Browsing by Author "Robalo, Joana"
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- Aeromonas spp. Prevalence, virulence, and antimicrobial resistance in an ex situ program for tThreatened freshwater fish—A pilot study with protective measuresPublication . Grilo, Miguel; Amaro, Guadalupe; Chambel, Lélia; Marques, Carolina S.; Marques, Tiago A.; Gil, Fátima; Sousa-Santos, Carla; Robalo, Joana; Oliveira, ManuelaEx situ breeding programs are important conservation tools for endangered freshwater fish. However, developing husbandry techniques that decrease the likelihood of disease, antimicrobial resistance, and virulence determinants acquisition during this process is challenging. In this pilot study, we conducted a captivity experiment with Portuguese nase (Iberochondrostoma lusitanicum), a critically endangered leuciscid species, to investigate the influence of simple protective measures (i.e., material disinfection protocols and animal handling with gloves) on the dynamics of a potential pathogenic genus, Aeromonas, as well as its virulence profiles and antimicrobial resistance signatures. Our findings show that antimicrobial resistance in Aeromonas spp. collected from I. lusitanicum significantly increased during the extent of the assay (5 weeks), with all isolates collected at the end of the study classified as multidrug-resistant. Additionally, humans handling fishes without protective measures were colonized by Aeromonas spp. The use of protective measures suggested a decreasing trend in Aeromonas spp. prevalence in I. lusitanicum, while bacterial isolates displayed significantly lower virulence index values when virulence phenotypical expression was tested at 22 °C. Despite this study representing an initial trial, which needs support from further research, protective measures tested are considered a simple tool to be applied in ex situ breeding programs for aquatic animals worldwide. Furthermore, current results raise concern regarding antimicrobial resistance amplification and zoonotic transmission of Aeromonas spp. in aquatic ex situ programs.
- Against all odds: a tale of marine range expansion with maintenance of extremely high genetic diversityPublication . Robalo, Joana; Francisco, Sara M.; Vendrell, Catarina; Lima, Cristina S.; Pereira, Ana; Brunner, Benedikt P.; Dia, Mamadou; Gordo, L. S.; Castilho, RitaThe displacement of species from equatorial latitudes to temperate locations following the increase in sea surface temperatures is among the significant reported consequences of climate change. Shifts in the distributional ranges of species result in fish communities tropicalisation, i.e., high latitude colonisations by typically low latitude distribution species. These movements create new interactions between species and new trophic assemblages. The Senegal seabream, Diplodus bellottii, may be used as a model to understand the population genetics of these invasions. In the last decades, this species has undergone an outstanding range expansion from its African area of origin to the Atlantic coast of the Iberian Peninsula, where now occurs abundantly. Mitochondrial and nuclear markers revealed a striking high haplotypic nucleotide and genetic diversity values, along with significant population differentiation throughout the present-day geographical range of the Senegal seabream. These results are not consistent with the central-marginal hypothesis, nor with the expectations of a leptokurtic distribution of individuals, as D. bellottii seems to be able to retain exceptional levels of diversity in marginal and recently colonised areas. We discuss possible causes for hyperdiversity and lack of geographical structure and subsequent implications for fisheries.
- Climatic alterations influence bacterial growth, biofilm production and antimicrobial resistance profiles in aeromonas spp.Publication . Grilo, Miguel L.; Pereira, Ana; Sousa-Santos, Carla; Robalo, Joana; Oliveira, ManuelaClimate change is expected to create environmental disruptions that will impact a wide array of biota. Projections for freshwater ecosystems include severe alterations with gradients across geographical areas. Life traits in bacteria are modulated by environmental parameters, but there is still uncertainty regarding bacterial responses to changes caused by climatic alterations. In this study, we used a river water microcosm model to evaluate how Aeromonas spp., an important pathogenic and zoonotic genus ubiquitary in aquatic ecosystems, responds to environmental variations of temperature and pH as expected by future projections. Namely, we evaluated bacterial growth, biofilm production and antimicrobial resistance profiles of Aeromonas species in pure and mixed cultures. Biofilm production was significantly influenced by temperature and culture, while temperature and pH affected bacterial growth. Reversion of antimicrobial susceptibility status occurred in the majority of strains and tested antimicrobial compounds, with several combinations of temperature and pH contributing to this effect. Current results highlight the consequences that bacterial genus such as Aeromonas will experience with climatic alterations, specifically how their proliferation and virulence and phenotypic resistance expression will be modulated. Such information is fundamental to predict and prevent future outbreaks and deleterious effects that these bacterial species might have in human and animal populations.
- Foraging behaviour and diet of Brown boobies Sula leucogaster from Tinhosas Islands, Gulf of GuineaPublication . Correia, Edna; Catry, Paulo; Sinclair, Frazer; Santos, Yodiney dos; Robalo, Joana; Lima, Cristina S.; Granadeiro, José PedroSeabirds are a highly threatened group, yet the foraging ecology of several species remains poorly understood. Brown boobies breed in all oceans in the tropical region and are common across their range. In Tinhosa Grande (São Tomé and Príncipe), this species breeds in one of the largest colonies of seabirds in the east tropical Atlantic. We studied the foraging ecology of Brown boobies from this colony during the chick-rearing period. Thirty-three birds were tracked with GPS loggers and their diet was analysed from 11 regurgitations, using traditional and DNA barcoding techniques for prey identifcation. A total of 127 completed foraging trips were identifed, 89% of which lasted less than 24 h. Females performed signifcantly longer trips and both sexes foraged preferentially over deep oceanic waters. The diet of Brown boobies included juvenile fsh and squid (Sthenoteuthis pteropus), comprising mostly fsh species whose juvenile phases live in the pelagic environment, and only migrate to coastal waters when adults. The most frequent of those prey found was Flying gurnard (Dactylopterus volitans). The relevance of such prey shows that Brown booby conservation depends not only on the management of their foraging areas and breeding sites but also on the correct management of the coastal adjacent areas that support the adult individuals of some of their prey. Our results suggest that the areas closest to the colony do not have available resources for these birds to feed on and that Brown boobies may be associate with subsurface marine predators or with sargassum patches to forage.
- Genetic hypervariability of a Northeastern Atlantic venomous rockfishPublication . Francisco, Sara M.; Castilho, Rita; Lima, Cristina S.; Almada, Frederico José Oliveira de; Rodrigues, Francisca; Šanda, Radek; Vukic, Jasna; Pappalardo, Anna Maria; Ferrito, Venera; Robalo, JoanaBackground: Understanding the interplay between climate and current and historical factors shaping genetic diversity is pivotal to infer changes in marine species range and communities’ composition. A phylogeographical break between the Atlantic and the Mediterranean has been documented for several marine organisms, translating into limited dispersal between the two basins. Methods: In this study, we screened the intraspecific diversity of 150 individuals of the Madeira rockfish (Scorpaena maderensis) across its distributional range (seven sampling locations in the Atlantic and Mediterranean basins) using the mitochondrial control region and the nuclear S7 first intron. Results: The present work is the most comprehensive study done for this species, yielding no genetic structure across sampled locations and no detectable Atlantic-Mediterranean break in connectivity. Our results reveal deep and hyper-diverse bush-like genealogies with large numbers of singletons and very few shared haplotypes. The genetic hyper-diversity found for the Madeira rockfish is relatively uncommon in rocky coastal species, whose dispersal capability is limited by local oceanographic patterns. The effect of climate warming on the distribution of the species is discussed.
- Genomics goes deeper in fisheries science: The case of the blackspot seabream (Pagellus bogaraveo) in the northeast AtlanticPublication . Cunha, Regina L.; Robalo, Joana; Francisco, Sara M.; Farias, Inês; Castilho, Rita; Figueiredo, IvoneRecent advances in genomics are an essential contributor to the assessment of fish stocks by providing a finescale identification of the species’ genetic boundaries. The blackspot seabream, Pagellus bogaraveo, is a commercial sparid distributed across the northeast (NE) Atlantic and the Mediterranean. Within the NE Atlantic, three P. bogaraveo stocks are currently defined: Azores; Atlantic Iberian waters; Celtic Sea and the Bay of Biscay. We used a genotyping-by-sequencing (GBS) approach to better define the spatial scale at which the species occurs in the NE Atlantic. Our findings revealed the existence of an additional genetic cluster in the eastern Atlantic (Gulf of C´ adiz) that was not identified in previous studies based on mitochondrial DNA or microsatellite data. The combined effect of ocean circulation patterns, complex bathymetry and the existence of local upwelling may play an important role on the retention of blackspot seabream larvae and adults, providing an explanation for the genetic differentiation between the specimens caught off the Gulf of C´ adiz and Peniche (Portugal). Results presented here revealed hidden intra-specific genetic differentiation and can inform a finer-scale sampling to determine the new stock boundaries in the Atlantic Iberian coasts.
- Historical biogeography of the Iberian Peninsula: multilocus phylogeny and ancestral area reconstruction for the freshwater fish genus Squalius (Actinopterygii, Leuciscidae)Publication . Perea, Silvia; Sousa‐Santos, Carla; Robalo, Joana; Doadrio, IgnacioThe Iberian Peninsula is one of the most ancient geological areas in Europe. Its complex orography is a consequence of several geological episodes related with two orogenic episodes that occurred from Late Devonian (Variscan orogeny) to the Cenozoic (Alpine orogeny). Unraveling the evolutionary history of strict freshwater fauna, such as leuciscid fishes, may contribute to our understanding of the paleogeographic history of a region and its configuration along time. Within the Iberian freshwater fish fauna, the genus Squalius is one of the oldest and most diversified leuciscids. Here, we used phylogenetic, phylogeographic, and ancestral area reconstruction approaches to infer relationships among Iberian drainages and the biogeographic history of these Squalius species, particularly of two of the most widely distributed species, S. carolitertii and S. pyrenaicus. Our results confirmed, in agreement with previous studies, an underestimation of the real diversity of Squalius in the Iberian Peninsula and identified divergent evolutionary lineages, highlighting the reticulate evolutionary history of the Iberian Squalius species. The ancestral reconstruction analyses indicated that several vicariance and dispersal processes occurred among different Squalius lineages, linked to the paleogeographic configuration of the Iberian Peninsula during the Cenozoic period.
- Mitonuclear genetics reveals a novel perspective on the stock structure and fishery management of skipjack tuna (Katsuwonus pelamis) in the Atlantic OceanPublication . Queiroz-Brito, Maria Clara G.; Mendonça, Fernando F.; Robalo, Joana; Arocha, Freddy; Diaha, N’Guessan Constance; Amandé, Monin Justin; Sow, Fambaye Ngom; Angueko, Davy; Travassos, Paulo; Torres, Rodrigo A.The skipjack tuna, Katsuwonus pelamis is the worldwide most fished and economically significant tuna species. In the Atlantic Ocean, the management strategy of the International Commission for the Conservation of Atlantic Tunas (ICCAT) includes two stocks: (a) eastern (SKJ-E) and (b) western (SKJ-W) stocks. However, the genetic cohesiveness between these stocks remains poorly understood. Here, we provide this information through mitochondrial [control region (CR)] and nuclear (intron S7) data. In both markers, high genetic diversity and no contraction signals in effective population sizes were found, supporting the species conservation status as ‘Least Concern’ by the IUCN and the results of the latest ICCAT assessment of the two stocks. In general, no well-defined genetic-geographic structure was detected, which may be explained by the specie life history strategies, such as large population effective sizes and migratory behavior, with a broad geographical distribution, that reduce the isolation, inbreeding, and genetic drift effects. However, pairwise FST values within and between the Eastern and Western Atlantic suggest some weak to moderate genetic differentiation. These results involved mainly the Eastern Temperate Zone, represented herein by the Azores archipelago. It is important to highlight that higher differentiation levels were found between sites from different stocks. In addition, the CR data revealed a weak but significant genetic differentiation between the eastern and western stocks (FST = 0.0006). These results can be used to improve and support the ICCAT management strategies of skipjack tuna stocks, highlighting the need for a reevaluation and possible alignment between Eastern and Western Atlantic management actions. Similar content being viewed by others
- Molecular epidemiology, virulence traits and antimicrobial resistance signatures of aeromonas spp. in the critically endangered iberochondrostoma lusitanicum follow geographical and seasonal patternsPublication . Grilo, Miguel; Isidoro, Sara; Chambel, Lélia; Marques, Carolina S.; Marques, Tiago A.; Sousa-Santos, C.; Robalo, Joana; Oliveira, ManuelaDespite the fact that freshwater fish populations are experiencing severe declines worldwide, our knowledge on the interaction between endangered populations and pathogenic agents remains scarce. In this study, we investigated the prevalence and structure of Aeromonas communities isolated from the critically endangered Iberochondrostoma lusitanicum, a model species for threatened Iberian leuciscids, as well as health parameters in this species. Additionally, we evaluated the virulence profiles, antimicrobial resistance signatures and genomic relationships of the Aeromonas isolates. Lesion prevalence, extension and body condition were deeply affected by location and seasonality, with poorer performances in the dry season. Aeromonas composition shifted among seasons and was also different across river streams. The pathogenic potential of the isolates significantly increased during the dry season. Additionally, isolates displaying clinically relevant antimicrobial resistance phenotypes (carbapenem and fluroquinolone resistance) were detected. As it inhabits intermittent rivers, often reduced to disconnected pools during the summer, the dry season is a critical period for I. lusitanicum, with lower general health status and a higher potential of infection by Aeromonas spp. Habitat quality seems a determining factor on the sustainable development of this fish species. Also, these individuals act as reservoirs of important antimicrobial resistant bacteria with potential implications for public health.
- Multilocus phylogeny and systematics of Iberian endemic Squalius (Actinopterygii, Leuciscidae)Publication . Perea, Silvia; Santos, Carla Sousa; Robalo, Joana; Doadrio, IgnacioInferring the evolutionary history of a group of species can be challenging given the many factors involved. In recent years, the increased availability of sequences of multiple genes per species has spurred the development of new methodologies to analyse multilocus data sets. Two approaches that analyse such data are concatenated supermatrix and coalescent-based species-tree analyses. In this study, we used both of these methods to infer the phylogenetic relationships of Iberian species of the genus Squalius from one mitochondrial and six nuclear genes. We found mitonuclear discordance in the phylogenetic relationships of the group. According to the mitochondrial gene analysis, all species were recovered as monophyletic except S. pyrenaicus; besides, in the concatenated supermatrix analysis of the nuclear markers, this species resolved as polyphyletic with three divergent evolutionary lineages. The coalescent-based nuclear species-tree analysis rendered a well-resolved phylogeny compared with the supermatrix analysis, which was unable to discern between S. carolitertii, S. castellanus and one of the evolutionary lineages of S. pyrenaicus. This result is likely due to the better integration of population uncertainty in the coalescent approach. Furthermore, Bayesian multilocus species delimitation analyses based on a BPP approach strongly supported the distinct nuclear lineages as different species. Nevertheless, the supermatrix analysis was able to obtain well-supported relationships in the divergent lineages with low numbers of individuals. Our study highlights the usefulness of different analytical methodologies to obtain a more complete picture of the evolutionary history of taxa, especially when discordant patterns among genes are found.