Are fishes selecting the trash they eat? Influence of feeding mode and habitat on microplastic uptake in an artificial reef complex (ARC).

Every year, coastal countries generate ∼275 million tons of plastic, and the oceans receive from 4.8 to 12.7 million tons3. Pollution by synthetic polymers is even more problematic for the environment when this material is fragmented into small portions, forming microplastics (MPs). In the present study, we analyze the selection of MPs by the ichthyofauna based on the availability of the morphotypes and polymeric composition of microplastic in the environment and compare the amount of MP in surface water, water column, sediments and fish in different organs, trophic categories, habitats and areas with and without artificial reefs. In order to achieve this goal, the shape, color, abundance and chemical composition of MPs in the digestive tract and gills of 18 fish species in artificial reefs area and control area, were evaluated. A total of 216 fish were analyzed, and 149 (60 %) had MPs in at least one organ and showed a mean concentration of 1.55 ± 3.31 MPs/g. Of the 18 fish species collected in the reef complex area, 17 (94 %) included individuals with at least one MP in digestive tract or gills. Four species showed the higher selectivity of MP types, colors, and polymers. More MPs were found in the fish, surface water, water column and sediment in the artificial reef area compared to the control areas. This is the first evidence of MP selection by commercially important fish species in artificial marine structures worldwide. These results provide useful information on MP pollution in RAs and highlight yet another issue that must be considered in the management of fisheries resources in the region and in other reef complexes around the world.

Ecological traits do not predict the uptake of microplastics by fishes in a Neotropical River.

Pollution by synthetic polymers is even more problematic to the environment when this material is fragmented into small portions, forming microplastics (MPs). We analyzed the contamination of ichthyofauna by MPs in an important river of the Atlantic Rainforest in regard to abundance, diversity of morphotypes, polymers, colors, and sizes of the synthetic particles in 20 species of fish. Fish were collected in November 2019 and in March 2020 in five sites along the Pomba River. Of the 101 fish analyzed, 49 (49%) presented MPs in at least one organ. Of the 20 species of fish collected 13 included individuals with at least one MP in their analyzed organs. The organs, trophic categories and feeding areas did not affect the general abundance of MPs types. Blue MPs were predominant, followed by the colors black, red, and white. MP fibers represented 91% of total MPs. Most MPs were between 2 and 3 mm in size. Polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polyvinylidene chloride "Nylon" (PVDC), and high-density polyethylene (HDPE) were detected in the fishes. The exposure of the fish species to MPs was associated mainly with individual size and species-specific aspects, regardless of ecological traits. Considering that 55% of the fish species studied are consumed by humans, it is necessary to study the potential impact of MP ingestion on human health and to understand to what extent we may be consuming both plastic particles and contaminants that are adsorbed to MPs.

Microplastics in water from the confluence of tropical rivers: Overall review and a case study in Paraiba do Sul River basin.

Rivers are known for carrying out a fundamental role in the transportation of human debris from continental areas to the marine environment and have been identified as hotspots for plastic pollution. We characterized microplastics (MPs) along confluence areas in the Paraíba do Sul River basin, the biggest river in southeastern Brazil. This water body crosses highly industrialized areas, with the highest population density, and the major water demand in South America. Considering the important ecological function of this extensive watershed and the implications of MP pollution, we evaluate the spatial variation of MP concentration in the confluence areas and upstream from the confluence. Samples were taken from the superficial layer of the water column in February and June 2022, using manta net with 300 µm mesh size. A total of 19 categories and 2870 plastic particles were determined. The confluences areas of rivers showed the highest concentration of MPs, highlighting the confluences of the Paraiba do Sul and Muriaé rivers (0.71 ± 0.25 MP/m3), followed by Paraíba do Sul and Dois Rios rivers (0.42 ± 0.23 MP/m3) and Paraíba do Sul and Pomba rivers (0.38 ± 0.14 MP/m3). Black fibers were the main category, followed by blue fibers and blue fragments. The MPs in the surface waters of Paraíba do Sul River is significantly influenced by the sampling points spatiality. This result corroborates other studies around the world and reinforces the argument that affluents are important sources for the introduction of MPs in larger rivers. Nevertheless, our results provide a better understanding of the different contributing factors and occurrence of MPs in river basins.

Multiple species ingest microplastic but few reflect sediment and water pollution on sandy beaches: A baseline for biomonitoring.

Databases recording the ingestion of microplastics by marine animals are growing. This is also recurrent on sandy beaches, where different biomonitors have been proposed to monitor the impacts of plastic pollution. We aimed to record the occurrence of suspected microplastic (SMP) in the digestive tract of multiple taxa (n = 45 identified species) and test whether some macroinvertebrates and fishes ingested SMPs proportionally with the pollution level of sediment and water; thus, we aimed to depict which sandy beach species could be used as biomonitors. Among all taxa, 10 macroinvertebrates and 12 fish species were reported to ingest SMP for the first time. SMP morphotypes proportion differed between abiotic and biotic compartments. Moreover, 10 of 12 taxa did not have SMP concentration linearly related with SMP in sediment and water. Our findings suggest that few species from sandy beaches can be used as efficient biomonitors, although almost all ingest plastic polymers.

The presence of COVID-19 face masks in the largest hypersaline lagoon of South America is predicted by urbanization level.

The inadequate disposal of face masks has caused a widespread presence of COVID-19 litter in the environment. We monitored 10 beach arcs along approximately 15 km of the largest hypersaline lagoon of South America looking for face masks during the lockdown (2021) and in the "new normal" (2022) period. Our working hypothesis is that the probability of finding face masks increases with higher urbanization levels, which was estimated by the Human Modification Metric. Approximately 3 × 10-3 face masks m-2 were found on nine of 10 beaches (90 %) during the lockdown. However, this reduced to 1 × 10-4 face masks m-2 found in eight beaches (80 %) after the lockdown. The probability of finding a face mask was significantly higher as urbanization increased (z = 2.799; p = 0.005). This situation imposes the need for a better waste management and environmental education actions, targeting the reduction of direct littering on coastal ecosystem.

Microplastics in fishes in amazon riverine beaches: Influence of feeding mode and distance to urban settlements.

Microplastic (MP) pollution is a global problem and has affected several biological levels even in protected areas. In the present study, MP contamination was investigated in fish associated with sandy beaches in a permanent environmental protection area in the Amazon. In order to achieve this goal, the shape, color, abundance, richness, and chemical composition of MPs in the digestive tract of 29 fish species in 24 beaches of the Machado River, western Brazilian Amazon, were evaluated. Linear mixed models (LMMs) were adjusted to test the effects of local human modification (HMc), distance from urban settlements, distance from the closest affluent, and trophic categories of fish species on microplastic abundance and richness in their digestive tracts. From the 1082 fish analyzed, 332 (30 %) presented MPs in their digestive tracts. A total of 617 MPs was found (1.8 ± 1.6 MPs; 4.5 ± 1.9 MPs/g fish). Omnivorous and insectivorous fish presented more MPs in sandy beaches located closer to urban settlements. However, carnivorous fish presented a higher abundance of MPs in their digestive tracts compared with the other trophic guilds. This is the first study to analyze plastic contamination in fish associated with sandy beaches in the Amazon (Brazil), and it revealed contamination of the ichthyofauna mainly related to the distance from urban settlements. Our results reinforce the need for better management of landscape surrounding protected areas to mitigate MP pollution.

Recovery of ghost crabs metapopulations on urban beaches during the Covid-19 "anthropause".

The majority of government authorities initially responded to COVID-19 pandemic by declaring lockdown to facilitate social distancing and minimize virus spreading. This period termed "anthropause" provided a unique opportunity to evaluate the recovery of wildlife in the absence of stressors on urban ecosystems. We assessed whether the anthropause associated with beach closures during the COVID-19 pandemic resulted in repopulation of the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) on urban beaches. For this purpose, we compiled a historic dataset (2013-2019) of the ghost crab density and performed biweekly burrow measurements from June/2020 to May/2021. Recovery of ghost crab metapopulation during the lockdown occurred even in more human-modified beaches. Burrow abundance significantly increased in urban sectors, but not in control site along with the time of pandemic. The reduction in the mean burrow opening diameter during this period evidenced that young metapopulation have thrived on urban beaches when recreational activities ceased. Our results show that urban beaches should not be exclusively managed for recreational purposes. Initiatives with a focus on wildlife conservation including spatial-temporal controlled beach closures may increase the biodiversity resilience.

Cumulative stressors impact macrofauna differentially according to sandy beach type: A meta-analysis.

Many studies have demonstrated human impacts on sandy beach macroinvertebrates. However, little is known about causative drivers among multiple co-occurring stressors and how these interact with natural habitat conditions to yield specific faunal responses. We performed a global meta-analysis to shed light on how interactions between human disturbances and beach morphodynamics shape macroinvertebrate populations. We found that supralittoral forms (Talitridae and Ocypodidae) responded more negatively to the Human Modification Metric (a proxy for urbanization) on dissipative beaches, whereas intertidal organisms (Hippidae and Cirolanidae) showed more negative responses on non-dissipative beaches. Based on these findings we propose the Cumulative Harshness Hypothesis (CHH), which predicts higher sensitivity of beach macroinvertebrates to human disturbances when inhabiting a harsher physical environment according to their life histories. Secondly, we compared the response of macroinvertebrates to urbanization levels from local to larger scales (from 500 to 50000 m). Supralittoral families responded more negatively to local urbanization, which leads to habitat loss due to removal or reduction of upper beach zones. Conversely, intertidal organisms with planktonic larval stages were more affected by urbanization at the largest spatial scales, which we hypothesize disrupts metapopulation dynamics by impacting the supply of larvae that could colonize human-disturbed beaches. The differential effects of human disturbances on macroinvertebrates according to beach morphodynamics suggest that the efficiency of these ecological indicators for beach monitoring is context-dependent. Focusing on multiple stressors rather than on a single one is also critical to mitigate human impacts on these threatened ecosystems.

Macroinvertebrates as biomonitors of pollutants on natural sandy beaches: Overview and meta-analysis.

This review synthesises information from published articles on the incorporation of pollutants by macroinvertebrates from sandy beaches, including both field samplings and bioassays. The hypothesis that macroinvertebrates quantitatively reflect the presence of pollutants in sediment, acting as biomonitors, was tested through a meta-analysis based on studies performed in situ. More than half of the studies were conducted in the Mediterranean. Of the 53 articles based on field samplings, less than half (40%) determined the concentration of pollutants in the sediment as well as in the organisms. Donacidae, Talitridae, and Hippidae were tested as biomonitors, mainly of trace elements. Donacidae and Talitridae reflected in their soft tissues the presence of most trace elements in the sediment, which was not the case with Hippidae. Few studies (≤2 articles) evaluated the response of these macroinvertebrates to persistent organic pollutants, hydrocarbons, or microplastic. A selection based on sampling of sediment and species not yet tested as biomonitors is necessary due to the scarcity of a baseline worldwide and because responses to pollutants may be species-specific.

Mortality of the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) due to vehicle traffic on sandy beaches: A road ecology approach.

Sandy beaches are not roads, but they have been used as such worldwide, threatening endemic fauna such as ghost crabs (Crustacea: Ocypodidae). The objective of the present study was to identify the spatial factors influencing the incidence of ghost crabs (Ocypode quadrata) killed by vehicles. This study included a systematic study of carcasses with clear signals of crushing by cars on beaches with distinct urbanization levels and on dirt roads crossing low-urbanized beach stretches. Predictive variables (e.g., tyre tracks on the sand, proxies of urbanization, distance from coastal lagoons and beach width) were obtained for the kill points and random points. Generalized linear models with binomial distributions showed that the number of tyre tracks nearby (positive correlation) and indicators of urbanization in the environment (negative correlation) were the main variables explaining ghost crab kills on the beach. Similarly, the likelihood of finding crabs killed by vehicles on the dirt road was associated with the areas with the densest ghost crab populations (higher beach width and low-urbanized areas). Therefore, as an important conservation strategy and mitigation action, vehicle traffic must be severely controlled mainly on low-urbanized beaches, both on the sand and dirt roads crossing natural beach vegetation.

Can the Atlantic ghost crab be a potential biomonitor of microplastic pollution of sandy beaches sediment?

The objective of the present study was to test whether the Atlantic ghost crab Ocypode quadrata is a reliable biomonitor of microplastic (MP) pollution of beach sediments. To test the hypothesis (H1) that the sediment is the main source of MP ingestion, the proportion of MP types (hard plastic, microfibers, pellet, soft plastic, and extruded polystyrene foam) in the gut content was compared with that on the strandline. The types of MPs in the gut content and sediment had similar proportions; black (~49%) and blue (~45%) microfibers were responsible for this similarity (55%), hence confirming H1. However, the second hypothesis (H2) that prevalence of MP in the gut content is related to its density on beach with distinct urbanization degree was not accepted. These results indicate that high trophic plasticity of the ghost crab and, consequently, multiple-sources of contamination may interfere with its use as a biomonitor of MP pollution.

Overview and trends of ecological and socioeconomic research on artificial reefs.

It is presented a systematic literature review of artificial reef research, including 620 studies throughout the world from 1962 to 2018. The primary focus of this study was to examine long-term trends in research, focusing on ecological and socioeconomic questions, and to develop new research directions for this field. From 1962 to the beginning of the 1990s, the United States and Japan were the main centers of artificial reef research. Subsequently, researchers in several other countries (particularly China, Australia, Italy, Brazil, and the United Kingdom) began to focus on this subject, resulting in an increase in the number of artificial reef studies. In general, publications about artificial reefs have concentrated on investigating the structure of populations and marine communities and evaluating new technical designs and materials to construct artificial habitats. The science of artificial reefs is responding to new challenges with an increase in more elaborate techniques, such as the use of remotely-operated submarines, organic indicators, isotopes, and molecular biology, while research that evaluates the socioeconomic aspects of artificial reefs is lacking. There are many aspects that deserve more research attention, such as the use of alternative inert materials, environmental impact assessment and mitigation, and analysis of conflicts with affected fisheries communities. The greater challenge is to overcome the apparent division between theory vs. application and to include robust management models of these artificial environments.

Interaction of the Atlantic ghost crab with marine debris: Evidence from an in situ experimental approach.

Sandy beaches pollution by marine debris imposes arguably threats for the biodiversity, but interaction of beach bioindicators (e.g., ghost crabs) with debris has been rarely assessed. We aimed to test whether the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) misidentifies marine debris as food sources. Cigarette butts, straws, popsicle sticks, paper napkins and styrofoams were mixed into solutions with odour of natural and industrialized food. The debris were placed around burrows on beaches with distinct human pressures (low, medium and high-impact). The species interacted with marine debris more frequently in situations of lower human impact, lower prey abundance and larger burrow diameter. These results indicate that in areas with low prey availability and larger individuals, interactions between ghost crabs and debris left by beach visitors and/or transported by winds and currents to low-impact beaches are more likely to occur, mainly near to urbanized areas.

Ethnoecology and socioeconomic around an artificial reef: the case of artisanal fisheries from southeastern Brazil / Etnoecologia e socioeconomia em torno de um recife artificial: o caso da pesca artesanal do sudeste do Brasil

Abstract: The objective of this study is to describe the ethnoecological aspects, valorization, and commercialization of target species caught by artisanal fishers on the northern coast of Rio de Janeiro, southeastern Brazil. The data were obtained through semi-structured interviews conducted with 60 fishers from the fishing community of Guaxindiba (21°29'S, 41°00'W), which is associated with the Z-1 fishers' colony. Eighty-nine species were cited by the fishers and 44.1% are important commercial fish in the region. The fishers cited five distinct zones used to fish: border zone (68 species), estuary (41 spp.), artificial reef (27 spp.), "malacacheta" (24 spp.), and open ocean (10 spp.). The fishery resources were classified according to their gastronomic and economic characteristics: primary fish (35 spp.), secondary fish (32 spp.), mixed fish (10 spp.), discarded fish (7 spp.), and fish used as bait (5 spp.). The price of the target species increases along the production chain due to the greater number of people involved, processing costs, and improvement of the product. The data from this study can contribute to local fisheries management and point out to the use of artificial reefs in the maintenance of fishery resources in northern Rio de Janeiro.

Resumo: O objetivo desse estudo é descrever os aspectos etnoecológicos, a valoração e a forma de comercialização das espécies-alvo capturadas na pesca artesanal praticada na costa norte do Rio de Janeiro, sudeste do Brasil. Os dados foram obtidos a partir de entrevistas semiestruturadas realizadas com 60 pescadores da comunidade pesqueira Guaxindiba (21°29'S, 41°00'O), vinculados à colônia de pescadores Z-1. Oitenta e nove espécies foram citadas pelos pescadores e 44,1% desse total são importantes para o comércio da região. Os pescadores citaram cinco zonas distintas que são utilizadas para a pesca: zona da "borda" (68 espécies), estuário (41 spp.), recife artificial (27 spp.), "malacacheta" (24 spp.) e mar aberto (10 spp,). Os recursos pesqueiros foram classificados de acordo com suas características gastronômicas e econômicas: pescado-de-primeira (35 spp.), pescado-de-segunda (32 spp.), pescado-mistura (10 spp.), pescado-de-descarte (7 spp.) e pescado-isca (5 spp.). O preço das espécies-alvo aumenta ao longo da cadeia produtiva em decorrência do maior número de pessoas envolvidas, dos gastos com insumos e do processo de beneficiamento do pescado. Os dados desse estudo podem contribuir para o manejo da pesca local e apontam para o uso de recifes artificiais na manutenção dos recursos pesqueiros no norte do Rio de Janeiro.

Evidence of marine debris usage by the ghost crab Ocypode quadrata (Fabricius, 1787).

Sandy beaches are sites of marine debris stranding, but the interaction of beach biota with waste is poorly studied. The objective of this study was to investigate whether the ghost crab Ocypode quadrata selects marine debris by types using a non-destructive method on sandy beaches of Southeastern Brazil. We found marine debris in 7% of 1696 surveyed burrows, and the ghost crabs selectivity was mainly by soft plastic (30%), straw (11%), rope (6%) and foam (4%). Burrows with marine debris showed higher occupation rate (~68%) compared to burrows without debris (~28%), indicating that these materials may increase the capacity of ghost crabs to memorize their burrows placement (homing). The percentage of marine debris was not always related to their amount in the drift line, but ghost crabs used more debris near urbanized areas. Future studies should test whether ghost crabs are using marine debris for feeding, homing or other mechanisms.

Benthic Community zonation in a breakwater on the north coast of the state of Rio de Janeiro, Brazil

The present study presents the vertical zonation pattern of the intertidal benthic organisms on granitic boulders in the Farol de São Tomé beach (22º02'S, 41º03'W), Rio de Janeiro State. Four sampling profiles using 20 x 20 cm quadrats through a photo quadrat technique revealed four horizontal bands: (1) Littoral Fringe characterized by empty space and Littorina; (2) Upper eulittoral mainly occupied by Chthamalus and bare rock; (3) Lower eulittoral characterized by Chthamalus, Phragmatopoma, Ulva and Centroceras; and (4) Sublittoral Fringe characterized by Ulva, Phragmatopoma and Hypnea. The high variability in the relative abundance of the dominant species among the profiles may be attributed to the high topographic irregularity, reflecting in different wave action intensity at the same height, and consequently favoring the establishment of different species. The frequent substrate alternation from granitic rock to Phragmatopoma sandy reefs might contribute to the small-scale spatial variability. The implantation of a breakwater on an area without natural rocky shores allowed the study of intertidal benthic communty zonation, and provide a baseline for the experimental studies.

O presente estudo teve como objetivo apresentar um esquema de zonação vertical de organismos bênticos da região entremarés em blocos graníticos na praia do Farol de São Tomé (22º02'S, 41º03'W) na costa norte do estado do Rio de Janeiro. Quadrados de 20 x 20 cm foram sobrepostos em quatro perfis e utilizado o método por foto quadrat com 100 pontos de interseção. A análise de agrupamento e a porcentagem de cobertura de organismos bênticos indicadores sugeriram um padrão na distribuição vertical da região entremarés com quatro faixas: Franja do Supralittoral caracterizado por espaço vazio e Littorina ziczac; Médiolitoral Superior ocupado por Chthamalus spp e espaço vazio; médiolitoral inferior caracterizado por Chthamalus spp, Phragmatopoma lapidosa, Ulva fasciata e Centroceras clavulatum; e Franja do Infralitoral caracterizado por U. fasciata, P. lapidosa e Hypnea musciformis. A alta variabilidade na abundância relativa das espécies dominantes entre os perfis na zona Médiolitoral é atribuída a alta irregularidade topográfica do substrato, refletindo em diferentes intensidades de exposição às ondas em uma mesma altura, o que favorece o estabelecimento de diferentes espécies. A alternância freqüente do tipo de substrato de rocha granítica para recifes arenosos de P. lapidosa pode ter contribuído para a variabilidade espacial em pequena escala. Este estudo preenche uma lacuna referente à comunidade bêntica e sua distribuição vertical no norte do estado do Rio de Janeiro. A adição do molhe em uma área caracterizada pela ausência de substrato consolidado natural possibilitou o estudo da zonação da comunidade bêntica entremarés, oferecendo uma base de dados para futuros trabalhos experimentais.

Epibenthic colonization on an artificial reef in a stressed environment off the north coast of the Rio de Janeiro State, Brazil

The influence of sedimentation and turbidity caused by the pluviometric precipitation and by the Paraiba do Sul River during the summer was investigated on an artificial reef along the north coast of Rio de Janeiro, Brazil. Four recruitment and four cumulative plates were removed monthly (January 2002 to February 2003) from the external surface of the concrete reef modules. Empty space was not a limiting factor the recruitment. Turnover rate and structural difference index were higher in the first months and reflected low change in the species dominance during almost the entire study period. The high correlation between the precipitation and the empty space suggested that rain influence the recruitment and the succession. The recruitment was possible despite stress factors such as sedimentation, turbidity, abrasion, strong bottom currents and a lack of natural consolidated substrate. Changes in the community structure reflected the substrate colonization history of a few resistant species and their subsequent interactions.

A influência da sedimentação e da turbidez causadas pela precipitação pluviométrica e vazão do rio Paraíba do Sul nos meses de verão foi investigada em um recife artificial na costa norte do Estado do Rio de Janeiro, Brasil. Quatro placas de recrutamento e quarto placas de sucessão eram retiradas mensalmente (Janeiro de 2002 a Fevereiro de 2003) da superfície externa de módulos recifais de concreto. Espaço vazio não foi um fator limitante para o recrutamento. A taxa de substituição de espécies e o grau de diferença na estrutura da comunidade foram superiores nos meses iniciais, refletindo as reduzidas mudanças na dominância das espécies durante o período de estudo. A alta correlação entre precipitação e espaço vazio sugere a influência da precipitação no recrutamento e sucessão dos organismos. Recrutamento foi possível mesmo com fatores estressantes como sedimentação, turbidez, correntes de fundo e falta de substrato consolidado natural. Mudanças na estrutura da comunidade refletiram a história da colonização do substrato das poucas espécies resistentes e suas subseqüentes interações.

Temporal and spatial variation on heavy metal concentrations in the bivalve Perna perna (LINNAEUS, 1758) on the northern coast of Rio de Janeiro State, Brazil

Este trabalho descreve as concentrações de Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn em Perna perna das praias de Barra do Furado (BF), Buena (B) and Ponta do Retiro (PR) na costa Norte do Estado do Rio de Janeiro. As concentrações dos metais foram determinadas em ICP-AES. As concentrações médias foram 0.3 ± 0.04 (Cd); 1,9 ± 0.6 (Cr); 6,13 ± 0.7 (Cu); 1.130 ± 113 (Fe); 22 ± 3,2 (Mn); 9.3 ± 4,6 (Ni); 0.4 ± 0.2 (Pb); 44 ± 5,8 (Zn) µg.g-1 de peso seco. Não ocorreram diferenças significativas para a maioria dos metais, em relação ao sexo. Variações espaciais significativas (p < 0.05) ocorreram para Cr, Pb e Ni com os maiores valores em BF. Variações temporais significativas (p < 0.05) ocorreram nas três praias, contudo, nenhuma tendência sazonal de acumulação foi observada. As concentrações dos metais foram similares aquelas áreas descritas sob baixo impacto de poluição por metais pesados, exceto para o Fe, cujos altos valores provavelmente estão associados a presença de substratos locais ricos em óxido de Fe.

Spatial and temporal variations of diurnal ichthyofauna on surf-zone of Säo Francisco do Itabapoana beaches, Rio de Janeiro State, Brazil

Spatial and temporal variations of diurnal ichthyofauna and the environmental variables influences on its distribution were studied at the surf-zone of three beaches of Säo Francisco do Itabapoana, northern coast of Rio de Janeiro, Brazil. From August/1999 to August/2000, three beach seine hauls were made monthly, and environmental variables were recorded. A total number of 4,562 fishes (74,155g) were sampled at the three beaches, where estuarine-dependent species prevailed (44 percent), followed by marine (31 percent), estuarine (19 percent) and freshwater species (3 percent). Species richness, number of individuals and wet weight were significantly higher at Gargaú, followed by Manguinhos and Barra do Itabapoana, respectively. Canonical Correspondence Analysis highlighted influences of the rivers flushing, salinity and plant abundance on the diurnal ichthyofauna distribution and dynamics of Säo Francisco do Itabapoana surf-zone