Stock estimate of brown mussel Perna perna and invasive bivalve Isognomon bicolor of natural beds from santos bay, SãO Paulo state, Brazil [Estimativa de estoque do mexilhão perna perna e da espécie invasora Isognomon bicolor em bancos naturais da baía de santos, SãO Paulo, Brasil]
Casarini L.M.,Pesquisador Cientifico do Institute Pesca |
Casarini L.M.,Institute Pesca APTA SAA |
Henriques M.B.,Pesquisador Cientifico do Institute Pesca
Boletim do Instituto de Pesca | Year: 2011
The aim of this study was to estimate the stock of the populations of bivalve Perna perna and Isognomon bicolor inhabiting Santos bay rocky shores and the biomass of P. perna extracted annually from this environment. From December 2006 to February 2008 were sampled on a bimonthly basis at the area occupied by both species. The stock of each bed was estimated by the method of partial count, which quantified the number of individuals sampled in the plots was multiplied by the total area calculated for the respective bed. The total area available was calculated from the rocky shore of 11.20 ha in the East Bay and the west 12.06 ha, but the occupation of mussel beds P. perna was only 5.02% and 2.98% respectively. The densities were significantly different (ANOVA: P<0.05) among species and months, but not for the bay side and intertidal and subtidal zones. At 65,074,096 and 6,906,112 individuals of P. perna and I. bicolor, respectively, from Santos bay populations were estimated. The total biomass of P. perna available for extraction was estimated at 58.27 t. The results indicate that the natural stocks of the mussel P. perna decreased compared to previous studies.
Limnology of nile tilapia pond: Diurnal assessment with the aim of best pratices for management [Limnologia de viveiro de criação de tilápias do nilo: Avaliação diurna visando boas práticas de manejo]
Mercante C.T.J.,Pesquisador Cientifico do Institute Pesca |
do Carmo C.F.,Pesquisador Cientifico do Institute Pesca |
Rodrigues C.J.,Instituto Chico Mendes Of Conservacao Da Biodiversidade |
Osti J.A.S.,Aquicultura e Pesca do Institute Pesca |
And 4 more authors.
Boletim do Instituto de Pesca | Year: 2011
Photosynthesis and breathing processes play an important role in the metabolism of pisciculture ponds. This study was performed in a tilapia pond in order to guide the best management practices based on the diurnal evaluation (120 h period) of limnological variables. To this end, it was determined the values of chlorophyll a, total phosphorus, total nitrogen, total ammonia, nitrite and nitrate, transparency, total alkalinity (carbon forms), water temperature, conductivity, turbidity, dissolved oxygen, pH, underwater radiation and phytoplankton. The sampling period occurred two months after populating the pond (December 16-20, 2006), phase 1, and after six months (March 2-6, 2007), phase 2. At each phase, samples were taken every 2 hours from 6 am until 8 pm for 5 days in a row (120 hours). The samples for phytoplankton quantitative analysis occurred on December 12, 2006 and March 06, 2007. The management practices promoted the enrichment of nutrients and high densities of green algae, therefore directed the dynamics of gases (O 2 and CO 2) through the photosynthesis process. In phase 2 there was an increase of oxidized forms of nitrogen and phosphorus. The behavior of the system between the hours of the study was repeated during the days, indicating that the scale of hours is more important in the dynamics of the system than the days to the dataset analyzed. These results demonstrate that management practices should consider the daily fluctuations of variables such as nitrite, carbon dioxide, pH, dissolved oxygen, deploying the most appropriate feeding schedules and the use of aerators, avoiding a possible fish kills.
Comparative economic analysis of full culture and fattening systens of mangrove oysters crassostrea spp. at cananéia estuary, São Paulo state, Brazil [Análise econômica comparativa dos sistemas de cultivo integral e de "engorda" da ostra do mangue crassostrea spp. no estuário de cananéia, São Paulo, Basil]
Henriques M.B.,Pesquisador Cientifico do Institute Pesca |
Henriques M.B.,Institute Pesca APTA SAA |
Machado I.C.,Pesquisador Cientifico do Institute Pesca |
Fagundes L.,Pesquisador Cientifico do Institute Pesca
Boletim do Instituto de Pesca | Year: 2010
The aim of this study was to compare two systems of production of the mangrove oyster Crassostrea spp. in the region of Cananéia-SP, the full culture and the "fattening" culture, expression used for the finishing phase of the culture cycle, on the technological and economic point of view, to show which system is most profitable. In the full culture, it was used the initial density of 42 oyster dozens m-2, and the survival rate at end of 22 months ranged from 25% to 50%. In the fattening culture were used oysters with average height of 50 mm at the initial density of 25 dozens m-2, which were grown for six months. The lowest survival rate observed in the "fattening" culture was 64%, and the highest 80%. The full culture has not demonstrated economic viability because its production cost is much higher than the selling prices charged in the local market. In the "fattening" culture it was found that the Internal Rate of Return (IRR) ranged from 20.65% to 102.11% from the sale prices of R$ 3.50 and R$ 4.50, in the two survival rates studied. The highest Net Present Value (NPV) obtained was R$ 355,286.74 for the sale price of R$ 4.50, with a rate of 10.75%, and the smaller was R$ 1,547.50 for the sale price of R$ 3.50 with a rate of 20%, at the lowest survival rate (64%). The results obtained confirm what has been observed in the region, the economic viability of the fattening culture. This fact can explain the expansion of the oyster "fattening" between the Cananéia producers.