Future climate-induced distribution shifts in a sexually dimorphic key predator of the Southern Ocean.

The response to climate change in highly dimorphic species can be hindered by differences between sexes in habitat preferences and movement patterns. The Antarctic fur seal, Arctocephalus gazella, is the most abundant pinniped in the Southern Hemisphere, and one of the main consumers of Antarctic krill, Euphausia superba, in the Southern Ocean. However, the populations breeding in the Atlantic Southern Ocean are decreasing, partly due to global warming. Male and female Antarctic fur seals differ greatly in body size and foraging ecology, and little is known about their sex-specific responses to climate change. We used satellite tracking data and Earth System Models to predict changes in habitat suitability for male and female Antarctic fur seals from the Western Antarctic Peninsula under different climate change scenarios. Under the most extreme scenario (SSP5-8.5; global average temperature +4.4°C projected by 2100), suitable habitat patches will shift southward during the non-breeding season, leading to a minor overall habitat loss. The impact will be more pronounced for females than for males. The reduction of winter foraging grounds might decrease the survival of post-weaned females, reducing recruitment and jeopardizing population viability. During the breeding season, when males fast on land, suitable foraging grounds for females off the South Shetland Islands will remain largely unmodified, and new ones will emerge in the Bellingshausen Sea. As Antarctic fur seals are income breeders, the foraging grounds of females should be reasonably close to the breeding colony. As a result, the new suitable foraging grounds will be useful for females only if nearby beaches currently covered by sea ice emerge by the end of the century. Furthermore, the colonization of these new, ice-free breeding locations might be limited by strong female philopatry. These results should be considered when managing the fisheries of Antarctic krill in the Southern Ocean.

La resposta al canvi climàtic en espècies amb dimorfisme sexual pot veure's dificultada per les diferències entre sexes respecte a les seves preferències d'ús de l'hàbitat i els seus patrons de moviment. L'os marí antàrtic (Arctocephalus gazella), és el pinnípede més abundant a l'Hemisferi Sud i un dels principals consumidors de krill antàrtic, (Euphausia superba), a l'Oceà Antàrtic. No obstant això, les poblacions que es reprodueixen al sector Atlàntic de l'Oceà Antàrtic estan disminuint, en part a causa de l'escalfament global. Els mascles i les femelles de l'os marí antàrtic difereixen considerablement en la seva mida corporal i ecologia tròfica, i es té poc coneixement sobre les seves respostes específiques al canvi climàtic. En aquest estudi hem utilitzat dades de seguiment per satèl·lit i models del Sistema Terrestre per predir els canvis en la idoneïtat de l'hàbitat per als mascles i les femelles d'os marí antàrtic de la Península Antàrtica Occidental sota diferents escenaris de canvi climàtic. Sota l'escenari més extrem (SSP5-8.5; temperatura mitjana mundial +4.4°C prevista per a 2100), les zones d'hàbitat idoni es desplaçaran cap al sud durant l'època d'hivernada (no reproducció), provocant una lleugera pèrdua d'hàbitat idoni. Tot i això, l'impacte serà més pronunciat per a les femelles que per als mascles. Aquesta reducció dels territoris d'alimentació durant l'hivern podria disminuir la supervivència de les femelles postdeslletades, reduint-ne el reclutament i posant en perill la viabilitat de la població. Durant l'època de cria, quan els mascles es troben majoritàriament en dejú a terra, els territoris d'alimentació idonis per a les femelles al voltant de les Illes Shetland del Sud romandran en gran part sense modificar-se, i n'emergiran de nous al mar de Bellingshausen. Com que les femelles d'os marí antàrtic es continuen alimentant durant la cria, els territoris d'alimentació de les femelles han d'estar raonablement a prop de la colònia de cria. Com a resultat, aquestes noves zones d'alimentació seran útils només si les platges properes, actualment cobertes de gel marí, emergeixen al llarg del segle. A més, la colonització d'aquests nous llocs de reproducció lliures de gel podria veure's limitada per la forta filopatria de les femelles. Aquests resultats haurien de tenir-se en compte en la gestió de les pesqueries de krill a l'Oceà Antàrtic.

Disentangling the influence of entanglement on recruitment in North Atlantic right whales.

North Atlantic right whales are Critically Endangered and declining, with entanglements in fishing gear a key contributor to their decline. Entanglement events can result in lethal and sub-lethal (i.e. increased energetic demands and reduced foraging ability) impacts, with the latter influencing critical life-history states, such as reproduction. Using a multi-event framework, we developed a Bayesian mark-recapture model to investigate the influence of entanglement severity on survival and recruitment for female right whales. We used information from 199 known-aged females sighted between 1977 and 2018, combined with known entanglements of varying severity that were classified as minor, moderate or severe. Severe entanglements resulted in an average decline in survival of 27% for experienced non-breeders, 9% for breeders and 26% for pre-breeding females compared with other entanglements and unentangled individuals. Surviving individuals with severe entanglements had low transitional probabilities to breeders, but surprisingly, individuals with minor entanglements had the lowest transitional probabilities, contrary to expectations underpinning current management actions. Management actions are needed to address the lethal and sub-lethal impacts of entanglements, regardless of severity classification.

Description of a large specimen of Paralepis elongata (Brauer, 1906) from Angola, southeastern Atlantic Ocean (Aulopiformes: Paralepididae).

The elongate barracudina, Paralepis elongata (Brauer, 1906), received limited attention in the past, with only a few individuals documented, mostly in publications focusing on the feeding habits of large predatory pelagic fishes. Furthermore, the taxonomic history of the species is complicated, with some earlier sources providing incorrect information that influenced subsequent works. As a result, the accurate distribution range of P. elongata remains uncertain. An adult male specimen of P. elongata, representing the largest known individual, is reported from off Angola, southeastern Atlantic. A detailed description is provided, and the literature records of the species are reviewed and discussed.

Quantifying larval dispersal portfolio in seabass nurseries using otolith chemical signatures.

The temporal asynchronies in larvae production from different spawning areas are fundamental components for ensuring stability and resilience of marine metapopulations. Such a concept, named portfolio effect, supposes that diversifying larval dispersal histories should minimize the risk of recruitment failure by increasing the probability that at least some larvae successfully settle in nursery. Here, we used a reconstructive approach based on otolith chemistry to quantify the larval dispersal portfolio of the European seabass, Dicentrarchus labrax, across six estuarine nursery areas of the northeast Atlantic Ocean. The analysis of natal and trajectory signatures indicated that larvae hatch in distinct environments and then dispersed in water masses featured by contrasting chemical signatures. While some trace elements appeared affected by temporal changes (Mn and Sr), others varied spatially during the larval stage but remained poorly affected by temporal fluctuation and fish physiology (Ba, Cu, Rb and Zn). We then proposed two diversity metrics based on richness and variations of chemical signatures among populations to reflect spatio-temporal diversity in natal origins and larval trajectories (i.e., estimates of dispersal portfolio). Along the French coast, the diversity estimates were maximum in nurseries located at proximity of offshore spawning sites and featured by complex offshore hydrodynamic contexts, such as the Mont St-Michel bay. Finally, our findings indicate that the dispersal portfolio was positively related with the local abundance of seabass juveniles, supporting the assumption that heterogeneity in dispersal history contributes to promote recruitment success in nurseries.

Environmental preferences and critical habitat for the velvet belly lanternshark (Etmopterus spinax) in Icelandic waters.

The velvet belly lanternshark (Etmopterus spinax) is a small, bioluminescent shark that is caught as bycatch in many deep-sea fisheries in the Atlantic Ocean. Using data from 10,597 seasonal research survey tows spanning 11 years, the distribution, relative abundance, life history, and environmental preferences of E. spinax in Icelandic waters was examined for the first time. E. spinax (n = 8774) were only captured in relatively deep offshore waters to the south and west of Iceland. Females grew to larger sizes than males and reached 50% sexual maturity at a total length of 50 cm. Females at a late stage of maturity and very small juveniles (<20 cm) were restricted to the central south Icelandic shelf, suggesting that this might be critical habitat for the reproduction of the species. Most of the sharks were captured at depths of 400-500 m, a relatively narrow depth range, and classified as a stenothermic warm-water species with habitat temperature restricted to about 6.3-8.0°C. Teleosts, crustaceans and cephalopods made up most of the diet. There was no indication of a decline in abundance over the time span of the survey. However, climate-induced warming of the deep ocean may shift the distribution of the species to more northerly waters within Iceland.

Possible transport pathway of diazotrophic Trichodesmium by Agulhas Leakage from the Indian into the Atlantic Ocean.

Diazotrophic cyanobacteria such as Trichodesmium play a crucial role in the nitrogen budget of the oceans due to their capability to bind atmospheric nitrogen. Little is known about their interoceanic transport pathways and their distribution in upwelling regions. Trichodesmium has been detected using a Video Plankton Recorder (VPR) mounted on a remotely operated towed vehicle (TRIAXUS) in the southern and northern Benguela Upwelling System (BUS) in austral autumn, Feb/Mar 2019. The TRIAXUS, equipped with a CTD as well as fluorescence and nitrogen sensors, was towed at a speed of 8 kn on two onshore-offshore transects undulating between 5 and 200 m over distances of 249 km and 372 km, respectively. Trichodesmium was not detected near the coast in areas of freshly upwelled waters but was found in higher abundances offshore on both transects, mainly in subsurface water layers down to 80 m depth with elevated salinities. These salinity lenses can be related to northward moving eddies that most probably have been detached from the warm and salty Agulhas Current. Testing for interaction and species-habitat associations of Trichodesmium colonies with salinity yielded significant results, indicating that Trichodesmium may be transported with Agulhas Rings from the Indian Ocean into the Atlantic Ocean.

Ocean climate and hydrodynamics drive decadal shifts in Northeast Atlantic dinoflagellates.

The abundance of large marine dinoflagellates has declined in the North Sea since 1958. Although hypotheses have been proposed to explain this diminution (increasing temperature and wind), the mechanisms behind this pattern have thus far remained elusive. In this article, we study the long-term changes in dinoflagellate biomass and biodiversity in relation to hydro-climatic conditions and circulation within the North Atlantic. Our results show that the decline in biomass has paralleled an increase in biodiversity caused by a temperature-induced northward movement of subtropical taxa along the European shelf-edge, and facilitated by changes in oceanic circulation (subpolar gyre contraction). However, major changes in North Atlantic hydrodynamics in the 2010s (subpolar gyre expansion and low-salinity anomaly) stopped this movement, which triggered a biodiversity collapse in the North Sea. Further, North Sea dinoflagellate biomass remained low because of warming. Our results, therefore, reveal that regional climate warming and changes in oceanic circulation strongly influenced shifts in dinoflagellate biomass and biodiversity.

Assessing sandy beach macrofaunal assemblages across geographically diverse morphodynamic environments.

While the physical characteristics of sandy beaches play a significant role in shaping the macrofaunal community features through morphodynamics, regional environmental factors may also account for deviations from the expected patterns. Here, we assess the concurrent effects of local morphodynamic factors and regional variables, such as sea surface temperature (SST), salinity, and chlorophyll-a (chl-a), on species richness and abundance of intertidal macrofaunal assemblages in four sandy beaches located along the estuarine gradient generated by the Río de la Plata (RdlP) in the southwestern Atlantic Ocean. Species richness was higher in dissipative beaches compared to intermediate ones, consistent with the predictions of the Swash Exclusion Hypothesis. However, this trend was not observed for total abundance, which significantly increased with chl-a. Both local and regional-scale environmental factors, such as salinity and chl-a, proved to be significant predictors in the arrangement of these communities. These results further support previous findings that highlight the critical role of the estuarine gradient of the RdlP in shaping life-history traits, population structure, and abundance of the resident intertidal macrofauna at both local and regional scales. The study underscores the importance of integrating environmental factors operating at different spatial scales to decipher community patterns in these physically-controlled environments.

Trophic ecology of sympatric sea turtles in the tropical Atlantic coast of Brazil.

The Tropical Atlantic coast of Brazil is a hotspot area for multiple sea turtle species at all life stages. The multiple nearshore reefs and beaches, oceanic islands, and the only atoll in the south Atlantic Ocean, are suitable for year-round foraging, migration corridors, and nesting activities of five sea turtle species. Still, relatively few studies have assessed trophic niche among sympatric sea turtles which can provide a better understanding of how closely related species compete/partition the available resources. Using multiple biogeochemical tracers (i.e., nitrogen (δ15N) and carbon (δ13C) stable isotopes, and mercury (Hg)), we disentangled the trophic niches of four sea turtle species - the green turtle (Chelonia mydas), the loggerhead turtle (Caretta), the hawksbill turtle (Eretmochelys imbricata), and the olive ridley turtle (Lepidochelys olivacea) - co-occurring in nesting and foraging habitats along the northeastern coast of Brazil. We found interspecific differences in isotopic and contamination niches, as well as intraspecific niche variation associated with life stage. Differences in the estimation niche models associated to life-stage in C. caretta support the notion of ontogenetic shift in habitat and diet composition previously reported for this species. Oceanic habitat signatures were observed in juvenile green turtles and adult olive turtles, while nearshore habitat signatures were observed in adult hawksbill turtles.

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. The absence of genetic heterogeneity between the locations in Atlantic - Mediterranean transitional zone adds new evidence that challenges the Strait of Gibraltar as a phylogeographic barrier for marine pelagic species. These results are proposed to the ICCAT Commission to establish management areas for this species, although they are not consistent with the recently adopted pelagic ecoregions. Finally, a panel of highly informative SNPs was developed for efficient and low-cost population assignment and the analysis of unresolved population structures.

Comparative analysis of metal pollution in the Atlantic Ocean and Mediterranean Sea: insights from Anemonia sulcata study.

In this study, we investigated metal concentrations in Anemonia sulcata specimens from various locations in the Atlantic Ocean and the Mediterranean Sea. A total of 84 individuals were sampled from specific zones, and their tissue samples were processed for metal analysis using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The results revealed notable differences in metal concentrations among the studied regions. The Atlantic Ocean and the Mediterranean Sea were found to have distinct patterns of marine pollution, influenced by a complex interplay of geographical, demographic, industrial, and environmental policy factors. Conversely, the semi-enclosed Mediterranean Sea has a lower natural dilution capacity, leading to the accumulation and prolonged presence of pollutants. Population density and industrial activities in coastal areas play a significant role in pollution disparities between the Mediterranean Sea and the Atlantic Ocean. The Mediterranean coasts, with higher population densities and intensive industrial operations, experience greater strain on marine ecosystems due to increased pollution sources. Additionally, environmental policies and management approaches differ between the two regions, contributing to variations in pollution response and regulation.

Continent-island boundary and environment-shaped evolution in the marine amphipod Ampithoe marcuzzii complex (Crustacea: Eumalacostraca: Ampithoidae).

Marine amphipods are crustaceans that lack a larval phase and consequently have low dispersion rates. Despite that, these crustaceans present a remarkable ability to be transported by rafting on natural floating substrata, especially macroalgae, where they find shelter, food and a mating ground. The species Ampithoe marcuzzii is widely distributed throughout the western Atlantic Ocean. Here, it was used as a model to study seascape genomics and phylogeography in invertebrates with low dispersion capacities. We anticipated that the lineages would present isolation-by-distance patterns. However, surface currents and other abiotic variables could facilitate connectivity among distant sites. Based on mitochondrial and nuclear genes, SNPs, and environmental associations, we observed the presence of a species complex within A. marcuzzii, separating mainland and insular populations. Each species showed an independent evolutionary history, with a strong latitudinal population structure and evidence of isolation-by-distance and isolation-by-environment, characterizing the 'continent' species. Historical expansion and environmental variables were observed associated with the southeastern population, and ecological niche modeling corroborated the region as a paleorefuge. Conversely, populations from 'islands' presented complicated evolutionary histories, with closer localities genetically isolated and distant localities connected. These findings indicate that insular populations with low dispersion capacity might be more susceptible to spatial connectivity by floating substrata and to changes in surface currents. In contrast, mainland populations might be more vulnerable to local climate changes due to lack of gene flow.

Fin whale song evolution in the North Atlantic.

Animal songs can change within and between populations as the result of different evolutionary processes. When these processes include cultural transmission, the social learning of information or behaviours from conspecifics, songs can undergo rapid evolutions because cultural novelties can emerge more frequently than genetic mutations. Understanding these song variations over large temporal and spatial scales can provide insights into the patterns, drivers and limits of song evolution that can ultimately inform on the species' capacity to adapt to rapidly changing acoustic environments. Here, we analysed changes in fin whale (Balaenoptera physalus) songs recorded over two decades across the central and eastern North Atlantic Ocean. We document a rapid replacement of song INIs (inter-note intervals) over just four singing seasons, that co-occurred with hybrid songs (with both INIs), and a clear geographic gradient in the occurrence of different song INIs during the transition period. We also found gradual changes in INIs and note frequencies over more than a decade with fin whales adopting song changes. These results provide evidence of vocal learning in fin whales and reveal patterns of song evolution that raise questions on the limits of song variation in this species.

Pulsed inputs of high molecular weight organic matter shift the mechanisms of substrate utilisation in marine bacterial communities.

Heterotrophic bacteria hydrolyze high molecular weight (HMW) organic matter extracellularly prior to uptake, resulting in diffusive loss of hydrolysis products. An alternative 'selfish' uptake mechanism that minimises this loss has recently been found to be common in the ocean. We investigated how HMW organic matter addition affects these two processing mechanisms in surface and bottom waters at three stations in the North Atlantic Ocean. A pulse of HMW organic matter increased cell numbers, as well as the rate and spectrum of extracellular enzymatic activities at both depths. The effects on selfish uptake were more differentiated: in Gulf Stream surface waters and productive surface waters south of Newfoundland, selfish uptake of structurally simple polysaccharides increased upon HMW organic matter addition. The number of selfish bacteria taking up structurally complex polysaccharides, however, was largely unchanged. In contrast, in the oligotrophic North Atlantic gyre, despite high external hydrolysis rates, the number of selfish bacteria was unchanged, irrespective of polysaccharide structure. In deep bottom waters (> 4000 m), structurally complex substrates were processed only by selfish bacteria. Mechanisms of substrate processing-and the extent to which hydrolysis products are released to the external environment-depend on substrate structural complexity and the resident bacterial community.

Source apportionment of fine atmospheric particles in Bloemfontein, South Africa, using positive matrix factorization.

Air pollution is of major health and environmental concern globally and in South Africa. Studies on the sources of PM2.5 air pollution in low- and middle-income countries such as South Africa are limited. This study aimed to identify local and distant sources of PM2.5 pollution in Bloemfontein. PM2.5 samples were collected from June 16, 2020 to August 18, 2021. Trace element concentrations were determined by EDXRF spectroscopy. By use of the US EPA PMF 5.0 program, local sources were determined to be combustion/wood burning (49%), industry (22%), soil dust (10%), base metal/pyrometallurgical and traffic (9.6%) and water treatment/industry (9.4%). The HYSPLIT program was applied to determine distant PM2.5 source areas and the following clusters were identified: Mpumalanga province (52%), Northern Cape province (35%), Indian Ocean (8%) and Atlantic Ocean (6%). The majority of the air was found to come from the Mpumalanga province in the north-east, while the majority of local sources are ascribed to combustion/wood burning. Results from this study can be used to develop an Air Quality Management Plan for Bloemfontein.

Feeding behavior of yellowfin tuna around two insular regions of the western Atlantic Ocean.

The yellowfin tuna is a very abundant tropical tuna species in the western equatorial Atlantic Ocean and an important fishery resource for the Brazilian tuna fleet. In this study we performed stable isotope analysis to better understand the spatial trophodynamics and dietary changes in yellowfin tuna around two insular marine protected areas in Brazil. A total of 65 yellowfin tuna specimens measuring between 47 and 138 cm LT (total length) were sampled around the archipelagos of Fernando de Noronha (FNA; n = 34) and Saint Peter and Saint Paul (SPSPA; n = 31) between July 2018 and September 2019. Bayesian mixing models and generalized additive models were used to investigate the contributions of four different prey items (zooplankton, cephalopods, fish larvae, and flying fish) to yellowfin tuna diet in each area and their potential changes in relation to predator growth. The four prey items were found to have different overall contributions between the two studied areas, with zooplankton being the most important prey in FNA, whereas flying fish was the most relevant prey to the species' diet in SPSPA. Significant changes in the species diet by size were also found, with fish smaller than 90 cm (TL) having a more generalist diet and larger animals relying more on consuming larger and more nutritious prey (i.e., flying fish). Our results suggest that these two marine protected areas play an important role in ocean dynamics, providing important and different foraging grounds for the development of this predator species.

Lead and cadmium in blood and tissues of Atlantic bluefin tuna (Thunnus thynnus L., 1758).

Cadmium (Cd) and lead (Pb) levels in blood and tissues of Atlantic bluefin tuna were analysed to gather information regarding their distribution, accumulation and inter-relationships, as well as to examine how sex affects them. In the whole population, the concentration range was from below the detection limit (bone) to 8.512 µg g-1 (liver) for Cd, and from below detection limit (bone and gills) to 0.063 µg g-1 (kidney) for Pb. The median concentration in the muscles (0.008 and 0.029 µg g-1 for Cd and Pb, respectively) was 10 times less than the maximum permitted for consumption. Sex was shown to be an important variable affecting concentrations of Cd in both liver and kidneys, so taking into account sex when interpreting results is highly recommended. The importance of Cd and Pb bioaccumulation in fishery by-products, increasingly important in commercial circuits, is also highlighted.

Building collaboration and synergy among regional blocs to reduce marine plastic waste pollution: A case for the Gulf of Guinea region.

The Gulf of Guinea (GoG) region in sub-Saharan Africa is a vast and diverse region stretching from Senegal to Angola, covering approximately 6000 km of coastline. It is an important shipping zone transporting oil and gas, as well as goods to and from central and southern Africa. Plastic waste has an impact on the major metropolitan centers of this region, as well as the beaches. The Gulf of Guinea region includes the coastal areas of countries such as Nigeria, Cameroon, Equatorial Guinea, Gabon, Sao Tome and Principe, the Republic of the Congo, the Democratic Republic of the Congo, Ghana, Cote d'Ivoire (Ivory Coast), Benin, and Togo. This study uses qualitative methodology to comparatively interrogate how to use legal instruments to reduce marine plastic pollution in the Gulf of Guinea region, which encompasses these coastal nations.

Unidirectional trans-Atlantic gene flow and a mixed spawning area shape the genetic connectivity of Atlantic bluefin tuna.

The commercially important Atlantic bluefin tuna (Thunnus thynnus), a large migratory fish, has experienced notable recovery aided by accurate resource assessment and effective fisheries management efforts. Traditionally, this species has been perceived as consisting of eastern and western populations, spawning respectively in the Mediterranean Sea and the Gulf of Mexico, with mixing occurring throughout the Atlantic. However, recent studies have challenged this assumption by revealing weak genetic differentiation and identifying a previously unknown spawning ground in the Slope Sea used by Atlantic bluefin tuna of uncertain origin. To further understand the current and past population structure and connectivity of Atlantic bluefin tuna, we have assembled a unique dataset including thousands of genome-wide single-nucleotide polymorphisms (SNPs) from 500 larvae, young of the year and spawning adult samples covering the three spawning grounds and including individuals of other Thunnus species. Our analyses support two weakly differentiated but demographically connected ancestral populations that interbreed in the Slope Sea. Moreover, we also identified signatures of introgression from albacore (Thunnus alalunga) into the Atlantic bluefin tuna genome, exhibiting varied frequencies across spawning areas, indicating strong gene flow from the Mediterranean Sea towards the Slope Sea. We hypothesize that the observed genetic differentiation may be attributed to increased gene flow caused by a recent intensification of westward migration by the eastern population, which could have implications for the genetic diversity and conservation of western populations. Future conservation efforts should consider these findings to address potential genetic homogenization in the species.

Natural and anthropogenic organic brominated compounds in the southwestern Atlantic ocean: Bioaccumulation in coastal and oceanic dolphin species.

Marine pollution is considered a current driver of change in the oceans and despite the urgency to develop more studies, there is limited information in the southern hemisphere. This study aimed to analyze the levels and profiles of natural (MeO-PBDEs) and anthropogenic (BFRs: PBDEs, HBB, PBEB) organic brominated compounds in adipose tissue of two species of dolphins with different distribution and trophic requirements from the Southwestern Atlantic Ocean; the short-beaked common dolphin (Delphinus delphis) and the Fraser's dolphin (Lagenodelphis hosei). In addition, we aim to investigate maternal transfer and biological pattern relationship (sex, age, sexual maturity) in short-beaked common dolphin bioaccumulation. The levels of both groups of contaminants were in the same order of magnitude as those reported for other marine mammals on both a regional and global scale. BFRs profiles were dominated by BDE 28 and BDE 47 in short-beaked common dolphin and Fraser's dolphin, respectively, whereas 2-MeO-BDE 68 was the most abundant natural compound in both species. Evidence of maternal transfer, temporary increase in BDE 154 levels and no influence of sex, age, or sexual maturity on brominated compound concentration was observed in short-beaked common dolphin. This study fills a gap in the knowledge of the Southwestern Atlantic Ocean providing new information on emerging organic pollutants bioavailability for dolphins and, therefore, for the different trophic webs. In addition, it serves as a baseline for further contamination assessments.