the largest specimens were 5 years old, they had 37 cm and 450 g. The average length of the female specimens was 33.357 ± 1.870 cm and the average mass was 328.571 ± 64.792 g. Analysing the population structure and the Fulton coefficient, we appreciate that in 2020, in the studied breeding areas, the Pontic shad flocks, in which females over 3 years of age predominated, had a good state of maintenance. [ABSTRACT FROM AUTHOR]

Fish production carries risks due to infectious diseases, unbalanced diet and environmental challenges which compromise fish welfare. Consumers demand a healthier and safer food and nutritionists recommend a diet low in saturated fat and rich in polyunsaturated fatty acids. The aim of this research is to investigate how diets supplemented with fatty acids affect the disease resistance of the carp species (Cyprinus carpio) 1 year of age, reared in a recirculating system. The experiment was performed in the recirculating pilot system, over a period of 2 months, using 120 specimens of carp (Cyprinus carpio) and three experimental feeding diets, supplemented with oils from various sources, rich in unsaturated fatty acids. In the experimental groups there were no mortality due to the use of oils rich in fatty acids that have the property to increase the immune system of the fish, compared to the control group where the survival was 86.66%. In the three experimental groups, at the end, a slightly higher level of proteins is observed in group T3 (18.18 g%), compared to group T2 (17.7 g%) and T1 (17.75 g%), the difference being proportional to the weight gain, but the difference is insignificant (p>0.05) which suggests the almost similar evolution of biological material in protein retention, regardless of the source of fatty acids. The feed conversion ratio and protein efficiency improved with the addition of lipids in the feeding diets. The addition of oils to feeding diets resulted in an increase in blood parameters measured in the experimental groups (PCV, Hb, Erythrocyte, MCV, MCH and MCHC), compared to parameters monitored at the beginning of the experiment and at the end of the experiment in the control group fed without oil supplements. [ABSTRACT FROM AUTHOR]

In Romania, Pontic shad (Alosa immaculata) is a fish with a high commercial value, with an average annual catch of 200-500 tons, according to ANPA statistics. The shad meat is appreciated for its fine taste, but also for its fat, which is made up of polyunsaturated fatty acids. The aim of this study is to bring new data on biological parameters, maintenance status and biochemical composition of Pontic shad (A. immaculata), during the period of maximum migration (April), on the Danube section the river mouth, where it flows into the Black Sea, and the point km 197, in Braila county. The samples were taken from 3 different points: St. Gheorghe arm (station 1), Isaccea village, Tulcea county at km 103 of the Danube (station 2) and Chiscani village, Braila county at km 197 of the Danube's mouth (station 3). The age of fish ranged from 3 to 5 years. The most abundant specimens are groups aged 3 years (40%) and 4 years (36%). The gender structure of catches is represented by 53% females and 47% males. The Fulton condition factor had values between 1.13 and 1.28, with the highest value at the beginning of the migration, in the area of the St. Gheorghe arm (1.28) and the lowest value (1.13) at 197 km from the Danube's mouth, in the intermediate area, at km 103 the value being 1.15. The percentages of lipids in the meat of the Pontic shad taken from stations 2 and 3 were relatively equal, of 17.62%, respectively 17.65%, the highest value being registered in station 1, at St. Gheorghe, where the value was 18.60%. The percentage of proteins for the biological material from Station 1 -- St. Gheorghe was 0.4% lower than that of the samples taken from Station 2 - Isaccea, km 130 and 0.85% lower than that from Station 3 - Chiscani, km 197, the differences being insignificant (P> 0.05). [ABSTRACT FROM AUTHOR]

The aim of this study is the comparative analysis of the anatomical components and the biochemical profile of one-year-old Oncorhynchus mykiss specimens, reared in recirculating system and in earth ponds. The analysis was performed by portioning the biological material in the main anatomical sections, followed by determining the biochemical parameters (moisture, ash, proteins and lipids), through standard methods of analysis corresponding to each parameter. Rainbow trout reared in a recirculating system has the meat percentage by 8.43%, the protein percentage by 19.93% and the fat percentage by 26.29% higher, compared to the rainbow trout reared in earth ponds. Rearing rainbow trout in a recirculating system is advantageous both due to the high production and the high quality of its biological value. [ABSTRACT FROM AUTHOR]

This present paper has the purpose to analyze the influence of environmental factors on catches and family structures of fish in the Danube River, sector km 1020 - km 1071. The biological material was collected from the autumn fishing between August and November 2019. During the four months, following the scientific fishing, 1.250 fish specimens belonging to 7 species were collected. The dominant family, Cyprinidae with a percentage of 74%, is represented by four species, namely Cyprinus caprio (carp), Carassius gibelio (crucian), Abramis brama (bream), Ctenopharyngodon idella (grass carp), followed by the family Percidae with a percentage of 23% represented by two species Sander lucioperca (pikeperch) and Exos lucius (pike), and the family Siluridae with a percentage of 3% represented by Silurus glanis (catfish). Both temperature and water levels were raised in correlation with total catches. [ABSTRACT FROM AUTHOR]

The main objective of the present paper was to evaluate the influence of the commercial probiotic BetaPlus® Ultra on the growth performance of the stellate sturgeon after 35 days of hatching, but the specific objective was to evaluate the food retention efficiency in the transition period from feeding with natural feed to that with commercial feed. For this purpose, a 93-day experiment was carried out with 6 experimental variants (5 different probiotic concentrations : V 1-1.28x1013 CFU, V2-2.56 x1013 CFU, V3 -3.84x1013 CFU, V4 - 5.12x1013 CFU, V5 -6.4x1013 CFU and V6- control variant, in duplicates). The experiment started with a number of 6000 exemplars of 35-day post hatched larvae (500 specimens/rearing unit) with a mean individual weight (± SD) of 0.35 ± 0.02 g and a total length between 3-5 cm. According to the rearing technology, sorting was carried out throughout the experimental period which led to the division of the experiment into 9 different experimental stages according to feeding protocol. Feeding efficiency, expressed by FCR and protein retention, indicated by PER shows an insignificant increase (p> 0.05) in the V2 variant and an insignificant decrease in the case where the probiotic (V6) was not administered. Therefore, according to this experiment, a concentration of 2.56x1013 CFU / kg of commercial probiotic BetaPlus® Ultra represents an optimum value for promoting the growth, feeding efficiency and retention of proteins of trout after more than one gram. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of the yeast Sacharomices Boulardii (SB), on the growth performance, the health and the survival rate of the carp (Cyprinus carpio) grown in recirculating system, by analyzing the biotechnological and biochemical indicators. The experiment was performed over a period of 30 days. The biological material used in this experiment was carp (Cyprinus carpio). A number of 150 fish, with an average body weight of approximately 100 grams, were equally distributed in 2 experimental tank and 1 control tank in the recirculating system. The yeast was supplemented with food, in a classic feed with a content of 32% protein, according to the specialized literature (SC Aquasarb, 1998)[15], in percentage of 0.75% in B1, respectively 2.5% in B2. In the control tank, B0, a classic feed was administered, without the addition of yeast. The growth parameters and the biochemical composition were determined at the beginning and the end of the experiment. The results showed that there are not very big differences regarding the individual weight growth between the 3 tank; however, the highest weight gain (33.95 g) was obtained in B2 compared to the lowest (33.51 g) obtained in the control tank, B0. The results also showed that at the end of the experiment the survival rate in B1 and B2 was 100%, compared to 96% in the control basin B0. A better food conversion rate, FCR, was obtained in B2 (1.20), compared to 1.30 in B1, respectively 1.45 in B0. The highest protein content in the fish carcass was present in B2 (18.01%), compared to 17.01 in B0, respectively 17.60 in B1. The conclusion is that supplementation of the carp feed grown in the recirculating system with probiotics from yeast Sacharomices boulardii has positive results on the growth performance, the health and the survival rate of the carp, the best results being obtained with a supplement of 2.5% probiotics. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to identify the influence of production systems on the nutritional value of four fish species belonging to the Cyprinidae family. The present study considered four species: Cyprinus carpio, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis and Ctenopharyngodon idella, reared in semi-intensive system, extensive system and in natural environment. Fish samples were harvested during summer months from Brateș Research and Development Farm - Galați (semi-intensive system), Cotul Chiului Experimental Base (extensive system) and from a natural environment represented by the confluence of the river Prut with the Danube river. From each production system, 20 fish samples were analyzed belonging to the four species considered for the experiment. The biochemical composition of fish meat (water content, ash, proteins and lipids) was analyzed and compared for the selected 2 years old cyprinid species, reared in different systems. The results have highlighted significant differences on the biochemical profile for the 4 species reared in the selected production systems. The biological material reared in the semi-intensive system had a higher proteins content and a lower lipids content compared to the extensive system or the natural environment, and the nutritional value of the fishes reared in the semi-intensive system was higher than the other samples analyzed. Fish with preferable biochemical characteristics in human nutrition result following the application of the semi-intensive system in aquaculture, by supplementing the natural food of the biological material with fodders that improve the nutritive properties of the fish meat. [ABSTRACT FROM AUTHOR]

The objective of this paper was to analyze the composition of phytoplankton communities in summer growth ponds, in the Brateș Experimental Base between April and September 2018. Sampling of phytoplankton was performed monthly. For the study of phytoplankton, the water was collected in glass bottles with a volume of 300 ml, from the surface horizon of the water (0 m). After sampling the samples were preserved with Lugol's fixative and sodium acetate (Utermöhl), in the following proportion 0.15 - 0.25 ml solution per 100 ml / sample. At the same time with the phytoplankton samples, water samples were taken to analyze the physico-chemical parameters of the water from the analyzed ponds. The interpretation of the results was done in accordance with the provisions of the Normative regarding the classification of surface water quality in order to establish the ecological status of the water bodies (MMGA Ord. no. 161/2006) and correlated with the data from the specialized literature for the waters with fish use. Following the analysis of the composition of phytoplankton communities in the growth ponds in summer I, in the Brateș Experimental Base, we observe a seasonal dynamics both in number of species and in abundance. the stage in which the different groups of algae winter, the water temperature and the presence or absence of certain substances in the water winter. Phytoplankton is represented by: diatoms, chlorophylls, cyanophyses and euglenophyses. Chlorophylls predominate quantitatively and qualitatively and develop throughout the year which reveals a high trophic level of the lake, during the hot period of the year the cyanophysics develop, sometimes with "flowering" phenomena. Diatoms have a smaller development compared to other groups of algae, and euglins are poorly represented throughout the study. From a chemical point of view, the parameters analyzed in the water samples fall into the second class of surface water quality, according to Ord. 161/2006. [ABSTRACT FROM AUTHOR]

Gyrodactylosisis a parasitic disease caused by species of genus Gyrodactylus, affecting most species of freshwater fish, characterized by the destruction of skin or rarely the gills. One of the ectoparasitosis that may cause an increase of mortalities in rainbow trout, is the tegumentary Gyrodactylosis. This paper studies the effect of administrating peracetic acid in the disinfestation of fish parasitized with Gyrodactylus derjavini Mikailov, 1975. The chemical substance used for treatment, Divosan Forte (15% peracetic acid), at a dose of 750 ml per day and after seven days of treatment, will achieve a maximum level of efficiency registered by a complete disinfestation. The correlation between the water chemistry during treatment period and the degree of infestation in trout, shows that the latter varies inversely with the organic substance and directly proportional to the pH of the water. Successful results advise the use of peracetic acid for treating Gyrodactylosis, in trout, with precautions and recommendations resulting from the presented study. [ABSTRACT FROM AUTHOR]

This paper presents the study results carried out on the development of intervention products in the prevention of carp species (Cyprinus carpio) disease. The food formulations have been supplemented with phyto-additives enhanced with antiparasitic and / or bacteriostatic qualities with direct benefits on the biological material. The biological material which was the subject of the experiment was a native fish species represented by one-year old carp (Cyprinus carpio), grown in the Brates Research and Development Farm, from Galati. The carp species was subsequently introduced in the recirculating aquaculture system, while being fed with different types of fish food. Three types of diets (3 food variants) with different sources of phyto-additives were developed to carry out the experiment. The growth parameters and biochemical compositions were determined in the population initially studied (farm carp) before being introduced in the recirculating aquaculture system and when the experiment was finished after 90 days of development, feeded with three experimental diets containing garlic, seabuckthorn and combinations thereof. The results of the study clearly indicate that the use of phyto-additive dietary supplements determined improved feed conversion rates in the experimental groups compared to the control groups. This confirms the positive effect of phyto-additive supplements, as previously demonstrated by other fish species experiments such as Yambo et al. (2007) and Lyons (2007) [7, 17], with the biological materials reaching the retail market required size much quicker. The existing studies confirm that there is a clear weight gain advantage in different aquaculture species which have been fed with diets containing natural substances which do not pose a risk to fish, human and environmental health (Georgieva K., 2018) [6]. Batch T3, which was fed with a phyto-additive mix (PER = 2.14 and PPV =43.63), was the most efficient protein harvest batch and batch C, which was fed with the standard food (PER = 1.7 and PPV = 35.16) proved to be the most inefficient. Phyto-additive diets which were used in carp nutrition (Cyprinus carpio) influenced favourably the nutritional quality of the specimens involved in the experiment and the previously reported results are consistent with those reported by Gabor E. et al., 2010 [4]. [ABSTRACT FROM AUTHOR]

The present paper presents the study results regarding the impact of extensive aquaculture on aquatic environment quality. The study was carried out at Cotu Chiului Research and Development Farm. The facility is located in the northern part of Galati county, adjacent to the pier-shore area of the Prut River Dam, in the km 36 protected natural area. The aquatic species 'structure and age stages of the biological material from Cotu - Chiului farm, is divided as follows: 51% goldfish, 19% catfish, 4% carp at different age stages, 26% plant feeder fish. Different indicators with high levels of pollution potential, such as nitrogen compounds (NO2-, NO3-, NH4+), phosphorus and organic matter, have been monitored to be able to evaluate the physical-chemical changes of the aquatic life environment from Cotu Chiului farm. The study has been carried out on monthly water and soil samples, over the period of one year. The samples were collected from three growth ponds (EC1, EC2, EC3) which have similar morpho-hydrographic characteristics. The study concluded that: - EC1 (December and November) - maximum values of nitrites (0.132±0.016 mg/l) and ammonia (0.142±0.008 mg/l), - EC 2 (July) - maximum concentration of phosphorus (0.07±0.004 mg/l), - EC1 and EC3 (August), EC2 (January) - high values of organic matter accumulations (96.63±0.1 mg/l) and respectively (91.95±0.12 mg/l). The physical-chemical parameters of the soil samples taken have registered the same evolution tendencies as the water characteristics from Cotu Chiului farm. [ABSTRACT FROM AUTHOR]

Present scientific work propose to evidenced the chemical composition of the volcanic tuff, regarding the water quality maintenance at the optimum parameters, for breeding technologies in recirculating system, for the different fishes species with economical value. During the last years, zeolites represent a material used frequently in the technology for environment protection, based on the ionic transfer capacity and the adsorption capacity. Due to these chemical proprieties, it is regarding its implementation into the Romanian aquaculture, for a technological assurance, with optimum physical-chemical proprieties for fishes farming. The performances of experimental module were verifying trough rearing operations of Huso huso sturgeon specie. Rearing experiment developed during a 136 days period in the following conditions: monitoring of hydro-chemical parameters of the system's technological water, using as filter the zeolyte; monitoring of health state; establishing of rearing rate in experimental units. According with the experiments, these zeolites could be and must to be a technologically constant in aquaculture through the role of depollutant, in generally. [ABSTRACT FROM AUTHOR]

Knowledge about biochemical composition of flash fish allow estimation about: general maintenance conditions, methods of availability to natural and supplementary trophy basis, nutritive value of flash and establishing the impact of environmental conditions to metabolic processes. In this study, some biochemical determinations of carp (Cyprinus carpio, L. 1758) tissues were investigated. The biochemical analysis of the meat has been effectuated in the experiment that took place during 60 days, in four breeding units of 500 liters in volume each. Four kind of variants were compared: V1-pellets with 30% crude protein, without probiotics; V2-pellets with 30% crude protein, with probiotics of 2.24×109 CFU/kg food; V3-pellets with 30% crude protein, with probiotics of 3.84×109 CFU/kg food; and V4-pellets with 30% crude protein, with probiotics of 7.04×109 CFU/kg food. We used BioPlus® 2B probiotics (a mixture of Bacillus licheniformis (DSM 5749) and Bacillus subtilis (DSM 5750). After analyses the biochemical composition in stage one was: V1-16.89% proteins, 1.57% lipids; V2-16.47% proteins, 2.5% lipids; V3-16.72% proteins, 1.87% lipids; V4-15.52% proteins, 1.69% lipids and in the second stage was: V1-14.47% proteins, 1.63% lipids; V2-15.70% proteins, 3.12% lipids; V3-14.45% proteins, 1.85% lipids; V4-15.24% proteins, 2.35% lipids. The obtained results showed that are insignificant differences (p>0.05) in the levels of proteins, fats and ash between the control variant (V1) and experimental variants (V2, V3, V4) where probiotic supplements were used. [ABSTRACT FROM AUTHOR]

The aim of the paper is to analyse the influence of environment factors on the capture and fish communities structure from Danube, between Siret River and Prut River mouth. Fish were collected from April to December 2011 in four fishing areas. During the year, 6027 kg, respectively 4805 fish of twenty three breeds were collected. Cyprinidae, the dominant family, 60.87% in term of number of breeds, was represented by 14 breeds (Cyprinus carpio, Carassius gibelio, Barbus barbus, Abramis brama, Abramis sapa, Blicca bjoerkna, Leuciscus idus, Vimba vimba, Aspius aspius, Pelecus cultratus, Chondrostoma nasus, Ctenopharingodon idella, Hypophthalmichthys molitrix, Hypophthalmichthys nobilis). Other families had the following structure: Clupeidae (4.35%) with one breed (Alosa pontica), Acipenseridae (13.04%) with 3 breeds (Huso huso, Acipenser stellatus, Acipenser ruthenus), Percidae (13.04%) with 3 breeds (Sander lucioperca, Zingel zingel, Zingel streber), Siluridae (4.35%) with one breed (Silurus glanis) and Esocidae (4.35%) with one breed also (Esox lucius). The highest capture was 2728.5 kg (45.29%), during the spring season (April- May), followed by autumn season (September -November), with 560.45 kg (9.29%). The water level and water flow showed high correlation with both number and total capture, respectively. [ABSTRACT FROM AUTHOR]

The paper is presenting some aspects regarding the structure of fish communities from 22 Km of predeltaic sector of Danube River, between the mouth of Siret River (km 155) and Prut River (Mm 72.5). The aim of the study is to assess the ecological status of the area, using the main ecological indices as abundance, dominance, constancy and ecological significance. From April to December 2011, in four fishing areas (km 150-151, Mm 77-78, Mm 76-77, Mm 74-74.5), 4805 fish of twenty three species, from six famillies, were collected. The best represented family is Cyprinidae with 14 breeds. The numerical abundance ranged between 2 fish/breed (zingel, common nase) and 2035 fish/breed (pontic shad). The pontic shad (42.35%), common bream (11.63%) and common carp (10.9%) are eudominant breeds, having the biggest potential in fish productivity. Pike-perch (75%), common bream (75%), common barbel (75%), vimbe (75%), white-eye bream (75%), asp (66.66%), prussian carp (66.66%), white bream (58.33%), common carp (58.33%), silver carp (58.33%) and sterlet (58.33%) are constant species with high adaptability. In term of ecological significance, Danube shad (14.11%), common bream (8.72%), common carp (6.36%) and common barbel (5.32%) are characteristic species. [ABSTRACT FROM AUTHOR]

To be aware of the health condition of the biological material in a fish farm allows us to establish the preventive measures required to prevent spreading of a disease and the treatment to be applied in case that a mass disease occurs. That is why to know the normal value of the serum glycemia, the total protein and the protein fractions in serum enables us to differentiate the normal physiological condition of the fish material under research from the eventual pathological modifications having occurred due to the defense reaction of the organism. The level of the serum glycemia representing a high value marker indicator of the stress condition, while the level of total protein in serum is, first of all, a synthetic indicator of the nutritional condition of the organism. The most part of diseases have but a little influence on the concentration of the total protein in the blood, but some influence on certain protein fractions, and they alter the ratio between albumins and globulins. A decrease below 0.3 in value of the ratio albumins/globulins in serum is significant for the health condition of fish. [ABSTRACT FROM AUTHOR]

Over the last decade there has been a drastic decline in sturgeon catches in the Lower Danube River system. The present paper analyses the past and present situation and suggests policies for a sturgeon recovery programme. [ABSTRACT FROM AUTHOR]

This paper aims to find new methods of laboratory investigations to identify the early stages of parasitic diseases in fish, to reduce mortality and improve disinfecting treatments. Hematology is used in ichthyopathology worldwide, especially in the case of infectious-contagious diseases, but we suggest studying the appropriateness of their widespread use in our country, extending them in the case of parasitic diseases with serious prognosis, to quantify the precise equivalence between the anatomicalpathological changes determined by the degree of fish infestation (resulting from the microscopic examination) and the physio-pathological ones expressed by the biochemical changes (shown by blood tests) that occur in the fish body, in various stages of a parasitic disease. The usefulness of performing a blood analysis, as a precision factor in paraclinical investigations, allows to determine the exact stage of the disease on which the effect of the disinfection treatment shows maximum efficiency and will also reveal the modality in which stocking densities of fish are influencing the immunity mechanism of the fish. From all the parasitic diseases we have chosen a protozoan Ichthyophthirius multifiliis (Fourchet 1876) infestation, which has a mortality of 50-90% on fish, due to a faster propagation rate, an aggressive behavior, it attacks the host tissue, penetrating deep into the subepithelial-skin and gills, thus achieving protection against chemotherapeutic substance used in the treatment, demonstrating the need to treate the disease in the early stages, when the parasite may be destroyed. The experimental results show that the degree of infestation is growing directly proportional to the stocking density, and inversely proportional with the size and immunity of the fish (the immunological parameters are increased by immunoglobulin M), the serological parameters (erythrocytes increase the hematocrit, hemoglobin and the total protein serum decrease), and the biochemical parameters (glucose, ALT and AST) increase due to the stress, disease state and the successive treatments. This study highlights how large losses in the fish farm sector can be effectively decreased, by using new, accurate analysis tools. The losses are caused by parasitic diseases that rapidly evolve and sometimes can be aggravated by the cumulative effect of adaptive stress, as frequent expression of technological errors, that act negatively on the defense mechanisms of fish. By correlating the results of hematologic analysis with those of the clinical and regular microscope examinations, the fish health can be monitored, through the growth period or in the case of biological material transfer from a fish farm to another, aiming to reduce the fish mortality by 89-98%. [ABSTRACT FROM AUTHOR]

The chemical and biochemical composition of caviar in 22 specimens of wild caught and of 2 farmed animals were measured. The results include grain size, protein and fat content, fatty acid composition of triglycerides and phospholipids, as well as the concentrations of relevant heavy metals and chlorinated hydrocarbons. The average protein content varied between 26.2 and 31.1% (wet weight) and fat from 10.9 to 19.4% (wet weight) with lowest values for caviar from farmed sturgeon. The triglycerides and phospholipids contained more n-3 fatty acids, especially eicosapentaenoic and docosahexaenoic acid than n-6 fatty acids. The copper and zinc concentrations varied between 1.20 and 1.69 and 10.3 and 12.4 mg/kg (wet weight), respectively. These values reflect the elevated requirement of sturgeons for these components. Lead content varied between 0.06 and 0.15 mg/kg (wet weight). The cadmium concentrations were less than 5 micrograms/kg (wet weight) leading to the conclusion that no accumulation took place in the eggs. The concentrations of sigma DDT and sigma PCB were extremely high in caviar from Huso huso compared to the samples of the other species thus reflecting the different food habits leading to increased bio-accumulation.