The reproductive hiology and cycle of Rioraja agassizi (Muller and Henle, 1841) (Chondrichthyes : Rajidae) in southeastern Brazil, SW Atlantic Ocean

Specimens of Rioraja agassizi were collected Lit Guaruja pier, São Paulo State, Brazil, from March 2005 to March 2006. A total of: 275 males were captured. Based on the analysis of the clasper length, gonad weight, clasper gland length, alar thorns and lobule diameter, the size-at-maturity was estimated to be 32 cm. There were 1049 females in the record. Size-at-maturity was calculated in 40 cm. Sexual resting females were observed. Gonadosomatic and hepatosomatic indexes varied significantly in both sexes throughout the year. However, ovulation, egg-laying and presence of sperm in the seminal vesicle were observed all year round. For this reason, an annual cycle with at least one peak in the sexual activity is proposed for this species.

Reproduction of species of the genus Cichla in a reservoir in Southeastern Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Visual communication stimulates reproduction in Nile tilapia, Oreochromis niloticus (L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Physiological maturity and relationships of growth and reproduction in the red mangrove crab Goniopsis cruentata (Latreille) (Brachyura, Grapsidae) on the coast of São Paulo, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relação peso/largura da carapaça e fator de condição em Dilocarcinus pagei Stimpson (Crustacea, Trichodactylidae), em São José do Rio Preto, São Paulo, Brasil

A biologia de caranguejos de água doce tem sido pouco enfocada na literatura carcinológica, especialmente em relação à Dilocarcinus pagei Stimpson, 1861. Este estudo visa analisar a relação peso/tamanho e variações temporais/sazonais do fator de condição, comparando com a biologia da espécie. Os exemplares foram coletados mensalmente na Represa Municipal de São José do Rio Preto (São Paulo), durante um período bianual (outubro/1994 a setembro/1996). Foram obtidos 962 espécimes (534 machos e 428 fêmeas), que foram mensurados (LC = largura do cefalotórax) e pesados (PE = peso úmido total). Os pontos empíricos da relação PE/LC foram analisados para cada sexo e submetidos à análise de regressão pela função potência (y = ax b) e representadas por: PE Machos = 0,0002LC3,º8 e PE Fêmeas = 0,0005LC2,82. O fator de condição foi calculado mensal e sazonalmente, sendo o das fêmeas cerca de 2,5 maior que o dos machos, possivelmente devido ao maior tamanho/peso das gônadas. de modo geral o verão foi caracterizado pela menor média de fator de condição (época reprodutiva), contrastando com a maior verificada no inverno (reorganização gonadal). Os resultados obtidos são enfocados pela primeira vez na literatura carcinológica, sendo de grande valia no manejo populacional e preservação desta espécie, que vem sendo intensamente explorada e usada como isca na pesca esportiva.

Ciclo reprodutivo do caranguejo violinista Uca rapax (Smith) (Crustacea, Brachyura, Ocypodidae) habitante de um estuário degradado em Paraty, Rio de Janeiro, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reproductive cycle of Hepatus pudibundus (Herbst, 1785) (Crustacea, Decapoda, Calappidae) in Ubatuba, SP, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Aspectos da reprodução e alimentação de Neoplecostomus microps (Loricariidae, Neoplecostominae) na microbacia do Ribeirão Grande, serra da Mantiqueira oriental (Estado de São Paulo)

Reproduction and feeding aspects of Neoplecostomus microps (Loricariidae, Neoplecostominae) in the Ribeirao Grande system, eastern Serra da Mantiqueira (São Paulo State). The Ribeirao Grande system is located in the slope of the Serra da Mantiqueira and is surrounded by Atlantic forest. Eight sites were surveyed in the Ribeirao Grande system, during the winter (July 2001), spring (October 2001), summer (February 2002) and fall (April 2002). Samples were made with an electrofishing device. Gonad maturation, levels of stomach fullness and fat content were analyzed and their distributions reported in an annual cycle. Neoplecostomus microps has a spawning in the spring through to summer. The size at sexual maturity is about 5.9 cm total length for males and 6.9 cm for females. The high values in October and February by the gonadosomatic index and the relative condition factor coincided with the spawning period. In the diet of N. microps were found Diptera larvae (Simulium, Chironomus), Plecoptera nymphs and Coleoptera aquatic Larvae (Psephenus). The increased feeding from summer to fall provided fat accumulation. During subsequent seasons, fish may utilize visceral fat reserves for maintenance and reproduction. The reproductive pattern and feeding are interpreted as being an adaptation with respect to temporal and spatial variation and food availability.

Relação peso-comprimento e fator de condição para Cichla cf. ocellaris e Cichla monoculus (Perciformes, Cichlidae) no reservatório de Volta Grande, Rio Grande - MG/SP

The aim of this paper was to analyze the length-weight relationship and the condition factor of two species of cichlids (Cichla cf. ocellaris and Cichla monoculus) (Perciformes, Cichlidae) that were inducted in Volta Grande Reservoir, Rio Grande. There was no difference in the length-weight relationship between the sexes for Cichla cf. ocellaris and Cichla monoculus. The allometric condition factor showed a fall in the spring and another smaller one in the winter. It happens when these fishes change their feeding activity. In the spring all the reproductive behavior are developed and, in the winter, there is a shortage of prey. The variation of the relative condition factor followed the variation of the allometric condition factor due to the low contribution of the gonads weight and the small amount of accumulated fat in the total weight. The length distribution, length-weight relationship and condition factor of these fishes vary in accordance with the time of introduction into the reservoir, the characteristics of the ecosystem as well as the interactions among the species at these sites.

Endocrine Disruptors and Hypothalamic Sexual Differentiation

The so-called endocrine disruptors have been described as compounds which interfere with the estrogen action in their receptors and may exert a crucial role in the development of the reproductive tract and in the brain sexual differentiation. Thus, conducts and/or exposure to these drugs in the perinatal period that apparently do not endanger the neonate may cause side effects. During embrionary development, the gonads, through discharge of a small quantity of reproductive hormones, will guarantee the phenotype of male or female at birth, as well as actuate in specific areas sexual differentiation of the central nervous system. Several experimental models have shown an interference of drugs acting as endocrine disruptors in hypothalamic sexual differentiation. Thus, reproductive function is impaired by exposure to estrogen in the perinatal life of rats and the mechanisms involved in this effect are distinct for males and females. Perinatal exposure to drugs which may be considered endocrine disrupters may induce an incomplete masculinization and defeminization of the central nervous system. Alterations in these processes, if present, generally are perceived only at puberty or adult reproductive life. These later alterations may include anomalies in the process of fertility or in sexual behavior.

Células sangüíneas, eletrólitos séricos, relação hepato e esplenossomáca de carpa-comum, Cyprinus carpio (Cyprinidae) na primeira maturação gonadal

This research studied the condition (Kn) relative factor, the hepatosomatic (HSR), the splenosomatic (SSR) relation, the erythrocytes, thrombocytes and leukocytes number, the glicogen locality by PAS method in thrombocytes and leucocytes and the total protein and electrolytes serices levels in both Cyprinus carpio L. sex. The female Kn showed higher value than the males. The female HSR average values were lower than the ones observed in males, while the leukocytes, lymphocytes and neutrophils percentage number were the highest. However, the males magnesium and choride serices levels were higher than the females. The HRS average values, hematocrit, haemoglobin concentration, average corspucular volume (ACV), average corpuscular haemoglobin concentration (ACHC), erythocytes number, trombocytes, monocytes, oesinophils, positive PAS leukocyte granular (PAS-LG), and total protein, sodium, potassium and calcium serices levels did not show significant statistics difference (p> 0.05) between males and females. The PAS method showed glicogen granules into the thronbocytes, eosinophils and neutrophils cytoplasm. Nevertheless, in the PAS-LG cytoplasm, neutral glicoprotein granules were also observed. Monocytes and lynfocytes showed negative reaction to PAS. In the teleosts, the gonodas matureness presents higher relation with the factor of condition. During the reprodution period it is unlikely to find the sexual effects isolated in the hemogram, because most of the time that is not the only factor to cause dimorphism.

Desenvolvimento morfolôgico dos ovários em embriões e fetos bovinos da raça Nelore

The morphologic events related to the prenatal development of the ovaries in 81 Nelore breed embryos and fetuses gathered in a local slaughterhouse, with age range from 26 to 240 days following fecundation were studied. The age of fetuses was estimated from measures taken in the cranium-caudal direction. The sex was identified from macroscopic observations and using Polymerase Chain Reaction (PCR) technique. For histology the gonads were fixed in Bourn's fluid for 24 hours and 5 μm thick section's were stained with hematoxylin-eosin. Formation of gonadal ridge and presence of germinal cells were found within it at 29 and 34 days, respectively. Oogonia and primordial follicles, unlike the growing follicles, exhibited significant differences in diameter in the various periods studied. Positive correlation (P<0.05) was found between the diameter of oogonia and their nucleus as well as between primordial and growing follicles with their oocytes and respective nuclei. The gonad was fully formed at 40 days. Primordial follicles, in the growing stage, and antral follicles first appeared, approximately at 95, 140, and 180 days, respectively. Despite the onset and duration of oogenesis being similar to that of taurine breeds, folliculogenesis initiates at an early stages in the Nelore breed.

Physiologic sexual maturity of the fiddler crab Uca rapax (Smith, 1870) (crustacea, ocypodidae) from two mangroves in Ubatuba, Brazil

The gonad development of Uca rapax was studied to achieve the size at onset of its sexual maturity. Crabs were sampled from April/2001 to March/2002 in the Itamambuca and Ubatumirim mangroves in Ubatuba, São Paulo, Brazil. The specimens were grouped in 10 size classes. Juveniles and adult crabs frequencies were assessed for each class. The size of carapace width in which 50% of males and females were considered mature was 14.8 and 12.1 mm (Itamambuca) and 13.6 and 11.4 mm (Ubatumirim), respectively for males and females. Males matured at higher sizes than females, probably due to a major investment in their somatic growth, while females spend their energy in the reproductive process, saving energy for eggs' production.

Relação peso-comprimento e fator de condição de Brycon opalinus (Pisces, Characiformes) no Parque Estadual da Serra do Mar-Núcleo Santa Virgínia, Mata Atlântica, Estado de São Paulo, Brasil

In this study, the length-weight relationship and the condition factor of Brycon opalinus were analyzed in three rivers within the Santa Virgínia Unit, at Serra do Mar State Park, in São Paulo State. The different conditions in these three environments were evidenced, such as the seasonality, reproductive period, and the differences between females and males according to the parameters which evidenced the best physiological condition of the fish. In this species, the condition factor varied along the seasons at all three collection sites. The length of the first gonadal maturation and the reproductive period were long, with the highest intensity in the spring and summer.

Aspectos da reprodução no gênero Characidium Reinhardt, 1867 (Crenuchidae, Characidiinae), na microbacia do Ribeirão Grande, serra da Mantiqueira, sudeste do Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)