Southwest Atlantic Research Articles

Environmental Influences on Illex argentinus Trawling Grounds in the Southwest Atlantic High Seas

To understand the spatial temporal distribution characteristics of Illex argentinus caught by trawl fishing vessels in the Southwestern Atlantic Ocean and their relationship with key marine environmental factors, this study analyzed the temporal and spatial changes in the fishing ground center of trawl vessels at the ten-day scale from December 2019 to May 2022, combining Chinese trawl fishing log data marine environmental data with satellite remote sensing marine environmental data. Utilizing the Maxent model, ten-day intervals were used as the temporal scale, and ten marine environmental factors, including sea surface temperature, sea surface height, sea surface salinity, chlorophyll concentration, temperature at 50 m and 100 m depth, and the meridional and zonal velocities of ocean currents were quantitatively analyzed to explore the correlation between the spatial distribution of catch and environmental factors. The study reveals that the trawl fishing grounds for Illex argentinus are divided into southern and northern grounds. The southern grounds first appear near 45°20′ S in December, gradually moving southeastward in February and March. The northern grounds do not appear until April, near 42° S in the high seas. On the ten-day time scale, the central fishing grounds of Illex argentinus show significant spatial variability but minor interannual differences. The Maxent model results indicate that sea surface temperature and chlorophyll a concentration are the key environmental factors influencing the spatial and temporal variability of the high seas trawl fishing grounds for most of the time, with high environmental contribution rates during the fishing season. While the range of suitable habitats with an HSI > 0.6 identified by the Maxent model varies significantly between years, a pattern is observed where the range expands at the start and end of the fishing season and contracts during the peak fishing season. This suggests that a more concentrated range of suitable habitats is conducive to accurate predictions of trawl fishing grounds, enabling efficient fishing operations.

Using social media image to identify threatened elasmobranch species caught by a small-scale fishery in a data-poor area.

Sharing fishing activity via social media attracts millions of views. The data from these shares includes key information for a fisheries database such as the species present in the catches and in many cases the number of specimens caught. Many countries in the Global South do not have official information about basic data on fishing activity, especially small-scale activity. In many of such countries like Brazil, overfishing poses a significant threat to numerous threatened species, including elasmobranchs, due to the frailty of fisheries management and law enforcement. The lack of a national (Brazil) data collection program makes sharing data on social media a potential source of fisheries related information. Hence, this study aimed to verify the potential of social media data to describe artisanal fishing and identify elasmobranch species caught by a small-scale fleet in a data-poor Equatorial Southwest Atlantic region. The identification of elasmobranch species was made based on 250 videos shared by local fishers publicly on social media (Youtube™). Among these, sharks and rays were observed in 19 (8%) and 42 (17%) videos, respectively. A total of 98 specimens were recorded, of which 80% could be identified to a species level. Most of the records comprised the stingrays Hypanus berthalutzae and Hypanus guttatus, while Ginglymostoma cirratum was the most recorded shark. More than half of the elasmobranch species recorded are listed at some level of threat according to the IUCN Red List. According to the Brazilian legislation, at least 20% of the species identified in these videos are considered Endangered (EN) or Critically Endangered (CR). Therefore, fishing activity shared via social media can be considered effective in identifying threatened elasmobranch species, as well as providing data on species occurrence, number of specimens, or rare sightings. It is suggested that fishing activity shared via social media be used in parallel with traditional methods (e.g. on-board data and landing observations) to obtain fisheries information and data about endangered species in data poor areas.

On the occurrence of the deep-sea barnacle Tetrachaelasma southwardi Newman & Ross, 1971 (Cirripedia, Balanomorpha, Bathylasmatidae) in the Mar del Plata Submarine Canyon, Argentina: supplementary description and taxonomic remarks on the genus

Tetrachaelasma southwardi Newman & Ross, 1971, a bathylasmatine balanomorph, has been recorded from the Mar del Plata Submarine Canyon (ca. 38°S, off the coast of Argentina), at two stations located at significantly different depths (1950 m and 2934 m). A total of 29 specimens, complete or damaged but with soft parts intact, were collected. This unusually large number of well-preserved specimens allows us to add supplementary descriptions and document intraspecific morphological variations. The differences between T. southwardi and T. tasmanicum Buckeridge, 1999, the second species of this genus, are re-evaluated. A map and an updated list including all the records of the genus Tetrachaelasma Newman & Ross, 1971 are provided. The distribution of the genus Tetrachaelasma in the Southern Ocean is discussed. Furthermore, a single specimen of another bathylasmatine balanomorph, which was assigned to the genus Bathylasma Newman & Ross, 1971, was also obtained at the 1950 m station herein studied. This is the first record of the genus Bathylasma from the South-West Atlantic. This specimen has one T. southwardi attached to it, marking the first time that members of these two genera have been found living together.

New insights into the reproduction and migration of the porbeagle shark Lamna nasus (Bonnaterre 1788) in the Southwest Atlantic Ocean.

The objective of this study was to estimate the reproductive parameters of porbeagle shark in the Southwest Atlantic Ocean and thus characterize the adult fraction of this population. Therefore, 1012 specimens were measured by scientific observers on board the commercial trawl fleet operating south of 50° S. The size range of the specimens was from 77 to 292 cm fork length (LF). The mean size at maturity was estimated to be 153 cm LF for males and 172 cm LF for females. Porbeagle shark catches were recorded throughout the year, with the highest frequency occurring between November and June. The presence of pregnant females was observed from December to July, along with an increase in the average size of embryos in each litter. The information presented in this study improves the knowledge of the reproductive biology and allows to propose a migratory pattern of adult porbeagle females in the Southwest Atlantic Ocean. The likely seasonal increase in vulnerability of this shark to austral trawl fishery, despite all conservation management measures established in Argentina, underscores the importance of promoting its proper management and conservation given the need to improve understanding of porbeagle population dynamics in the Southern Hemisphere.

Sea turtle strandings in the temperate Southwest Atlantic: Analysis of drivers and potential causes

Abstract Marine megafauna are subject to several threats due to the increasing exploitation of marine ecosystems. Mortality is frequently evidenced by the occurrence of stranded individuals in coastal zones; however, conclusive identification of its drivers and causes is challenging. In this study, we explore the hypothesis that bycatch in trawling is one of the anthropic drivers of sea turtle strandings in the temperate Southwest (SW) Atlantic, where green (Chelonia mydas), loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) turtles forage seasonally. Beach survey data during March, April and May from 2014 to 2018 were used to characterize strandings and relate their spatio‐temporal distribution to physical and anthropic variables. Loggerhead (47.4%) and leatherback turtles (49.3%) were the most common stranded species, whereas green turtles were recorded only occasionally (3.3%). Based on the size distribution, strandings reflected both juvenile and adult mortality, with variations between species. Generalized linear models showed that sea turtle strandings were influenced by winds and sea surface temperature, while there was no evidence of a relationship with fishing effort. Further studies should assess drowning due to bycatch as a cause of turtle death, since interaction with fisheries is commonly reported in the area and drowned animals may or may not wash ashore. This study raises awareness and assesses, for the first time, the mortality of threatened sea turtle species in a poorly known region of its distribution.

Vertical structure of reef fish assemblages and light penetration reveal new boundaries of mesophotic ecosystems in the subtropical Southwestern Atlantic

In the Southwest Atlantic, fisheries and in situ observations suggest that mesophotic reefs occur further south than has been reported in the literature, and a description of these subtropical regions is still lacking. We used Baited Remote Underwater stereo-Videos to explore unrevealed patterns in the vertical structure of fish assemblages on subtropical Atlantic reefs, contrasting shallow and mesophotic habitats. Our data on species turnover and light penetration reveal that in the subtropical Atlantic, the boundaries between shallow and mesophotic habitats occur at depths of 18 m, which is shallower than most previous studies have shown. Generalized additive mixed models identified different environmental and management factors as important predictor variables that explain distribution of fish assemblages’ attributes. Besides adding new evidence about mesophotic limits, we described variations in the vertical structure of fish assemblages, providing important information for the description and conservation of mesophotic environments in subtropical regions.

One new genus and five new species of deep-sea bryozoans from the subantarctic Southwest Atlantic

In this study we introduce one new genus and five new species of cheilostome bryozoans based on material collected mainly at bathyal depths in the Subantarctic Southwest Atlantic by the vessels ARA Bahía Blanca, BO Puerto Deseado and RV Meteor. Bathyanasca incubatrix gen. nov., sp. nov., Chondriovelum perforatum sp. nov., Aspidostoma adeoniforme sp. nov., Talivittaticella bathyalis sp. nov. and Turritigera formidabilis sp. nov. are described and illustrated. Bathyanasca incubatrix, characterized by the lack of ovicells and the incubation of embryos within the autozooidal cavity, is tentatively classified in the family Calloporidae. Present results contribute to support the hypothesis of close faunal affinities between Antarctica and relatively deep areas around southern South America.

Critical areas for sea turtles in Northeast Brazil: a participatory approach for a data-poor context.

Fishing is one of the main threats to sea turtles due to the risk of entanglement in lost nets, vessel collision and mortality due to incidental catches. In Brazil, most of the studies regarding fishing interactions with sea turtles are focused on pelagic longline fisheries in the South and Southeast regions. However, their main reproductive areas in Southwest Atlantic RMU occur in Northeast Brazil, which overlaps small-scale coastal gillnet fisheries. Here, we aimed to use ethnobiology and participatory approaches as simple and cost-effective methods to identify areas for sea turtle conservation where impacts from small-scale fisheries are most likely. Expert captains were trained to recording sea turtle sightings during navigations from the landing port to the fishing grounds, informing their folk nomenclatures. By interpolation of environmental data (chlorophyll and bathymetry) and ecological data, we predicted habitats of 3,459.96 km² for Caretta caretta, Chelonia mydas, and Eretmochelys imbricata and fishing zones of 1,087 km² for management in 20 m and 50 m depths. Our results contributes to ongoing discussions of bycatch mitigation for sea turtle species and identification of habitats. We highlights the importance of considering particularities of overlapped areas in marine spatial planning and co-management arrangements.

Fatal interactions of albatrosses with weather radiosondes/balloons on the Southern and Southeastern coasts of Brazil

Weather radiosondes play a crucial role in gathering atmospheric data for weather modeling and forecasting. However, their impact on marine wildlife, particularly seabirds, has raised concerns regarding the potential threats posed by these instruments. This study aims to assess the adverse effects of weather balloons on albatrosses, with a focus on the Southwest Atlantic region. The research reveals seven cases of entanglement of radiosonde equipment, leading to severe injuries and mortality along the Southern and Southeastern coasts of Brazil. Recommendations for mitigating the environmental impact of weather balloons include the adoption of biodegradable materials in their design and the implementation of improved retrieval protocols. Furthermore, the study stresses the importance of continued monitoring and research to address the interaction of weather radiosondes with marine animals. This approach is vital for ensuring the sustainable collection of scientific data while minimizing harm to marine life and ecosystems.

Biological patterns of reproduction of the Brazilian sardine Sardinella brasiliensis in the purse seine fishery of Southwest Atlantic Ocean: A long-term assessment

Recent estimates of the size at first maturity (L50) of Sardinella brasiliensis showed contradictory results with a decreasing in the fish stock biomass encompassed by increasing values of L50. The methodological approach used hereby allowed to separate sardines classified in the virginal maturity stage from those categorized in the recovery stage, and ready for one next spawning event. This study evaluated the hypothesis of the existence of separated stocks experiencing distinct environmental conditions and fishing pressures which may have altered L50 estimates using a robust dataset based on biological samples collected along the entire species distribution area in the southeast-south Brazilian coast [Rio de Janeiro (RJ), São Paulo (SP), Paraná (PR), Santa Catarina (SC) and Rio Grande do Sul (RS)] between 2000 and 2018. A reclassification of the gonadal maturity stages provided a more realistic estimate of L50. Combining biological, reproductive, fishing data and the mean temperature of the catch (MTC), the leave-one-out classification correctly re-assigned individuals with an overall accuracy of 85% [100% (RJ), 45% (SP), 99% (PR), 99% (SC) and 82% (RS)]. The connectivity between the local populations of S. brasiliensis off RJ (23°S) and the southern populations is limited, contrasting to spatial structured semi-discrete population-units found between SP and RS (24°S-30°S). The northern extreme population-unit (RJ, 22°S-23°S) showed an expressive reduction of L50, and a negative correlation was detected between the increasing MTC values and the abundance of early maturing individuals and recruits of the species. Stock specific L50 estimates seemed to act as indicators of long term environmental fluctuations.

First record of the genus Togula (Gymnodiniales, Dinophyceae) and of the species T. jolla for the South-West Atlantic coastal waters

In the framework of a phytoplankton and biotoxin monitoring program implemented since 2008 in marine coastal waters of the Buenos Aires Province (Argentina), a gymnodinioid, photosynthetic dinoflagellate was isolated from a sample collected in Santa Teresita, establishing the strain LPCc007. The strain was identified as belonging to the psammophilic genus Togula by light microscopy based on the following distinctive characters: morphology of the cell dorso-ventrally flattened, and course of the cingulum, highly asymmetric, descending, with its ends displaced by about one to two thirds of the total length of the cell and joined by an oblique intercingular groove. The comparative morphological analysis between the motile vegetative cells of the isolated strain and the three species of the genus described to date, did not reveal significant differences that would allow it to be determined at a specific level. Instead, the pattern of development of longitudinal grooves on the hypocone of cells about to undergo mitosis observed in strain LPCc007, perfectly agrees with that described for T. jolla as a differential character. The morphological identification was consistent with LSU rDNA (D1-D2) based phylogeny that showed the sequence aggregation in the T. jolla clade. This is the first report of the genus Togula and the species T. jolla from Argentina and the South-West Atlantic Ocean coastal waters.

Chemical analysis of marine microdebris pollution in macroalgae from the coastal areas of Argentina

Marine microdebris (MDs, <5 mm) and mesodebris (MesDs, 5–25 mm), consist of various components, including microplastics (MPs), antifouling or anticorrosive paint particles (APPs), and metallic particles (Mmps), among others. The accumulation of these anthropogenic particles in macroalgae could have significant implications within coastal ecosystems because of the role of macroalgae as primary producers and their subsequent transfer within the trophic chain. Therefore, the objectives of this study were to determine the abundance of MDs and MesDs pollution in different species of macroalgae (P. morrowii, C. rubrum, Ulva spp., and B. minima) and in surface waters from the Southwest Atlantic coast of Argentina to evaluate the ecological damage. MDs and MesDs were chemically characterized using μ-FTIR and SEM/EDX to identify, and assess their environmental impact based on their composition and degree of pollution by MPs, calculating the Polymer Hazard Index (PHI). The prevalence of MDs was higher in foliose species, followed by filamentous and tubular ones, ranging from 0 to 1.22 items/g w.w. for MPs and 0 to 0.85 items/g w.w. for APPs. It was found that macroalgae accumulate a higher proportion of high-density polymers like PAN and PES, as well as APPs based on alkyd, PMMA, and PE resins, whereas a predominance of CE was observed in surrounding waters. Potentially toxic elements, such as Cr, Cu, and Ti, were detected in APPs and MPs, along with the presence of epiplastic communities on the surface of APPs. According to PHI, the presence of high hazard score polymers, such as PAN and PA, increased the overall risk of MP pollution in macroalgae compared to surrounding waters. This study provided a baseline for MDs and MesDs abundance in macroalgae as well as understanding the environmental impact of this debris and their bioaccumulation in the primary link of the coastal trophic chain.

A Faunistic Revision of Longnose Skates of the Genus Dipturus (Rajiformes: Rajidae) from the Southern Southwestern Atlantic Ocean, Based on Morphological and Molecular Evidence

The identity of longnose skates (Dipturus-Zearaja-like skates) in the southern cone of the Americas has been a topic of extensive debate. This study employs a comprehensive analysis encompassing morphometrics, claspers, and the examination of COI and NADH2 sequence data to conclusively demonstrate the existence of only two longnose skate species in the southwestern Atlantic Ocean, extending south of 35 °S. Notably, Dipturus argentinensis Díaz de Astarloa, Mabragaña, Hanner and Figueroa, 2008 is revealed as a junior synonym of D. trachyderma (Krefft and Stehmann, 1975). Dipturus leptocaudus (Krefft and Stehmann, 1975) remains a northern valid species, but the specimen from the Falkland Islands (Malvinas) is recognized as a misidentification of D. trachyderma. Zearaja flavirostris (Philippi, 1892) and Dipturus lamillai Concha, Caira, Ebert and Pompert, 2019 are confirmed as junior synonyms of Zearaja brevicaudata (Marini, 1933). These findings contradict the previous report of six species within the same region over the last decade and underscore the presence of D. trachyderma and Z. brevicaudata south of 35 °S in the southwestern Atlantic. Additionally, this study notes the occurrence of only one specimen of Z. chilensis (Guichenot, 1848) in the Falkland Islands (Malvinas), suggesting an unusual frequency of this eastern Pacific skate in the southern Southwest Atlantic. Given that clasper morphology serves as the key distinguishing trait between Dipturus and Zearaja species, we provided a detailed analysis of the clasper characteristics of the Atlantic D. trachyderma, unequivocally situating it within Dipturus. The diagnostic characteristics include: (i) the presence of cartilage with the distal portion referred to as the sentinel, a feature absent in Zearaja; (ii) longer ventral terminal cartilage with the distal end referred to as the funnel, compared to Zearaja; and (iii) a non-spatulate distal lobe, a distinctive trait specific to Dipturus.

A reconstruction of the marine mammal harvest by the Real Compañía Marítima through the analysis of historical sources (AD 1790–1804)

Humans have altered marine ecosystems over very long-time scales and historical data is often needed to understand the true magnitude of human impacts. The Southwest Atlantic Ocean has a long history of large-scale removal of marine vertebrates due to whaling, sealing, and fishing in the past three centuries. Historical catch records are crucial in assessing the conservation status of these historically over-exploited populations and setting suitable recovery goals. However, several gaps in the history of exploitation of many populations limit our ability to judge recoveries success. This study examines the history of the Spanish fishing company, the Real Compañía Marítima (Royal Maritime Company), and reconstructs its catches of marine mammals in Patagonia and on the north coast of the Río de la Plata. The analysis of a wide range of historical sources reveals that, between the years 1790 and 1804, the Company extracted less than 100 southern right whales Eubalaena australis, some 200,000 South American fur seals Arctocephalus australis and South American sea lions Otaria flavescens, and a few southern elephant seals Mirounga leonina. Although the Company’s whale catch is negligible compared to that of other nations in the same whaling grounds, the amount of fur seals and sea lions removed from the ecosystem deserves attention. This historical survey provides us with the first estimate of the catches made by the Real Compañía Marítima. However, these figures only represent a small part of the extractive activities that took place in the region and further research is encouraged to assess the true dimension of human impacts on Southwest Atlantic ecosystems. The incorporation of retrospective data into ecological studies can be laborious and may have inherent biases, but it also provides valuable information for comprehending modern ecosystems and formulating appropriate conservation plans.

Understanding the feeding ecology of the broadnose sevengill shark (Notorynchus cepedianus) in Patagonia, Argentina

The broadnose sevengill shark (Notorynchus cepedianus) is classified as Vulnerable by the IUCN, and its population in the Southwest Atlantic is declining. Despite some progress in understanding the ecological requirements of the sevengill shark, there are still several information gaps. Essential aspects of its trophic ecology, such as main prey items or key feeding grounds, remain uncertain and this information is essential for developing effective conservation strategies. Stable isotopes and spontaneous regurgitations were analyzed to describe the trophic ecology of sevengill sharks within a marine protected area (MPA) of Península Valdés in Patagonia, Argentina. Analysis of spontaneous regurgitations revealed that the southern elephant seal (Mirounga leonina) was the primary prey item (70%) for the sevengill shark, during abundance peaks of both species in the MPA. However, the stable isotope analysis indicated that the teleosts were the main prey item, and the overall contribution of the elephant seal to the diet of the sevengill shark was around 30%. In addition, the contribution of each prey group varied with the size of the individuals. The estimated trophic position was 4.43, placing the species among the apex predators of the region. This study confirmed the use of the MPA as an essential foraging ground and contributed to identifying its main prey items. Also, it reflects the need to expand conservation tools beyond this particular coastal protection.

Modulations of ocean-atmosphere interactions on squid abundance over Southwest Atlantic

Anthropogenic shifts in seas are reshaping fishing trends, with significant implications for aquatic food sources throughout this century. Examining a 21-year abundance dataset of Argentine shortfin squids Illex argentinus paired with a regional oceanic analysis, we noted strong correlations between squid annual abundance and sea surface temperature (SST) in January and February and eddy kinetic energy (EKE) from March to May in the Southwest Atlantic. A deeper analysis revealed combined ocean-atmosphere interactions, pinpointed as the primary mode in a rotated empirical orthogonal function analysis of SST. This pattern produced colder SST and amplified EKE in the surrounding seas, factors crucial for the unique life stages of squids. Future projections from the CMIP6 archive indicated that this ocean-atmosphere pattern, referred to as the Atlantic symmetric pattern, would persist in its cold SST phase, promoting increased squid abundance. However, rising SSTs due to global warming might counteract the abundance gains. Our findings uncover a previously unrecognized link between squids and specific environmental conditions governed by broader ocean-atmosphere interactions in the Southwest Atlantic. Integrating these insights with seasonal and decadal projections can offer invaluable information to stakeholders in squid fisheries and marine conservation under a changing climate.

A new Acanthotetilla sponge from the Southwest Atlantic (Tetillidae, Spirophorina, Tetractinellida, Demospongiae), with an updated discussion on the diversity, distribution and morphologic characters of Acanthotetilla spp.

Acanthotetilla is a genus of tetillid sponges diagnosed by the presence of medium-sized, heavily spined oxeas, which are known as megacanthoxeas (or simply acanthoxeas). Currently, seven species are known worldwide: three from the Western Atlantic (A. gorgonosclera, A. rocasensis and A. walteri), three from the Western Indian (A. hemisphaerica, A. enigmatica and A. seychellensis) and one from the Western Pacific (A. celebensis). A megacanthoxea-bearing specimen was obtained from the Fernando de Noronha Archipelago, Southwest Atlantic, in 2016. It is described here as a new Acanthotetilla, namely, A. noronhensis sp. nov. This new species has two categories of megacanthoxeas, like A. celebensis from Celebes/Sulawesi Sea, Indonesia. However, the former differs from the latter, as well as from other congeners, by the combination of endolithic habit and spiculation. Acanthotetilla noronhensis sp. nov. is known on the basis of a single specimen from a large collection of sponges from Fernando de Noronha. Besides, the species was not found in other sponge collections from different areas of Brazil, including oceanic areas. Thus, the new species has probably a low abundance and restricted distribution, alike all other known Acanthotetilla species, aside A. celebensis, which (regardless its low abundance) occurs in a large sector of the western Pacific. Despite A. noronhensis sp. nov. and A. celebensis being separated by a wide geographic distance, the unique occurrence of two categories of megacanthoxeas might suggest closer phylogenetic relationship and biogeographic history as well. A wider discussion on the diversity, distribution and morphologic characters of Acanthotetilla spp. is supplied in this study. A comparative taxonomic table and a taxonomic identification key to Acanthotetilla spp. is supplied as well.

Biological and ecological traits rather than geography control mercury (Hg) in scutes of marine turtles from the Southwest Atlantic

The use of sentinel species in monitoring programs for toxic metals such as mercury (Hg) is essential to understand these pollutants' impact on the environment. For this purpose, it is essential to use organisms that have a lifespan compatible with the residence time of Hg in the oceans, and preferably with a wide geographical distribution, such as sea turtles. Here, we assess the regional variability of Hg concentrations using carapace scutes of four sea turtle species along the foraging and spawning area in the northeast coastline of Brazil. Mercury concentrations in samples showed no relationship with the environmental Hg levels (obtained from literature). Rather, Hg concentrations varied according to species-specific biological, and ecological traits. Characteristics such as the ontogenetic shift in the diet of Chelonia mydas, capital breeding in females, depth of foraging in oceanic waters, and selectivity of food items, such as in Eretmochelys imbricata, significantly influenced Hg concentrations.

Satellite tagging confirms long distance movement and fast dispersal of Patagonian toothfish (Dissostichus eleginoides) in the Southwest Atlantic

IntroductionTo better understand Patagonian toothfish (Dissostichus eleginoides) movement and habitat in the Southwest Atlantic, fifty popup satellite archival tags (PSATs) were deployed off Davis Bank on North Scotia Ridge between 2019 and 2020 on individuals ranging from 97-139 cm total length.MethodsPSATs (18 Lotek Wireless PSATFLEX and 32 Wildlife Computers MiniPAT) were programmed to detach after completing 1 to 16-month missions recording pressure (depth) and water temperature.ResultsSix tags failed to report, and among the remaining 44 reporting tags, 34 reported on schedule, up to 487 days at sea – the longest electronic tag deployment for this species to date. Although the majority of PSATs reported within 50 km from the release sites, confirming high site fidelity, 12% of tags reported more than 200 km away, showing connectivity to Shag Rocks and South Georgia in the Southern Ocean. Toothfish moved across the Antarctic Polar Front through/to areas with no fishing activities, and hence, explained the absence of any previous conventional tag recapture. A 1-month transit to the Falkland/Malvinas Plateau Basin also revealed that toothfish can attain a surprisingly high movement rate of 33 km day-1.DiscussionFishery independent examples of toothfish presence and their movement capabilities are inviting us to broaden our examination on how toothfish move around their Scotia Arc habitats and link up different regional aggregation sites in the South Atlantic.

Living benthic foraminifera from Almirante Câmara and Grussaí canyons and adjacent slope areas (Campos Basin, Southwest Atlantic): Response to trophic and hydrodynamic conditions

Living (rose Bengal stained) benthic foraminiferal faunas, grain size, geochemical parameters (total organic matter, chlorophyll-a, pheophytin-a, molecular markers, and vertical flux of particulate organic matter) were investigated in 14 stations in two submarine canyons Almirante Câmara and Grussaí considered mature and immature, respectively, and on the adjacent continental slope, from 400 to 1300 m water depth, in the southwestern Atlantic Ocean. Samples were retrieved during two campaigns, in the austral winter 2008 and the austral summer 2009. The density, richness, and species composition of the benthic foraminiferal fauna decrease with depth in the canyons and along the adjacent slope transects, reflecting the availability and quality of sedimentary organic matter. Both canyons act as traps of labile organic matter, mainly towards the head of the Almirante Câmara canyon, promoting high specimen density, species richness, and the occurrence of species indicative of pulses of phytodetritus (e.g., Bolivina pacifica, Nonionella opima, and Nonionella stella). Towards the deeper regions of Almirante Câmara canyon and in the adjacent slope area, the lower abundance, diversity, and richness reflect more oligotrophic conditions and an adverse environment in terms of easily metabolizable organic matter. This multiproxy study demonstrates that the canyons in the southeastern Brazilian continental margin play an important role in accumulating organic matter.