• European Marine Science
• 2014-2023close
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Aquaculture is one of the most prosperous economic sectors. Nevertheless, the natural outbreaks of several infectious diseases make the sector to deal with important economic losses. One of the most important pathogens in the Mediterranean Sea is nodavirus (NNV). NNV is the agent causing viral encephalopathy and retinopathy in more than 170 fish species including some of the most impact in Spanish hatcheries as European sea bass (Dicentrarchus labrax). Antimicrobial peptides (AMPs) are short aminoacidic sequences which constitute important mediators of the innate immune response in teleost fish. AMPs can kill directly a broad range of pathogens such as bacteria or viruses and modulate the host immune response leading to a more effective clearance of pathogens. These properties along with the world emergency in antimicrobial resistance (AMR) make AMPs good candidates to replace traditional antimicrobials. Therefore, we aimed to analyze the molecular regulation of European sea bass defensin beta genes upon NNV infection and after NNV vaccination. To achieve our objective, European sea bass were infected with NNV and samples of head-kidney (HK), brain and gonad were taken. In addition, gonadal cells from healthy males were in vitro stimulated with NNV. Then, ovary samples of control females or vaccinated against NNV (pBAD vaccine) were taken, as well as fertilized eggs and larvae from the same groups. To support our data, we also analyzed in silico the potential antiviral activity of the protein encoded by the studied genes. Our results show that defensin beta 1 gene is up-regulated upon in vivo NNV infection even if in the in silico study showed the lesser predicted activity. Interestingly, the in vitro NNV challenge resulted in no variation of the defensin beta 1 gene, while defensin beta 2.1 and 2.2 genes were blocked upon this stimulus. Strikingly, females vaccinated with pBAD greatly down-regulate defensin beta 2.2 expression. Moreover, larvae from vaccinated mother up-regulate all defensin beta genes. In conclusion, defensin beta 1 gene seems to be involved in the defense against viruses while defensin beta 2 genes appear to possess a more specific function in gonad. Evaluación de los efectos de las microalgas, incluidas en dietas de dorada, sobre el crecimiento, supervivencia y resistencia a infecciones. ALGAFISH

The IEO has maintained since late 60s, a local database with basic information on oceanographic campaigns, formerly known as ROSCOF reports, which were established in the framework of IODE initiatives, as a low-level inventory for future access to data. Technological advances in recent decades and different coordination activities between NODCs have favored the implementation of these reports in standardized digital formats (Cruise Summary Reports, CSR) that allow their integration in international repositories as SeaDataNet or POGO. However, this inventory and cataloging activity has suffered ups and downs over 40 years of activity, changes in storage criteria and periods of less activity. In the search for a unique criterion that can last over time and that unifies this information as much as possible with the data generated in these campaigns, an exhaustive review of the existing information has been carried out. The result has been the retrieval of information from short-term campaigns carried out on smaller vessels with great coastal activity, as well as updating information regarding old campaigns performed on the first half of the 20th century onboard of decommissioned vessels. All this is completed with the systematic campaigns carried out by INTECMAR in the Galician rias, research vessels operated by the national Fisheries Administration, and information on research surveys carried out by foreign ships in national waters, forming a catalog of more than 4000 entries. This approach is also followed by the UTM-CSIC, on its own-managed vessels and campaigns carried out since 1991. The common approach allows a unified response to the governmental needs for the planning of future campaigns, and in successive improvements in data recovering, archiving and accessing at NODC/CEDO.

El objetivo de este informe es la creación de fichas comparativas de los planes nacionales de ordenación del espacio marítimo de los países socios de MSPMED con el fin de detectar los puntos comunes y las principales diferencias entre ellos. MSPMED

Between 24 January and February 2019, selected Between 24 January and February 2019, selected seamounts of the Discovery Rise complex were explored during a research survey conducted on board the RV Dr. the RV Dr. FridtjofNansen (IMR – Norway) following recommendations of the Southeast Atlantic Fisheries Organization (SEAFO) to identify the occurrence and distribution of ‘Vulnerable Marine Ecosystems’ (VMEs) in sectors of sub-area D of SEAFO Convention Area, including areas precautionarily closed for longline fishing. Estudio de los recursos marinos vivos del Atlántico Sur, Océano Austral, Índico y Pacífico. ATLANSUR

Nervous Necrosis Virus (NNV) is one of the most challenging pathogens for aquaculture development nowadays, mainly affecting marine teleost fish of major interest to the aquaculture industry and causing great economic losses. NNV consist in four genotypes, which seem to have a tropism for certain teleost fish species. Among them, gilthead seabream (Sparus aurata) has been considered as a non-susceptible species to the disease produced by traditional NNV genotypes. However, there are some evidences that indicate seabream is able to develop the disease in the presence of certain reassortant strains of NNV, called RGNNV/SJNNV, which possesses the RNA1 segment of the RGNNV genotype and the RNA2 segment of the SJNNV genotype, which may cause a new threat to aquaculture. Therefore, the main objective of this study was to evaluate the susceptibility of gilthead seabream larvae to the reassortant strains RGNNV/SJNNV and SJNNV/RGNNV. For this purpose, larvae were exposed to 104 TCDI50/mL in triplicate tanks with the reassortant strains. Samples of 5 individual larvae were collected at different days post-infection and used for gene expression and infective NNV isolation. Our data show that both reassortants produced mortalities, although the RGNNV/SJNNV was the one which produced the highest mortality and viral gene transcription, which significantly increased from 1 to 7 days post-infection. In conclusion, our study demonstrate that seabream larvae are susceptible to both RGNNV/SJNNV and SJNNV/RGNNV reassortants under laboratory conditions. Further studies should be performed to understand the pathogenicity of the NNV reassortant strains to prevent and control future outbreaks in aquaculture farms.

The salmon louse is a highly abundant ectoparasitic copepod of salmonids in the North Pacific and Atlantic. Widespread and rapid development of resistance to chemical agents used to delouse salmonids on marine farms is now threatening the continued development of the aquaculture industry and have served as a potent catalyst for the development of alternative pest management strategies. These include freshwater and warm-water treatments to which the louse is sensitive. However, given the well-documented evolutionary capacity of this species, the risk of developing tolerance towards these environmental treatments cannot be dismissed. Two common-garden experiments were performed using full-sibling families of lice identified by DNA parentage testing to investigate whether one of the fundamental premises for evolution, in this context genetic variation in the capacity of coping with fresh or warm water, exists within this species. Significant differences in survival were observed among families in both experiments, although for the salinity experiment, it was not possible to unequivocally disentangle background mortality from treatment-induced mortality. Thus, our data demonstrate genetic variation in tolerance of warm water and are suggestive of genetic variation in salinity tolerance. We conclude that extensive use of these environmental-based treatments to delouse salmonids on commercial farms may drive lice towards increased tolerance.