Navegando por Assunto "Biologia reprodutiva"

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Acesso aberto (Open Access)
Avaliação da biologia reprodutiva de Plagioscion squamosissimus (HECKEL, 1840) e Plagioscion surinamensis (BLEEKER, 1873) no terminal de Vila do Conde e área adjacente (Barcarena - PA)
(Universidade Federal do Pará, 2009-04-29) BARBOSA, Neuciane Dias; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081; FRÉDOU, Flávia Lucena; http://lattes.cnpq.br/4779271407117528
The Port of Vila do Conde, situated in the city of Barcarena/PA, have been exposed to a number of environmental disasters in recent years which can eventually cause the disequilibrium of the use that the aquatic resources make of the environment and consequently to the ecosystem as a whole. Artisanal fishery in this region is relevant, detaching Plagioscion squamosissimus and P.surinamensis as the mains sources of income and food for the population. The objective of this study was to describe the areas of concentration and the reproductive biology of P. squamosissimus and P. surinamensis in the adjacent area of Vila do Conde, mainly identifying the importance of the use of these environments for reproduction. Aiming to identify to the period and fishing sites of greater species abundance, it was obtained the index of abundance CPUE (Kg/viagem) based on data collected from June 2007 to May 2008. The determination of the use of the area for reproduction and the description of reproductive biology was based on 40 to 53 individuals of each species collected from the commercial fishery in a bimensal basis. In laboratory, total length and total weight was registered and gonads were removed for the identification of sexual maturity. The abundance of P. squamosissimus is maximum between September and February and for P. surinamensis it is registered between March the May. The weight-length relationship showed isometry for the females of P. squamosissimus and for both sexes of P. surinamensis. For males of P. squamosissimus positive alometry was registered. The sexual ratio was favorable to the males for P. surinamensis (1,05male: 1female) and favorable to the females (1,11female: 1male) for P. squamosissimus. The value of L50 (length at first maturity) for P. squamosissimus was 16,14 cm for females and 21,43 cm for males. The length at first maturity for P. surinamensis was 27,65 cm for females and 27,13 cm for the males. The percentage of individuals in reproduction of the P. squamisissimus is considerable. The peak of the reproduction of this species (October/November and February/March) coincides with the peak of abundance, indicating that this species is in the area for reproduction. P.surinamensis presented greater percentage of immature and maturing individuals, indicating that this species uses this area mainly as a nursery. For P. surimamensis, reproductive individuals was mainly reported in August/September and October/November.
Acesso aberto (Open Access)
Biologia reprodutiva de Sabellaria wilsoni (Polychaeta: Sabellaridae) na ilha de Algodoal-Maiandeua (Pará)
(Universidade Federal do Pará, 2011-11-01) PINTO, Álvaro José de Almeida; FERREIRA, Maria Auxiliadora Pantoja; http://lattes.cnpq.br/1832728101486131; ROSA FILHO, José Souto; http://lattes.cnpq.br/3223362071251898
The Polychaeta Sabellaria wilsoni occurs from the Gulf of Mexico to Argentina, building sandy reefs from the intertidal zone to 25 m depth. These reefs play an important role in structuring and functioning of sandy beach ecosystems in the Amazon Coast. This work studied the reproductive biology of S. wilsoni in Algodoal Island (PA, Brazil), describing sex ratio, gametogenic process and breeding period. Sampling occurred monthly between May 2008 and April 2009. In the laboratory 100 individuals were randomly chosen and measured (total length – from the operculum to the beginning of the anal funnel); and from these, 20 specimens were prepared for histological studies. Slides were observed under optical microscope to describe reproductive structures, and to determine sex and maturation stage (based on a four grade scale). The size of organisms ranged from 4.5 ± 1.89 mm to 11.5 ± 2.83 mm, with females larger and more numerous than males (sex ratio 0.6:1 - M:F). Female gametes develop on projection of blood vessels and are subsequently released into the coelom. In males spermatogenesis is associated with intersegmental septa wall, and sperm is released into the coelom. Gametes are released to the environment through nephridia and fertilization is external. Reproduction occurs all year round with peaks on September-November and March-April. The main cues to reproduction are an increase in hydrodynamics on August, as an adaptation of the Polychaeta to the future reef destruction, which occurs between October and November; and an increase of space available for colonization, after the reef destruction.
Acesso aberto (Open Access)
Caracterização espermática de Parancistrus nudiventris Rapp Py-Daniel & Zuanon, 2005 (Siluriformes, Loricariidae), espécie amazônica endêmica do Rio Xingu, Pará, Brasi
(Universidade Federal do Pará, 2025-03-21) LOPES, Thaís da Silva; SOUSA, Leandro Melo de; http://lattes.cnpq.br/6529610233878356; https://orcid.org/0000-0002-0793-9737
Acesso aberto (Open Access)
Ecologia do bagre Ageneiosus ucayalensis Castelnau, 1855 (Siluriformes: Auchenipteridae) em uma ria fluvial da Amazônia oriental
(Universidade Federal do Pará, 2015) OLIVEIRA, Valéria de Albuquerque; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
Acesso aberto (Open Access)
Estudo da biologia reprodutiva de Crassostrea gasar (Adanson, 1757) no nordeste paraense
(Universidade Federal do Pará, 2012-04-30) PAIXÃO, Leonardo Fernandes da; FERREIRA, Maria Auxiliadora Pantoja; http://lattes.cnpq.br/1832728101486131; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081
The present study analyzed gonadal development in Crassostrea gasar from an Amazonian estuary and characterized the relationship between the reproductive cycle and the variation in abiotic factors. Samples of approximately 20 oysters were collected each month between August, 2009, and December, 2010. The study period was divided into four seasonal periods (dry, dry-rainy transition, rainy, and rainy-dry transition). The salinity, pH, temperature, and dissolved oxygen concentration of the water were measured in situ during the collection of specimens. The gonads were dissected and analyzed histologically. A total of 353 specimens were collected, of which 190 were female, 161 were male, and two were hermaphrodite. Histologically, the specimens were classified in four gonadal stages: I – immature; II – maturing; III – mature, and IV – spawned (females) and spermiated (males). Of the abiotic factors analyzed, only salinity and rainfall varied significantly over the study period, with correlations being found between these factors and gonadal maturation, suggesting that they influence the reproductive cycle of the species. A predominance of mature (stage III) and maturing individuals were recorded during the rainy and rainy-dry periods (low salinity and high rainfall), whereas immature (I) and spawned/spermiated (IV) specimens were more common during the dry and dry-rainy periods (high salinity and low rainfall). Given this, the collection of seeds for farming would be recommended during the latter period, when spawned/spermiated oysters were more common.
Acesso aberto (Open Access)
Gonadal development in the freshwater crab Sylviocarcinus pictus (H. Milne Edwards, 1853) (Brachyura: Trichodactylidae) from the Guamá river, state of Pará, Brazil
(2012-09) SILVA, Leiliane Souza da; MARTINELLI-LEMOS, Jussara Moretto; FERREIRA, Maria Auxiliadora Pantoja; ROCHA, Rossineide Martins da
The development stages of male and female gonads in the freshwater crab Sylviocarcinus pictus (H. Milne Eduards, 1853) were described through macroscopic and microscopic (histology) examinations. The histological description was based on 40 specimens (20 each sex). Four gonadal development stages were found for females: immature, ripening, mature and spawned. The following female cells were found: ovogonia, oocytes in initial vitellogenesis, oocytes in advanced vitellogenesis, follicular cells and post-ovulatory follicles. Three development stages were found for males: immature, maturing and mature, with the indication of: spermatogonia, spermatocytes, spermatids, spermatozoids and spermatophores. These data suggest the pattern described in the literature. Size at sexual maturity was 32.3 mm of carapace width for males and 31.5 mm for females. The gonadal stages observed macroscopically by volume and color were validated through histological analysis and proved to be useful method for the rapid identification of sexual maturity in the species. The present study offers previously unpublished data on the reproductive biology of Sylviocarcinus pictus.
Acesso aberto (Open Access)
Reproductive characteristics and the weight-length relationship in Anableps anableps (Linnaeus, 1758) (Cyprinodontiformes: Anablepidae) from the Amazon Estuary
(2011) OLIVEIRA, Valéria de Albuquerque; FONTOURA, Nelson Ferreira; MONTAG, Luciano Fogaça de Assis
The present study analyzed the length-weight relationship and some aspects of the reproductive biology of Anableps anableps from the mouth of the Maracanã River, in the Brazilian state of Pará. The specimens were collected using two 30 m-long gillnets with 15 and 20 mm mesh size, as well as a 1 m-diameter hand net with a 10 mm mesh. A total of 865 specimens were collected, from which an adult sex ratio of 2.12 females per male was recorded (χ² = 13.07; p<0.05). Females presented positively allometric growth, whereas males were negatively allometric. In the additional analyses, the gonads of 371 female specimens were observed microscopically. Gonadal development was classified in three stages: immature (5.0%), maturing (12.0%), and mature (83.0%). Embryonic development was classified in five phases, according to the size of the embryo and the vitelline sac. Mean fecundity was 12 eggs/embryos per female (range: 1-37 eggs/embryos). A significant relationship was recorded between the standard length of females and ovaries weight (R² = 0.257; p < 0.001), and the number of embryos carried (R² = 0.573; p < 0.001). Mean body length of females at initial sexual maturation (L50) was estimated at 11.7 cm. The species reproduced throughout the year.
Acesso aberto (Open Access)
Seasonal changes in the gonadossomatic index, allometric condition factor and sex ratio of an auchenipterid catfish from eastern Amazonia
(2011) FREITAS, Tiago Magalhães da Silva; ALMEIDA, Vitor Hudson da Consolação; MONTAG, Luciano Fogaça de Assis; ROCHA, Rossineide Martins da; FONTOURA, Nelson Ferreira
The aim of the present study was to evaluate the seasonal pattern of the gonadosomatic index (GSI), condition factor (K), and sex ratio in the catfish Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) as an approach to identify its reproductive period. A total of 589 A. longimanus specimens (251 males and 338 females) were captured in the rivers of the Caxiuanã National Forest, in the Brazilian state of Pará, between July, 2008 and July, 2009. Among the male specimens, 171 were classified as adults and 80 as juveniles, while there were 249 adults and 89 juvenile females. Using a sinusoidal equation, analysis of the GSI revealed a reproductive asynchrony between the genders, with males attaining their highest GSI values in January, while females peaked in March. For males, the sinusoidal regression for GSI values was significant only when used the complete data set (P=0.001), wears no trend was identified for bimonthly means (P=0.136). For females, by contrast, significant values were obtained for both the complete data set (P=0.012) and bimonthly GSI means (P=0.026). For the condition factor, the sinusoidal equation returned significant seasonal variation in both raw data (P=0.02) and with mean values (P=0.00) for males, but only with raw data for females (P=0.04), which appears to reflect variation in the energy budget between genders. With regard to the sex ratio, more reproductive females were captured than males in January and March, 2009, which suggests a pattern of segregation related to the reproductive process. These parameters are fundamental to the assessment, protection, and management of natural fish stocks, as well as providing guidelines for the development of conservation strategies.
Acesso aberto (Open Access)
Sistema reprodutor feminino de três espécies do gênero Saimiri Voigt, 1831 (Primates: Cebidae): observações macroscópicas e histológicas
(Universidade Federal do Pará, 2014-08-18) LOPES, Gerson Paulino; QUEIROZ, Helder Lima de; http://lattes.cnpq.br/3131281054700225; DOMINGUES, Sheyla Farhayldes Souza; http://lattes.cnpq.br/2794753357251149
The platyrrhine primates show variation in their reproductive aspects, their strategies, behaviors, physiology and morphoanatomy. Some of these variations may be consequences of the coevolution of the constituent elements of the genitalia of both sexes through sexual selection. Morphological differences may represent a high degree of specialization of the intraspecific genital organs, which entails a "lock-key" mechanism, which may constitute one of the mechanisms of copulatory and reproductive isolation, with implications in the speciation processes. In females, anatomical and physiological barriers within the vagina, cervix, uterus, uterus-tubal junction, and uterine tubes may be obstacles to male gametes towards fertilization and may influence the outcome of potential sperm competition. In neotropical primates, some morphological descriptions pointed out several similarities and differences between the components of the female reproductive system. Saimiri sciureus, Saimiri oerstedii and Saimiri collinsi were described in primates of the Saimiri genus. Recently, previously identified forms as S. sciureus and considered as subspecies of this, were elevated to the level of species. Among them are Saimiri macrodon and Saimiri cassiquiarensis. These species are widely distributed in the Amazon and occur in peripatria with Saimiri vanzolinii in the Mamirauá Reserve, Central Amazonia. The limits of the geographical distribution of the three species are well delineated, but the mechanisms that promote the reproductive isolation are still not clear. The possibility of hybrids and the progressive invasion of S. cassiquiarensis in the area of S. vanzolinii occurrence are of concern. Some mixed groups were observed in the contact zone between S. vanzolinii and S. cassiquiarensis. The absence of geographical barriers requires that segregation between these species be elucidated by other parameters, such as reproductive isolation due to morphological incompatibility. In this context, we describe the female reproductive system of these species in order to evaluate the possibility that genital morphology constitutes a mechanism of reproductive isolation between them, through the anatomical, topographic and histological description of the external genitalia and internal organs of the female reproductive system. We found that these species share many similarities in most of the organs analyzed. Although some important differences have been identified that may play a relevant role in the evolution of the components of the reproductive system of these species, these differences are not enough to compose a mechanism of reproductive isolation for these three species of Saimiri. Our descriptions provide important information that can assist in the construction of conservation strategies for these and other species of the Saimiri genus. As well as subsidizing the development of reproductive biotechnologies, especially endangered species such as S. vanzolinii, and elucidating questions about evolutionary aspects of the components of the reproductive system of these species and other primates.