Elemental Concentrations in the Shells of the Mussel Perna perna: Discrimination of Origin.

The potential use of elemental concentrations and element:calcium (Ca) ratios as indicators of provenance for bivalve mollusks on the Brazilian coast is evaluated herein for the first time. The approach was applied to shells of the mussel Perna perna (target of extractive fisheries) from geographically close areas but under distinct environmental and anthropogenic influences. Both concentrations of the elements normalized by Ca and the total concentrations can be applied to discriminate the mussels' origin. However, the canonical approach using the total concentrations indicated variations regarding the discriminatory power, and the concentrations of the elements normalized by Ca were more robust in differentiating the provenance of the shells. The origin of mussels was better discriminated by six elementary ratios: Al:Ca, Fe:Ca, K:Ca, Mg:Ca, Mn:Ca and Na:Ca. Thus, monitoring studies aiming to discriminate the origin of P. perna individuals along their distribution based on these elementary ratios of the shell are recommended.

Risk of exposure to Hg and pesticides residues in a traditional fishing community in the Amazon: a probabilistic approach based on dietary pattern.

Exposure to mercury (Hg) and pesticides (o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE) in the Amazon through eating fish is of concern due to the large participation of this food in the diet of traditional fishing communities. The aim of this study was to evaluate the estimated daily intake (EDI) and the incremental lifetime cancer risk associated with Hg and o.p'DDT, p.p'DDT, o.p'DDE, and p.p'DDE in an Amazonian community. The results showed that for Hg, the EDI from carnivorous and detritivorous fish had the highest values, while for pesticides, the EDI from detritivorous fish intake had the highest value. The incremental lifetime cancer risk was below the permitted limit. A recommendation for controlling the high risk of exposure includes the reduction of detritivorous fish ingestion and/or replacement with herbivorous fish, which had lower EDI. We highlight the importance of investigating the human dietary patterns when estimating risk of exposure to Hg and pesticides.

From Past Use to Present Effects: Total Mercury in Crustaceans and Fish in the Inner Estuary of Paraíba do Sul River, Southeast Brazil.

Total mercury (Hg) concentration and stable isotope ratios (δ13C and δ15N) were used as chemical tracers in two crustaceans and four fish species that are targets of subsistence fishery in the inner estuary of the Paraíba do Sul River. This fluvial environment in southeast Brazil has a large historical utilization of Hg. δ15N was a better predictor of Hg concentration in the muscle (edible part) than δ13C; i.e., the Hg concentration was more closely related to the trophic position of species than species' trophic habitat. Consumers at higher trophic levels had higher Hg concentrations. The Hg concentration was below the maximum permissible limits established by the Brazilian Government in fishery products, and there are no human risks related to its consumption.

Trace elements and stable isotopes in egg yolk of green turtles on Rocas Atoll, Brazil.

This study analyzed trace elements (As, Ba, Cd, Cu, Fe, Mn, Pb, Zn) and stable isotopes of carbon and nitrogen in egg yolk samples of female green turtles that nested in Rocas Atoll, Brazil, in 2017 and 2018. The trace elements concentration varied between years, with higher concentrations in 2017, suggesting that the nesting groups come from different foraging sites. The isotopic data indicated high overlap between years (73%), leading to an ambiguous interpretation on the turtles' foraging site. The Normalized Total Load presented a low association (0.01 < R2 < 0.41) with the stable isotopes. The Normalized Total Load that represents the trace element load in egg yolk is a holistic approach that can be applied elsewhere to predict ecotoxicology pathways in any animal species. We recommend a continuous monitoring to verify how the trace elements load behave in the nesting green turtles on Rocas Atoll.

Trace elements in green turtles (Chelonia mydas) from Rocas Atoll, NE Brazil: Baseline reference from a pristine nesting site.

This study presents the first report on the concentration of trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) in the blood and egg fractions of green turtles from Rocas Atoll, a pristine nesting site in NE Brazil. The highest concentrations of all elements were in the blood or shell samples. In order, iron, Zn, Cu, Al and As presented the highest concentrations in all tissues. The nonessential trace elements were below the limit of detection for more than 50% of the yolk (Al, Cd and Pb) and albumen samples (Al, As, Ba, Cd and Pb). This study will serve as a baseline reference for future monitoring of the ecotoxicology of breeding green turtles in the southwestern Atlantic Ocean.

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.

Trace metals in two commercial shrimps from southeast Brazil: Baseline records before large port activities in coastal waters.

This study presents baseline records of trace metals for two commercial shrimps from the inner continental shelf of southeast Brazil (~22°S). Organisms were sampled in 2004, 10 years before the beginning of large port activities in coastal waters. The concentrations of trace metals in muscle tissues (µg.g-1 w.w.) of Xyphopenaues kroyeri and Artemesia longinaris are as follows: Al: 141.57 and 146.71, Fe: 83.17 and 91.68, Zn: 28.69 and 29.70, Cu: 7.19 and 3.94, Mn: 1.47 and 1.72, Pb: 1.14 and 0.60, V: 0.66 and 0.56, Ni: 0.38 and 0.34, Cr: 0.42 and 0.29, and Cd: 0.15 and 0.14, respectively. Significantly higher concentrations of Cu and Pb were recorded for X. kroyeri. In general, the concentrations are below the maximum permissible limits for metals in fishery/food products, as established by the Brazilian Agency for Sanitary Vigilance (ANVISA), except for Pb and Cr. These baseline records are relevant for future monitoring.

Hg and δ15N in juvenile green turtles from southeastern Brazil (~23°S): Inferences about contamination levels and recruitment to coastal waters.

Total mercury (THg) and δ15N were analysed in liver and muscle of juvenile green turtles (Chelonia mydas) from a foraging site in southeastern Brazil (~23°S) to evaluate contamination levels and make inferences about the timescale that animals were recruited from oceanic to coastal waters. The values for THg and δ15N in liver and muscle were 432.2 and 72.8 µg kg-1 and 10.0‰ and 9.2‰, respectively. THg concentrations in tissues indirectly indicated that the main food resources for this consumer (i.e., macroalgae) had negligible levels of this element. Thus, this foraging site could be considered a pristine area in terms of Hg contamination. The THg and δ15N in liver were derived by more recent food ingestion than those in muscle. The juvenile green turtles that died because of incidental captures in fisheries practiced along this foraging site were individuals newly recruited from oceanic waters.

Debris ingestion by carnivorous consumers: Does the position in the water column truly matter?

The hypothesis that carnivorous consumers associated with the seabed are more likely to ingest marine debris was tested based on stomach content analysis of fish (Trichiurus lepturus and species of Ariidae) and cetaceans (Sotalia guianensis and Pontoporia blainvillei). Among 596 stomach contents, only 22 (3.7%) contained debris. The debris was flexible plastic, nylon yard, paper, latex, styrofoam and cigarette filter. The proportion of stomach contents with debris varied among species: P. blainvillei (pelagic demersal consumer) presented the highest frequency of ingestion (15.7%), while T. lepturus (pelagic consumer), S. guianensis (pelagic consumer) and Ariidae (demersal consumer) presented similar frequencies (1.3-1.8%). Therefore, a feeding site in the water column does not predict the probability of debris ingestion. Concerning these species, this probability seems to be more associated with prey-capture strategies (or feeding behavior), regardless of debris availability in the environment.

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.

Mn2+ concentrations in coastal fish otoliths: understanding environmental and biological influences from EPR.

The Mn2+ concentrations in the sagittae otoliths of 12 fish families (and 19 species) that co-occur in a coastal area of southeastern Brazil (~21°S) were quantified using electron paramagnetic resonance (EPR). Inferences were made about the relationship between fish habitat and trace element incorporation. Inferences were made on the relationship between trace element concentration and otolith shape. The differences in Mn2+ concentrations among the species suggest that habitat (and feeding habits) might drive the incorporation of this trace element into fish otoliths, with higher values in bottom-associated fish species than in surface-associated species. In surface-associated fish species, the correlation between trace element concentrations and otolith shape was stronger than in bottom-associated species. Thus, while the Mn bioavailability in a fish's habitat, especially from feeding resources, is a local driving influence of trace element incorporation in sagittae otoliths, species-specific requirements also have an influence. Quantitative EPR is a non-destructive technique that is very useful when the available samples cannot be damaged, like with otolith collections.

Marine debris boost in juvenile Magellanic penguins stranded in south-eastern Brazil in less than a decade: Insights into feeding habits and habitat use.

The Magellanic penguin (Spheniscus magellanicus) is a marine sentinel for the southern Atlantic Ocean that is a proxy of environmental quality. The presence of marine debris (macro-debris) in the stomach contents of emaciated juvenile penguins stranded from 21°S to 23°S was compared at different times (2000 and 2008), and the debris ingestion pathway was determined. The frequency of marine debris in the stomachs doubled in less than a decade, and flexible plastics remained the main ingested item over time (68-70%). The pelagic octopus, Argonauta nodosa, which inhabits the sea surface, was the most important prey species recovered in the stomach contents. The poor physical condition of the penguins that reach the northern migration limit (study area) reduces the diving capacity of the animals and increases their vulnerability to debris ingestion. Considering their preferred prey and physical condition, we conclude that the penguins likely ingested the marine debris in surface waters.

Assessment of trace elements, POPs, (210)Po and stable isotopes ((15)N and (13)C) in a rare filter-feeding shark: The megamouth.

With less than 60 records being reported worldwide, the megamouth (Megachasma pelagios) is today one of the least known shark species inhabiting our oceans. Therefore, information concerning the biology and ecology of this enigmatic organism is very scarce and limited to feeding behaviour and preferred habitat. The present work reports new data on the concentrations of trace elements, organic mercury, POPs and (210)Po in hepatic and muscular tissues of a specimen found stranded in the southeastern coast of Brazil. Additionally, we provide new evidence based on stable isotope analysis (δ(15)N and δ(13)C) confirming the preference for the pelagic habitat and the zooplanktivorous feeding behaviour of the megamouth. These results are consistent with the low concentrations of organic pollutant compounds and other elements measured in our samples.

How marine debris ingestion differs among megafauna species in a tropical coastal area.

The marine debris ingested by megafauna species (Trichiurus lepturus, Chelonia mydas, Pontoporia blainvillei, and Sotalia guianensis) was recorded in a coastal area of southeastern Brazil (21-23°S). Marine debris was recorded in all species, mainly consisting of plastic material (flexible and hard plastics - clear, white, and colored- and nylon filaments). The 'pelagic predators' T. lepturus and S. guianesis showed the lowest percent frequencies of debris ingestion (0.7% and 1.3%, respectively), followed by the 'benthic predator' P. blainvillei (15.7%) and the 'benthic herbivorous C. mydas (59.2%). The debris found in C. mydas stomachs was opportunistically ingested during feeding activities on local macroalgal banks. In the study area, the benthic environment accumulates more anthropogenic debris than the pelagic environment, and benthic/demersal feeders are more susceptible to encounters and ingestion. The sub-lethal effects observed in C. mydas, such as intestinal obstruction due to hardened fecal material, should be considered a local conservation concern.

Marine debris ingestion by coastal dolphins: what drives differences between sympatric species?

This study compared marine debris ingestion of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in a sympatric area in Atlantic Ocean. Among the 89 stomach contents samples of P. blainvillei, 14 (15.7%) contained marine debris. For S. guianensis, 77 stomach contents samples were analyzed and only one of which (1.30%) contained marine debris. The debris recovered was plastic material: nylon yarns and flexible plastics. Differences in feeding habits between the coastal dolphins were found to drive their differences regarding marine debris ingestion. The feeding activity of P. blainvillei is mainly near the sea bottom, which increases its chances of ingesting debris deposited on the seabed. In contrast, S. guianensis has a near-surface feeding habit. In the study area, the seabed is the main zone of accumulation of debris, and species with some degree of association with the sea bottom may be local bioindicators of marine debris pollution.

Population structure of the crab Callinectes ornatus Ordway, 1863 (Brachyura: Portunidae) bycatch in shrimp fishery in northern Rio de Janeiro state, Brazil / Estrutura populacional do siri Callinectes ornatus Ordway, 1863 (Brachyura: Portunidae) capturado incidentalmente na pesca de camarão no litoral norte do estado do Rio de Janeiro, Brasil

This study provides the first data on the population structure of swimming crab Callinectes ornatus Ordway, 1863 bycatch from coastal shrimp fishing in northern Rio de Janeiro State, Brazil (21º 30'-21º 50' S and 41º 05'-41º 07' W). Crabs were collected monthly from April 2006 to March 2007. A total of 5,611 specimens were analyzed, of which 3,951 were males and 1,660 ovigerous and non-ovigerous females. The overall sex ratio (2:1) differ significantly from the expected 1:1 proportion, being the mature males significantly predominant as bycatch in this fishery. The specimens' carapace width and weight varied from 27 to 126 mm (mean: 77.3 ± 12.3 mm) and 1.2 to 128.2 g (mean: 31.0 ± 14.4 g) for males, and 30 to 101 mm (mean: 63.4 ± 9.3 mm) and 1.7 to 66.0 g (mean: 16.4 ± 7.4 g) for ovigerous and non-ovigerous females. Seasonal comparisons did not reveal differences between the number of specimens captured in dry and rainy periods considering both sexes and maturity stages. The size at first maturity was 79 mm for males and 65 mm for females, and the carapace width-weight relationship indicated an alometric pattern for both sexes. The bycatch swimming crabs are locally used as bait, but the capture tendency for a specific sex/age-group can affect this population structure over time.

Este estudo fornece os primeiros dados sobre a estrutura populacional do siri Callinectes ornatus Ordway, 1863 capturado incidentalmente através da pesca camaroneira realizada no litoral norte do estado do Rio de Janeiro, Brasil (21º 30'-21º50' S e 41º 05'-41º 07' O). Os siris foram coletados mensalmente entre abril de 2006 a março de 2007. Um total de 5.611 espécimes foram analisados, dos quais 3.951 eram do sexo masculino e 1.660 fêmeas ovígeras e não ovígeras. A razão sexual (2:1) diferiu significativamente da proporção 1:1 esperada, sendo os machos maduros significativamente predominantes como captura incidental nesta pescaria. A largura da carapaça e o peso dos espécimes variaram de 27 a 126 mm (média: 77,3 ± 12,3 mm) e 1,2 a 128,2 g (média: 31,0 ± 14,4 g ) para machos, e 30 a 101 mm (média: 63,4 ± 9,3 mm ) e 1,7 a 66,0 g (média: 16,4 ± 7,4 g) para fêmeas ovígeras e não ovígeras. As comparações sazonais não revelaram diferenças entre o número de espécimes capturados nos períodos seco e chuvoso, considerando ambos os sexos e estágios de maturidade. O tamanho de primeira maturação foi de 79 mm para machos e 65 mm para as fêmeas, e a relação largura da carapaça-peso indicou padrão alométrico para ambos os sexos. Os siris capturados incidentalmente são utilizados localmente como isca, mas a tendência de captura sobre um grupo sexual/etário específico pode afetar a estrutura dessa população ao longo do tempo.

Mercury and nitrogen isotope in a marine species from a tropical coastal food web.

The present study raised the hypothesis that the trophic status in a tropical coastal food web from southeastern Brazil can be measured by the relation between total mercury (THg) and nitrogen isotope (δ(15)N) in their components. The analysed species were grouped into six trophic positions: primary producer (phytoplankton), primary consumer (zooplankton), consumer 1 (omnivore shrimp), consumer 2 (pelagic carnivores represented by squid and fish species), consumer 3 (demersal carnivores represented by fish species) and consumer 4 (pelagic-demersal top carnivore represented by the fish Trichiurus lepturus). The values of THg, δ(15)N, and trophic level (TLv) increased significantly from primary producer toward top carnivore. Our data regarding trophic magnification (6.84) and biomagnification powers (0.25 for δ(15)N and 0.83 for TLv) indicated that Hg biomagnification throughout trophic positions is high in this tropical food web, which could be primarily related to the quality of the local water.

Feeding preference of adult females of ribbonfish Trichiurus lepturus through prey proximate-composition and caloric values

In the present study we analysed the proximate-composition and caloric values of the preferred prey consumed by ribbonfish, Trichiurus lepturus L. 1758 (adult females), that are distributed in the inner continental shelf from northern Rio de Janeiro State, southeastern Brazil (~22ºS), assessing the potential of nutritional and energetic approach as a tool to understand the feeding selective pattern of this marine top carnivore. The preferred prey of this predator composed of fish co-specifics, Pellona harroweri, Chirocentrodon bleekerianus, Lycengraulis grossidens, Peprilus paru, squid Doryteuthis plei, and shrimp Xiphopenaeus kroyeri were collected from 2007 to 2010 for proximate-composition (water, protein, lipid, ash, and carbohydrate) and caloric value analyses. The correspondence analysis showed that protein is the main component in the prey species (61.32% of variance explained), standing out from the other nutrients. Lipid has the highest percentage related to L. grossidens, ash to X. kroyeri and carbohydrate to D. plei. The strong correlations between protein and caloric value (positive) and lipid and caloric value (negative) indicated that T. lepturus is attending its energy demand through the prey protein content. This work elucidated the feeding preference of adult females of T. lepturus in relation to nutritional and caloric content of their preferred prey. The species showed food selectivity to prey that provide more energy per ingested biomass, so that the feeding events can maximize the predator's caloric gain, which is obtained by a protein-based diet.

No presente estudo foram analisadas a composição centesimal e o valor calórico das presas preferenciais consumidas pelo peixe-espada, Trichiurus lepturus L. 1758 (fêmeas adultas), que se distribuem na plataforma continental interna do norte do estado do Rio de Janeiro, sudeste do Brasil (~ 22ºS). O objetivo foi avaliar o potencial da abordagem nutricional e energética como ferramenta para compreender o padrão de seletividade alimentar deste carnívoro marinho. As presas preferenciais deste predador, compostas por co-específicos e pelos peixes Pellona harroweri, Chirocentrodon bleekerianus, Lycengraulis grossidens e Peprilus paru, pela lula Doryteuthis plei e pelo camarão Xiphopenaeus kroyeri, foram coletadas entre 2007 e 2010 para análise da composição centesimal (água, proteína, lipídio, cinzas e carboidratos) e do valor calórico. A análise de correspondência mostrou que a proteína é o principal componente nas espécies de presa (61,32% da variância explicada), destacando-se dos outros nutrientes. Para o lipídio a maior porcentagem esteve relacionada com L. grossidens, cinzas com X. kroyeri e carboidratos com D. plei. As fortes correlações entre proteína e valor calórico (positiva) e lipídio e valor calórico (negativa) indicaram que T. lepturus está atendendo sua demanda de energia através do teor de proteína das presas. Este trabalho elucidou a preferência alimentar de fêmeas adultas de T. lepturus em relação ao conteúdo nutricional e calórico das presas preferenciais. A espécie apresentou seletividade alimentar por presas que fornecem mais energia por biomassa ingerida, de modo que os eventos de alimentação maximizem o ganho calórico do predador, que é obtido por uma dieta à base de proteínas.

Estrutura populacional do siri-baú, Hepatus pudibundus (Herbst 1785) no Norte do Estado do Rio de Janeiro, Sudeste do Brasil / Population structure of the flecked box crab, Hepatus pudibundus (Herbst 1785) in Northern Rio de Janeiro State, Southeastern Brazil

O presente estudo descreve as primeiras informações sobre a estrutura populacional do siri-baú, Hepatus pudibundus, na costa Norte do Estado do Rio de Janeiro (21° 30' e 21° 50' S). Entre abril de 2006 e março de 2007 foram realizadas coletas mensais (n = 12) com rede de arrasto de fundo em embarcações da pesca camaroneira local. Os espécimes foram classificados quanto ao sexo e maturidade, medidos e pesados. No total, foram capturados 523 indivíduos de H. pudibundus: 299 (57,2 por cento) machos e 224 (42,8 por cento) fêmeas. De modo geral, a razão sexual na população se manteve estável ao longo do período de estudo, com ligeiro predomínio de machos. Os espécimes adultos foram mais numerosos do que os juvenis. Os machos foram maiores e mais pesados que as fêmeas, com médias da largura da carapaça de 46,8 ± 9,1 mm e peso de 23,4 ± 13,2 g, em comparação com 45,3 ± 6,6 mm e 18,8 ± 7,9 g para as fêmeas. As relações entre peso e largura da carapaça foram ajustadas pelas equações P = 0,0002.LC I3,0391 (R2 = 0,97) (machos) e P = 0,0003.LC I2,8734 (R2 = 0,94) (fêmeas). A espécie H. pudibundus tem pouca representatividade na pesca camaroneira regional, mas o presente estudo indica sua ocorrência regular em associação às águas costeiras do Norte do Estado do Rio de Janeiro.

The present study describes the first information about the population structure of the flecked box crab, Hepatus pudibundus, in Northern Rio de Janeiro State (21° 30' and 21° 50' S). From April 2006 to March 2007 monthly samples (n = 12) were conducted using a bottom trawl net aboard local shrimp fishery boats. The specimens were classified by gender and maturity status, measured and weighed. In total, 523 individuals of H. pudibundus were captured: 299 (57.2 percent) males and 224 (42.8 percent) females. In general, the sex ratio was constant over the studied period, with slight predominance of males. The adult specimens were more numerous than the juveniles' ones. Male specimens were larger and heavier than females, with averages of 46,8 ± 9,1 mm in carapace width and 23,4 ± 13,2 g in weight, compared to 45,3 ± 6,6 mm and 18,8 ± 7,9 g for females. The relationships between weight and carapace width were adjusted by the equations W = 0.0002.CW I3.0391 (R2 = 0.97) (males) and W = 0.0003.CW I2.8734 (R2 = 0.94) (females). The species H. pudibundus has little significance to the regional shrimp fishery, but this study indicates its regular occurrence in coastal waters from Northern Rio de Janeiro State.