Navegando por Assunto "Hemiodus unimaculatus"

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Acesso aberto (Open Access)
A pesca e os aspectos reprodutivos da jatuarana escama grossa Hemiodus unimaculatus (Bloch, 1794) na área de influência da usina hidrelétrica de Tucuruí-Pará
(Universidade Federal do Pará, 2011-10-31) PINHEIRO, Jossandra Carvalho da Rocha; NAKAYAMA, Luiza; http://lattes.cnpq.br/3771896759209007; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081
The Hemiodus unimaculatus (Jatuarana Tick Scale) is a hemiodontidae Benthopelagic of significant commercial importance, generating food, employment and income to fishermen in the influenced area by the reservoir in the hydroelectric plant of tucurui (Tucurui HEP). The present study analyzed the fishing and the reproductive aspects, as the structure in length and weight of the population, the weight-length relation, the average length of first gonadal maturation (L50), the sex ratio and the period of breeding in the area of influence of the Tucurui HEP (upstream in the reservoir and the downstream). Were analyzed temporal series of landing data (2000 to 2008 period) and interviews from July to October 2010 in the three areas of Tucurui HEP, with dealt information about the location and characterization of the fishery and fishing widget. For the study about reproductive aspects, the specimens analyzed were collected monthly, from January 2006 to December 2007, in the reservoir and downstream of the dam. A H. unimaculatus was landed in three areas influenced by the Tucurui HEP during all year, being the upstream responsible for the highest production. There is statistically significant seasonality throughout the year, characterizing production peaks, being the upstream in May, June and October, January and from May to June in the reservoir, and the downstream from May to August. The main locations for the capture of the schools are the edges and beaches, being the main capture procedure the gillnets. The principal boarding port is located in Itupiranga city, where is the HEP Tucurui upstream. Among the fish caught in the reservoir (429) and the downstream (545), the biggest variation occurred in the reservoir (12.5 to 29 cm of total length). The weight-length relation has presented negative allometry in both sub-areas. The L50 considered for grouped sexes was 27.6 cm in reservoir and 22.2 cm the downstream. The sex ratio for the total samples was favorable females in both areas, being 1.6 and 1.9 in reservoir and downstream, respectively. The reproductive period was recorded in March (raining season) in the reservoir and the downstream from November to March (periods transactional dry/rainy and rainy). Considering that the specie occurs in all the HEP Tucurui areas and the tendency of annual production are increasing continually the upstream, the need to implement enhanced local infrastructure and measures for development in order to maintain the sustainability of fishery.
Acesso aberto (Open Access)
Seletividade de captura, dinâmica populacional, análise de estoque e sustentabilidade da pesca de Hemiodus unimaculatus (Bloch, 1794) a montante da barragem de Tucuruí, Brasil
(Universidade Federal do Pará, 2013-04-23) MARTINS, Jeronimo Carvalho; CINTRA, Israel Hidenburgo Aniceto; http://lattes.cnpq.br/6632466008150577; SARPEDONTI, Valérie; http://lattes.cnpq.br/2358097649881792
Hemiodus unimaculatus (Bloch, 1794) is one of the main species landed into the area of influence of Tucuruí Hydroelectric plant; however there is little information available about the fishery and biology of the species in the area. Therefore, this study aims to investigate spatial changes of H. unimaculatus, determine selectivity curves for the fishing nets used and calculate some parameters of population dynamics. The study area was located on Tucuruí’s dam, including the reservatory (flooded area) and up-river section. The samples were colected on a quaterly basis for the years 2001, 2003, 2005, 2006 and 2006, and semiannually in 2002 and 2004, in five areas located in the lake and two areas upstream, usinga battery of gillnets 50 m long and 3 m high, with a stretched mesh size of 40, 60, 80, 100 mm between opposing nodes. The Kruskal-Wallis test was used to compare mean total length and weight of the specimens at a significance level of 5%, the spatio-temporal variation of the catch was determined by cluster analysis and the SIMPER; selectivity for network construction curves selection, and population aspects (growth, longevity, mortality, recruitment and yield per recruit) with the aid of the FISAT II. Results showed that females were bigger and heavier than males. During the first period (2001 – 2003) the study area was shared in spawning grounds and growth, while in the final period (2005-2007) there was no difference in the use of space. The mesh of 60 mm is the most suitable for fishing, considering the capture of 50% of adults. The sex ratio was 1.44:1 favorable to females (χ2 c = 28.86; p < 0.0001). Relations total weight / total length showed a positive correlation and did not differ between sexes (t = -0.097; p = 0.9229), with males and females exhibited isometric growth. The condition factor was not different between the sampling points, suggesting that the species uses the entire study area as a feeding zone. The von Bertalanffy growth parameters were L∞ = 358 mm, k = 0.55 yr-1 and t0 = -0.15 year. The average total mortality and natural were 3.04 yr-1 and 0.7 yr-1, respectively. The exploitation rate was estimated at 0.77 and the yield per recruit showed that the rate of exploitation of the H. unimaculatus stock should be reduced by 52% to maintain the recruitment and spawning. So with all the information generated, it can be seen that change in the structure and spatio-temporal dynamics of H. unimaculatus is a process of continuous adaptation and appropriate fisheries management becomes essential for the preservation of the species. To reach this goal, it is necessary to review the current fisheries legislation, seeking an optimal mesh size for catching the species, decrease the rate of exploitation and regularly monitor the selectivity and population parameters.