La efectividad de una ley de protección al servicio de la conservación de un recurso marino: El ejemplo del camarón fantasma Callichirus major (Decapoda, Callianassidae) de la costa de Brasil

RESUMEN La mortalidad por pesca ha sido pocas veces estudiada aislando el efecto causado por las capturas. En este estudio se analizó este aspecto usando como modelo biológico al camarón fantasma Callichirus major (Say, 1818), el cual es colectado intensamente en varias regiones de la costa de Brasil. Para ello, la densidad de las galerías y la demografía poblacional de C. major fue analizada en las playas de Gonzaga e Itararé, dos playas contiguas del Estado de São Paulo, Brasil. La playa de Gonzaga fue considerada como control debido a que desde 1992 una ley municipal impide las capturas de C. major, mientras que Itararé fue considerada como tratamiento ya que en este lugar este camarón es recolectado durante todo el año. Los resultados mostraron que la densidad de las galerías y el tamaño de las hembras fueron significativamente mayores en la playa de Gonzaga que en Itararé. En Itararé, la proporción sexual no mostró diferencias significativas de la relación 1:1, lo cual no se ajustó a lo observado en el área sin mortalidad por pesca y al patrón general reportado en otras especies de camarones fantasma del mundo en donde las hembras predominan sobre los machos. El potencial reproductivo fue significativamente menor en Itararé, como efecto del menor número de hembras presentes en esta área sometida a la pesca intensiva de camarones. De acuerdo con una estimativa inicial, un 71% de los individuos murieron por efecto de la pesca en Itararé. Esto hace inviable el sostenimiento ambiental de C. major en esta área dada la actual presión de extracción. La presencia de C. major en la playa de Itararé y probablemente en otras áreas próximas donde es capturada, estaría favorecida por el permanente suministro de larvas procedentes de la playa de Gonzaga, en Santos, que está protegida por ley y fiscalización municipal.

ABSTRACT Studies on mortality due to fishing based on isolating the effect caused by catches are scarce. The present study analyzed this aspect using the ghost shrimp Callichirus major (Say, 1818) as a biological model, which is heavily harvested along the Brazilian coast. For that purpose, density of burrows and population structure of C. major was examined at two adjacent beaches, Gonzaga and Itararé, from the State of São Paulo, Brazil. Gonzaga beach was considered as control because since 1992 a municipal law prevents the capture of C. major, whereas Itararé as treatment since in this place the species is harvested throughout the year. Burrow density and female CL size were significantly higher in Gonzaga than that Itararé. Sex-ratio did not differ significantly from 1:1 in Itararé, differing from the observed in the area without fishing mortality and also to the general pattern reported in other species of ghost shrimps in which females outnumbered than males. Reproductive potential was significantly smaller in Itararé than Gonzaga, as result of the reduced number of females present in this area relative to Gonzaga. A preliminary estimation indicates that 71 % of shrimps in Itararé died as result of fishing. This information suggests non-viability of C. major in this area given the current pressure of fishing. Presence of C. major in the beach of Itararé and probably in other nearby areas where exploitation occurs would be favored by the permanent supply of larvae from Gonzaga beach where the species is protected by and municipal surveillance.

La efectividad de una ley de protección al servicio de la conservación de un recurso marino: El ejemplo del camarón fantasma Callichirus major (Decapoda, Callianassidae) de la costa de Brasil / The effectiveness of a protection law in favor of conservation of an marine resource: The example of the ghost shrimp Callichirus major (Decapoda, Callianassidae) of the coast of Brazil

La mortalidad por pesca ha sido pocas veces estudiada aislando el efecto causado por las capturas. En este estudio se analizó este aspecto usando como modelo biológico al camarón fantasma Callichirus major (Say, 1818), el cual es colectado intensamente en varias regiones de la costa de Brasil. Para ello, la densidad de las galerías y la demografía poblacional de C. major fue analizada en las playas de Gonzaga e Itararé, dos playas contiguas del Estado de São Paulo, Brasil. La playa de Gonzaga fue considerada como control debido a que desde 1992 una ley municipal impide las capturas de C. major, mientras que Itararé fue considerada como tratamiento ya que en este lugar este camarón es recolectado durante todo el año. Los resultados mostraron que la densidad de las galerías y el tamaño de las hembras fueron significativamente mayores en la playa de Gonzaga que en Itararé. En Itararé, la proporción sexual no mostró diferencias significativas de la relación 1:1, lo cual no se ajustó a lo observado en el área sin mortalidad por pesca y al patrón general reportado en otras especies de camarones fantasma del mundo en donde las hembras predominan sobre los machos. El potencial reproductivo fue significativamente menor en Itararé, como efecto del menor número de hembras presentes en esta área sometida a la pesca intensiva de camarones. De acuerdo con una estimativa inicial, un 71% de los individuos murieron por efecto de la pesca en Itararé. Esto hace inviable el sostenimiento ambiental de C. major en esta área dada la actual presión de extracción. La presencia de C. major en la playa de Itararé y probablemente en otras áreas próximas donde es capturada, estaría favorecida por el permanente suministro de larvas procedentes de la playa de Gonzaga, en Santos, que está protegida por ley y fiscalización municipal.(AU)

Studies on mortality due to fishing based on isolating the effect caused by catches are scarce. The present study analyzed this aspect using the ghost shrimp Callichirus major (Say, 1818) as a biological model, which is heavily harvested along the Brazilian coast. For that purpose, density of burrows and population structure of C. major was examined at two adjacent beaches, Gonzaga and Itararé, from the State of São Paulo, Brazil. Gonzaga beach was considered as control because since 1992 a municipal law prevents the capture of C. major, whereas Itararé as treatment since in this place the species is harvested throughout the year. Burrow density and female CL size were significantly higher in Gonzaga than that Itararé. Sex-ratio did not differ significantly from 1:1 in Itararé, differing from the observed in the area without fishing mortality and also to the general pattern reported in other species of ghost shrimps in which females outnumbered than males. Reproductive potential was significantly smaller in Itararé than Gonzaga, as result of the reduced number of females present in this area relative to Gonzaga. A preliminary estimation indicates that 71 % of shrimps in Itararé died as result of fishing. This information suggests non-viability of C. major in this area given the current pressure of fishing. Presence of C. major in the beach of Itararé and probably in other nearby areas where exploitation occurs would be favored by the permanent supply of larvae from Gonzaga beach where the species is protected by and municipal surveillance.(AU)

La efectividad de una ley de protección al servicio de la conservación de un recurso marino: El ejemplo del camarón fantasma Callichirus major (Decapoda, Callianassidae) de la costa de Brasil / The effectiveness of a protection law in favor of conservation of an marine resource: The example of the ghost shrimp Callichirus major (Decapoda, Callianassidae) of the coast of Brazil

La mortalidad por pesca ha sido pocas veces estudiada aislando el efecto causado por las capturas. En este estudio se analizó este aspecto usando como modelo biológico al camarón fantasma Callichirus major (Say, 1818), el cual es colectado intensamente en varias regiones de la costa de Brasil. Para ello, la densidad de las galerías y la demografía poblacional de C. major fue analizada en las playas de Gonzaga e Itararé, dos playas contiguas del Estado de São Paulo, Brasil. La playa de Gonzaga fue considerada como control debido a que desde 1992 una ley municipal impide las capturas de C. major, mientras que Itararé fue considerada como tratamiento ya que en este lugar este camarón es recolectado durante todo el año. Los resultados mostraron que la densidad de las galerías y el tamaño de las hembras fueron significativamente mayores en la playa de Gonzaga que en Itararé. En Itararé, la proporción sexual no mostró diferencias significativas de la relación 1:1, lo cual no se ajustó a lo observado en el área sin mortalidad por pesca y al patrón general reportado en otras especies de camarones fantasma del mundo en donde las hembras predominan sobre los machos. El potencial reproductivo fue significativamente menor en Itararé, como efecto del menor número de hembras presentes en esta área sometida a la pesca intensiva de camarones. De acuerdo con una estimativa inicial, un 71% de los individuos murieron por efecto de la pesca en Itararé. Esto hace inviable el sostenimiento ambiental de C. major en esta área dada la actual presión de extracción. La presencia de C. major en la playa de Itararé y probablemente en otras áreas próximas donde es capturada, estaría favorecida por el permanente suministro de larvas procedentes de la playa de Gonzaga, en Santos, que está protegida por ley y fiscalización municipal.

Studies on mortality due to fishing based on isolating the effect caused by catches are scarce. The present study analyzed this aspect using the ghost shrimp Callichirus major (Say, 1818) as a biological model, which is heavily harvested along the Brazilian coast. For that purpose, density of burrows and population structure of C. major was examined at two adjacent beaches, Gonzaga and Itararé, from the State of São Paulo, Brazil. Gonzaga beach was considered as control because since 1992 a municipal law prevents the capture of C. major, whereas Itararé as treatment since in this place the species is harvested throughout the year. Burrow density and female CL size were significantly higher in Gonzaga than that Itararé. Sex-ratio did not differ significantly from 1:1 in Itararé, differing from the observed in the area without fishing mortality and also to the general pattern reported in other species of ghost shrimps in which females outnumbered than males. Reproductive potential was significantly smaller in Itararé than Gonzaga, as result of the reduced number of females present in this area relative to Gonzaga. A preliminary estimation indicates that 71 % of shrimps in Itararé died as result of fishing. This information suggests non-viability of C. major in this area given the current pressure of fishing. Presence of C. major in the beach of Itararé and probably in other nearby areas where exploitation occurs would be favored by the permanent supply of larvae from Gonzaga beach where the species is protected by and municipal surveillance.

Yes, they can: three-banded armadillos Tolypeutes sp. (Cingulata: Dasypodidae) dig their own burrows

It is believed that the two species of Tolypeutes Illiger, 1811are the only armadillos that do not dig their own burrows, and that these species simply re-use burrows dug by other species. Here, we show that Tolypeutes matacus (Desmarest, 1804) and Tolypeutes tricinctus (Linnaeus, 1758) dig their own burrows. We describe the burrows and three other types of shelters used by them, and provide measurements and frequency of use of the different types of shelter. We have studied free-ranging individuals of T. matacus in two locations in Central Brazil and individuals of T. tricinctus in semi-captivity in the Northeast of Brazil. Individuals of T. matacus were found primarily in small burrows (76%), straw nests (13%), shallow depressions covered with leaf-litter (7%) or in straw nests made on shallow depressions (4%). Adult males and females of T. matacus did not differ in frequency of use of different types of shelter. Sub-adults T. matacus used shallow depressions and nests more often (40%) than adults (22%) and nurslings (10%). Nurslings of T. matacus reused the shelters more frequently (66%), than sub-adults (46%) and adults (35%). Adult females reused burrows and other types of shelter more frequently than adult males. Tolypeutes tricinctus rested mainly in burrows and under leaf-litter, but did not dig depressions or build nests. Tolypeutes tricinctus occasionally used burrows dug by Euphractus sexcinctus (Linnaeus, 1758), but T. matacus never used burrows dug by other species. Nursling T. matacus always shared shelter with an adult female therefore, both used shelters with similar frequency. Adult females and nurslings of T. matacus reused shelters in higher frequency. That can be explained by the fact that adult females with offspring tend to remain for consecutive nights in the same burrow when cubs are recently born. Due to their smaller body size, sub-adult T. matacus used shelter strategies that require less energetic effort more frequently than...

Yes, they can: three-banded armadillos Tolypeutes sp. (Cingulata: Dasypodidae) dig their own burrows

It is believed that the two species of Tolypeutes Illiger, 1811are the only armadillos that do not dig their own burrows, and that these species simply re-use burrows dug by other species. Here, we show that Tolypeutes matacus (Desmarest, 1804) and Tolypeutes tricinctus (Linnaeus, 1758) dig their own burrows. We describe the burrows and three other types of shelters used by them, and provide measurements and frequency of use of the different types of shelter. We have studied free-ranging individuals of T. matacus in two locations in Central Brazil and individuals of T. tricinctus in semi-captivity in the Northeast of Brazil. Individuals of T. matacus were found primarily in small burrows (76%), straw nests (13%), shallow depressions covered with leaf-litter (7%) or in straw nests made on shallow depressions (4%). Adult males and females of T. matacus did not differ in frequency of use of different types of shelter. Sub-adults T. matacus used shallow depressions and nests more often (40%) than adults (22%) and nurslings (10%). Nurslings of T. matacus reused the shelters more frequently (66%), than sub-adults (46%) and adults (35%). Adult females reused burrows and other types of shelter more frequently than adult males. Tolypeutes tricinctus rested mainly in burrows and under leaf-litter, but did not dig depressions or build nests. Tolypeutes tricinctus occasionally used burrows dug by Euphractus sexcinctus (Linnaeus, 1758), but T. matacus never used burrows dug by other species. Nursling T. matacus always shared shelter with an adult female therefore, both used shelters with similar frequency. Adult females and nurslings of T. matacus reused shelters in higher frequency. That can be explained by the fact that adult females with offspring tend to remain for consecutive nights in the same burrow when cubs are recently born. Due to their smaller body size, sub-adult T. matacus used shelter strategies that require less energetic effort more frequently than...(AU)

Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast / Biologia populacional do caranguejo Armases angustipes (Crustacea, Decapoda, Sesarmidae) na costa tropical brasileira

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.(AU)

Os caranguejos semiterrestres são importantes elementos da fauna em regiões costeiras. O objetivo do presente trabalho foi analisar a estrutura populacional do caranguejo Armases angustipes (Dana, 1852) nos estuários dos rios Ariquindá, considerada uma área não impactada, e Mamucabas, considerada uma área pouco impactada, localizados no litoral sul do Estado de Pernambuco, Brasil. A espécie ocorreu em todos os meses do ano em ambos os estuários. O número de indivíduos variou entre os meses, sendo maior nos meses de transição entre as estações do ano. Isso, provavelmente, é devido às variações sazonais significativas da temperatura do ar e da toca e da salinidade da toca. Não houve dimorfismo sexual relativo aos tamanhos de A. angustipes no manguezal do Rio Ariquindá, mas os machos foram maiores do que as fêmeas no manguezal do Rio Mamucabas. Em ambos os estuários, a proporção sexual não diferiu da proporção mendeliana, mas mostrou um desvio para as fêmeas. A análise da variação temporal na proporção sexual pôde evidenciar diferenças significativas em alguns meses do ano. Essas variações ocorrem devido a eventos cíclicos que atuam distintamente sobre cada sexo. Em ambos os estuários, as classes de tamanho de largura de carapaça foram igualmente representadas por ambos os sexos. As fêmeas ovígeras de A. angustipes só ocorreram em alguns meses do ano, especialmente no verão, em ambos os estuários. Provavelmente, a maior produtividade primária observada no verão favorece a atividade reprodutiva, uma vez que estas algas servem como alimento para as larvas. Os espécimes da população do rio Ariquindá são mais longos e mais largos do que os do rio Mamucabas. Este fato, associado à menor abundância de caranguejos e menor frequência de fêmeas ovígeras observadas no rio Mamucabas, é um indicativo de que esta população pode estar sendo influenciada pelos impactos ambientais que este estuário tem recebido.(AU)

Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast / Biologia populacional do caranguejo Armases angustipes (Crustacea, Decapoda, Sesarmidae) na costa tropical brasileira

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

Os caranguejos semiterrestres são importantes elementos da fauna em regiões costeiras. O objetivo do presente trabalho foi analisar a estrutura populacional do caranguejo Armases angustipes (Dana, 1852) nos estuários dos rios Ariquindá, considerada uma área não impactada, e Mamucabas, considerada uma área pouco impactada, localizados no litoral sul do Estado de Pernambuco, Brasil. A espécie ocorreu em todos os meses do ano em ambos os estuários. O número de indivíduos variou entre os meses, sendo maior nos meses de transição entre as estações do ano. Isso, provavelmente, é devido às variações sazonais significativas da temperatura do ar e da toca e da salinidade da toca. Não houve dimorfismo sexual relativo aos tamanhos de A. angustipes no manguezal do Rio Ariquindá, mas os machos foram maiores do que as fêmeas no manguezal do Rio Mamucabas. Em ambos os estuários, a proporção sexual não diferiu da proporção mendeliana, mas mostrou um desvio para as fêmeas. A análise da variação temporal na proporção sexual pôde evidenciar diferenças significativas em alguns meses do ano. Essas variações ocorrem devido a eventos cíclicos que atuam distintamente sobre cada sexo. Em ambos os estuários, as classes de tamanho de largura de carapaça foram igualmente representadas por ambos os sexos. As fêmeas ovígeras de A. angustipes só ocorreram em alguns meses do ano, especialmente no verão, em ambos os estuários. Provavelmente, a maior produtividade primária observada no verão favorece a atividade reprodutiva, uma vez que estas algas servem como alimento para as larvas. Os espécimes da população do rio Ariquindá são mais longos e mais largos do que os do rio Mamucabas. Este fato, associado à menor abundância de caranguejos e menor frequência de fêmeas ovígeras observadas no rio Mamucabas, é um indicativo de que esta população pode estar sendo influenciada pelos impactos ambientais que este estuário tem recebido.

Density and spatial distribution of Ocypode quadrata (Decapoda, Ocypodidae) in an insular environment in the state of Rio de Janeiro, southeastern Brazil / Densidade e distribuição espacial de Ocypode quadrata (Decapoda, Ocypodidae) em um ambiente insular no estado do Rio de Janeiro, sudeste do Brasil

Ocypode quadrata is a crab species distributed from United States of America to Brazil which is frequently found in supratidal zones of sandy beaches, where they built burrows. The counting of the number of burrows allows sample of both population densities and spatial distribution of individuals. To study these parameters of O. quadrata in Vila Dois Rios, southeastern Brazil, were delimited plots (3.14 m2) to distances from nearest backshore vegetation that varied from 1 to 10 m (60 plots = 188.4 m2). Burrows density in Vila Dois Rios was 0.67 burrows/m2 (126 burrows). The density of burrows of this species might vary influenced by local environmental factors (e.g. tides). The distances of the burrows from the vegetation and the diameter of its openings averaged 357.1 ± 272.7 cm (N = 83) and 15.1 ± 8.3 mm (N = 83), respectively. Larger burrow openings were built near thevegetation. It is possible that larger-sized individuals might exclude smaller ones from this region which may have more protection against energy of tides and flooding and a potential higher availability of food resources. Moreover, smaller-sized crabs might occupy areas near the sea due to lesser capacity of excavation than adults and/or to avoid the risk of desiccation due to their high surface/volume ratio. This study in Vila Dois Rios reinforces the occurrence of the construction of burrows near to the vegetation by larger O. quadrata.(AU)

Ocypode quadrata é uma espécie de caranguejo distribuída desde os Estados Unidos da América até o Brasil frequentemente encontrada em zonas supratidais de praias arenosas, onde constroem tocas. A contagem do número de tocas permite amostrar densidades populacionais e a distribuição espacial dos indivíduos. Para estudar estes parâmetros de O. quadrata em Vila Dois Rios, sudeste do Brasil, foram delimitadas parcelas (3.14 m2) a distâncias a partir davegetação pós-praia que variaram de 1 a 10 m (60 plots = 188.4 m2). A densidade de tocas em Vila Dois Rios foi de 0.67 tocas/m2(126 tocas). A densidade de tocas desta espécie pode variar influenciada por fatores ambientais locais (e.g. marés). A distância dos abrigos a partir da vegetação pós-praia e a largura das aberturas dos abrigos mediram 357,1 ± 272,7 cm (N = 83) e 15,1 ± 8,3mm (N = 83), respectivamente. Tocas com aberturas maiores foram construídas próximas à vegetação. É possível que indivíduos maiores possam excluir aqueles menores desta região que oferece maior proteção contra a energia das marés e inundações e uma potencial maior disponibilidade de recursos alimentares. Além disso, caranguejos menores podem ocupar áreas mais próximas ao mar devido à sua menor capacidade de escavação do que a de adultos e/ou para evitar os riscos de dessecação devido à sua relativa maior relação superfície/volume. Este estudo em Vila Dois Rios reforça a ocorrência da construção de tocas próximas à vegetação por indivíduos maiores O. quadrata.(AU)

Density and spatial distribution of Ocypode quadrata (Decapoda, Ocypodidae) in an insular environment in the state of Rio de Janeiro, southeastern Brazil / Densidade e distribuição espacial de Ocypode quadrata (Decapoda, Ocypodidae) em um ambiente insular no estado do Rio de Janeiro, sudeste do Brasil

Ocypode quadrata is a crab species distributed from United States of America to Brazil which is frequently found in supratidal zones of sandy beaches, where they built burrows. The counting of the number of burrows allows sample of both population densities and spatial distribution of individuals. To study these parameters of O. quadrata in Vila Dois Rios, southeastern Brazil, were delimited plots (3.14 m2) to distances from nearest backshore vegetation that varied from 1 to 10 m (60 plots = 188.4 m2). Burrows’ density in Vila Dois Rios was 0.67 burrows/m2 (126 burrows). The density of burrows of this species might vary influenced by local environmental factors (e.g. tides). The distances of the burrows from the vegetation and the diameter of its openings averaged 357.1 ± 272.7 cm (N = 83) and 15.1 ± 8.3 mm (N = 83), respectively. Larger burrow openings were built near thevegetation. It is possible that larger-sized individuals might exclude smaller ones from this region which may have more protection against energy of tides and flooding and a potential higher availability of food resources. Moreover, smaller-sized crabs might occupy areas near the sea due to lesser capacity of excavation than adults and/or to avoid the risk of desiccation due to their high surface/volume ratio. This study in Vila Dois Rios reinforces the occurrence of the construction of burrows near to the vegetation by larger O. quadrata.

Ocypode quadrata é uma espécie de caranguejo distribuída desde os Estados Unidos da América até o Brasil frequentemente encontrada em zonas supratidais de praias arenosas, onde constroem tocas. A contagem do número de tocas permite amostrar densidades populacionais e a distribuição espacial dos indivíduos. Para estudar estes parâmetros de O. quadrata em Vila Dois Rios, sudeste do Brasil, foram delimitadas parcelas (3.14 m2) a distâncias a partir davegetação pós-praia que variaram de 1 a 10 m (60 plots = 188.4 m2). A densidade de tocas em Vila Dois Rios foi de 0.67 tocas/m2(126 tocas). A densidade de tocas desta espécie pode variar influenciada por fatores ambientais locais (e.g. marés). A distância dos abrigos a partir da vegetação pós-praia e a largura das aberturas dos abrigos mediram 357,1 ± 272,7 cm (N = 83) e 15,1 ± 8,3mm (N = 83), respectivamente. Tocas com aberturas maiores foram construídas próximas à vegetação. É possível que indivíduos maiores possam excluir aqueles menores desta região que oferece maior proteção contra a energia das marés e inundações e uma potencial maior disponibilidade de recursos alimentares. Além disso, caranguejos menores podem ocupar áreas mais próximas ao mar devido à sua menor capacidade de escavação do que a de adultos e/ou para evitar os riscos de dessecação devido à sua relativa maior relação superfície/volume. Este estudo em Vila Dois Rios reforça a ocorrência da construção de tocas próximas à vegetação por indivíduos maiores O. quadrata.

First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae) recruits co-inhabiting burrows of conspecific crabs

Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763), rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW) of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae) recruits co-inhabiting burrows of conspecific crabs

Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763), rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW) of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae) recruits co-inhabiting burrows of conspecific crabs

Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763), rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW) of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

Densidade populacional do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763) (Crustacea, Brachyura, Ocypodidae) na região de Iguape (SP)

A densidade e estrutura populacional de Ucídes cordatus na região de Iguape (SP) foram analisadas, verificando a influência dos fatores ambientais (atmosféricos, hídricos e edáficos), da vegetação do manguezal composta predominantemente por A vícennía schaueriana (AS), Laguncularia racemosa (LR), Rhízophora mangle (RM), e o nível da água na maré cheia. A densidade foi quantificada pela contagem das galerias, sendo maior nos bosques de LR (10,3:f:5,3 galerias m-2), seguido por RM (1 ,8:f:O,9 galerias m-2) e AS (1,5:f:O,9 galerias m-2). Áreas de manguezal mais secas com o mesmo tipo de vegetação (LR) apresentaram maior densidade quando comparada as áreas alagadas (3,5:tO,8 galerias m-2). O diâmetro das galerias (DG) foi maior nas áreas de RM (45,9:f:11 ,9mm), seguida por AS (41 ,9:f:1 O,9mm) e LR (26,6:f:7,7mm). A densidade foi correlacionada positivamente com AS, teores de Ca no sedimento e a salinidade da água. A equação obtida para a relação DGxLC (DG=O,716LC1,o21; N=222; R2=O,72; LC = largura cefalotorácica em mm) permitiu a conversão dos dados de DG em LC estimado (LCe). Com base na distribuição de freqüência de LCe, a classe média calculada foi inferior a obtida diretamente dos animais capturados. A caracterização da população de U. cordatus com base nas galerias pode ser indicada no monitoramento dos estoques populacionais, por ser uma espécie de difícil captura. Manguezal com predominância de RM apresentaram maior potencial extrativo (85,7%), seguida por AS (79,3%) e menor em LR (34,3%). Áreas de LR por apresentar elevada abundância de indivíduos de pequeno porte devem ser preservadas e consideradas como uma reserva dos estoques naturais desse recurso

The density and population structure of the mangrove crab, Ucides cordatus were described in Iguape region (SP), evaluated the influence of environmental factors (atmospheric, hydrologic and edaphic), mangrove vegetation: Avicennia schaueriana (AS), Laguncularia racemosa (LR), Rhizophora mangle (RM), and the local inundate degree. The burrow density was higher in L. racemosa mangrove forest (10,3:f:5,3 burrows m-2) than R. mangle (1,8:tO,9 burrows m-2) and A. schaueriana (1,5:f:O,9 burrows m-2). Dried mangrove forest composed only by LR showed high density when compared to wet areas with the same vegetation (3,5:1:0,8 burrows m-2). The burrow diameter (DG) was also registered, with large size in RM (45,9:t11,9mm), followed by AS (41,9:t10,9mm) and LR (26,6:t7,7mm). The equation from DGxLC relationship (DG=O,716LC1,o21; N=222; R2=0,72; LC = carapace width) allowed the conversion between DG to LC estimated (LCe). The frequency distribution of LCe resulted a low median size class when compared to LC data. Mangrove with high presence of RM showed high abundance of commercially crab (85,7%), followed by AS (79,3%) and LR (34,3%). Due to the hard animal capture, the population of U. cordatus characterized by burrows, could be used to register the abundance of crab population. Areas of LR were considered as a natural reserve of population stock, and might be preserved by the low potential fishery and high presence of small individuais