scholarly journals Mediterranean Aquaculture in a Changing Climate: Temperature Effects on Pathogens and Diseases of Three Farmed Fish Species

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1205
Author(s):  
Maria Chiara Cascarano ◽  
Orestis Stavrakidis-Zachou ◽  
Ivona Mladineo ◽  
Kim D. Thompson ◽  
Nikos Papandroulakis ◽  
...  

Climate change is expected to have a drastic effect on aquaculture worldwide. As we move forward with the agenda to increase and diversify aquaculture production, rising temperatures will have a progressively relevant impact on fish farming, linked to a multitude of issues associated with fish welfare. Temperature affects the physiology of both fish and pathogens, and has the potential to lead to significant increases in disease outbreaks within aquaculture systems, resulting in severe financial impacts. Significant shifts in future temperature regimes are projected for the Mediterranean Sea. We therefore aim to review and discuss the existing knowledge relating to disease outbreaks in the context of climate change in Mediterranean finfish aquaculture. The objective is to describe the effects of temperature on the physiology of both fish and pathogens, and moreover to list and discuss the principal diseases of the three main fish species farmed in the Mediterranean, namely gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), and meagre (Argyrosomus regius). We will attempt to link the pathology of each disease to a specific temperature range, while discussing potential future disease threats associated with the available climate change trends for the Mediterranean Sea.

2020 ◽  
Vol 33 ◽  
pp. 7
Author(s):  
Eirini-Slavka Polovina ◽  
Evelina Kourkouni ◽  
Costas S. Tsigenopoulos ◽  
Pablo Sanchez-Jerez ◽  
Emmanuel D. Ladoukakis

Microsatellite markers were used to investigate the genetic structure of the two most important cultured fish in the Mediterranean Sea, the gilthead seabream (Sparus aurata) and the European seabass (Dicentrarchus labrax), from two (one wild and one farmed) populations in Western Mediterranean (Spain) and from two (one wild and one farmed) populations Eastern Mediterranean (Greece). All populations were in Hardy-Weinberg disequilibrium. Interestingly, wild and farmed populations for both species from Greece were genetically differentiated and could be distinguished from each other. We used Bayesian methods for cluster analysis of farmed and wild populations. Our analysis has implications for the identification of escapees from fish farms to the wild.


2021 ◽  
Vol 11 (23) ◽  
pp. 11528
Author(s):  
Enkeleda Ozuni ◽  
Ani Vodica ◽  
Marta Castrica ◽  
Gabriele Brecchia ◽  
Giulio Curone ◽  
...  

Anisakidae are nematodes that commonly parasitize in the coelomic cavity and viscera of several fish species. They can be found in flesh, which is why they have an important economic and public health impact. The aim of the current work was to assess the presence and prevalence of Anisakis larvae in fish species caught in the coastal area of the Karaburun Peninsula in Vlora Bay (Albania). A total of 856 of wild teleosts and 219 specimens of farmed fish were collected over a 5-year period (from 2016 to 2020). The results showed that out of a total of 1075 analyzed samples, 361 (33.58%) were parasitized with L3 larvae. In particular, only Solea vulgaris returned negative results, while Sparus aurata, Dicentrarchus labrax, and Sardinella aurita showed the lowest prevalence (4.55%, 9.17%, and 10.53%, respectively) and mean abundance (0.84, 1.19, and 0.92, respectively). Conversely, Scomber japonicus and Scomber scombrus showed the highest prevalence (74.07% and 68.00%, respectively) and mean abundance (188.24 and 249.82, respectively). The data suggest that the coastal area of the Karaburun Peninsula (southern Albania) may be a high-risk area for zoonotic diseases, and the consumption of raw or undercooked fish caught in the Vlora district could result in the acquisition of human anisakiasis. For these reasons, it is necessary to improve the surveillance plan.


Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 610
Author(s):  
Davide Mugetti ◽  
Katia Varello ◽  
Andrea Gustinelli ◽  
Paolo Pastorino ◽  
Vasco Menconi ◽  
...  

Mycobacterium pseudoshottsii, a slow-growing mycobacterium closely related to M. marinum, has been isolated only in wild fish in the United States and in Japanese fish farms to date. Here, we report cases of mortality in three farmed fish species (Dicentrarchus labrax, Sparus aurata, and Sciaenops ocellatus) caused by M. pseudoshottsii in Italy. Samples underwent necropsy, histology, and culture with pathogen identification based on PCR and sequencing of housekeeping genes (16S rRNA, hsp65, rpoB). Multifocal to coalescing granulomatous and necrotizing inflammation with acid-fast bacilli were observed in the parenchymatous organs, from which M. pseudoshottsii was isolated and identified. Phylogenetic analysis confirmed the results of gene sequencing and allowed subdivision of the isolates into three distinct groups. M. pseudoshottsii poses a potential threat for Mediterranean aquaculture. Its origin in the area under study needs to be clarified, as well as the threat to the farmed fish species.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1567
Author(s):  
Patrícia G. Cardoso ◽  
Odete Gonçalves ◽  
Maria F. Carvalho ◽  
Rodrigo Ozório ◽  
Paulo Vaz-Pires

Freshness is considered one of the most important parameters to judge the quality of most fish products. In the current study, the seasonality effect on the freshness profile of different economic fish species was evaluated for the first time, using three different approaches (sensory: Quality Index Method (QIM) and European (EC) Scheme; physical: Torrymeter (TRM) values; and microbiological analyses: Total Viable Counts (TVC) and degradative bacteria). Over a year, individuals of farmed fish Sparus aurata and Dicentrarchus labrax, as well as the wild fish Trachurus trachurus, Scomber colias, and Sardina pilchardus, were sampled seasonally for the evaluation of their freshness profile over 10 days on ice. In general, data showed an increase in QIM values, a decline in TRM, and an increase of spoilage bacteria throughout the storage time, revealing a clear temporal degradation of the quality of the fish. Additionally, some signs of seasonality effect could only be observed for some species. For example, the seabass D. labrax showed lower numbers of degradative bacteria in winter than in the other seasons, suggesting a high potential to be marketed in a fresher condition, especially during that season. On the other hand, S. colias showed higher freshness scores (i.e., higher TRM values in spring and autumn and lower numbers of bacteria in summer) from spring to autumn. However, from the five studied species, S. colias presented the lowest freshness values, indicating a higher fragility of this species. This information is extremely relevant for consumers and retailers that want to invest in higher quality products, as they would thus be able to choose certain species in detriment of others. Additionally, obtained data showed that farmed species reached day 10 of storage time with lower values of QIM and microbial counts (cfu), as well as higher values of TRM, in relation to wild species. These results reinforce the idea that farmed fish can, under proper conditions, present high quality/freshness profile.


2020 ◽  
Author(s):  
C. Peñaloza ◽  
T. Manousaki ◽  
R. Franch ◽  
A. Tsakogiannis ◽  
A. Sonesson ◽  
...  

AbstractSNP arrays are powerful tools for high-resolution studies of the genetic basis of complex traits, facilitating both population genomic and selective breeding research. The European seabass (Dicentrarchus labrax) and the gilthead seabream (Sparus aurata) are the two most important fish species for Mediterranean aquaculture. While selective breeding programmes increasingly underpin stocky supply for this industry, genomic selection is not yet widespread. Genomic selection has major potential to expedite genetic gain, in particular for traits practically impossible to measure on selection candidates, such as disease resistance and fillet yield. The aim of our study was to design a combined-species 60K SNP array for both European seabass and gilthead seabream, and to validate its performance on farmed and wild populations from numerous locations throughout the species range. To achieve this, high coverage Illumina whole genome sequencing of pooled samples was performed for 24 populations of European seabass and 27 populations of gilthead seabream. This resulted in a database of ~20 million SNPs per species, which were then filtered to identify high-quality variants and create the final set for the development of the ‘MedFish’ SNP array. The array was then tested by genotyping a subset of the discovery populations and demonstrated a high conversion rate to functioning polymorphic assays on the array (92% in seabass: 89% in seabream) and repeatability (99.4 - 99.7%). The platform interrogates ~30K markers in each fish species, includes features such as SNPs previously shown to be associated with performance traits, and is enriched for SNPs predicted to alter protein function. The array was demonstrated to be effective at detecting population structure across a wide range of fish populations from diverse geographical origins, and to examine the extent of haplotype sharing among Mediterranean fish farms. Therefore, the MedFish array enables efficient and accurate high-throughput genotyping for genome-wide distributed SNPs on each fish species, and will facilitate stock management, population genomics approaches, and acceleration of selective breeding through genomic selection.


2016 ◽  
Vol 60 (2) ◽  
Author(s):  
M. Úbeda-Manzanaro ◽  
J.B. Ortiz-Delgado ◽  
C. Sarasquete

<p>Multiple genes and transcription factors are involved in regulation and control of the complex process of sex determination and differentiation of fish species. Also more, several hormonal factors and some environmental conditions can also be adequate spawning strategies and stimuli for inducing reproduction of fish species. <em>Brdt</em> gene belongs to the bromodomain-extraterminal domain (BET) family of transcriptional coregulators. In mammals, <em>Brdt</em> gene is almost exclusively expressed in testis. Furthermore, Brdt protein is involved in elongating spermatids, and is required for proper spermatogenesis and male fertility. However, from our understanding of fish species, the role of this gene as key, during gametogenesis, still remains unknown. In this study, two <em>Brdt</em> mRNA transcripts were isolated from two teleostean fish species, gilthead seabream and European seabass. In both species the shorter form lacked a functional C-terminal domain, which may involve a different function as transcriptional regulator. The pattern of <em>Brdt</em> expression showed that the highest levels occurred in the gonads. Significantly lower levels of expression were detected in brain, pituitary and different organ systems (heart, kidney, gills, among other somatic tissues) from both studied species. <em>In situ</em> hybridization approach evidenced that <em>Brdt</em> mRNA expression was restricted to specific cell-types of the germ line, during both oogenesis and spermatogenesis processes.</p>


2006 ◽  
Vol 12 (3) ◽  
pp. 261-268 ◽  
Author(s):  
M. Tejada ◽  
A. Huidobro ◽  
G. Fouad Mohamed

Two farmed fish species of great importance in the European market, gilthead seabream ( Sparus aurata; GSB) and seabass ( Dicentrarchus labrax; SB) reared in different conditions were analysed to determine the best index to be used for calibration of a prototype designed for rapid measurement of freshness in ice stored fish. Sensory evaluation (quality index) was related to K-value (percent of the ratio of inosine plus hypoxanthine to adenosine-5-triphosphate (ATP) and breakdown products) and Torrymeter readings, chosen as indices that detect early changes in the ice stored fish. Higher K-values were obtained in SB than in GSB, however the degradation of ATP and derivatives followed the same pattern in the different lots in each species. No statistical differences in the evolution of K-value for the same storage time were observed, irrespective of the amount of ATP and breakdown products, muscle composition and rearing conditions of the fish. K-value correlated strongly with storage time and sensory evaluation measured in the raw fish, however, correlation of Torrymeter readings with storage time or sensory evaluation was much lower. This makes K-value a good index in these species for calibrating an apparatus designed to measure time-related changes in fish in response to chill storage.


2021 ◽  
Author(s):  
Alba de la Vara ◽  
William Cabos ◽  
Dmitry V. Sein ◽  
Claas Teichmann ◽  
Daniela Jacob

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.


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