Genome sequencing and analysis of black flounder (Paralichthys orbignyanus) reveals new insights into Pleuronectiformes genomic size and structure.

Black flounder (Paralichthys orbignyanus, Pleuronectiformes) is a commercially significant marine fish with promising aquaculture potential in Argentina. Despite extensive studies on Black flounder aquaculture, its limited genetic information available hampers the crucial role genetics plays in the development of this activity. In this study, we first employed Illumina sequencing technology to sequence the entire genome of Black flounder.

Atlantic bonito (Sarda) genomic analysis reveals population differentiation across Northeast Atlantic and mediterranean locations: Implications for fishery management.

The Atlantic bonito (Sarda, family Scombridae) is a pelagic species and one of the most exploited small tuna species. Despite its economic importance, biological information is scarce with no associated management directives. In this study, using a population genomic approach resulted in a lack of panmixia of two genetic pools with different effective population sizes (east central-tropical Atlantic and northeast Atlantic-Mediterranean) and an intermixing zone in Atlantic Morocco.

Environmental DNA Assay for the Detection of the American Bullfrog () in the Early Stages of the Invasion in the Ebre Delta.

The American bullfrog () is considered to be one of the most harmful invasive species. In the Iberian Peninsula, this species had been cited occasionally until the year 2018, when appeared in the Ebre Delta, and, for the first time, it started breeding in a territory of the Peninsula. Using environmental DNA (eDNA) analysis and visual surveys, the American bullfrog invasion in the Ebre Delta was monitored across two consecutive years (2019-2020).

Ascaridoid parasites in European sardine throughout the annual cycle: Variability in parasitic load according to host stock features.

In recent years, a drop in the condition of the European sardine has been observed. Although several causes have been attributed to this issue, as overfishing and climate change, little is known about the link between ascaridoid nematode parasitisation and fish status. In this study, sardines were obtained from four fishing grounds along the Mediterranean (Alboran, Northern Spain, Northern Adriatic, and Aegean), and one location in the Atlantic Ocean (Southern Portugal).

Attitudes of Spanish hospital staff towards COVID-19 vaccination and vaccination rates.

Background: COVID-19 vaccine hesitancy seems to be universal across countries and subgroups, and so are its determinants. We studied the willingness and factors associated with the decision to be vaccinated against COVID-19 in healthcare workers (HCW) in a Spanish tertiary hospital. Furthermore, we compared the percentage of willingness to vaccinate against COVID with actual vaccination rates among HCW in our hospital.

Genetic validation of the unexpected presence of a tropical tuna, bigeye tuna (Thunnus obesus), in the Mediterranean.

Bigeye tuna (Thunnus obesus, Lowe, 1839) is one of the eight recognized species of the genus Thunnus. It is considered a tropical species distributed in the Atlantic, Pacific and Indian Oceans. To date, no validated presence of this species has been reported inside the Mediterranean Sea.

Tuna Species Substitution in the Spanish Commercial Chain: A Knock-On Effect.

Intentional mislabelling of seafood is a widespread problem, particularly with high-value species like tuna. In this study we examine tuna mislabelling, deliberate species substitution, types of substitution and its impact on prices. The survey covered the commercial chain, from Merca-Barna to fishmongers and restaurants in the Spanish Autonomous Community of Catalonia.

Individual Spawning Duration of Captive Atlantic Bluefin Tuna (Thunnus thynnus) Revealed by Mitochondrial DNA Analysis of Eggs.

This study presents the first results on Atlantic bluefin tuna (Thunnus thynnus) individual spawning duration and its short-term temporal behavior. The study was based on direct measurements resulting from mtDNA analysis of the offspring of spawners held in transport cages during the 2013 spawning monitoring survey in Balearic waters. The number of females consisted of approximately 259 individuals with an average weight of 186 kg.

Multilocus Bayesian Estimates of Intra-Oceanic Genetic Differentiation, Connectivity, and Admixture in Atlantic Swordfish (Xiphias gladius L.).

Previous genetic studies of Atlantic swordfish (Xiphias gladius L.) revealed significant differentiation among Mediterranean, North Atlantic and South Atlantic populations using both mitochondrial and nuclear DNA data. However, limitations in geographic sampling coverage, and the use of single loci, precluded an accurate placement of boundaries and of estimates of admixture.

Stage-specific gene expression during spermatogenesis in the Senegalese sole (Solea senegalensis), a fish with semi-cystic type of spermatogenesis, as assessed by laser capture microdissection and absolute quantitative PCR.

Spermatogenesis is a complex process where hormonal signals regulate the interaction of different cell types in a tight spatial and temporal fashion. The Senegalese sole (Solea senegalensis) is a marine flatfish that, in contrast to many fish, exhibits a semi-cystic, asynchronous pattern of spermatogenesis progression. This pattern is characterized by the release of spermatids into the tubule lumen, where they transform into spermatozoa.

The kisspeptin system genes in teleost fish, their structure and regulation, with particular attention to the situation in Pleuronectiformes.

It is well established that Kisspeptin regulates the onset of puberty in vertebrates through stimulation of the secretion of gonadotropin-releasing hormones. However, the function of kisspeptin in peripheral tissues and in other functions is still poorly understood. Recently, the evolution and distribution of kisspeptin genes in vertebrates has been clarified.

Multilocus comparative phylogeography of two aristeid shrimps of high commercial interest (Aristeus antennatus and Aristaeomorpha foliacea) reveals different responses to past environmental changes.

Phylogeographical studies can reveal hidden patterns in the evolutionary history of species. Comparative analyses of closely related species can further help disentangle the relative contributions of processes responsible for such patterns. In this work, the phylogeography of two aristeid species, Aristeus antennatus and Aristaeomorpha foliacea, was compared through multiple genetic markers.

Sex-specific changes in the expression of kisspeptin, kisspeptin receptor, gonadotropins and gonadotropin receptors in the Senegalese sole (Solea senegalensis) during a full reproductive cycle.

Kisspeptin is thought to have a major role in the control of the onset of puberty in vertebrates. However, our current understanding of its function in fish and how it integrates with other hormones is incomplete due to the high diversity of this group of animals and a still limited amount of available data. This study examined the temporal and spatial changes in expression of kisspeptin, gonadotropins and their respective receptors in the Senegalese sole during a full reproductive cycle.

DNA methylation of the gonadal aromatase (cyp19a) promoter is involved in temperature-dependent sex ratio shifts in the European sea bass.

Sex ratio shifts in response to temperature are common in fish and reptiles. However, the mechanism linking temperature during early development and sex ratios has remained elusive. We show in the European sea bass (sb), a fish in which temperature effects on sex ratios are maximal before the gonads form, that juvenile males have double the DNA methylation levels of females in the promoter of gonadal aromatase (cyp19a), the enzyme that converts androgens into estrogens.

Gene structure analysis of kisspeptin-2 (Kiss2) in the Senegalese sole (Solea senegalensis): characterization of two splice variants of Kiss2, and novel evidence for metabolic regulation of kisspeptin signaling in non-mammalian species.

Kisspeptin signaling in the brain is involved in the control of the onset of puberty in vertebrates. In this study, we present novel evidence indicating that kisspeptin may link energy balance and reproduction. For that purpose, we determined the complete gene structure of kisspeptin in a teleost fish, the Senegalese sole (Ss).

Gene structure of the Kiss1 receptor-2 (Kiss1r-2) in the Atlantic halibut: insights into the evolution and regulation of Kiss1r genes.

Kisspeptin and its receptor, Kiss1r, play an essential role in the control of the onset of puberty in vertebrates. We characterized the cDNA and genomic DNA encoding Kiss1r in Atlantic halibut (Hippoglossus hippoglossus). The 1146bp open reading frame predicts a 381 amino acid protein with high homology to the Kiss1r-2 of other teleost fish.

A validated methodology for genetic identification of tuna species (genus Thunnus).

Background: Tuna species of the genus Thunnus, such as the bluefin tunas, are some of the most important and yet most endangered trade fish in the world. Identification of these species in traded forms, however, may be difficult depending on the presentation of the products, which may hamper conservation efforts on trade control. In this paper, we validated a genetic methodology that can fully distinguish between the eight Thunnus species from any kind of processed tissue.

Genomic resources for a commercial flatfish, the Senegalese sole (Solea senegalensis): EST sequencing, oligo microarray design, and development of the Soleamold bioinformatic platform.

Background: The Senegalese sole, Solea senegalensis, is a highly prized flatfish of growing commercial interest for aquaculture in Southern Europe. However, despite the industrial production of Senegalese sole being hampered primarily by lack of information on the physiological mechanisms involved in reproduction, growth and immunity, very limited genomic information is available on this species.

Results: Sequencing of a S.

Identification of two isoforms of the Kisspeptin-1 receptor (kiss1r) generated by alternative splicing in a modern teleost, the Senegalese sole (Solea senegalensis).

The KISSPEPTIN-1 receptor (KISS1R) and its ligands (KISSPEPTINS) are implicated in the regulation of the onset of puberty. We report the coding region and genomic structure of the kiss1r gene of a modern teleost, the Senegalese sole (Ss). Ss kiss1r cDNA contained an opening frame of 1137 bp, which results in a predicted 378 amino acid protein.

Stage-specific gene expression during fish spermatogenesis as determined by laser-capture microdissection and quantitative-PCR in sea bass (Dicentrarchus labrax) gonads.

The role of genes implicated in the regulation of spermatogenesis and their patterns of expression is still poorly understood. In this study, we took advantage of the cystic arrangement of the teleost testis to set up a laser capture microdissection procedure to isolate cells from cysts containing spermatogonia, spermatocytes, spermatids, or spermatozoa. We then used quantitative PCR to determine the stage-specific expression patterns of the germ cell marker vasa; gonadal aromatase (cyp19a); estrogen receptors (ers) alpha, beta1, and beta2 (era, erb1, and erb2, respectively); 11beta-hydroxylase (cyp11b1); androgen receptor beta (arb); insulinlike growth factor 1 (igf1); and sox17.

Comparative phylogeography of Atlantic bluefin tuna and swordfish: the combined effects of vicariance, secondary contact, introgression, and population expansion on the regional phylogenies of two highly migratory pelagic fishes.

Comparative phylogeography has revealed remarkable patterns of concordance in the maternal phylogenies of many species. The phylogeography and historical demography of the mitochondrial control region I for 607 Atlantic bluefin tuna (Thunnus thynnus) and 275 swordfish (Xiphias gladius) were analyzed to clarify the complex phylogenetic signals in the North Atlantic-Mediterranean region where they are sympatric. Atlantic bluefin tuna mtDNA is polyphyletic, and includes rare sequences sister to Pacific bluefin tuna (Thunnus orientalis) and introgressed albacore (Thunnus alalunga) sequences.

Consequences of the historical demography on the global population structure of two highly migratory cosmopolitan marine fishes: the yellowfin tuna (Thunnus albacares) and the skipjack tuna (Katsuwonus pelamis).

Background: Yellowfin and skipjack tuna are globally distributed in the world's tropical and sub-tropical oceans. Since little, if any, migration of these fishes occurs between the Atlantic and Indo-Pacific Oceans, one might expect to see genetic differences between sub-populations in these ocean basins. However, yellowfin and skipjack tuna have extremely large population sizes.