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Marine plastic pollution has a range of negative impacts for biota and the colonization of plastics in the marine environment by microorganisms may have significant ecological impacts. However, data on epiplastic organisms, particularly fungi, is still lacking for many ocean regions. To evaluate plastic associated fungi and their geographic distribution, we characterised plastics sampled from surface waters of the western South Atlantic (WSA) and Antarctic Peninsula (AP), using DNA metabarcoding of three molecular markers (ITS2, 18S rRNA V4 and V9 regions). Numerous taxa from eight fungal phyla and a total of 64 orders were detected, including groups that had not yet been described associated with plastics. There was a varied phylogenetic assemblage of predominantly known saprotrophic taxa within the Ascomycota and Basidiomycota. We found a range of marine cosmopolitan genera present on plastics in both locations, i.e., Aspergillus, Cladosporium, Wallemia and a number of taxa unique to each region, as well as a high variation of taxa such as Chytridiomycota and Aphelidomycota between locations. Within these basal fungal groups we identified a number of phylogenetically novel taxa. This is the first description of fungi from the Plastisphere within the Southern Hemisphere, and highlights the need to further investigate the potential impacts of plastic associated fungi on other organisms and marine ecosystems. [ABSTRACT FROM AUTHOR]

Feeding ecology of green turtles was investigated between January 2005 and April 2008 at Arvoredo Reserve, Brazil (27°17′S, 48°18′W). Data were obtained through the performance of observational sessions, geo-referenced counts, benthic surveys, capture and recapture of individuals, and oesophageal lavages. This protected area was identified as an important green turtle feeding ground, used year-round by juveniles (curved carapace length = 32–83 cm). Turtles fed close to the rocky shores of the area and selected grazing sites commonly at hard-to-reach, near-vertical portions of the rocks. They were less active in cold months, and more abundant at shallow areas of the reef (0–5 m), where their preferred food items occurred. Their diet was dominated by macroalgae species but invertebrates were also present. Their main food item was the red algae Pterocladiella capillacea, which seems to be eaten through periodical cropping of its tips. Observational methods such as the ones applied here could be incorporated to other research programs aiming to understand the relationships between Chelonia mydas feeding populations and their environment. [ABSTRACT FROM AUTHOR]

The silver porgy (Diplodus argenteus) is an occasional cleaner of two species of fish in the southern portion of the south-west Atlantic. We record herein for the first time this fish species associating with green turtles (Chelonia mydas) and cleaning their carapaces. Only juveniles were recorded cleaning turtles, scraping off microorganisms that fouled the carapace. [ABSTRACT FROM AUTHOR]

Estuaries and salt marshes are important coastal ecosystems that present unique characteristics in terms of nutrient cycling, salinity, habitats, flora and fauna. Despite their ecological importance, there is scarce knowledge on the occupation, distribution and ecology of insects, including Tipuloidea, in these environments. This study aimed to evaluate the composition, seasonality and effect of abiotic factors on the abundance, diversity and structure of a Tipuloidea assemblage at the Patos Lagoon salt marshes, located at the south of the Neotropical region. We sampled crane-flies from three zones along the estuary by installing two Malaise traps at the low and high vegetation strata of each zone. Sampling was conducted uninterruptedly every fifteen days between August/2015 and July/2016, and collected insects were identified morphologically based on specific literature. 5248 crane-flies were identified covering six species and twenty-five morphospecies. Abundance and frenquency of occurrence of species revealed a gap in the presence of constant species at the middle estuary. Dicranomyia , Gonomyia , Teucholabis and Zelandotipula species were additional (accessory) species only in the upper estuary, while Symplecta cana only in the lower estuary. This shows that different species prefer distinct points along the estuary. Higher abundance of crane-flies was correlated with elevated temperature and humidity. Symplecta pilipes was an exception, presenting increase in abundance under lower temperatures. Seasonal change in Tipuloidea species composition was observed, with higher evenness of Dicranomyia , Geranomyia , Rhipidia domestica and Symplecta cana (15–20%) during summer, and dominance of Symplecta pilipes in winter (80%). The gap at the middle estuary can possibly be due to stress caused by large fluctuations in salinity in the zone. In addition, the seasonal differences can have significant ecological consequences such as the modification of the Tipuloid species that compose the detritivorous and/or succivorous trophic guild, and consequently influence the upper trophic levels of the salt marsh environment. [ABSTRACT FROM AUTHOR]

Estuaries are dynamic environments, key for the survival of innumerous ecologically or economically important fish species. Among these species are Neotropical silversides ( Atherinella brasiliensis ), which are resident and abundant in Brazilian estuaries and used as a complementary source of income and food for local communities. To better understand silverside populations in Brazil, we evaluated the genetic diversity, structure and demography of fish sampled at six estuaries from the northeastern to the southern coast, using Random Amplified Polymorphic DNA and mitochondrial DNA (D-loop) markers. High haplotype diversities (h ranging from 0.75 to 0.99) were found in all populations except Carapebus, located in Southeast Brazil (h = 0.54). A total of 69 mtDNA haplotypes were found, with Itaparica (Northeast Brazil) and Carapebus presenting only exclusive haplotypes, while some were shared among populations in the South. Strong regional structure was observed, with very high differentiation between Itaparica and Carapebus, as well as among these two populations and the ones from the Southern region (Paranaguá, Conceição, Camacho and Patos). Among southern areas, low/moderate structure was detected. Most populations showed unimodal mismatch distributions indicating recent demographic expansion, while Carapebus presented a multimodal distribution characteristic of a stable or bottlenecked population. Times since possible population expansion were highest in Itaparica (32,500 ya) and Carapebus (29,540 ya), while in the Southern region longest time was observed at Conceição (25,540 ya) and shortest at Patos (9720 ya). In a general manner, haplotype diversities were directly related to times since population expansions; again, Carapebus was the exception, displaying long time since expansion but low diversity, possibly due to a recent bottleneck caused by the isolation and human impacts this lagoon is subject to. Isolation by Distance was significant for Itaparica and Carapebus, and considering the extremely high differentiation of these populations, we suggest that they could be undergoing speciation. To adequately manage and maintain the genetic variability of silversides in Brazilian estuaries, we propose three distinct management units for this species: 1) Itaparica; 2) Carapebus; and 3) Southern Brazil. [ABSTRACT FROM AUTHOR]

Recent studies on the genus Lampris revealed five cryptic species within Lampris guttatus; however, the new phylogenetic structure of the globally distributed group claims more information from the South Atlantic Ocean. The present work, with a focus on the Lampris genus fishes from the Southwest Atlantic Ocean (SWAO), aims to (i) fulfill a gap in the distribution description of the recently uncovered species from the group (ii), making comparative analysis to molecular and morphological studies on the group and (iii) easily diagnose characters to facilitate identification in the field. The analysis of partial mitochondrial cytochrome c oxidase I gene sequences (705 pb) led to the identification of Lampris australensis and Lampris megalopsis and their genetic diversity. Compared with other oceanographic regions, both species presented high haplotypic diversity and low population structure. Principal component analysis using morphometric data revealed two distinct morphotypes with a slight overlap. PC-LDA analysis also showed two well-separated groups, with a high percentage of correctly classified fish for L. australensis and L. megalopsis. We also demonstrate that both species can be morphologically distinguished. This study confirms L. megalopsis as a globally distributed species and expands the distribution of L. australensis, which can now be considered circumglobal along the subtropical waters of the southern hemisphere. Understanding species captured as bycatch in fisheries based on their correct identification is fundamental for establishing conservation and management initiatives for marine fish populations. [ABSTRACT FROM AUTHOR]

Since seafood is considered an important source of organotin compounds (OTCs), the present study assessed the potential risk to human health of ingesting butyltins (BTs) and phenyltins (PhTs) along with this type of food. Seafood samples were collected at five fishing sites in the Yucatán Peninsula (Mexico) during February and March 2018. In general, organotins were detected in all samples, suggesting a widespread occurrence of these compounds in the investigated region. The average concentration of total organotins in the muscle of demersal fish (Lutjanus synagris , Lutjanus campechanus , Calamus pennatula , Haemulon plumierii , Rhomboplites aurorubens), pelagic fish (Euthynnus alletteratus , and Opisthonema oglinum), gastropods (Melongena bispinosa and Strombus pugilis), oyster (Crassostrea virginica) and shrimp (Penaeus duorarum) was 146.7 ± 76.2, 93.1 ± 92.6, 61.0 ± 53.0, 76.7 ± 2.6, and 28.8 ± 2.7 ng Sn g−1 dry weight, respectively. Overall, MPhT among PhTs was the dominant compound in fish, while TBT among BTs was the dominant compound in shellfish. Regarding the toxic OTCs, TBT followed by DBT were the predominant compounds in all seafood species, while TPhT was below the quantification limit in most samples. The estimated daily intake values were lower than the tolerable daily intake (TDI) for the sum of organotins established by the European Food Safety Authority (EFSA). Furthermore, the hazard quotients (HQ) and hazard indices (HI) values were all lower than 1, suggesting that daily exposure to these levels of organotins is unlikely to cause any harm to the human health of seafood consumers at the Yucatán Peninsula. Thus, consumers may not be at risk through the inclusion of these investigated seafood species in their normal diet. However, due to the increasing coastal urbanization, maritime activities, and the likely illegal use of tin-based paints in Mexico, additional monitoring is needed to assess organotin levels in other regions along the Mexican coastal zone and using other seafood species. [Display omitted] • Seafood from the Yucatán Peninsula is contaminated by organotins (OTs). • MPhT followed by TBT were the predominant OTs in fish muscle, and crustaceans and mollusks tissues. • Fish was the main contributor to human OTs exposure. • TBT > DBT ≫ TPhTs were the main contributors to the toxicity assessed. • Seafood consumption does not seem to pose any risk to consumers in the study area. [ABSTRACT FROM AUTHOR]

Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes. [ABSTRACT FROM AUTHOR]

Levels of booster biocides (Irgarol, diuron, chlorothalonil, dichlofluanid and DCOIT), organotins (TBT, DBT, MBT, TPhT, DPhT and MPhT) and antifouling paint particles (APPs) were assessed in sediments of sites under the influence of maritime activities along the coastal zone of the Yucatán Peninsula, Mexico. Imposex incidence and organotin levels were also evaluated in seven caenogastropod species. The incidence of imposex was detected in five species from sites nearby fishing harbors and marinas, including the first reports to Gemophos tinctus and Melongena bispinosa. Butyltins levels were higher than phenyltins in gastropod tissues, sediments, and APPs. Regarding booster biocides, chlorothalonil was the most frequently detected compound and DCOIT was the most abundant biocide in sediments. DCOIT levels were registered in APPs from fishing harbors and marina areas. In addition, the highest levels of TBT, Irgarol, diuron and DCOIT exceeded the threshold limits set by international sediment quality guidelines, indicating that toxic effects could be expected in some of the studied areas, thus being a potential threat to marine life. Based on such outputs, Mexico urgently needs to adopt restrictive actions aiming at conserving the rich biological heritage of the Yucatán Peninsula. [Display omitted] • First comprehensive study of antifouling residues and biological effects in the Yucantán Peninsula. • Imposex and organotins were reported for the first time in gastropods from the Yucatán Peninsula. • Marinas, shipyards and fishing harbors are relevant sources of antifouling biocides. • TBT, Irgarol, diuron and DCOIT levels exceeded threshold limits set by international guidelines. • Antifouling residues are a relevant environment issue in the coastal areas of the Yucantán Peninsula. [ABSTRACT FROM AUTHOR]

The red crab Chaceon notialis is endemic to the Southwestern Atlantic (Brazil, Uruguay and Argentina), occurring from 200 to 1600 m deep. The species belongs to the Geryonidae family and exhibits a K-strategist life cycle. Due to its increased exploitation over recent decades, this marine resource requires attention regarding its conservation and management. In this work, were analyzed red crab populations from the three countries that cover the species' entire distribution range, assessing diversity and differentiation through morphometric and genetic analyses. The evaluated morphometric measurements were length and width of the carapace; length, width and height of the chelae propodus; and female abdomen width. For genetic evaluation, the following mitochondrial DNA regions were used: the partial 12S gene and the entire Control Region (861 bp); and the partial Cytochrome c oxidase subunit I (1252 bp). The morphometric results showed two distinct phenotypic groups (one from Brazil/Uruguay and the other from Argentina), with significant differences in female abdomen width and chela size. Genetic analyses, however, revealed only a single panmictic population, with no genetic structuring among the analyzed stocks. These findings suggest that the management measures applied in each country will influence the population dynamics of the others, and that international cooperation is necessary for achieving sustainable fisheries of this valuable resource. Since commercial fishing of the red crab C. notialis is not conducted in Argentina, we propose that this area can act as a biological reserve for this species. Due to the commercial importance of this crab, knowledge of the species' diversity is of fundamental importance for its management, conservation, and to provide baselines for future biological and ecological studies. • Morphometric analyses identified two morphologically distinct red crab groups. • Chelae size and abdomen width are the main characteristics that separated groups. • Molecular analyses (mtDNA) identified a single panmictic population. • Planktonic larval distribution may influence the lack of genetic structure. • A coordinate fishery management between countries is suggested. [ABSTRACT FROM AUTHOR]

The southwestern Atlantic Ocean (SWA) represents an important foraging ground for loggerhead sea turtles (Caretta caretta). Most studies at the region have focused on adult females and juveniles, and little is known about males. Here, we present the first insights about origin and foraging ecology of male loggerheads from the SWA, by integrating genetic and stable isotope analysis (SIA). Skin samples were obtained from 26 males stranded along the southern coast of Brazil (from 31°21′S–51°05′W to 33°44′S–53°22′W), from February 2014 to March 2017. Samples of potential food sources (benthic and pelagic organisms) were also collected for SIA. A fragment of the mitochondrial DNA control region was sequenced and a Bayesian Mixed Stock Analysis was performed to estimate natal origins of male loggerheads. Bayesian Stable Isotope Mixing Models were fitted to assess the relative contribution of different food sources assimilated by males. Most males exhibit endemic haplotypes from Brazilian rookeries, followed by a low frequency of a haplotype from the North Atlantic and the Mediterranean Sea, as well as olive ridley (Lepidochelys olivaea) haplotype, showing hybridization. SIA showed life stage-related differences in feeding and habitat use by male loggerheads, with benthic invertebrates dominating the diet of adults, while pelagic prey items dominated the diet of juveniles. Our findings demonstrate the importance of southern Brazil neritic and oceanic habitats for male loggerheads and highlight the value of this area for the maintenance of SWA reproductive management units, which are the main contributors to these feeding aggregations. [ABSTRACT FROM AUTHOR]

Although marine plastic pollution has been the focus of several studies, there are still many gaps in our understanding of the concentrations, characteristics and impacts of plastics in the oceans. This study aimed to quantify and characterize plastic debris in oceanic surface waters of the Antarctic Peninsula. Sampling was done through surface trawls, and mean debris concentration was estimated at 1,794 items.km−2 with an average weight of 27.8 g.km−2. No statistical difference was found between the amount of mesoplastics (46%) and microplastics (54%). We found hard and flexible fragments, spheres and lines, in nine colors, composed mostly of polyurethane, polyamide, and polyethylene. An oceanographic dispersal model showed that, for at least seven years, sampled plastics likely did not originate from latitudes lower than 58°S. Analysis of epiplastic community diversity revealed bacteria, microalgae, and invertebrate groups adhered to debris. Paint fragments were present at all sampling stations and were approximately 30 times more abundant than plastics. Although paint particles were not included in plastic concentration estimates, we highlight that they could have similar impacts as marine plastics. We call for urgent action to avoid and mitigate plastic and paint fragment inputs to the Southern Ocean. [ABSTRACT FROM AUTHOR]