Search

The meat quality and the mortality rate of the European flat oyster, Ostrea edulis (Linnaeus, 1758) was investigated using two different farming technologies: the traditional method of cementing them on nylon ropes, and the alternative of placing the oysters at a depth of 4 m, in plastic boxes covered with protective netting. Total annual mortality of oysters was 39.8% when cemented on ropes and 12.65%. when cultured in boxes. The highest meat index value of cemented oysters was recorded in April (17.4) and the lowest in August (8.9). The meat index of oysters cultured in the boxes was also the highest in April (15.6), but the lowest value was recorded in January (11.4). During all twelve months of this investigation, oysters in the boxes qualified at the highest category (”speciales”), according to the french classification. According to the same categorization, cemented oysters qualified at the highest category during ten months of the year, and to the excellent or “fines” category, in August and September. The results suggest a consideration of the replacement of the traditional technology of cultivation on nylon ropes, with the potentially more profitable cultivation in plastic boxes.

Objective of the study was to determine the fatty acid and proximate composition of ventral ordinary tail muscle of Atlantic bluefin tuna, both farmed and wild, compare those findings with plasma parameters of farmed bluefin reared on a diet based on herring and sardine, and analyze the lipid profile of the species. The total lipid content of farmed bluefin was 0.922 g/100 g, or 3.49 g of SAFA, 4.48 g of MUFA, 2.58 g PUFA n-3, and 0.37 g of PUFA n-6 fatty acids ; for wild specimens it was 0.920 g/100 g, or 2.85 g of SAFA, 4.82 g of MUFA, 2.78 g PUFA n-3, and 0.27 g of PUFA n-6 fatty acids. Major fatty acids in this study were 16:0 ; 16:1, n-7 ; 18:1, n-9 and DHA 22:6, n-3 acids. The sum of these major components accounted for more than 57 % and 80 % of the total fatty acids in all samples of farmed and wild tuna, respectively. No significant differences in proximate composition were demonstrated between farmed and wild samples, except for energy value, in favor of the farmed tuna. Statistically, GLU tends to increase together with CHOL and TRIG, since for these pairs it showed positive correlation coefficients and P > 0.05. Some measured tuna metabolites demonstrated strong mutual correlations, especially GLU, CHOL and TRIG, which are crucial factors in lipid profile of animals. Measuring blood biochemical parameters showed an excellent indicator to the, along with the general condition of the organisms, overall metabolic equilibrium in bluefin tuna farmed for human consumption, which in proximate composition differed from wild specimens only in energy value, while significant differences were observable in their fatty acid profiles.

Gibberellins (GAs) were identified and quantified during flower and fruit development in the Christmas rose (Helleborus niger L.), which differs from other popular model species in two ways (1) following anthesis the initially white or rose sepals turns green, which persists until fruit ripening, (2) the seed is shed before embryo maturation. Using an LC-MS/MS system, we identified GA1 and GA4 as major bioactive GAs in fruit and sepal tissues. In the fruits, the endogenous amounts of GA4 peaked during rapid pericarp and embryo growth whereas that of GA1 during the subsequent period of rapid nutrient deposition in the seeds and continued pericarp enlargement. In the sepals, the flux through the GA biosynthetic pathway was highest prior to the light green stage when the photosynthetic system was induced. The greening of unfertilized, depistillated, and deseeded flowers was less than the seed-bearing controls ; and the greening (chlorophyll accumulation) could be restored by treatment of the deseeded fruit with exogenous GA1 and GA4. The sepals of unfertilized and depistillated flowers indeed contained very low levels of GA4 and gradually decreasing levels of GA1. However, the concentrations of their precursors and metabolites were less affected. These data suggest that a signal(s) from the fruit stimulates GA biosynthesis and in turn greening in the sepals.

Indigenous populations of brown trout (Salmo trutta L.) throughout Europe have been seriously affected by environmental degradation, harvest and enhancement and are constantly decreasing. Brown trout is classified as a vulnerable species according to the Croatian Red List. Croatia’s Gacka River is one of the most fascinating karstic rivers in Croatia ; it is a part of the Adriatic drainage and among the best-known trout sites in the world. Brown trout in Gacka River grows faster than in other karstic rivers, owing particularly to the optimal water temperature with minor oscillations, plenty of oxygen and the water’s mildly alkaline chemical structure. During the past three decades, the river has been managed by several administrations, which occasionally maintained poorly documented stocking activities. Although stocking was generally regarded as a main tool in the conservation and enhancement of fish populations, today it is well known that inappropriate stocking is a threat to the genetic integrity of wild populations. The importance of the project lies in the preservation of indigenous brown trout of verified genetic profile and the possibility of stocking Gacka River with native, genetically authenticated phyilogenetic lineages of fish in its natural habitat thus creating the conditions for a richer offer through development of fishing tourism of already well-known trout river. The project relies on the construction of the basic infrastructure for breeding of captured indigenous brown trout, taking into account the priorities of environmental protection and sustainable socio-economic development. Indigenous spawners were fished out, checked for the presence of pathogens, their sexual products genetically analyzed, and authenticated lineage produced from eggs to fry size suitable for stocking and further growing. The project thus has direct impact on the following: - preservation and breeding of endangered lineages of brown trout, - controlled stocking with bred, genetically verified fish with checked health status, - potential for providing a high quality offer for brown trout sport fishing, - increased possibilities for a quality offer of brown trout as a culinary specialty, - increase in the overall quality of the tourist offer in the region, - greater awareness for the importance of preserving a clean environment, - new conditions for creating new jobs through employment in the breeding center and self-employment related to the work and development of the centre, - increased global recognition of the region and Croatia as a breeding center for indigenous species. The center is the only of its kind in the wider region that combines breeding facilities with scientific research. An entire component of the project is dedicated to the improvement of skills and know-how in the field of business management and fish breeding technology. Therefore, apart form protecting it from extinction, the model is developed for the rehabilitation and breeding of the brown trout, applicable in other regions and countries.

Ceratothoa oestroides is a cymothoid parasite of cage-cultured sea bass. The adult female and male parasites settle in the buccal cavity of fish. It is a nonspecific host fish parasite with records in six different fish families but no records in wild sea bass. Their life cycle involves only one host. It is considered as one of the most threatening parasitic diseases in Croatia with a high economic impact. A three-year health status monitoring of cultured sea bass was carried out in this study. A total of 1154 parasited sea bass from the same population was examined. Six samplings per year in the first two years were conducted. In the third year, 24 samplings were performed only during winter and summer. Result showed significant very high positive correlation between length and weight of host fish and parasite length during the first year while high positive correlation was found in the second year between the same biometric measures. During the winter period in the third year, the length of female parasites was in a low positive correlation with the length and weight of parasited fish while in the summer period the length of female parasites was in a moderate positive correlation with the length and in a low positive correlation with the weight of host fish.

In Croatia sea bass is cultured in floating cages. In these conditions direct contact between cultured and wild fish, drawn by easy to get food, can not be avoided. This lead to frequent parasitical diseases. Ceratothoa oestroides is a cymothoid isopod parasitic to the buccal cavity of sea bass. The parasite causes losses in the production of farmed sea bass due to the increased mortality rate in fingerlings and the lower market value achieved for the product. A three year health status monitoring of cultured sea bass was carried out in this study. The monitoring result confirmed that the prevalence of Ceratothoa oestroides was significantly higher in the samples taken in the first year than in the following year of the research. The parasitised fish had significantly lower weight and length than healthy fish of the same age. Condition factor is not a very sensitive measure of pathology effects caused by cymothoid parasites. Parasite length and weight are in positive correlation with the lenght and weight of the parasitised fish. The reproductive activity of Ceratothoa oestroides does not vary seasonelly, no positive influence of the sea temperature or moon phases on the reproductive activity of Ceratothoa oestroides was observed. The female fecundity of the female increases with the duration of daylight.

Nema sažetka

Freshwater crayfish of the family Astacidae (phyllum Arthropoda, order Decapoda) are represented with more than 540 species in Europe and four of them are indigenous in Croatia: Astacus astacus (Linnaeus, 1758) or noble crayfish, Astacus leptodactylus (Eschscholtz, 1823), Austropotamobius torrentium (Schrank, 1803) or stone crayfish and Austropotamobius pallipes (Lereboullet, 1858) or white-clawed crayfish. Three species (noble, stone and white-clawed crayfish) are listed in the IUCN Red List of Threatenes Species as vulnerable (VU) and are protected by the Croatian law ; the Law of Nature Conservation and the Rule Book on Protection of Crayfish. Also, the presence of one nonindigenous species (Orconectes limosus) was confirmed in marshes of the Nature Park Kopački rit, Croatia.

The frequencies of erythrocytic nuclear abnormalities (ENA), micronuclei (MN), vacuolated nuclei (VN) including cytoplasmic vacuoles (CV) were monitored in the peripheral blood of cultured shade fish Argyrosomus regius (Asso, 1801). Sampling was performed through three seasons: at the end of the winter (March), spring (May) and summer (July) at one location from southern Adriatic Sea (Croatia). ENA comprised blebbed, lobed and notched nuclei, which were the most frequent features, while the MN, VN and CV appeared sporadically. The highest level of ENA and MN were detected in July, and VN in March, respectively. The rarest appearance of these parameteres were recorded in May. Inversely, cytoplasmic vacuoles were the most frequent in May and the least in July. The Spearman rank order correlation test revealed a significant positive correlation between the frequencies of ENA and MN (P < 0.05, r = 0.44), ENA and VN (P < 0.05, r = 0.56). Also, the frequency of MN significantly positively correlated with water temperature (P < 0.05, r = 0.42) and negatively with level of oxygen (P < 0.05, r = - 0.42). Cytoplasmic vacuoles did not correlate with any measured parameters. Our results demonstrate that these parameters displayed a distinct seasonal variation.

Fresh seafood (fish, shellfish, crustaceans, molluscs) were randomly selected and collected from the biggest inland market in Croatia in warm and cold season of the year and they were examined for presence of V. parahaemolyticus and enterobacteria through winter and summer seasons. Consumption of raw or undercooked seafood, particularly shellfish, contaminated with V. parahaemolyticus may lead to development of acute gastroenteritis characterized by diarrhoea, headache, vomiting, nausea, abdominal cramps and low fever. The Enterobacteriaceae count is considered as one of the indexes of fish quality because it is related to storage under ice, washing and evisceration. Unacceptable Enterobacteriaceae levels were obtained in 40 % of the summer fish samples. The poorest quality regarding high counts of enterobacteria was found for summer molluscs and fish, respectively, with up to 3x103 CFU/g. The overall prevalence of V. parahaemolyticus was 5 %. The recovery rate was higher in shellfish in both seasons than in other specimens or specific season conditions. The ubiquitous nature of Vibrio species in marine and estuarine environments makes it impossible to obtain seafood free of these bacteria. The significance for public health is dependant on the health status of the consumer as well as on the concentration and on the pathogenicity of bacteria. Seafood consumers should be acquainted with possible health hazards related with the consumption of raw or undercooked seafood, especially shellfish since careful handling of seafood, prevention of cross-contamination at the processing or food preparation are crucial in preventing infections associated with seafood pathogens.

Plasma biochemical profile was examined in cage cultured shade fish Argirosomus regius in order to evaluate physiological profile and provide detailed picture of its seasonal changes. Biochemical procedures were employed to study trygliceride (TRIG), cholesterol (CHOL), total protein (TP), glucose (GLU), urea (BUN), inorganic phosphate (PHOS), calcium (Ca), creatine kinase (CK), lactate dehydrogenase (LDH), ammonia (NH3), magnesium (Mg), aspartate aminotransferase (AST), amylase (AMYL), alkaline phosphatase (ALKP), creatinine (CREA), gamma glutamyltransferase (GGT) and total bilirubin (TBIL). The results were evaluated through different statistical analyses. Conventional statistical methods do not provide solutions that meet the goals of the research, so machine learning methodology was used to construct and evaluate classifiers as well as to assess parameter (plasma metabolites and enzymes) importances with respect to the target variable (season). It is evident that about half of the parameters (UREA, ALKP, NH3, CHOL, Ca, PHOS, GLU and CREA) have significant importance (i.e. exhibit significant differences between seasons) for seasonal discrimination models. It is also important to stress that using only a subset of most important parameters is generally enough to obtain high accuracy classifiers, which suggests rather high correlation between these parameters on a seasonal scale.

nema sažetka

Recovery of Aeromonas hydrophila from the liver, kidney and spleen of screened mullet was described in this work. Affected fish did not manifest external signs of disease, while necropsy findings revealed haemorrhages from the liver, and posterior kidney.

The purpose of this study was the identification and quantification of biochemical parameters over a 1-year cycle and to provide a detailed picture of seasonal changes in plasma metabolites and enzymes. Using the novel methods of machine learning techniques, the authors created and generated for the first time comprehensible classification models for exploring the importance of blood chemistry parameters, strength, mutual interactions or dependencies, and reliability of particular parameters within the seasonal groups.

Extensive lesions, skin ulcers, exophthalmia and ascitic fluid are described in carp fingerlings upon onset of Aeromonas hydrophila infection.

The brown trout is the most widely distributed fish specied native to Eurasia and North Africa. However, the species has also been extensively introduced worldwide, mailnly for fishing reasons. In the past two decades, genetic variation of brown trout has been extensively studied throughout its natural range. Such studies have demonstrated five distinct phlogenetic lineages defined by mitochondrial DN control region sequences.Established haplotypes in Plitvice lakes were assigned to both Atlantic and Danubian phylogenetic lineages.

Predstavljen je način djelovanja i organizacijska struktura Centra za dijagnostiku bolesti riba, rakova i školjaka.

Genetic variation of brown trout, Salmo trutta L., has been extensively studied throughout Europe. Such studies have demonstrated five distinct phylogenetic lineages defined by mitochondrial DNA (mtDNA) control region sequences. Croatia is an important geographic region where no systematic studies of genetic variation have been made. MtDNA control region variation from 9 individuals originating from Gacka River were analysed, in order to assess their phylogenetic lineages affiliation, and address the question of autochthony of populations in the river. Based on a sequencing of the 334 bp fragment at the 5' end of the mtDNA control region, two haplotypes were identified. Although Gacka River is a part of the Adriatic drainage, 4 individuals (45 %) were assigned to Atlantic haplotype Ad1 and 5 individuals (55 %) were assigned to Danubian haplotype Da2. The presence of Atlantic and Danubian haplotypes primarily reflects introgressioon stemming from the stocking of hatchery-reared fish, although natural status could not be excluded. These results are of great importance for future adequate management and conservation of natural brown trout populations in this region.

In this study, cestode parasites were collected from abdominal cavity of chub Leuciscus cephalus living in Çaparlı patlak Dam Lake during a period of 12 months. Of 431 fish examined, 100 were infected. Plerocercoids of Ligula intestinalis were found in 23% of the fish. Infection increased significantly with age and length of the fish. The ratio of parasite weight to fish total weight was found to be between 7.76% and 30.36%. The number of parasites varied from 1 to 21 ; the lenght of parasites ranged from 3 to 41 cm. The prevalence of fish infected with L. intestinalis was significantly highest between July and September. There were no mortalities. Some copepods and the comorant, Phalacrocarax carbo have been found as hosts in the life cycle of L. intestinalis.

The blood plasma of reptiles is a colourless or greenish - yellow to orange fluid, depending on the species. It comprises some 60 to 80 per cent of the blood volume. The plasma contains a great variety of different substances, most of them present in trace quantities. The composition of blood plasma shows a great variation in reptiles. There are no strictly basal conditions to define reference values in reptilian physiology. The data on seasonal measurements of haematological parameters are scarce, and so are the reference values involving the plasma biochemistry annual cycle. Balkan whip snake (Hierophis gemonensis) is one of most common snakes of costal Croatia and its islands. The results we have shown here consider some plasma biochemical values of captive Balkan whip snakes, in controlled enviroment Measured plasma biochemical parameters were: total protein, glucose, cholesterol, urea, triglycerides, AST, LDH, CK, ALP, calcium and phosphorus. The aim of this study is to determine haematological and biochemical reference ranges in blood for Balkan whip snake. These results could be used for better understnding of reptilian hematology.

Background and purpose: Cell contains enzymes that are necessary for their function. Modifications in enzyme activity occur by cell death, increases or decrease enzyme production, obstruction of normal excretory route, increase cell membrane permeability, or impair circulation. Seawater challenge test in fish influence in cell membrane permeability. The use of a biochemical particularly enzyme approach has been advocated to provide an early warning of potentially damaging changes in stressed fish. The aim of this study was to determine glutamate-oxaloacetate and glutamic-pyruvic transaminase (GOT, GPT) activity of two ploidy (diploid– DP ; triploid– TP) fish group and correlate them with differences attributable to seawater acclimation. Materials and methods: Challenge test was performed in Pacific seawater. Blood samples (n=7/time point) were taken from fish held in fresh water, FW (0h) and after transfer into sea water SW (1.5, 3, 6 and 12 hours and 1, 2, 4 and 8 days following transfer). Plasma GOT and GPT were analysed using biochemical analyzer CHEM 1. Results: Fish plasma GOT level in FW showed significant differences (P

Na predavanju su opisane mogućnosti i posljedice (po autohtone vrste i okoliš) unošenja alohtonih vrsta riba u vodotoke.

Predavanje o ihtiofauni rijeke Gacke i smjernice u očuvanju autohtone potočne pastrve.

Svi testovi za brzu identifikaciju bakterijskih izolata razvijeni su mahom za identifikaciju bakterija iz porodice Enterobacteriaceae ljudi i toplokrvnih životinja. Oni mogu biti vrlo korisni za dijagnosticiranje nekih bakterija iz riba, iako neke od njih nisu uključene u bazu podataka tih sustava. U njihovom korištenju potreban je oprez zbog mogućih pogrešnih interpretacija, a korišteni testovi u ovom radu davali su proturječne nalaze oko identifikacije Vibrio vulnificus izolata, stoga se preporuča korištenje konvencionalnih metoda uz svaki brzi test.

In the Adriatic environment, a decision regarding the most advantageous timing for smolt transfer may be more complex due to higher prevailing temperatures and greater salinities than seen for example in the Pacific. The blood, blood enzymes in particular, as reliable parameters for any metabolic activity, give an indication to the changes which might have caused them. The main objective of this study was to clarify how differently water temperature and salinity affect the apartate and alanin aminotransferase (AST and ALT) levels during sea water acclimation of coho salmon smolts. Challenge test was performed in the Adriatic Sea, Croatia (Cro) and Pacific seawater, Canada (Ca). Blood samples were collected fro eaqual numbers (n=7/time point) of two fish groups at regular predetermined intervals in fresh water (fw) and after entering seawater (sw) for up to 8 days. Enzymes AST and ALT were determined using Chem-1 analyzer. Higher temperatures and greater salinities in the Adriatic than in the Pacific were established. In fw plasma ALT values between Cro and Can coho were not statistically significant. After transfer to sw, ALT-Cro levels decreased and were lower to the 8th day. ALT-Can values decreased during the 24 hours post transfer and then slowly increased to the 8th day. No significant differences were found between AST-Can and AST-Cro levels at the beginning of the experiments in fw. After 8th day plasma-Can were significantly higher than AST-Cro levels (p

Važnu ulogu u ekosustavu ribnjaka ima fitoplankton koji kao indikator ukazuje na bonitet vodnog biotopa. Istraživanje fitoplanktona provedeno je na po dvjema uzgojnim površinama ribnjačarstva Siščani i Vukšinac.U ribnjacima je glavni nasad bio dvogodišnji šaranski mlađ. Kvalitativnim analizama fitoplanktona utvrđeno je ukupno 125 vrsta planktonskih alga. U vrijeme istraživanja glavni fitoplanktonski stanovnici ribnjaka bili su predstavnici skupina Euglenophyceae, Bacillariophyceae i Chlorophyceae.Zastupljenost indikatorskih vrsta saprobnosti bila je od 30% do 47, 8% od ukupnog količinskog sastava fitoplanktona istraživanih ribnjaka, a dominirali su beta-mesosaprobni indikatori. Vrijednost P-B Indeksa saprobnosti izračunane prema indikatorskim vrstama na istraživanim ribnjacima ribnjačarstva sisčani kretale su se od 1, 7 do 2, 5, a na ribnjacima ribnjačarstva Vukšinac od 1, 7 do 2, 2. Prema dobivenim vrijednostima P-B Indeksa saprobnosti zajednica mrežnog fitoplanktona ima beta-mesosaprobni karakter čija obilježja pripradaju bonitetu II. vrste.

Kakvoća vode u prirodnim i kontroliranim ekosustavima jedan je od preduvjeta očuvanja zdravstvenog stanja organizama koji žive u njoj. Svrha je rada bila istražiti sastav fitoplanktona i fizikalnokemijskih pokazatelja kakvoće vode u odnosu na pojavu endoparazitoza u ciprinidnim ribnjacima. Istraživanja su provedena na dva ribnjaka od svibnja do rujna 1997. godine. U kvalitativnom sastavu fitoplanktona učestvovale su uglavnom sve sistemske skupine. Za procjenu kakvoće vode važne su indikatorske vrste, čija je zastupljenost u ukupnom količinskom sastavu fitoplanktona bila oko 80%. Tijekom cijele uzgojne sezone dominirali su beta-mezosaprobni indikatori. Dobivene vrijednosti fizikalno-kemijskih pokazatelja bile su rezultat klimatskih uvjeta u istaživanom razdoblju i odražavale su ekološku situaciju ribnjaka. Na osnovi parazitološke pretrage probavnog trakta riba, utvrđeni su nametnici iz skupine Cestoidea (Botriocephalus acheilognthi i Caryophillaeus fimbriceps) endoparaziti koji se uglavnom javljaju kod pogoršanja kakvoće vode.

Svrha istrazivanja je bila pratiti biokemijske parametre krvi (enzime: transaminaze AST i ALT ; laktat dehidrogenaze (LD) ; kreatin kinaza (CK) i alkalna fosfataza (AP) dviju genetskih skupina srebrnih lososa (diploidi i triploidi), te utvrdjivanje razlike/aktivnosti enzima koje nastaju uslijed promjene kakvoce vode (slatka i morska voda). Na osnovi dobivenih rezultata sagledali bi ovisnost kakvoce vode i metabolickih procesa kroz razinu enzima. U provedenim istrazivanjima pratili smo fizikalno-kemijsku kavocu vode na ribogojilistu u Luknji, morske vode na kaveznom uzgajalistu Zrnovnica, te sletke i morske vode u akvarijskom prostoru u West vancouver Laboratoriju, Kanada. Uzorci ribe (5-7) za odredjivanje biokemijskih parametara krvi uzimani su u slatkoj vodi, te nakon 1, 5 ; 3 ; 6 ; 12 ; sati, te 1 ; 2 ; 4 i 8 dana po prebacivanju u morsku vodu. Uyimala se riba za biomretrijska mjerenja, odredjivanje njenog zdravstvenog stanja, te krv za biokemijske pretrage (AST, ALT, LD, CK, AP). Uzorci plazme obradjivani su uz pomoc biokemijskog analizatora CHEM I. Iz dobivenih rezultata mozemo zakljuciti da je prilikom prilagodjavanja srebrnih lososa zivotu u moru doslo do smanjene permeabilnosti stanicnih membrana (pad razine AST=, povecanja sinteze aminokiselina, sto na koncu rezultira boljim rastom riba (rast razine ALT), minimalne razlike u metabolizmu ugljikohidrata (pad razine LD), smanjenog metabolizma kroz smanjeni prijenos fosfatne skupine iz fosfokretina na ATP (pad razine CK), te smanjenje fosforizacije odnosno smanjenog djelovanja AP na esterski vez fosforne kiseline i alkohola. Neosporna je dakle cinjenica , koja proizlazi iz izlozenih rezultata, da je doslo do promjena u aktivnosti istrazivanih enzima prilikom promjene kakvoce vode. S obzirom da se zdravstvenim pregledom nije moglo utvrditi nikakvo ostecenje organa, a uginuca su bila minimalna, mozemo jedino zakljuciti da se radilo o kratkotrajnim funkcionalnim promjenama.

The river Krka estuary possesses some specific hydrogeological characteristics. Due to the large organic production, it is abundant in natural shellfish populations, with mussels (Mytilus galloprovincialis Lamarck) as a dominant biomass. These organisms are capable of consuming plankton and detritus for their vital needs through filtering water. The investigation comprised the four seasons from August to May. Shellfish were collected by diving to a depth of 4 m. Digestive system contents were diluted in distilled water prior to microscopic examination of contents. Samples were homogenized prior to determination of proteins, lipids, moisture and ash. Determinations were undertaken by using standard laboratory methods. During shellfish collection, plankton and water samples were taken, and qualitative phytoplakton composition was determined by using standard keys. Quantitative analyses of phytoplankton samples showed predominance of Bacillariophyceae, represented by 56 species. The group Dinophyta was represented by 40 species. Analysis of the mussels digestive tract contents identified the presence of 18 phytopkankton species, representing 18.4% of the total species found. In the alimentation of the mussels, the Bacillariophyceae were represented. The genera Dinophysis and Procentrum of the Dinophyta were identified in the mussel digestive tract. The analysis of chemical composition of proteins, lipids, water and ash was made to determine the nutritive value of the mussels. According to the analyses of chemical compostion of the consumable part of the mussels (muscles), the largest oscillations were recorded for moisture percentage . During the investigation, the following values were found: moisture-from 72.90% to 80.33% proteins-from 12.36% to 14.86% lipids-from 1.35% to 2.14% and ash-from 2.20% to 2.65%. Total energetic values, ranging from 265.65kJ to 337kJ, were in the proportion of the values found for proteins and lipids.

Cilj istraživanja bio je dobiti uvid u zdravstveno stanje pregledavanih linjaka i determinirati iz njih izdvojene bakterije. Istraživanja su nastavljena na prethodna (1989. i 1990. godine), kada su iz pregledavanih riba iz izdvojene samo ubikvitarne vodene bakterije. Zdravstvenom pretragom linjaka i bakteriološkom obradom izdvojenih izolata dobili smo podatke koji upućuju na dobar zdravstveni status riba u jezeru, te na postojanje ubikvitarnih i specifičnih ribljih bakterija kao potencijalnih uzročnika bolesti riba. Najveći broj izolata pripada skupini Aeromonas hydrophila, zatim Flavobacterium sp., Acinetobacter sp., Lactobacillus sp., te Aeromonas salmonicida. Te bakterije bi, u slučaju izraženog stresa riba i neravnoteže čimbenika koji uvjetuju život u vodi, mogle dovesti do pojave bolesti.

Današnje spoznaje o bolestima morskih riba, uzrokovanih virusima, JOS su uvijek nedostatne. Do sada je u riba koje cijeli svoj životni ciklus ili samo jedan njegov dio provedu u morskoj sredini utvrđeno nekoliko virusnih bolesti (limfocistis, virusna nekroza eritrocita, sindrom čiravosti bakalara, encefalitis, virusna hemoragijska septikemija, zarazna hematopoezna nekroza, zarazna nekroza gušterače, chum reovirusna infekcija, branhionefritis, rabdovirusna infekcija jegulja). Neke se od njih u prvome redu pojavljuju u slatkovodnoj fazi razvoja domaćina, ali postoje bilješke da se zaraza nastavlja i u preživjelih primjeraka koji dospiju u morsku sredinu. Kako se povećava broj morskih vrsta riba u kontroliranom uzgoju, tako se uočava i sve veći broj patoloških stanja uzrokovanih virusima, pa je tom području potrebno posvetiti pažnju u budućim istraživanjima., Adequate knowledge on fish diseases caused by viruses is still lacking. Up until now, in fish which live their entire life cycle or part of it in the sea, some viral diseases have been determined (lymphoeytis, viral necrosis of crythrocytes, ciravosti cod syndrome, encephalitis, viral hemoragic septichemistry, viral hematopoetic necrosis, viral gusteraca necrosis, chum renviral infection, branchionephritis, rabdociral eel infection). Some of these diseases primarily occur in the freshwater phase of host development, although recordings exist that the virus is carried on in surving samples which succeed in making it to the sea. As the number of sea fish species increases in controlled culture a increasing number of pathological cases are observed, which is caused by viruses. Therefore, in this area it is necessary to emphasize future investigations.

Kakvoća uzgojne sredine je od bitnih čimbenika uspješne ribarske proizvodnje, jer izravno utječe na rsst, kondicijsko i zdravstveno stanje riba. Svrha rad bila je istažiti kvalitativni sastav fitoplanktona i fizikano-kemijskih pokazatelja kakvoće vode u odnosu na pojavu ektoparazitoza u ciprinidnim ribnjacima. Istraživanja su provedena na ribnjacima 4 i 5 ribnjačarstva Lipovljani od svibnja do rujna 1993., 1994., 1995. godine. Budući da je ovo ribnjačarstvo bilo pod izravnim ratnim uvjetima, proces normalizacije prijeratnog intenzivnog uzgoja još traje. Tijekom istaživanja u ribnjacija je glavni nasa bio šaranski malđ. Kvalitativna i kvantitativna obrad fitoplanktona, te osnovnih fizikalno kemijskih pokazatelja obavljena je metodama koje se korist u limnologiji. Zdravstveni pregled riba obavljen je u smislu općeg kliničkog, mikroskopskog i patoanatomskog pregleda. U sastavu fitoplanktona sudjelovale su vrste iz skupina: Bacteriophyceae, Cyanophyceae, Dinophyiceae, Euglenophyceae, Chrysophyceae, Bacillariophyceae i Chlorophyceae. Skupina Bacteriophyceae bila je zastupljena s vrstom Sphaerotilus dichotomus i pojavila se samo u lipnju 1995. godine u ribnjaku 5. Iaku su utvrđenu indikatori jačeg i slabijeg onečišćenje vode, prevladavali su predstavnici beta mesosaprobnog stupnja. Dobivene vrijednosti fizikalno kemijskih pokazatelja kretale su se u granicama karakterističnim za ciprinidne ribnjake. Veće promjene uočene su u koncentraciji otopljenog kisika u voi, čije su vrijednoti tijekom istraživanja 1993.-1995. bile između 2, 2 mgl/1, u srpnju 1995. u ribnjaku 5, i 19, 8 mg/l, u kolovozu 1993. godine u ribnjaku 4. Na osnovi zdravstvenog pregleda riba od ektoparazita utvrđeni su predstavnici rodova Trichodina, Dactylogyrus, Gyrodactyrus i Ichthyophtirius, ektoparaziti koji se uglavnom javljaju kod pogoršanja kakvoće vode i povišenih temperatura vode. U svim ibnjacima utvrđena je jača invadiranost riba ektoparazitom Dactylogyrus.

Kisele kiše postaju jedan od najvažnijih problema čovjekova okoliša, a rezultat su onečišćenosti atmosfere nastale zbog bržeg industrijskog razvoja. Uzroci su oslobađanje oksida sumpora i dušika, koji uz određene kemijske reakcije prelaze u sulfate i nitrate, te mokrim ili suhim taloženjem dolaze do tla. Djeluju na jezera, rijeke, cijeli životinjski i biljni pokrov, uključujući i sva dobra stvorena ljudskom rukom. U dužem razdoblju kisele kiše mogu uništiti organizme koji žive u vodi nekih slatkovodnih ekosustava, ovisno o lokalnim geološkim značajkama (prisutnost prirodnih neutralizatora kiselina u tlu) koje neko područje čine više ili manje osjetljivim na kiselost. Istraživači su utvrdili da je djelovanje H+ na organizme koji žive u vodi različito ovisno o vrstama i koncentracijama kiselosti. Za mnoge vrste problemi započinju već kod pH ≤ 6, a samo nekoliko otpornih vrsta preživljava kod pH ≤ 4,7. Kiselost mijenja kemijski i biokemijski sastav tkiva, smanjuje osmoregulaciju, utječe na razinu hormona u krvi, djeluje na smoltifikaciju riba, te prekida njihovu reprodukciju. Zakiseljavanje osjetljivih vodenih ekosustava u sjevernim dijelovima Zemlje poklapa se s porastom kiselosti oborina. Da ovaj problem ne bi poprimio još šire razmjere, potrebno ga je što hitnije riješiti, bilo kontrolom otpuštanja onečišćivača u atmosferu, bilo sanacijom već nastalih posljedica., Acid rains is one of the most relevant problems of the human environment, the result being pollution of the atmosphere caused by ever growing industrial development. It is caused by the freeing of sulphuric oxides and oxygen, which along with certain chemical reactions transfer into sulphate and nitrate, and through wet or dry sediments reach the ground. This has an effect on lakes, rivers, the entire animal and plant kingdom, including all the good creations of mankind. Over a longer time period acid destroy organisms which live in the water of some freshwater ecosystems, depending on local geological characteristics (presence of natural neutralizers of acid in the ground) which makes an area more of less sensitive to acidity. Investigators have determined that the activity of H+ on organisms which live in the water depend differently on species and concentrations of acidity. For many species the problems begin already with pH ≤ 6, and only a few resistant species survive at pH ≤ 4.7. Acidity changes chemical and biochemical tissue composition, decreases the osmoregulation, influences the level of hormones in the blood, has an effect on fish smoltification, and interrupts its reproduction. Acidifying sensitive water ecosystems in the Northern hemisphere corresponds with the increase of acid precipitation. To prevent this problem from spreading even more it is necessary to solve it as soon as possible, either by controlling the release of pollutants into the atmosphere, or improving of the already occurring consequences.

Virtually no comprehensive work has been published on tuna plasma chemistry parameters and its correlation with tissue histological status. This work will be useful for establishing plasma biochemistry reference values for bluefin tuna. Heparinized blood samples were collected from bluefin tuna. Plasma biochemical analyses were performed using standard techniques. Organ tissues were processed histologically and stained with haematoxylin/eosin. Mean, median, standard deviation, standard error of mean, 25th percentile, 75th percentile and range difference of minimum and maximum values were calculated for each variable measured. Obtained values represent preliminary results. All blood biochemistry parameters, except ALT, passed a Kolmogorov-Smirnov normality test. In a number of hepatocytes, different degrees of fatty changes were visible. Normal ranges of plasma activity vary between species and normal values must be produced from a representative population of each species. This work will be followed up by other studies on blood chemistry values of bluefin in the Adriatic Sea involving more individuals from several locations that could provide a base for reference levels