This paper aims to show the importance of knowing the health status of fish populations in their natural environment and its influence on fish stocks at the Romanian coast. To assess the interrelationship between fish health status and the state of stocks, the following fish species: turbot, sprat, anchovies and horse mackerel were analysed from the pathological point of view. Pathological analyses performed between 2015 and 2017 revealed the presence of infections caused by bacteria of the genus Aeromonas and Vibrio and parasitic diseases Trichodinosis, Botriocephalosis and Nematodosis. The presence of these diseases in natural fish populations may represent a real danger to the state of existing stocks, but also to their evolution.

This study aimed to investigate the effects of the probiotic Betaplus® and prebiotic Technomos®as feed additives for Nile tilapia in terms of growth performance, health profiles, and resistance to infection with Aeromonas hydrophila and Pseudomonas fluorescens. A total of 960 healthy juvenile Nile tilapia (1.5 ± 0.01 g) were randomly divided into four experimental variants with three replicates for each variant. Fish were fed a commercial diet (control group, V0), supplemented with BetaPlus® probiotics–1%×BW (V1), TechnoMos® prebiotics–1% × BW (V2), and with BetaPlus® probiotics and TechnoMos® prebiotics in a ratio of 1:1%×BW (V3). Results on growth performance showed the best values in the probiotic variant, correlated with the health profile and the relative survival percentage after the challenge test with A. hydrophila and P. fluorescens. Similarly, the effects of dietary supplementation with probiotics and prebiotics on physiological conditions also recorded beneficial results in the synbiotic variant, where a high survival percentage was obtained after infection with the two pathogenic bacteria. In conclusion, the results of this study indicate that dietary supplementation with feed additives consisting of mentioned probiotics, prebiotic, and their combination as synbiotics has the potential to promote growth performance, improving tilapia immunity and increasing survival after the challenge test.

Sprat is one of the fish species with special commercial importance in the Romanian marine area, but its share in the catches of the recent years has significantly diminished. The paper is a synthesis of long-term observations on catches of sprat in the Romanian area considering the evolution of fishing effort by both active and passive gears and considering the state of environmental conditions in the period. The main elements analysed are: dynamics of sprat catches and its share on fishing gears; evolution of fishing effort; sprat stock status and fishing agglomerations biomass; environmental conditions influence on the status and distribution of fishing agglomerations; evolution of biological parameters of the sprat.

"Pelagic fish species can be affected by a series of infectious and parasitic diseases. The data used for this study are represented by the biological material collected between 2018 and 2019, from trap nets along the Romanian Black Sea waters. To establish the degree of parasitism, the following species of pelagic fish were studied: Sprattus spratus -sprat, Engraulis encrasicholus - anchovy and Trachurus mediterraneus- horse mackerel. Four species of endoparasites were identified, belonging to nematodes, as follows: Hysterothylacium aduncum, Contracaecum sp., Porrocaecumsp. and Anisakis sp. The parasites, especially found as larvae, more in free state and less trapped in the internal organs, infested the abdominal cavity, leading to degenerations, atrophies and reduction of the fish functions. The intensity of the parasitism infestation could be lethal, the size of the stocks being severely damaged. At the analysed fish species, the infestation degree was under 20 parasites per host, a low number of species recording the maximum value of 40 parasites per host. The parasites tend to accumulate with the increase of the fish's size, young stages being less affected. Key-Words: parasites, fish, nematodes, intensity, infestation degree "

The paper presents the analysis of hyponeustonic species present in the south-western part of the Black Sea, in October 2019, within the ANEMONE Project. From the qualitative and quantitative point of view, two species were identified: Anomalocera patersonii Templeton, 1837 (WoRMS) and Pontella mediterranea Claus, 1863 (WoRMS). The analyzed samples showed significant densities of these species, being found in different development stages, from nauplii to copepodites but also as adults and having a representative distribution on the entire analyzed surface. A. patersonii was abundant in the northern part of the Romanian marine area, the southern marine area of Bulgaria and in Turkey central area, while P. mediterranea recorded a higher abundance in the Romanian Black Sea area.