O imposex consiste no surgimento de caracteres sexuais masculinos em fÃmeas de moluscos prosobrÃnquios expostos à contaminaÃÃo por compostos orgÃnicos de estanho (COEs). Essa contaminaÃÃo à oriunda de tintas de aÃÃo antiincrustante utilizadas em embarcaÃÃes de todo mundo. Como o imposex leva ao desenvolvimento de caracteres mensurÃveis, o mesmo vem sendo usado como ferramenta de bioindicaÃÃo para esse tipo especÃfico de poluiÃÃo. O presente trabalho teve como objetivo monitorar a contaminaÃÃo por organoestÃnicos ao longo das Ãreas sob a influÃncia dos 10 principais terminais portuÃrios da regiÃo nordeste do Brasil e comparar o desenvolvimento do imposex nas espÃcies de muricÃdeos utilizadas no estudo. Essas espÃcies foram: Stramonita haemastoma e Stramonita rustica. Os Ãndices usados para quantificar o imposex foram o VDSI. o RPSI, o RPLI e a % de imposex. Em todos os terminais portuÃrios estudados observou-se pelo menos uma estaÃÃo onde se detectou a presenÃa do imposex o que sugere fortemente a presenÃa de contaminaÃÃo por COEs. Entretanto os Ãndices observados revelaram-se baixos quando comparados aos Ãndices obtidos em outros monitoramentos realizados em regiÃes muito industrializadas da Europa e da Ãsia. Mesmo quando comparados aos resultados observados na BaÃa de Guanabara no litoral do estado do Rio de Janeiro os Ãndices de imposex no nordeste do Brasil revelam-se pouco elevados. Isso reforÃa dados jà mencionados na literatura que sugerem que a contaminaÃÃo por compostos orgÃnicos de estanho à mais severa em regiÃes mais industrializadas do mundo. Os estudos comparativos quanto ao desenvolvimento do imposex nas espÃcies S. haemastoma a e S. rustica mostraram que a primeira à mais sensÃvel à contaminaÃÃo por COEs uma vez que mesmo quando submetidas experimentalmente a concentraÃÃes iguais e ao mesmo tempo de exposiÃÃo S. haemastoma apresentou uma resposta muito mais severa que sua congÃnere S. rustica. Das 82 estaÃÃes analisadas durante o presente estudo, 32 mostraram-se completamente livres de quaisquer indÃcios de imposex o que sugere que o imposex nÃo se manifesta naturalmente nas referidas espÃcies. / Imposex consists of a superimposition of male sexual characteristics in female prosobranch molluscs exposed to organotin compounds (OCs) contamination. This contamination is caused by biocides present in antifouling paints used on boats all over the world. Since imposex leads to measurable characters, those have been used for biological-effect monitoring of this type of contamination. This present work had the objective to monitor the organotin contamination along the areas under influence of the 10 most important harbours in the northeastern coast of Brazil, and also to compare the imposex development in the muricid species studied. Those species were Stramonita haemastoma and Stramonita rustica. The indices used to quantify the imposex development were VDSI, RPSI, RPLI and the imposex percentage. In all harbour areas, there was at least one site where imposex was detected, what strongly suggests the presence of OCs contamination. However, the indices observed appeared to be lower when compared to the indices of other monitorings in industrialized regions, such as Europe and Asia. When compared to studies in Guanabara Bay â Rio de Janeiro, Brazil, the indices also seemed very low. This reinforces the data already mentioned in other studies, which suggests that the higher the level of industrialization in an area more severe is the contamination by organotin compounds. Comparative studies of imposex development in the species Stramonita haemastoma and S. rustica revealed that the former is more sensitive to OCs contamination, once that, when submitted experimentally to equal concentrations and same exposure time, S. haemastoma presented a much greater response than S. rustica. In this present study, 82 sites were analyzed, 32 appeared to be free from any imposex evidence, what suggests that imposex does not appear as a natural characteristic in those S. haemastoma and S. rustica.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-11-10T12:10:24Z No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_DistribuicaoEcomorfologiaNeritina.pdf: 1152074 bytes, checksum: 70b745e624e7002a78f08f93b2c8f879 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-11-10T17:15:30Z (GMT) No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_DistribuicaoEcomorfologiaNeritina.pdf: 1152074 bytes, checksum: 70b745e624e7002a78f08f93b2c8f879 (MD5) / Made available in DSpace on 2014-11-10T17:15:30Z (GMT). No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_DistribuicaoEcomorfologiaNeritina.pdf: 1152074 bytes, checksum: 70b745e624e7002a78f08f93b2c8f879 (MD5) Previous issue date: 2012 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente estudo avaliou a distribuição de Neritina zebra em um gradiente vertical em afloramentos rochosos e a distribuição entre os afloramentos de rochosos e argilitodo entremarés em um estuário na Amazônia brasileira. Os locais de coletas são caracterizados por águas oligohalinas, sendo localizadas nos distritos dede Icoaraci, Mosqueiro e município de Colares na região costeira do Estado do Pará. Para avaliar a distribuição vertical nos substratos rochosos, os moluscos foram amostrados na faixa inferior e média do mesolitoral. Na faixa inferior do mesolitoral, onde ocorrem os substratos argilito e rocha, estes foram amostrados para verificar seu efeito na distribuição entre os substratos. Em cada tipo de substrato e faixa do entremarés foram amostrados aleatoriamente 22 réplicas utilizando-se um quadrante de 25cm² na estação chuvosa e de estiagem. Análises de Variâncias foram realizadas para testar (1) o efeito da zona do entremarés e (2) o tipo de substrato na densidade de N. zebra. A análise dos resultados da distribuição vertical mostrou que a zona inferior os indivíduos juvenis apresentam maior densidade que a zona média, e um padrão oposto parece ocorrer com espécimes adultos. Quanto à distribuição nos diferentes substratos, os resultados mostraram que existem maiores densidades nos substratos rochosos que nos argilosos para os indivíduos juvenis, mas não foi encontrado um padrão para os indivíduos adultos. Esta variabilidade no padrão de densidades entre os substratos e entre as zonas do entremarés mostrou influência das estações e dos locais de coleta, apresentando Icoaraci com as menores densidades, o que pode estar associado à atividade antrópica naquela localidade. / The present study evaluates the vertical distribution of Neritina zebra in rocky outcrops in the lower and middle intertidal, intertidal as well as the horizontal distribution between rocky and clay substratas of an estuary in the Brazilian Amazon. The sampling areas are located in an oligohaline area in Icoaraci, Mosqueiro and Colares, at the coast of the State of Pará, Brasil. To evaluate the vertical distribution on orocky substrata, substratamolluscs were esampled in the lower and middle intertidal. intertidal In the lower mesolittoralmto, where clay and rocky substrata occur, substrataoccursamples were collected to verify the effect of the substrata on othe distribution of the mollusc.For each substrata and intertidal zonet zone, 22 replicates were randomly sampledusing a quadrant of 25x25cm² during the rainyrainy and dry season. An Analysis of Variance was seasonAAVancewasperformed to test (1) the effect of the intertidal zone and (2) the substrata onsubstratao the density of N. zebra. Analysis Athe vertical distribution results showed that in the lower zone, ,juvenile individuals show a higher density than in the middle zone, and an oppositeand anp pattern compared with adults appear to occur.Regarding the distribution on the different substrata,on the differentsubstrata results showed higher densities ono rocky substrate than onon clay substrata for young individuals, whereas no definite pattern was detected for adultss. This variability between the substrata and intertidal zones showed the influence of the seasons and the sampling sites. Icoaraci showed theshowedlowest densities, which can be associated to the anthropic activities in that area.

Tarebia granifera is a prosobranch freshwater gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This snail has recently also invaded the iSimangaliso Wetland Park, often reaching population densities of over 20000 ind.mˉ2 and dominating benthic invertebrate communities. A multiple method approach was used to address several aspects of the biology and ecology of this non-native invasive species (NIS). The tolerance of T. granifera to salinity and temperature was investigated through the experimental manipulation of these factors. T. granifera survived exposure to temperatures between 0 ºC and 47.5 ºC. More remarkably, this snail was able to survive a salinity of 30 for 65 - 75 days. Population density and size structure were monitored in estuaries and coastal lakes. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation. The persistence of T. granifera was largely ensured due to the wider environmental tolerance of adults (20 - 30 mm shell height) which carried an average of 158 ± 12.8 SD brooded juveniles. Multiple introductions were not essential for the success of this parthenogenetic NIS. Using gut fluorescence and carbon budget techniques it was estimated that T. granifera consumes 0.5 - 35% of the total available microphytobenthic biomass per day, or 1.2 - 68% of the daily primary benthic production. The carbon component estimated from the gut fluorescence technique contributed 8.7 - 40.9% of the total gut organic carbon content. A stable isotope mixing model was used together with gut content analysis to estimate the diet of T. granifera and dominant native gastropod species, potentially competing for resources. Results were used in the formulation of an index of isotopic dietary overlap (IDO, %). This approach yielded detailed information both on general changes in ecosystem functioning and specific species interactions. Before/After-Control/Impact (BACI) logic was used in a multivariate approach to separate human perturbations from natural spatio-temporal variability displayed by communities, and to further separate perturbations due to NIS. Human intensification of drought negatively affected biodiversity and T. granifera may exacerbate this problem by displacing native species from critical refugia and contributing towards biotic homogenization. The present findings constitute a contribution to the scientific knowledge on biological invasions and a useful tool towards adaptive management in the iSimangaliso Park. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2012.

Globalization has seen an unprecedented dispersal of exotic and alien species worldwide resulting in worldwide homogenization and sometimes extinction of indigenous or endemic taxa. When an exotic species becomes established in a new habitat the invasive organisms are capable of having an impact on indigenous community dynamics and the overall structure and function of ecosystems. Furthermore, the impact of invasion is determined by the geographical range, abundance and the per-capita or per-biomass effect of the invader. However, the success of the introduced organisms is reliant on their ability to acclimate to the physiochemical conditions of the newly invaded environment.Freshwater ecosystems are especially vulnerable to invasions because there are numerous potential routes of introduction including intentional pathways such as stocking, and unintentional pathways such as the release of ballast water and aquarium releases. Efforts to limit the introduction of invasive species or to manage established exotic populations are often hindered by insufficient understanding of the natural history of problematic species. Relatively little is known regarding the physiological tolerances of many taxa. Knowledge about specific species ecophysiological constraints allows for the prediction of future patterns of invasion more accurately, including where an introduced organism would probably survive, thrive and disperse. Furthermore, data on the physiological tolerances of an introduced exotic organism may provide data necessary for effective management and control. This studyinvestigated three invasive species in the Nseleni River system in a protected area in KwaZulu-Natal. The species studied were, Tarebia granifera (Quilted melania – Lamarck, 1822), Pterygoplichthys disjunctivus (Suckermouth armoured catfish - Weber, 1991) and Eichhornia crassipes (water hyacinth – (Martius) Solms-Laubach,). The Nseleni River flows into Lake Nsezi which is responsible for providing potable water to the surrounding towns and industry, as well as the surrounding rural communities. The Enseleni Nature reserve has become the centre for biodiversity dispersal in the immediate area, due to the change in landscape surrounding the protected area.An important step in developing alien invasive species management strategies in protected areas is determining their extent and invasive traits. Tarebia granifera is a prosobranch gastropod originally from South-East Asia that has become invasive in several countries around the world including South Africa. Snail populations were sampled at nine sites throughout the Nseleni/Mposa river system every six weeks over a twelve month period. The snail was abundant throughout the system, especially in shallow waters of less than 1m in depth.The first positive identification the loricariid catfish Pterygoplichthys disjunctivus for the Nseleni River was in 2006. The original introduction is believed to have been via the aquarium trade. The aim of the study was to assess the usefulness of the unified framework with regard to management of fish invasions by assessing the invasion stage of the loricariid population and identifying appropriate management actions using the Blackburn et al. (2011) framework. The fish were sampled at nine different sites and three different depths over a period of twelve months, as well as when two ichthyological surveys were carried out on the Nseleni River system. This invasive fish has been located throughout the system and both male and female fish were collected. The smallest fish sampled was a fingerling of a day or two old and the smallest pregnant female was a mere 270mm TL. This is a clear indication that this fish is breeding in the river system.Although T. granifera and P. disjunctivus were abundant in the Nseleni/Mposa river system, it was not clear what their role in the system was, and in particular if they were competing with any of the indigenous species. Therefore, isotope samples were collected from numerous taxa over a two week period, with the exception of Pterygoplichthys disjunctivus samples, which were collected over 12 months. The δ13C and δ15N signatures of all samples were determined. The niche overlap between the invasive and indigenous snails was effectively zero (1.02E-13%), indicating no shared food resources. The medium ranges of dNRb (7.14) and dCRb (9.07) for the invasive fish indicate that it utilizes a wider range of food resources and trophic levels than the majority of indigenous fish. A medium CDb value (2.34) for the invasive fish species, P. disjunctivus, describes medium trophic diversity, with three indigenous species possessing higher diversity and three possessing lower diversity. Furtherresults indicated that there was no direct dietary competition between P. disjunctivus and indigenous species. Eichhornia crassipes was first recorded on the Nseleni River in 1978, and has been shown to have a significant negative impact on the biodiversity of the Nseleni/Mposa River system and therefore required a control intervention. Although biological control using the two weevil species Neochetina eichhornia (Warner) and N. bruchi (Hustache) has been credited with affecting a good level of control, the lack of a manipulated post-release evaluation experiments has undermined this statement. Five experimental plots of water hyacinth of 20m2 were sprayed with an insecticide to control weevils. After ten months the plants in the sprayed plots were significantly bigger and heavier than those in the control plots that had natural populations of the biological control agents. This study has shown unequivocally that biological control has contributed significantly to the control of water hyacinth on the Nseleni/Mposa River system.The management plan for the Enseleni Nature Reserve identifies the need to control invasive and/or exotic organisms within the boundary of the protected area. In addition, set guidelines have been implemented on how to control these organisms, so that indigenous organisms are least affected. Lack of control of exotic organisms can have serious consequences for indigenous species. It is therefore of utmost importance that the population dynamics of the invading organism be understood, what the potential impact could be and how to control them. Furthermore, it has also acknowledged the threat of possible exotic species invasions from outside of the protected area that might result in threats to the protected area and that these must be investigated, researched and managed.This thesis has identified Tarebia granifera, Pterygoplichthys disjunctivus and Eichhornia crassipes as being a threat to indigenous biodiversity within the protected area, as well as in adjacent areas to the protected area. The thesis will therefore investigate the hypothesis that both Tarebia granifera and Pterygoplichthys disjunctivus are having a direct negative effect on available food resources for indigenous species of organisms. In addition, this thesis will investigate if theNeochetina species that have previously been introduced onto E. crassipes are having any negative effect on this invasive alien aquatic plant.

The aim of this work was to evaluate the limits of ranges of European land snail species along the north-south gradient. To work out the document it was necessary to prepare the set of digitalized maps, that enabled to create the database of ranges of the individual land snails species. Based on obtained data I tried to identify places where the northern and southern borders of species ranges are the most frequent. The landsnails' ranges are affected not only by particular life requirements of the individual species (potential limits), but also by other conditions, especially climatic, geographical and historical (truncated limits). In this work I focused on their differentiation. Above mentioned process also enabled me to track the north- south changes in species richness of the landsnails taking into consideration the truncated and potential limits. The most important natural barriers constraining that numerous of species cannot naturally widespread from the south to the north are the Scandinavian Mountains, the Alpes and the Carpathians and suprisingly also southern borders of german and polish lowlands. On the other hand, spreading of the species form the north to the south is limited only by the Alpes. I also tried to distinguish the group of species whose ranges are not influenced by these...

To show how predaceous fish and dragonflies affect benthic community structure, we conducted enclosure experiments in the littoral zone of Bays Mountain Lake, Tennessee. A 'natural' benthic assemblage was subjected to all combinations of 2 densities of 3 predator treatments - small sunfish, 0 or 4/m2; large dragonfly larvae, 0 or 15/m2; and dragonfly eggs at 2 densities, 90 or 900/m2. Treatments were assigned randomly in each of 6 spatiotemporal blocks. Net effects of predation over 4 mo show that small sunfish had 'strong' effects (>50% reduction of densities) on triclads, large daphnid cladocerans, and snails, and 'moderate' effects (50% > reduction > 25%) on small dragonflies and ostracods; all these effects were statistically significant, except the one on ostracods. Large dragonflies had moderate non-significant effects on triclads and ostracods. There were no significant increases in prey density associated with fish predation; but chydorid cladocerans and midge larvae showed 'weak' non-significant increases that might be caused by 'indirect effects' of fish predation on invertebrate predators or grazers. There were only 2 significant interaction terms indicative of 'higher-order interactions': Fish X Dragonfly on the large daphnid Simocephalus, and Fish X Egg Density on snails, which were associated with relatively low probabilities. In both cases, the net effect of dragonflies was to reduce prey densities more when fish were present.

Wetlands are limnic ecosystems that greatly benefit biodiversity and provide ecosystem services like water purification and carbon sequestration across the globe. However, they have for centuries suffered disturbances and intentionally been altered to make way for anthropogenic activity. In recent times many wetlands are being restored and new ones are constructed in an effort to recreate the former dynamic between wetlands and the surrounding landscape and its ecosystems. The ecological status of wetlands can be monitored by performing inventories of invertebrate indicator species. Limnic snails and mussels make for good monitoring candidates, due to their ability to bioaccumulate toxic substances, sensitivity to environmental changes and general presence in wetland habitats. Snails and mussels are also among the most threatened groups of organisms in limnic ecosystems, but do despite this seldom get included in conservation plans. This study, a collaboration with Hushållningssällskapet in Halland, investigated the occurence of limnic snails and mussels in constructed wetlands ordered in different age categories. The general purpose of the study is to expand the knowledge about the species composition of snails and mussels that occur in the catchment area of Trönninge river. Furthermore, another aim is that the results will be of use for future studies of wetland ecology and the roles that snails and mussels fill in it. / Våtmarker är viktiga sötvattenssystem för biologisk mångfald och bidrar med ekosystemtjänster över hela världen, bland annat renande av vatten och lagring av kol. De har dock under sekler påverkats och förstörts för att bistå människans olika syften. Idag konstrueras nya våtmarker eller restaureras för att återskapa processer som samverkar med de ekosystem som ingår i landskapsbilden. Våtmarkers ekologiska status kan undersökas genom insamling av evertebrata indikatorarter. I dessa biotoper är ofta sötvattensmollusker som snäckor och musslor både vanligt förekommande och reagerar på miljöförändringar. De renar vattnen på föroreningar och lagrar toxiska ämnen i sina kroppar, vilket gör dem till bra kandidater för miljöövervakning. Snäckor och musslor hör idag till de mest hotade grupperna av organismer i limniska ekosystem, men inkluderas trots detta sällan i bevarandeplanering. I denna inventeringsstudie undersöktes förekomsten av snäckor och musslor i anlagda våtmarker av olika ålderskategorier. Studien genomfördes i samarbete med Hushållningssällskapet i Halland och syftar bland annat till att tillföra utökad kännedom om snäckor och musslors artsammansättning i Trönningeåns avrinningsområde. Målsättningen är att resultaten ska komma till användning för framtida studier som inriktar sig på våtmarkers ekologiska status i allmänhet och framförallt snäckor och musslors roller i dessa.

名古屋大学年代測定総合研究センターシンポジウム報告

Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-03-23T21:33:26Z No. of bitstreams: 1 NayaraGM_DISSERT.pdf: 2481190 bytes, checksum: b1ca8d847270148db31443c379c38868 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-04-13T14:59:25Z (GMT) No. of bitstreams: 1 NayaraGM_DISSERT.pdf: 2481190 bytes, checksum: b1ca8d847270148db31443c379c38868 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-04-13T14:59:35Z (GMT) No. of bitstreams: 1 NayaraGM_DISSERT.pdf: 2481190 bytes, checksum: b1ca8d847270148db31443c379c38868 (MD5) / Made available in DSpace on 2017-04-13T14:59:49Z (GMT). No. of bitstreams: 1 NayaraGM_DISSERT.pdf: 2481190 bytes, checksum: b1ca8d847270148db31443c379c38868 (MD5) Previous issue date: 2016-03-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of this study was providing population biology and reproduction data and to determine the shell utilization pattern of Clibanarius antillensis at Baixa Grande Beach, State of Rio Grande do Norte, Brazil (4°57’22”S / 37°08’13”W), using the percentage of the different shell type that were occupied and the morphometric relationship between hermit crabs and occupied shells. Specimens were collected at two-months intervals from October 2012 to August 2013, using sampling effort of two collectors for 1 hour during spring low tides. The hermit crabs collected were identified and had their carapace shield length measured (mm). All occupied gastropod shells were identified and had their shell biometric parameters (aperture width, aperture length and internal volume) measured (mm). A total of 576 individuals ofClibanarius antillensis was obtained of which 191 were males (33.16%), 140 nonovigerous females (24.31%), 125 intersex (21.70%) and 120 ovigerous females (20.83%), using seven species of gastropods. Cerithium atratum and Stramonita haemastoma were the most occupied shells, with 69.97%, and 24.31%, respectively. The average size of male ranged from 1.43 to 9.64 mm of CEC (4.29 ± 1.56 mm); 1.6 to 6.88 mm for non ovigerous females (3.79 ± 1.18 mm); 1.42 to 8.38 mm for intersex (3.69 ± 1.36 mm) and 2.1 to 7.27 mm for ovigerous females (3.76 ± 1.09 mm). Sexual dimorphism was recorded by the larger average size attained by males in relation to females (ovigerous and non-ovigerous) and intersexes. The shells of C. atratum had higher frequency of occupation by smaller organisms, especially in the size class 3.00 -] 4.00mm, while Stramonita haemastoma housed larger organisms, predominantly in the size class 4,00--] 5.00mm. There were differences in the pattern of occupation by males, not ovigerous females, intersex and ovigerous females. Males were significantly higher than the other categories. The size difference strongly influenced the shell utilization pattern, principaly in S. haemastoma, which has the largest Shell volume, being preffered by males. The other categories have occupied most significantly shells of C. atratum due to small size and lower width of the apperture width and length of the shells. Annual size-frequency distirbutions were unimodal, with non-normal distribution. The overall sex ratio was 1: 1.36 (M: F) and did not differ significantly from the expected sex ratio of 1: 1. Ovigerous females were present in all year-round. The fecundity of the studied population was of 178.14, with an average number of eggs of 178.14 ± 85.61 ranging from 51 eggs (CEC = 3.21 xvi mm) to 325 eggs (CEC = 6.77 mm), being much smaller than that of subtropical popultions of this species. The regression analysis shows that the number of eggs increase linearly with the increase of crabs shield lenght and internal volume of shells. Regression analysis showed a positive correlation between the dimensions of hermit crabs and the utilized shells. In this study, occupation by C. antillensis varied as a function of shell morphometric charactistic, with intraspecific differences in occupation partterns also occuring at Baixa Grande Beach / O objetivo desse estudo foi fornecer dados populacionais e reprodutivos da espécie de caranguejo-eremita Clibanarius antillensis Stimpson, 1859, e definir sua preferência na ocupação de conchas de gastrópodos nos recifes de arenito, da praia de Baixa Grande, Areia Branca, Rio Grande do Norte (4°57’22”S / 37°08’13”W). As coletas foram realizadas a cada dois meses, de outubro de 2012 a agosto de 2013, utilizando esforço amostral de dois coletores por hora durante as marés baixas de sizígia. Os caranguejos-eremitas foram coletados manualmente e, em laboratório, as conchas dos moluscos e os exemplares de anomuros foram identificados e medidos. Um total de 576 indivíduos foram coletados, sendo 191 machos (33,16%), 140 fêmeas não ovígeras (24,31%), 125 intersexos (21,70%) e 120 fêmeas ovígeras (20,83%), ocupando 7 espécies de gastrópodos, sendo Cerithium atratum a mais ocupada (69,97%), seguida de Stramonita haemastoma (24,31%), Pisania pusio (1,22 %), Leucozonia nassa (3,47%), Tegula viridula (0,52%), Anachis obesa (0,35%) e Olivella minuta (0,17%). O tamanho médio dos indivíduos machos variou de 1,43 a 9,64 mm de CEC (média de 4,29 1,56 mm); de 1,6 a 6,88 mm de CEC para as fêmeas não ovígeras (3,79 1,18 mm); de 1,42 a 8,38 mm de CEC para os intersexos (3,69 1,36 mm) e de 2,1 a 7,27 mm de CEC para as fêmeas ovígeras (3,76 1,09 mm). A população apresentou dimorfismo sexual quanto ao tamanho, sendo os machos significativamente maiores do que demais categorias. Os machos ocorreram em 10 classes de tamanho, os intersexos em nove enquanto as fêmeas (ovígeras e não-ovígeras) ocorrem em apenas seis classes. Houve diferença também no padrão de ocupação de conchas. As conchas de S. haemastoma foram preferidas por machos, devido às maiores dimensões de comprimento e largura da abertura da concha, e espaço internodessas conchas. As demais categorias ocuparam mais significativamente conchas de C. atratum, devido ao seu tamanho reduzido e medidas da abertura de concha menores, promovendo maior proteção contra estresses ambientais e bióticos. As conchas de C. atratum tiveram maior frequência de ocupação por organismos menores, principalmente na classe de tamanho 3,00--]4,00 mm, enquanto S. haemastoma abrigou organismos maiores, com predominância na classe de tamanho 4,00--]5,00 mm. A distribuição da população nas classes de tamanho foi unimodal, com distribuição não normal (KS = 0,15; p <0,001), o que reflete um recrutamento contínuo ao longo do ano. A razão xiv sexual total foi de 1: 1,36 (M:F) e não diferiu significativamente da razão sexual esperada de 1:1. As fêmeas ovígeras estiveram presentes em todos os meses amostrados. O índice de fecundidade média foi de 178,14, com número médio de ovos de 178,14 85,61 variando de 51 ovos (CEC = 3,21 mm) a 325 ovos (CEC = 6,77 mm). Existe uma correlação positiva entre o tamanho do escudo cefalotorácico e do volume interno da concha com o número de ovos, sendo que a primeira é a que mais explica a variação na quantidade de ovos.Ao analisar as medidas do comprimento da abertura, largura da abertura e volume interno das conchas elas mostraram uma correlação positiva com o tamanho dos caranguejos-eremitas / 2017-03-23