Occurrence and Community Structure of Wild Fish Within Adriatic Sea Fish Farms

Simple SummaryCryptosporidium is a widespread pathogen that infects a broad range of vertebrates, including humans, in which it is one of the main causes of diarrhea worldwide. Marine fishes also harbor Cryptosporidium species, including zoonotic ones. The goal of this study is to evaluate the presence of Cryptosporidium species in edible marine fishes using molecular tools. The area of study, located in the Western Mediterranean, is an important area for marine fish production and capture. The following three groups were studied: cultivated fish, wild fish that aggregate in the surroundings of marine fish farms and wild fish from extractive fisheries. Results show that the most affected group is the group of wild fish from the vicinity of fish farms. Two species were mainly identified, C. molnari (fish specific) and zoonotic C. ubiquitum. The presence of zoonotic C. ubiquitum in two European sea bass (Dicentrarchus labrax) highlights a potential risk for fish consumers.Fish not only harbor host-specific species/genotypes of Cryptosporidium, but also species like zoonotic C. parvum or anthroponotic C. hominis, which can pose a risk for fish consumers. This study aims to investigate fish cryptosporidiosis in an important aquaculture and fishery area of the Western Mediterranean (Comunidad Valenciana, Spain). We analyzed 404 specimens belonging to the following three groups: cultivated fish (N = 147), wild synanthropic fish (N = 147) and wild fish from extractive fisheries (N = 110). Nested PCR targeting the 18S rRNA gene, followed by sequencing and phylogenetic analysis, were performed. Positive isolates were also amplified at the actin gene locus. An overall prevalence of 4.2% was detected, with the highest prevalence in the synanthropic group (6.1%). C. molnari was identified in thirteen specimens from seven different host species. Zoonotic C. ubiquitum was detected in two European sea bass (Dicentrarchus labrax). One isolate similar to C. scophthalmi was detected in a cultivated meagre (Argyrosomus regius), and one isolate, highly divergent from all the Cryptosporidium species/genotypes described, was identified from a synanthropic round sardinella (Sardinella aurita). This study contributes to increasing the molecular data on fish cryptosporidiosis, expanding the range of known hosts for C. molnari and identifying, for the first time, zoonotic C. ubiquitum in edible marine fishes, pointing out a potential health risk.

The nutritional quality of commercially important farmed fish species, i.e. sea bream (Sparus aurata), sea bass (Dicentrarchus labrax), dentex (Dentex dentex) and turbot (Scophthalmus maximus) was investigated. Dentex was shown to have twice as high omega-3 fatty acid content and two to four times higher eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid content as compared to other fish species. The recommended n-6/n-3 ratio was determined in all fish species, whereas the recommended PUFA/SFA ratio was not seen in turbot. Except of turbot, all other fish species matched the recommended atherogenic index (AI), the thrombogenic index (TI) and the ratio of hypocholesterolemic over hypercholesterolemic fatty acids (HH), while the highest the flesh lipid quality (FLQ) value was determined in dentex.

In this study, the role of aquaculture activity as a source of selected metals was analyzed. Significant differences in element content between cultured (Dicentrarchus labrax, Sparus aurata) and wild fishes as well as between fish muscle and their feed were detected. Higher concentrations of trace elements (i.e., As, Cu, Hg, Se) in wild fish tissues in comparison with cultured ones indicate additional sources of metals beside fish feed as natural and/or anthropogenic sources. Generally, mean Cd, Cu, Pb, Se, and Zn concentrations in cultured (0.016, 1.79, 0.14, 0.87, and 34.32μg/g, respectively) and wild (0.011, 1.97, 0.10, 1.78, and 23,54μg/g, respectively) fish samples were below the permissible levels, while mean As (2.57μg/g in cultured, 4.77μg/g in wild) and Cr (5.25μg/g in cultured, 2.92μg/g in wild) values exceeded those limits. Hg values were lower in cultured (0.17μg/g) and higher in wild (1.04μg/g) fish specimens. The highest elemental concentrations were observed in almost all fish samples from Korčula sampling site. The smallest cultured sea basses showed As (4.01μg/g), Cr (49.10μg/g), Pb (0.65μg/g), and Zn (136μg/g) concentrations above the recommended limits; however, values decreased as fish size increased. Therefore, the majority of metal concentrations in commercial fishes showed no problems for human consumption. Also calculated Se:Hg molar ratios (all >1) and selenium health benefit values (Se-HBVs) (all positive) showed that consumption of all observed fishes in human nutrition is not risk.

Virulence and Molecular Typing of Vibrio harveyi Strains Isolated from Cultured Dentex, Gilthead Sea Bream and European Sea Bass

Protein sparing effect of dietary lipids in common dentex ( Dentex dentex): A comparative study with sea bream ( Sparus aurata) and sea bass ( Dicentrarchus labrax)

Diversifying aquaculture in Saudi Arabia with the inclusion of finfish species already reared in the Mediterranean Sea requires a sufficient understanding of the preferences and limits of cultured fish under local conditions. This study was conducted using three finfish species, juveniles (135–155g), meager (Argyrosomus regius), European seabass (Dicentrarchus labrax), and greater amberjack (Seriola dumerili), to assess their growth performance under high temperatures for three-month-long thermal trials. Each species trial was performed in triplicates in a recirculating aquaculture system, while three temperature ranges, 24°C–25°C, 28°C–29°C, and 33°C–34°C, were tested, representing the average temperatures in the Mediterranean and Red Seas. Both meager and European seabass performed similarly between the first two temperatures, indicating that the optimum range lies within that thermal window. Growth performance indicates that it is lower for meager than it is for European seabass. The greater amberjack’s growth performance was similar for the first two temperatures. The temperature of tolerance was 33°C for all species. The species appeared to have similar thermal tolerance with notable differences in the preferable temperature for optimum performance. The findings of this study can be used to improve the growth performance and feed efficiency of Mediterranean species farming in temperature ranges ranging from 24°C–28°C.

Comprehensive two‐dimensional gas chromatography‐mass spectrometry was exploited for the obtainment of fatty acid fingerprints in fish and molluscs from South Italy. Scope of the lipidomic investigation was to highlight differences in the fatty acid profiles of samples from aquaculture and from the wild. The fish species under investigation were Sparus aurata and Dicentrarchus labrax, typically cultivated in Italy and commonly found in the fish market. Another aim was to find a correlation between the diet fed to fish and the expression of specific fatty acids in muscle composition. Beyond fish, two species of bivalves were analyzed to assess their lipidomic composition: Mytilus galloprovincialis (mussels) and Venerupis aurea var. laeta (clams). Both species originated from two salt lakes in South Italy. GC × GC–MS analysis showed that omega‐3 fatty acids were naturally more concentrated in wild fish, whereas their presence in cultivated fish was lower and in favor of omega‐6 and oleic acids, as an evident consequence of food supplementation. Bivalves reported a consistent amount of PUFA, although presenting some differences in the quality of fatty acids. As an additional parameter of investigation, the content of mercury was determined in all the samples by means of a Direct Mercury Analyzer, based on Atomic Absorption Spectroscopy. Wild fish reported a level of mercury that was ten times higher than in aquafarmed fish, and the maximum amount tolerated by the EC regulation. On the contrary, the level of mercury in molluscs was in general very low, particularly when compared with samples from other Italian sites of collection.Practical applications: One of the possible applications of the GC × GC methodology here presented could be the detection of a common food fraud. In the Mediterranean Sea, gilthead sea bream and sea bass are today rarely found in sea open waters. Basically, fish sold in the market comes from cultivation. Due to the fact that wild fish is more appreciated by the consumer, quite often fish sellers are encouraged to lie about the real origin of fish. The bidimensional plots shown in this study represent an extraordinary tool for differentiating the two types of fish. Also, this study provides substantial support to aquafarmers, who can draw useful advice on how to tune optimal diets to be fed to fish. In fact, it was demonstrated that fish feed highly affects fatty acid composition.The fatty acid composition of aquafarmed and wild caught fish and shellfish from the Mediterranean Sea was investigated. Comprehensive gas chromatography (GC × GC) was the analytical technique that allowed obtaining highly structured fingerprints of fatty acids.

Successful cryopreservation in biodegradable containers of sperm from aquaculture Mediterranean fishes

Species specificity in the magnitude and duration of the acute stress response in Mediterranean marine fish in culture

Viral nervous necrosis outbreaks caused by the RGNNV/SJNNV reassortant betanodavirus in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax)

Circadian feeding schedules in gilthead sea bream (Sparus aurata) and European sea bass (Dicentrarchus labrax): A comparative approach towards improving dietary fish oil utilization and n-3 LC-PUFA metabolism

ABSTRACTGilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) production from aquaculture has been increasing since the 1990s. Nowadays, about 95% of their production comes from aquaculture. In this study, we analyse if the rapid growth in the aquaculture production of both species has affected the capture fisheries prices of both species. In other words, we investigate if there is market integration between wild and farmed gilthead seabream and European seabass. In order to do this analysis, we use data from the main gilthead seabream and European seabass markets in Spain. The results show that there is no market integration between wild and farmed gilthead seabream and European seabass. This implies that capture fisheries are not affected by increases in the aquaculture production of both species. But gilthead seabream and European seabass aquaculture producers face a smaller demand that explains the difficulties this aquaculture segment is facing.

MACAROMOD: A tool to model particulate waste dispersion and benthic impact from offshore sea-cage aquaculture in the Macaronesian region

Compositional and organoleptic quality of farmed and wild gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) and factors affecting it: A review

Selection of marine fish for integrated multi-trophic aquaponic production in the Mediterranean area using DEXi multi-criteria analysis