Abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri (Decapoda: Penaeidae): an exploited species in southeast Brazil / Abundância e distribuição espaço-temporal do camarão Xiphopenaeus kroyeri (Decapoda: Penaeidae): uma espécie em explotação no sudeste do Brasil

Abstract This study evaluated the abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri in the coastal region of Macaé, state of Rio de Janeiro, southeastern Brazil. Monthly samples were obtained from March 2008 to February 2010 in six stations located in Inner (5, 10 and 15m depth) and Outer (25, 35 and 45m depth) areas. It was used a commercial fishery boat equipped with an otter-trawl net (3.5 m mouth width, mesh size 20mm and 15mm in the cod end). Water samples were taken for determination of temperature and salinity, and sediment samples for determination of texture and organic matter content. A total of 7146 shrimps were sampled. About 95% of all shrimps were caught in the shallow area, i.e., depths <20m. Greatest abundances were recorded in winter and spring. No significant correlation was observed between sediment (phi) and abundance. The distribution of X. kroyeri in the studied area was closely related to seasonal cold waterfront of the South Atlantic Central Water (SACW) and temperature was the main factor affecting the species abundance.

Resumo Este estudo avaliou a abundância e a distribuição espaço–temporal do camarão Xiphopenaeus kroyeri na área costeira da região de Macaé, estado do Rio de Janeiro no sudeste do Brasil. As coletas foram realizadas mensalmente de março de 2008 a fevereiro de 2010 em seis transectos localizados na área interna (5, 10 e 15m profundidade) e na área externa (25,35 e 45m profundidade). Foi utilizado um barco de pesca comercial equipado com uma rede de arrasto tipo otter-trawl (3,5m abertura de boca, 20mm de malha e 15mm de ensacador). Foram obtidas amostras de água para determinação da temperatura e da salinidade e amostras de sedimento para determinação da granulometria e teor de matéria orgânica. Um total estimado de 7146 camarões foi amostrado. Aproximadamente, 95% de todos os camarões foram capturados “Inner Area”, ou seja, profundidades <20m. As maiores abundâncias foram registradas no inverno e na primavera. Não houve correlação significativa entre o sedimento (phi) e abundância. De acordo com os resultados deste estudo, a distribuição do X. kroyeri na área de estudo está intimamente ligada à sazonalidade da frente térmica da ACAS e a temperatura é o principal fator que afetou a abundância da espécie.

Abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri (Decapoda: Penaeidae): an exploited species in southeast Brazil.

This study evaluated the abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri in the coastal region of Macaé, state of Rio de Janeiro, southeastern Brazil. Monthly samples were obtained from March 2008 to February 2010 in six stations located in Inner (5, 10 and 15m depth) and Outer (25, 35 and 45m depth) areas. It was used a commercial fishery boat equipped with an otter-trawl net (3.5 m mouth width, mesh size 20mm and 15mm in the cod end). Water samples were taken for determination of temperature and salinity, and sediment samples for determination of texture and organic matter content. A total of 7146 shrimps were sampled. About 95% of all shrimps were caught in the shallow area, i.e., depths <20m. Greatest abundances were recorded in winter and spring. No significant correlation was observed between sediment (phi) and abundance. The distribution of X. kroyeri in the studied area was closely related to seasonal cold waterfront of the South Atlantic Central Water (SACW) and temperature was the main factor affecting the species abundance.

Reproductive features of the swimming crab Callinectes danae(Crustacea, Portunoidea) on the subtropical coast of Brazil: a sampling outside the estuary.

The life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs' reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.

Reproductive features of the swimming crab Callinectes danae(Crustacea, Portunoidea) on the subtropical coast of Brazil: a sampling outside the estuary / Características reprodutivas do siri Callinectes danae(Crustacea, Portunoidea) na região subtropical da costa do Brasil: uma amostragem fora do estuário

AbstractThe life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs’ reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.

ResumoO siri Callinectes danae é estuarino dependente em seu ciclo de vida, sendo que os estudos que levantam informações sobre os aspectos da sua biologia devem também abranger regiões marinhas. Assim, o presente estudo teve como objetivo investigar a maturidade sexual, bem como a preferência ocupacional por adultos em diferentes estágios gonadais e sua periodicidade reprodutiva fora da região estuarina. Para tanto, três enseadas da porção subtropical do litoral sudeste brasileiro foram amostradas mensalmente, durante dois anos. Para cada enseada, seis transectos foram estabelecidos, quatro deles paralelos à linha de praia (5, 10, 15 e 20m de profundidade), um transecto exposto e outro abrigado à ação de ondas. Os resultados mostraram que o padrão de distribuição espaço-temporal de adultos de C. danae foi similar nas três enseadas, embora uma maior abundância tenha sido encontrada em Ubatumirim. Fêmeas ovígeras e com gônadas desenvolvidas foram encontradas em maior abundância que fêmeas com gônadas rudimentares e em desenvolvimento, principalmente nos transectos mais profundos. Apesar das regiões amostradas possuírem características ambientais diferenciadas, o padrão reprodutivo da espécie não sofreu alterações, apresentando reprodução contínua, com maior abundância de fêmeas reprodutivas na primavera e verão. Machos atingiram maturidade em tamanhos maiores que as fêmeas nas três enseadas.

Population biology of the commercially exploited shrimp Artemesia longinaris (Decapoda: Penaeidae) in an upwelling region in the Western Atlantic: comparisons at different latitudes.

This study characterized the population biology of the dendrobranchiate penaeid shrimp Artemesia longinaris Spence Bate, 1888, focusing on population structure, sexual maturity, reproductive period and recruitment, and comparing reproductive parameters of a different populations along western South Atlantic. Samples were collected monthly from March, 2008 to February, 2010 in Macaé, northern coast of Rio de Janeiro State, Brazil, a region influenced by the Cabo Frio upwelling. There was a significantly higher percentage of females and with larger sizes than males. Both carapace length and sexual maturity in Macaé were similar to the dimensions found in populations in the South of the continent (Argentina). Reproductive females were present in all months, with main peaks during winter and summer. Recruitment was also continuous, with peaks, usually one to two months after the appearance of reproductive females, after the reduction of the bottom temperature values of water. These data suggest that November to January would be the appropriate months for legal off-season, due to the higher intensity of spawning females and juveniles during this period. The results of this study contribute to the understanding of the biology of A. longinaris, and could also be a reference to monitor this important fishery resource and consequent legal off-season. Furthermore, this population located at the northern limit of the species distribution is a source of highly relevant comparison for population studies in other areas.

Population biology of the commercially exploited shrimp Artemesia longinaris (Decapoda: Penaeidae) in an upwelling region in the Western Atlantic: comparisons at different latitudes / Biologia populacional do camarão explorado comercialmente Artemesia longinaris (Decapoda: Penaeidae) em uma região de ressurgência do Atlântico Ocidental: comparação em diferentes latitudes

This study characterized the population biology of the dendrobranchiate penaeid shrimp Artemesia longinaris Spence Bate, 1888, focusing on population structure, sexual maturity, reproductive period and recruitment, and comparing reproductive parameters of a different populations along western South Atlantic..Samples were collected monthly from March, 2008 to February, 2010 in Macaé, northern coast of Rio de Janeiro State, Brazil, a region influenced by the Cabo Frio upwelling. There was a significantly higher percentage of females and with larger sizes than males. Both carapace length and sexual maturity in Macaé were similar to the dimensions found in populations in the South of the continent (Argentina). Reproductive females were present in all months, with main peaks during winter and summer. Recruitment was also continuous, with peaks, usually one to two months after the appearance of reproductive females, after the reduction of the bottom temperature values of water. These data suggest that November to January would be the appropriate months for legal off-season, due to the higher intensity of spawning females and juveniles during this period. A comparação latitudinal dos parâmetros reprodutivos, não confirma o paradigma de que tamanho do corpo e a maturidade sexual das fêmeas são menores em regiões tropicais e aumentam em direção às maiores latitudes, reforçando a hipótese da influência e importância da ACAS na dinâmica reprodutiva de A. longinaris na região The results of this study contribute to the understanding of the biology of A. longinaris, and could also be a reference to monitor this important fishery resource and consequent legal off-season. Furthermore, this population located at the northern limit of the species distribution is a source of highly relevant comparison for population studies in other areas.

Este estudo caracterizou a biologia populacional do camarão Artemesia longinaris Spence Bate, 1888, com foco na estrutura populacional, a maturidade sexual, período reprodutivo e de recrutamento, e comparação dos parâmetros reprodutivos de diferentes populações ao longo do Atlântico Sul ocidental. As amostras foram coletadas mensalmente de março de 2008 a fevereiro de 2010, em Macaé, litoral norte do Rio de Janeiro, Brasil, região influenciada pela ressurgência de Cabo Frio. Houve uma porcentagem significativamente maior de fêmeas e com tamanhos maiores do que os machos. Ambos, comprimento da carapaça e maturidade sexual, em Macaé foram similares às dimensões encontradas em populações do sul do continente (Argentina). Fêmeas reprodutivas estiveram presentes em todos os meses com os principais picos no inverno e verão. O recrutamento também foi contínuo, normalmente um a dois meses após o aparecimento de fêmeas reprodutivas, após a redução da temperartura da água de fundo. Estes dados sugerem que o período de novembro a janeiro seriam os meses apropriados para o defeso, devido à maior intensidade de fêmeas reprodutoras e juvenis durante este período. A comparação latitudinal dos parâmetros reprodutivos, não confirma o paradigma de que tamanho do corpo e a maturidade sexual das fêmeas são menores em regiões tropicais e aumentam em direção às maiores latitudes, reforçando a hipótese da influência e importância da ACAS na dinâmica reprodutiva de A. longinaris na região. Os resultados deste estudo contribuem para o entendimento da biologia de A. longinaris, e também pode ser uma referência para monitorar esse importante recurso pesqueiro e, consequente período de defeso. Além disso, esta população situada no limite do norte da distribuição das espécies é uma fonte de comparação altamente relevante para estudos populacionais em outras áreas.

Differential habitat use by demographic groups of the redfinger rubble crab Eriphia gonagra (Fabricius, 1781).

The structurally diverse rocky shores along the northern coast of the state of São Paulo, Brazil, support a varied fauna and provide refuges for many organisms. Some of these environments allow for extensive microhabitats, among them the sand reefs formed by the polychaete Phragmatopoma lapidosa, which occupy much of this area. The beauty of the landscape attracts large numbers of tourists, who contribute to the damage to the sand reef colonies, causing an imbalance in the patterns of population distribution and of this ecosystem. We describe the structure and population biology of the redfinger rubble crab Eriphia gonagra, and investigated the differential occupation of the habitat by each demographic category of this species. Crabs were sampled monthly for two consecutive years on the rocky coast of Grande Beach, Ubatuba, São Paulo, during spring low tides. Sampling was carried out over an area of approximately 1200 m2, during two hours on the rock surface and another two hours on the sand reefs. A total of 1407 crabs were collected; 776 on the sand reef (SR) and 631 on the rocky shore (RO). The majority of juvenile crabs inhabited the SR, while adult crabs were equally distributed in both microhabitats. This study showed that the SR is a natural nursery ground for the establishment of the early juvenile stages of E. gonagra, which use the reefs as a refuge and food resource. Many other organisms (mollusks, echinoderms, polychaetes etc.) settle on the reefs, and these areas may be among the most important in maintaining benthic diversity in the region.

Differential habitat use by demographic groups of the redfinger rubble crab Eriphia gonagra (Fabricius, 1781) / Ocupação diferencial do habitat por grupos demográficos do caranguejo de dedos vermelhos Eriphia gonagra (Fabricius, 1781)

The structurally diverse rocky shores along the northern coast of the state of São Paulo, Brazil, support a varied fauna and provide refuges for many organisms. Some of these environments allow for extensive microhabitats, among them the sand reefs formed by the polychaete Phragmatopoma lapidosa, which occupy much of this area. The beauty of the landscape attracts large numbers of tourists, who contribute to the damage to the sand reef colonies, causing an imbalance in the patterns of population distribution and of this ecosystem. We describe the structure and population biology of the redfinger rubble crab Eriphia gonagra, and investigated the differential occupation of the habitat by each demographic category of this species. Crabs were sampled monthly for two consecutive years on the rocky coast of Grande Beach, Ubatuba, São Paulo, during spring low tides. Sampling was carried out over an area of approximately 1200 m2, during two hours on the rock surface and another two hours on the sand reefs. A total of 1407 crabs were collected; 776 on the sand reef (SR) and 631 on the rocky shore (RO). The majority of juvenile crabs inhabited the SR, while adult crabs were equally distributed in both microhabitats. This study showed that the SR is a natural nursery ground for the establishment of the early juvenile stages of E. gonagra, which use the reefs as a refuge and food resource. Many other organisms (mollusks, echinoderms, polychaetes etc.) settle on the reefs, and these areas may be among the most important in maintaining benthic diversity in the region.

Os costões rochosos do litoral norte paulista, devido à sua constituição diversificada, sustentam uma grande diversidade de espécies animais e vegetais, além de proporcionar uma série de abrigos para proteção de muitos organismos. Em alguns destes costões ocorre a formação de microhabitats, entre eles os recifes de areia formadas pelo poliqueta Phragmatopoma lapidosa, que ocupam grande parte desta área. A paisagem diferenciada do local atrai um grande número de turistas, o que contribui para a deterioração das colônias que constituem esse recife, causando um desequilíbrio nos padrões de distribuição das populações desse ecossistema. Este trabalho visou levantar informações sobre a estrutura e dinâmica populacional de Eriphia gonagra, além de investigar uma ocupação diferencial do habitat por diferentes grupos etários deste caranguejo. Os caranguejos foram amostrados mensalmente, durante dois anos consecutivos, no costão rochoso da Praia Grande, Ubatuba, São Paulo, Brasil, em períodos de marés baixas de sizígia. A coleta ativa dos indivíduos foi efetuada em uma área de aproximadamente 1200 m2 por um período de duas horas na superfície rochosa e outras duas horas nos recifes de areia. Foi capturado um total de 1407 indivíduos, sendo 776 no recife de areia (SR) e 631 na superfície rochosa (RO). A maior parte dos jovens habita o recife, enquanto adultos encontram-se igualmente distribuídos nas duas áreas amostradas. Este estudo mostra que os recifes de areia podem ser considerados berçários de suma importância para o estabelecimento dos estágios juvenis de E. gonagra, que utilizam tais locais para proteção e alimentação. Muitos outros organismos (moluscos, equinodermos, poliquetas etc) se estabelecem sobre os recifes, sendo que essas áreas podem estar entre as mais importantes na manutenção da diversidade bêntica na região.

Reproductive pattern of the South American endemic shrimp Artemesia longinaris (Decapoda: Penaeoidea), off São Paulo State, Brazil

Sexual maturity, temporal reproductive pattern, and recruitment of juveniles were examined for the penaeoid shrimp Artemesia longinaris sampled for five and a half years in a tropical locality off the coast of São Paulo (23º S), Brazil. Monthly samples were taken from January 1998 to June 2003 at depths between 5 and 45 m. Ovarian maturity was used to examine breeding in adult females. Recruitment was defined as the percentage of juveniles of the total number of individuals in each month and season. A total of 10 288 females and 5 551 males were collected. Estimated sizes (carapace length) at the onset of sexual maturity were 11.0 mm and 13.4mm for males and females, respectively. Over the five and a half years, females with ripe gonads were found in every season, with the highest percentages in summer (January-March). Juvenile shrimps occurred year-round. These results suggest a continuous reproduction of A. longinaris with temperature acting as an environmentalstimulus for the duration of the ovary development cycle. These data and the hypothesis of the intrusion ofthe South Atlantic Central Water mass, which lowered water temperature and raised plankton production, suggestthat the end of spring and the beginning of summer were the principal reproductive months. The classicalparadigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higherlatitudes seems to apply to this species.

El objetivo del presente trabajo fue el estudio de la madurez sexual, la reproducción temporal y el reclutamientodel camarón Artemesia longinaris, en el litoral del estado de São Paulo (23ºS), Brasil. El material fue recolectadomensualmente entre enero 1998 y junio 2003, hasta una profundidad de 45 m. La periodicidad de la madurez gonadalfue verificada en las hembras adultas. El reclutamiento se definió como porcentaje de camarones inmaduros sobre el total de individuos en cada mes y estación. Se obtuvo un total de 10 288 hembras y 5 551 machos. Las tallas dela madurez gonadal estimadas fueron 11.0 mm (machos) y 13.4 mm (hembras). En los cinco años y medio del estudio, el verano (enero-marzo) siempre tuvo mayor porcentaje dehembras con gónadas maduras. En la mayoría de los meses, se recolectaron camarones inmaduros. Estos resultadossugieren que A. longinaris se reproduce en forma continua, y que la temperatura es el estimulo ambiental para la duracióndel desarrollo gonadal. Eso es evidente en los periodos con mayor desarrollo gonadal (primavera y verano) enaguas más frías y mejor oferta de alimento ofrecido por la penetración de las Aguas Centrales del Atlántico Sur y por el aumento en la productividad planctónica. Para este camarónse aplica el paradigma del efecto latitudinal en la reproducciónde especies marinas, donde en regiones tropicales se observa una continuidad en el desarrollo gonadal y en las zonas templado-frías una estacionalidad reproductiva.

ESR dating of a subfossil shell from Couve Island, Ubatuba, Brazil.

The occurrence of subfossil material in bottom sediments of Couve Island, Ubatuba region, São Paulo State, is confirmed. The analyzed material consists of a bivalve shell that was dated by the electron spin resonance technique. By the additive irradiation method an archaeological absorbed dose of (25 +/- 5) Gy was obtained and calibration with other dating works in the same area allows the inference of an age of (25 +/- 5) x 10(2) years. The importance of this finding and its paleoecological implications could contribute to elucidating the nature of short-term environmental changes in the Brazilian coastline during the Holocene, as well as becoming an important tool to the understanding of the distribution and biological aspects of the bivalve fauna.

Relative growth of Petrochirus diogenes (Linnaeus, 1758) (Crustacea, Anomura, Diogenidae) in the Ubatuba region, São Paulo, Brazil.

The purpose of this paper is to investigate the relative growth and heterochely in the hermit crab Petrochirus diogenes. Hermit crabs were collected in the Ubatuba region, SP, from 1993 to 1996; using a commercial fishing boat equipped with two double-rig nets. Body mass of each individual was weighed and their cephalothoracic shield and chelar propodus size were measured. Body mass and chelar propodus size were regarded as dependent variables and plotted against length of cephalothoracic shield according to the allometric equation y = a x x(b). A total of 479 individuals were obtained being 307 males and 172 females. Cephalothoracic shield width follows an isometric growth for both sexes. Otherwise, right cheliped dimensions show different relative growth patterns and left cheliped ones present a positive allometry in males and females. Unlike brachyurans, ontogenetic changes in the growth rate of chelar propodus are not clearly discernible, which prevents the accurate detection of allometric variations. In both sexes, the right cheliped is larger than the right one. Cheliped size is a sexual dimorphic feature with males bearing larger chelipeds than females. Heterochely may be particularly adaptive in agonistic interactions and precopulatory behaviour in P diogenes.