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‣ Population biology and regeneration of forbs and shrubs after fire in Brazilian Campos grasslands

FIDELIS, Alessandra; MUELLER, Sandra Cristina; PILLAR, Valerio DePatta; PFADENHAUER, Joerg
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.932505%
Fire is an important factor in several ecosystems, affecting plant population biology. Campos grasslands are under constant influence of disturbance, mostly grazing and fire. However, few studies evaluated the effect of fire on plant population biology of grassland species. Therefore, we aim to analyze the effect of fire on the population biology of four species, from different functional groups and regeneration strategies: Chaptalia runcinata (forb, resprouter, absence of belowground organ), Vernonia flexuosa (forb, resprouter, presence of rhizophore), Eupatorium ligulaefolium (shrub, resprouter, presence of xylopodium) and Heterothalamus psiadioides (shrub, obligate seeder). Seven plots were established in different sites in southern Brazil: frequently burned (FB) and excluded from fire since 6 years (E). All plots were subjected to controlled burns during summer. Before experiments, populations were sampled. Further observations were carried out after 90 and after 360 days of fire experiments. In addition, we counted the number of seedlings and resprouters recruited after fire. Heat shock experiments were conducted with two species (H. psiadioides and V. flexuosa), as well as the study of the bud bank of the following species: E. ligulaefolium and V. flexuosa. The obligate seeder species had all individuals killed by fire and established only after 1 year. Resprouters...

‣ Population biology of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in Southeastern Brazil

PETRACCO, Marcelo; CARDOSO, Ricardo S.; CORBISIER, Thais N.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
57.0034%
The reproductive biology and population dynamics of the cirolanid isopod Excirolana armata (Dana, 1853) were analysed through monthly samples from December 2003 to November 2005 on Una beach, Sao Paulo state (24 degrees S), in Southeastern Brazil. Sampling was performed along three transects established from the base of foredunes to the waterline. On Una beach, E. armata showed continuous reproduction with higher abundances of ovigerous females in winter and spring (July-November) with a higher peak of juveniles in spring (November 2004). The fecundity ranged from 2 to 18 eggs/embryos per female, depending on the female length. The incubation period was estimated as 2 months. The life span of males and females was nearly 1 year. The short life span and the high energetic expenditure inherent to reproduction with maternal care, probably kept females from producing more than one brood in their lifetime. When comparing the population of E. armata on Una beach (24 degrees S) with populations in Southern Brazil (32 degrees S), Uruguay (34 degrees S) and Argentina (36 degrees S), it was verified that several biological population traits (length of the smallest juvenile, length of the largest individual, length of the smallest and largest ovigerous females...

‣ Population biology and diet of the puffer fish Lagocephalus laevigatus (Tetraodontiformes: Tetraodontidae) in Caraguatatuba Bay, south-eastern Brazil

Denadai, M. R.; Santos, F. B.; Bessa, E.; Bernardes, L. P.; Turra, A.
Fonte: CAMBRIDGE UNIV PRESS; NEW YORK Publicador: CAMBRIDGE UNIV PRESS; NEW YORK
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.62619%
This study describes the spatio-temporal distribution, population biology, and diet of the puffer fish Lagocephalus laevigatus in Caraguatatuba Bay, south-eastern Brazil. Monthly samples were taken between August 2003 and October 2004 by trawls in two areas, south and north, at depths of 1 to 4 m. The fish were measured and their sex and reproductive stage determined. The abundance of this species was compared between areas and among months, and the items in the diet were identified and quantified. Lagocephalus laevigatus was rare in Caraguatatuba Bay, where only 199 small individuals (4.8 to 15.4 cm) were obtained in the entire study period, suggesting that this species uses the estuary as a nursery. None of the specimens of L. laevigatus captured in Caraguatatuba Bay were sexually mature. Higher densities of L. laevigatus in the bay were recorded in the south area and between October and December 2003, i.e. in the spring, suggesting that spawning may occur from late winter to spring (August through to November). The diet items consumed by L. laevigatus in Caraguatatuba Bay were, as expected from the current literature, crustaceans, mainly amphipods, and fish. However, the most-consumed item was the sea whip Leptogorgia setacea (Cnidaria). This feeding habit may be related to the presence of toxins (tetrodotoxin and saxitoxin) that are frequently found in the skin and viscera of L. laevigatus...

‣ Comparative population biology of Uca rapax (Smith, 1870) (Brachyura, Ocypodidae) from two subtropical mangrove habitats on the Brazilian coast

Castiglioni, D. D.; Negreiros-Fransozo, M. L.
Fonte: Taylor & Francis Ltd Publicador: Taylor & Francis Ltd
Tipo: Artigo de Revista Científica Formato: 1627-1640
Português
Relevância na Pesquisa
56.612227%
The structure of two populations of the fiddler crab Uca rapax in two subtropical mangrove habitats near Ubatuba, State of São Paulo, Brazil were compared. The size - frequency distribution, sex ratio, and recruitment were evaluated. Sampling was performed monthly from April 2001 to March 2002 in the Itamambuca and Ubatumirim habitats. Crabs were caught manually for 15 min by two collectors during low tide. The carapace width of each crab was measured with a digital caliper, and the sex and ovigerous state were recorded. The median size of the carapace width of males was greater than that of females at both sites (P<0.05). The median size of the crabs from Itamambuca was larger than at Ubatumirim (P<0.05). Only 28 ovigerous females were obtained from both mangroves, which suggested that females might remain in their burrows during the incubation period. The highest recruitment pulse occurred in winter for both populations, probably as a consequence of high reproductive activity during summer. The sex ratio in the size classes showed an anomalous pattern, with a higher frequency of females in the intermediate size classes. This may be related to a greater energy requirement for reproduction in females, thus delaying growth. The variable environmental conditions to which Uca rapax populations are subject appear to act directly or indirectly on the population...

‣ Popularion biology of abdominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir (low Tietê river, São Paulo State, Brazil)

Vidotto-Magnoni, Ana Paula; Carvalho, Edmir Daniel
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 56-63
Português
Relevância na Pesquisa
56.860015%
The aim of this study is to characterize some population biology parameters of P. squamosissimus, A. altiparanae and S. maculatus, the dominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir, low Tietê river. Fish samplings were performed monthly between September/2002 and August/2003, using gill nets with different mesh sizes. Females of all species have larger standard lengths than males (Mann-Whitney, p < 0.0001), and are more frequent in superior size classes (Kolmogorov-Smirnov, p < 0.0001). All populations presented isometric growth, but differences between males and females were observed. Only P. squamosissimus presented a gender ratio different from 1:1, with a higher proportion of males (1:2, X2, p < 0.05). The onset of gonadal maturation occurs at 15 cm in P. squamosissimus, 9 cm in S. maculatus and at 8.9 cm in A. altiparanae. In all species populations, the adults predominate over juveniles. The allometric condition factor (K) of P. squamosissimus and S. maculatus presented higher values in the periods from March-May and June-August, and A. altiparanae in the period from March-May (Kruskal-Wallis, p < 0.05). These results indicate that the populations successfully exploit the lentic environment...

‣ Comparison of the population biology of Epialtus bituberculatus from two rocky shores with distinct hydrodynamic patterns

De Paiva Barros-Alves, Samara; Alves, Douglas Fernandes Rodrigues; Cobo, Valter José
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 693-702
Português
Relevância na Pesquisa
56.76983%
The population biology of Epialtus bituberculatus was compared between two different intertidal localities with differing levels of wave exposure. Sampling was conducted monthly between January and December, 2001 on seaweed banks of Sargassum cymosum in the intertidal zone of the rocky shores Grande (GR) (23°23′S-45°03′W) and Domingas Dias (DD) (23°29′S-45°08′W). Four hundred and twenty-eight crabs were captured at the GR site: 111 juvenile males, 106 adult males, 57 juvenile females, 17 adult females and 137 ovigerous females; while 455 specimens were obtained at the DD site: 76 juvenile males, 113 adult males, 37 juvenile females, 40 adult females and 189 ovigerous females. The population from GR showed a non-normal distribution and from DD a normal distribution. The sex-ratio (female/male) was 1:0.97 at GR (χ2 = 0.77, P = 0.084), whereas it was 1:1.41 at DD (χ2 = 13.03, P < 0.001). The largest individuals occurred at DD (U = 78249.0, P < 0.001). The estimated size at sexual maturity was 6.3 and 5.0 mm carapace width (CW) for males, and 5.4 and 5.2 mm CW for females, from GR and DD, respectively. The observed differences in E. bituberculatus between the studied localities might be explained by the different degrees of wave exposure between sites. However...

‣ Biologia populacional e fecundidade do anfipode endobionte Leucothoe sp. (Crustacea, Amphipoda, Leucothoidae) associado a Phallusia nigra (Chordata, Tunicata) do Canal de São Sebastião, litoral norte do estado de São Paulo; Population biology and fecundity of Leucothoe sp. (Crustacea, Amphipoda, Leucothoidae) associated to Phallusia nigra (Chordata, Tunicata) from the São Paulo Sebastião, northern of the State of São Paulo

Silvana Gomes Leite Siqueira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/02/2007 Português
Relevância na Pesquisa
56.746846%
Este estudo teve como objetivo caracterizar a biologia populacional e a fecundidade do gamarídeo Leucothoe sp. associado à ascídia Phallusia nigra no Canal de São Sebastião, Litoral Norte do Estado de São Paulo. A estrutura populacional, crescimento, razão sexual, fecundidade, dimorfismo sexual e mortalidade deste anfípode foram observadas bimestralmente em oito costões do infralitoral e relacionados com a temperatura da água e a biomassa das ascídias. Em cada período e local foram coletadas três ascídias. Indivíduos de todos os estágios de desenvolvimento de Leucothoe sp. foram encontrados associados a P. nigra, caracterizando o ambiente como estável e propício para a sua reprodução e alimentação. A associação não variou no período de estudo, não foi influenciada pela biomassa da ascídia e nem pela temperatura da água. A maior parte da população de Leucothoe sp. foi composta de jovens. O menor número de indivíduos adultos pode estar relacionado a fatores como mortalidade e à busca dos jovens por novos hospedeiros. Os dados referentes à estrutura de tamanho e crescimento indicam que Leucothoe sp. pode viver entre 7,2 e 11 meses caracterizando um ciclo de vida semi-anual. A razão sexual de Leucothoe sp. foi desviada a favor das fêmeas...

‣ Population biology of Eudendrium caraiuru (Cnidaria, Anthoathecata, Eudendriidae) from São Sebastião Channel, Southeastern Brazil

Oliveira,Otto M. P.; Marques,Antonio C.
Fonte: Fundação Zoobotânica do Rio Grande do Sul Publicador: Fundação Zoobotânica do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2005 Português
Relevância na Pesquisa
56.67436%
The ecology of Eudendrium spp. from the Brazilian coast is poorly known, although it already proved to be useful and important as a tool to solve some taxonomical problems of the genus. The seasonality and reproduction patterns of a population of Eudendrium caraiuru Marques & Oliveira, 2003 were studied. Data were sampled from test panels immersed in the water off Cabelo Gordo de Dentro beach, in São Sebastião Channel, Southeastern Brazil, from July 1999 to July 2000, every three months. Eudendrium caraiuru was active throughout the study period. Reproductive peaks of the species were regulated by cold and low-salinity water, although part of the population always bore mature gonophores. In addition to morphological differences, ecological differences between E. caraiuru and its similar species, E. glomeratum Picard, 1951, especially from well known populations of the Mediterranean Sea, corroborated that these species are diverse lineages of a unique ancestor.

‣ Population biology of Allocreadium lobatum Wallin, 1909 (Digenea: Allocreadiidae) in the creek chub, Semotilus atromaculatus, mitchill (Osteichthyes: Cyprinadae), in a Nebraska Creek, USA

Willis,Monte S
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2001 Português
Relevância na Pesquisa
66.860015%
Allocreadium lobatum Wallin, 1909 has been reported in cyprinid species of freshwater fish in Canada and in the United States. The population biology of A. lobatum in the host Semotilus atromaculatus Mitchill was studied from May through December 1991, in a USA creek. Overall prevalence (64%) and mean intensity (4.4 ± 0.4) were greater than previously reported while abundance, reported for the first time, was 2.8 ± 0.3. Several trends in A. lobatum population biology as a function of S. atromaculatus length were identified. Mean intensity and abundance of A. lobatum increased with host size and significant differences in prevalence and A. lobatum lengths were found to correlate with host lengths.

‣ Population biology of Parides anchises nephalion (Papilionidae) in a coastal site in Southeast Brazil

FREITAS,A. V. L.; RAMOS,R. R.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2001 Português
Relevância na Pesquisa
56.746846%
A population of Parides anchises nephalion was studied during seven months in SE Brazil. The population size was about 10-20 individuals (with theoretic maximum near 60 individuals), with small variations in some months. Sex ratio was male biased, with males dominating in all months. The age structure was not stable, with an increase in new individuals before the population peak in December. The residence time was 14.1 ± 8.2 days for males and 9.0 ± 3.6 to females, with the maximum registered of 30 days. Males can travel distances of up to 400 m, but most individuals were always recaptured in the same site. The mean forewing length was greater in females. The population features agree with those found in other species of Parides in other neotropical sites.

‣ Population biology and distribution of the tanaid Kalliapseudes schubarti Mañé-Garzon, 1949, in an intertidal flat in Southeastern Brazil

Leite,F. P. P.; Turra,A.; Souza,E. C. F.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2003 Português
Relevância na Pesquisa
56.67436%
The population biology and the spatial and temporal distribution of Kalliapseudes schubarti Mañé-Garzon, 1949, a common tanaidacean in mud flats and estuaries in southern and southeastern Brazil, was studied in the Araçá region, São Sebastião (SP), Brazil. This species showed a clustered dispersion in the area and the individuals were concentrated in the superficial sediment layer (5 cm). Higher densities of K. schubarti were recorded in areas characterized by moderately sorted fine sediment. Multiple regression analysis revealed a positive influence of the organic matter contents and a negative effect of the silt-clay contents on the abundance of K. schubarti. This species showed a marked temporal variation with very low abundance in winter and fall (March to August). Sexual dimorphism was evidenced with males being larger than females. Ovigerous females were also larger than pre-ovigerous ones. Sex ratio was skewed towards females. Seven cohorts were identified during the sampling period, the estimated longevity was 12 months, and no seasonal oscillation in growth was evidenced. The continuous reproduction, as evidenced by the presence of larval phases (manca II and neutron) and reproductive females throughout the year, and high fecundity among the tanaids associated with fast growth and limited longevity support the case for the opportunistic life strategy suggested for this species in the literature.

‣ Population biology of Aegla platensis (Decapoda: Anomura: Aeglidae) in a tributary of the Uruguay River, state of Rio Grande do Sul, Brazil

Dalosto,Marcelo M.; Palaoro,Alexandre V.; Oliveira,Davi de; Samuelsson,Évelin; Santos,Sandro
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 Português
Relevância na Pesquisa
56.90275%
Aeglids are freshwater anomurans that are endemic from southern South America. While their population biology at the species-level is relatively well understood, intraspecific variation within populations has been poorly investigated. Our goal was to investigate the population biology of Aegla platensis Schmitt, 1942 from the Uruguay River Basin, and compare our data with data from other populations. We estimated biometric data, sex ratio, population density and size-class frequencies, and frequencies of ovigerous females and juveniles, from the austral spring of 2007 until autumn 2008. Sexual dimorphism was present in adults, with males being larger than females. Furthermore, males and females were significantly larger than previously recorded for the species. The overall sex ratio was 1.33:1 (male:female), and population density ranged from 1.8 (spring) to 3.83 ind.m-² (winter). Data from this population differ from published information about A. platensis in almost all parameters quantified except for the reproductive period, which happens in the coldest months, and a population structure with two distinct cohorts. Difference among studies, however, may be in part due to methodological differences and should be further investigated in order to determine their cause. In addition to different methodologies...

‣ POPULATION BIOLOGY AND DIET OF THE SOUTHERN KINGCROAKER Menticirrhus americanus (LINNAEUS, 1758) (PERCIFORMES: SCIAENIDAE) IN CARAGUATATUBA BAY, SOUTHEASTERN BRAZIL

Turra, Alexander; Santos, Flavia Borges; Bessa, Eduardo; Fernandez, Wellington Silva; Bernadochi, Ligia Coletti; Denadai, Marcia Regina
Fonte: INST OCEANOGRAFICO, UNIV SAO PAULO; SAO PAULO Publicador: INST OCEANOGRAFICO, UNIV SAO PAULO; SAO PAULO
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.72716%
This study evaluated the spatio-temporal distribution, population biology and diet of Menticirrhus americanus in Caraguatatuba Bay. Samples were taken monthly between August 2003 and October 2004, by trawling in two previously selected areas. The northern area is more exposed to wave activity and is influenced by a river, functioning as a small estuary. In contrast, the southern area is relatively sheltered from wave energy and influenced to a lesser degree by smaller rivers. The fishes' length was measured, and the sex and gonadal stage macroscopically identified. The abundance of this species was compared between areas and among months. The diet was identified and quantified. M. americanus occurred in equal proportions in the two study areas, being most abundant in April 2004, followed by December 2003 and January 2004. The population was dominated by small immature individuals. The few individuals in maturation or mature that were captured showed no seasonal pattern of distribution. This species had a varied diet, feeding on worms (nemerteans, sipunculans and echiurans), mollusks (bivalves and cephalopods), polychaetes, crustaceans and fish. The presence of intact nematodes in the intestine suggests that these are parasites. The results demonstrated that M. americanus has a homogeneous spatial and temporal distribution in Caraguatatuba Bay...

‣ Historia natural e biologia populacional de Phloeophana longirostris Spinola 1847 (Heteroptera: Phloeidae) na Serra do Japi, Jundiai, SP; Natural history and population biology of Phloeophana longirostris Spinola 1837 (Heteroptera: Phloeidae), in Serra do Japi, Jundiai, SP

Thais Cifuentes Postali
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/01/2009 Português
Relevância na Pesquisa
66.902104%
Phloeophana longirostris e uma especie de percevejo pertencente aos Phloeidae, uma pequena familia de insetos tropicais. Sao organismos de habito fitofago, que vivem camuflados sobre o tronco de suas plantas hospedeiras, se assemelhando a liquens. Esse trabalho reune, com base em dezoito meses de estudo na Serra do Japi, observacoes naturalisticas da historia natural e biologia da especie. Tambem foram investigadas a estrutura e a biologia populacional de P. longirostris, e se ha correlacao dos parametros populacionais com os fatores climáticos precipitação e temperatura. Os individuos de P. longirostris foram encontrados em areas de mata, somente sobre arvores de Croton floribundus Spreng (Euphorbiaceae), em locais com ocorrencia de liquens. Sua defesa e primariamente baseada em sua camuflagem nas arvores hospedeiras, e formigas Crematogaster spp. foram os principais predadores de P. longirostris ao longo do estudo. A especie apresenta cuidado maternal, com a protecao dos ovos e das ninfas, que ficam sob o abdomen materno ate pouco depois da primeira ecdise. O crescimento das ninfas e lento, e estas apresentam cinco instares ate atingirem a fase adulta. Na fase adulta ha dimorfismo entre machos e femeas, e as femeas sao maiores que os machos. A estrutura da populacao de P. longirostris variou ao longo do estudo...

‣ Biologia populacional do poliqueta Polydora neocaeca associado a bancos de Mytella charruana = : Population biology of the polychaete Polydora neocaeca associated with Mytella charruana mussel beds; Population biology of the polychaete Polydora neocaeca associated with Mytella charruana mussel beds

Rachel Furioso Daolio
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/08/2014 Português
Relevância na Pesquisa
56.831377%
Os polidorídeos são poliquetas da família Spionidae cuja característica principal é a presença de cerdas em forma de ganchos no 5° setígero. Algumas espécies habitam fundos não consolidados, enquanto que outras, como Polydora neocaeca, habitam substratos consolidados, podendo ou não perfurar estruturas calcárias como corais e conchas de moluscos. A forma de perfuração é pouco compreendida, existindo hipóteses de que seja mecânica, química ou a combinação desses processos. A infestação raramente causa a morte direta dos hospedeiros, porém os torna suscetíveis a outros parasitas e doenças. Por essa razão, os polidorídeos são considerados pestes pela indústria de moluscos. Polydora neocaeca parasita o mexilhão Mytella charruana que pode ser encontrado formando bancos na região entremarés de praias abrigadas. Dois bancos de M. charruana localizados nas praias do Camaroeiro e da Cidade na enseada de Caraguatatuba (Litoral Norte do Estado de São Paulo) foram estudados de março de 2006 a março de 2007. Na porção central de cada banco, foram traçados transectos perpendiculares à linha d'água, sendo sorteado mensalmente um de cada banco para amostragem. Em cada transecto, substratos de três níveis foram coletados com o auxílio de um delimitador de 0...

‣ Population biology of the burrowing crab Neohelice granulata, (Crustacea: Decapoda: Varunidae) from a tropical mangrove in Brazil

Gregati,Rafael A.; Negreiros-Fransozo,Maria L.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 Português
Relevância na Pesquisa
56.789287%
The population biology of the burrowing crab Neohelice granulata (Dana, 1851) from a mangrove in Jabaquara Beach, Paraty, state of Rio de Janeiro, Brazil (23º13'04"S and 44º42'47"W), was studied with respect to the following traits: size-frequency distribution, recruitment, reproductive period, fecundity, and sex ratio. Specimens were sampled monthly from April, 2003 to March, 2004, at the river margins during low tide periods. Size, sex, presence of eggs, and stage of the female gonad were recorded. Ovigerous females had their eggs removed and counted. The reproductive period was continuous and the highest frequency of ovigerous females was recorded in the fall and winter. Mature gonads were found throughout the year and recruitment was continuous but more intense during the summer. The fecundity of N. granulata (30028.3 ± 10861.2 eggs) was high in comparison to studies in other localities. In general, the proportion of males was similar to that of females (1:0.92); however, males were predominant in the fall (1:0.77) and winter (1:0.75). All the information available so far on the reproduction of N. granulata involves populations from subtropical salt marshes; therefore, comparative studies including other habitats, such as mangrove forests...

‣ Population biology and distribution of the portunid crab Callinectes ornatus (Decapoda: Brachyura) in an estuary-bay complex of southern Brazil

Watanabe,Timoteo T.; Sant'Anna,Bruno S.; Hattori,Gustavo Y.; Zara,Fernando J.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 Português
Relevância na Pesquisa
66.789287%
Trawl fisheries are associated with catches of swimming crabs, which are an important economic resource for commercial as well for small-scale fisheries. This study evaluated the population biology and distribution of the swimming crab Callinectes ornatus (Ordway, 1863) in the Estuary-Bay of São Vicente, state of São Paulo, Brazil. Crabs were collected from a shrimp fishing boat equipped with a semi-balloon otter-trawl net, on eight transects (four in the estuary and four in the bay) from March 2007 through February 2008. Specimens caught were identified, sexed and measured. Samples of bottom water were collected and the temperature and salinity measured. A total of 618 crabs were captured (332 males, 267 females and 19 ovigerous females), with a sex ratio close to 1:1. A large number of juveniles were captured (77.67%). Crab spatial distributions were positively correlated with salinity (Rs = 0.73, p = 0.0395) and temperature (Rs = 0.71, p = 0.0092). Two peaks of recruitment occurred, in summer and autumn, and ovigerous females were mostly captured during summer, showing a seasonal reproductive pattern. The results showed that C. ornatus uses the bay as a nursery area for juvenile development. Callinectes ornatus is not yet a legally protected species...

‣ Population biology of spine shrimp Exhippolysmata oplophoroides (Holthuis) (Caridea, Hippolytidae) in a subtropical region, São Paulo, Brazil

Fransozo,Vivian; Costa,Rogério C.; Bertini,Giovana; Cobo,Valter J.
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 Português
Relevância na Pesquisa
56.67436%
The population biology of Exhippolysmata oplophoroides (Holthuis, 1948) was studied in Ubatuba Bay (23º26'S, 45º02'W), Ubatuba, São Paulo, Brazil, from September/1995 to August/1996. Each sampling comprised eight transects (14 000 m² each), sampled monthly with three repetitions. The specimens were classified with respect to the presence or absence of eggs in the abdominal appendages. Spine-shrimps occurred only on six transects, being most abundant on transect II, with the highest incidence in late spring and throughout the summer months. Ovigerous and non-ovigerous shrimps were present year-round, in an approximately similar proportion (1:1). Site II in Ubatuba Bay is characterized by high salinity and oxygen values, temperature between 26 and 29ºC, low organic matter content in the sediment, and a bottom composed of very fine sand; these environment and biological features allow the establishment and maintenance of the population of E. oplophoroides.

‣ Popularion biology of abdominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir (low Tietê river, São Paulo State, Brazil)

Vidotto-Magnoni, Ana Paula; Carvalho, Edmir Daniel
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 55-63
Português
Relevância na Pesquisa
56.860015%
The aim of this study is to characterize some population biology parameters of P. squamosissimus, A. altiparanae and S. maculatus, the dominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir, low Tietê river. Fish samplings were performed monthly between September/2002 and August/2003, using gill nets with different mesh sizes. Females of all species have larger standard lengths than males (Mann-Whitney, p < 0.0001), and are more frequent in superior size classes (Kolmogorov-Smirnov, p < 0.0001). All populations presented isometric growth, but differences between males and females were observed. Only P. squamosissimus presented a gender ratio different from 1:1, with a higher proportion of males (1:2, X2, p < 0.05). The onset of gonadal maturation occurs at 15 cm in P. squamosissimus, 9 cm in S. maculatus and at 8.9 cm in A. altiparanae. In all species populations, the adults predominate over juveniles. The allometric condition factor (K) of P. squamosissimus and S. maculatus presented higher values in the periods from March-May and June-August, and A. altiparanae in the period from March-May (Kruskal-Wallis, p < 0.05). These results indicate that the populations successfully exploit the lentic environment...

‣ Harnack Inequalities and Heat-kernel Estimates for Degenerate Diffusion Operators Arising in Population Biology

Epstein, Charles L.; Mazzeo, Rafe
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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This paper continues the analysis, started in [2, 3], of a class of degenerate elliptic operators defined on manifolds with corners, which arise in Population Biology. Using techniques pioneered by J. Moser, and extended and refined by L. Saloff-Coste, Grigoryan, and Sturm, we show that weak solutions to the parabolic problem defined by a sub-class of these operators, which consists of those that can be defined by Dirichlet forms and have non-vanishing transverse vector field, satisfy a Harnack inequality. This allows us to conclude that the solutions to these equations belong, for positive times, to the natural anisotropic Holder spaces, and also leads to upper and, in some cases, lower bounds for the heat kernels of these operators. These results imply that these operators have a compact resolvent when acting on $C^0$ or $L^2.$ The proof relies upon a scale invariant Poincare inequality that we establish for a large class of weighted Dirichlet forms, as well as estimates to handle certain mildly singular perturbation terms. The weights that we consider are neither Ahlfors regular, nor do they generally belong to the Muckenhaupt class $A_2.$; Comment: This version corrects a small gap in the argument used to estimate the contribution of vector fields and potentials with log-divergent coefficients (the old Lemma B.2)