Navegando por Assunto "Plagioscion squanossissimus"

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Acesso aberto (Open Access)
Avaliação da atividade gonadal de machos e fêmeas de pescada branca, Plagioscion squamosissimus (Heckel, 1840), (Pisces, Teleostei, Sciaenidae) no rio Pará (PA)
(Universidade Federal do Pará, 2006) NEGRÃO, José Nazareno Cunha; OHASHI, Otávio Mitio; http://lattes.cnpq.br/5547874183666459
Male and female adults of P. squamosissimus (Pisces, Teleostei, Sciaenidae) were collected monthly in the Para River that surrounds Capim insland, state of Para (S 010 34. 971` ; W 0480 52.932`), during the month of february 2004 to february 2005, having 234 specimes. The gonads were collected, mounted and processed in accordance with the standard methods of paraffin and analysis using a light microscope. The species under analysis is one of the principal sources of animal protein for the local population, fishing being uninterrupted and intensive throughout the year based on information given by local fisherman, the collection process appears to be determined by an apparent qualiquantitative reduction in local stock. The species represents spawn divisions, the gonad development was characterized in state of repose, maturation, mature and empty or half-empty. Mature gonads were found on the months of december, january and july. Correlation analysis between the maturing state of gonads, seasonal variations in relation to gonadosomatic indexes (GSI) and also the occurrence of spawn in the respective months. Nevertheless, the information obtained in correlation to GSI and mature oocyte mediums and between spermatozoa percentages by seminiferous tubule, respectively, also indicate spawning in the respective months, and apparently that the species represents a more intensive spawning period or a primary spawning period between the months of december and january, and a second or less intensive spawning period in the months of july. Based on the tubular morphology method, eight of the seminiferous epithelium cycle stages (SEC) were determined, stage 1 being seminiferous tubule that are comprised of primary spermatogonia and cysts of the secondary spermatogonia; stage 2 is comprised of primary and seconday spermatogonia and spermatocytes cysts; stage 3 is characterized by primary and secondary spermatogonias, spermatocyte cysts and young spermatids; stage 4 with seminiferous tubule characterized by presence of spermatogonias primary and secondary, spermatocyte and by presence of young and later spermatids cysts; stage 5 represents all of the previously mentioned cells and is highlighted by presence of spermatozoa in the tubule lumen; stage 6 is characterized by reduction of cysts of germinative cells and a considerable increase in number of spermatozoa in the tubular lumen; stage 7 is characterized by seminiferous tubule that contain few cysts of germinative cells and is marked by the begining of a mass emptying of spermatozoa of the tubule lume; stage 8 is the last of the SEC and is characterized by the apparent disorganization of the remaining germinative cellular cysts in the seminiferous tubule.
Acesso aberto (Open Access)
Utilização de peixes nativos da Amazônia como biomarcadores na avaliação da qualidade da água de uma área industrial no rio Pará - PA - Brasil
(Universidade Federal do Pará, 2011) MONTES, Caroline da Silva; FERREIRA, Maria Auxiliadora Pantoja; http://lattes.cnpq.br/1832728101486131; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081
Indiscriminate dumping of toxic substances impairs and deteriorates the water quality. Fish gills have a large surface area; they remain in close contact with the external environment and are particularly sensitive to changes in water quality, for this reason they are quite relevant for environmental monitoring. This study analyzes the gill structure of the fish species Plagioscion squamossissimus and Lithodoras dorsalis from two different sites located an Amazon estuary. A total of 324 specimens were used, this total 176 were P. squamossissimus and 148 L. dorsalis, removing the second gill arch for histological, ultrastructural and immunohistochemical analyses. The histological changes were analysed semiquantitatively according to the histopathological evaluation. The sampled sites differ regarding the rate of occurrence of altered animals, only site A showed healthy animals, 84% of L. dorsalis and 77% of P. squamossissimus had normal gill structure, with the lamellae lined by simple squamous epithelial, composed of pillar, mucous and chloride cells. However, all the specimens collected in sites B revealed tissue changes in the gill lamellae such as: aneurysm; epithelial lifting; cell proliferation; lamellar fusion and cell hypertrophy, this result was also confirmed by scanning electron microscopy. TUNEL analysis indicated that only animals captured on site B showed apoptotic cells. The presence of injury in gill tissues in the animals captured on site B emphasizes the need for more effective pollution control measures with regards to discarding pollutant loads as well as the need for urban planning in this region.