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- ItemThe small-scale urban reservoir fisheries of Lago Paranoá, Brasília, DF, Brazil(2007) Walter, Tatiana; Petrere Junior, MiguelIn many cases in large urban centers, which have appropriate waterbodies, small-scale fisheries are the only source of cheap protein for the poor. In Lago Paranoá, located in Brasília, the capital city of Brazil, fishing was studied by conducting interviews with 53 fishers filling in logbooks from March, 1999 to March, 2000 in three fishing communities. The fishers come from the poorest towns around Brasília, known as satellite-towns. They have been living there on average for 21.7 years (s = 9.6 years), their families have 4.9 members (s = 3.6) on average and 44.2% do not have a basic education. However, such characteristics are similar to the socioeconomic indices of the metropolis where they live. In spite of being illegal between 1966 and 2000, fishing generated an average monthly income of U$ 239.00 (s = U$ 171.77). The Nile Tilapia Oreocrhromis niloticus is the main captured species (85% of a total number of landings in weight of 62.5 t.). Fishing is carried out in rowing boats, individually or in pairs. The fishing equipment used are gillnets and castnets. Gillnets were used actively, whereby the surface of the water is beaten with a stick to drive Tilapias towards nets as they have the ability to swim backwards. This fishing strategy was used in 64.7% of the fisheries, followed by castnets (31.1%) and by gillnets which were used less (4.2%). The fish is sold directly in the streets and fairs of the satellite-towns to middlemen or to bar owners. Three communities have different strategies in terms of fishing equipments, fishing spots and commercialization. Consequently, there are statistically significant differences in relation to the monthly income for each one of these communities.
- ItemRemarks on the morphology and distribution of some rare centric diatoms in southern Brazilian continental shelf and slope waters(2012) Garcia, Marinês; Odebrecht, ClarisseThis paper provides information on the morphology and occurrence of extant diatoms of the family Asterolampraceae and Azpeitia species of the southernmost Brazilian continental shelf and slope waters in the Southwestern Atlantic Ocean (28 - 34°S), under the influence of Tropical, Subtropical, Subantarctic Waters, terrestrial discharges from La Plata River and Lagoa dos Patos lagoon. Plankton was sampled (20 µm net; vertical hauls) at the same 27 stations in winter 2005 and summer 2007. Among Asterolampraceae, Asteromphalus flabellatus was the most frequent species (57% of samples) observed mainly in winter samples (92%) in Subtropical Shelf Water but also under the influence of La Plata River plume (salinity <35). Lower frequencies were observed for Asterolampra marylandica, Asteromphalus elegans, Asteromphalus heptactis and Spatangidium arachne. Four species of Azpeitia were observed: A. barronii and A. neocrenulata for the first time in the South Atlantic Ocean while A. africana and A. nodulifer had already been registered in equatorial and southern areas of Brazil. All Azpeitia species were rare (19%) in offshore samples (100-200 m depth. Remarks on the morphology based on light and scanning electron microcopy observations are provided along with their distribution in the study area.
- ItemA brief history if white spot syndrome virus and its epidemiology in Brazil(2013) Santos, Raíssa; Varela, Ana Paula; Cibulski, Samuel Paulo; Lima, Francisco Esmaile Soares; Spilki, Fernando Rosado; Heinzelmann, Larissa Schemes; Luz, Roger Bordin da; Abreu, Paulo Cesar Oliveira Vergne de; Roehe, Paulo Michel; Cavalli, Lissandra SoutoWhite spot syndrome virus (WSSV) is considered the most threatening infectious agent in shrimp aquaculture. Since its fi rst occurrence in 1992, this pathogen has caused economic losses approach one billion US dollars per year. WSSV is a tailed, rod-shaped nucleocapsid, double stranded DNA virus, which belongs to Nimaviridae family. In this report, it is presented a concise overview on WSSV fi rst occurrence and the diff erent features of the virus. Besides, it is reported an update on epidemiology with special attention to its occurrence in Brazil.
- ItemTransport of marine-derived nutrients to subtropical freshwater food webs by juvenile mullets: a case study in southern Brazil(2014) Oliveira, Mauro César Lamim Martins de; Bastos, Rodrigo Ferreira; Claudino, Marlucy Coelho; Assumpção, Cindy Marques; Garcia, Alexandre MirandaIn higher latitudes of the northern hemisphere, anadromous fishes can act as biological vectors, moving marine-derived nutrients into freshwater ecosystems during their reproductive migration. Much less information is available on the potential role of marine and estuarine-related fishes as biological vectors in subtropical latitudes. Here, we investigated whether mullet juveniles might transport marine nutrients into the freshwater food webs of coastal streams in southern Brazil (32°17’S, 52°15’W). To test this hypothesis, we analyzed the stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in 10 basal production sources and 10 consumer species, including juvenile mullets, at 3 sites (surf zone, lower stream reach, headwater reach) along a marine-freshwater gradient. Our results revealed a significant decreasing trend in δ15N and δ13C values from the sea to the freshwater sites, suggesting an importation and incorporation of marine-derived nutrients into the coastal stream. A mixing model showed a marked shift in assimilation from marine to freshwater production sources by mullet Mugil liza juveniles as they moved from the surf zone into the coastal stream (lower stream and headwater reaches). Our mixing model also indicated that material of marine origin is assimilated by freshwater predators, particularly those found at the lower stream reach. Further experimental and field work is needed to evaluate the implications of marine-derived carbon and nitrogen transport by juvenile mullets for the structure and dynamics of food webs in coastal streams
- ItemSpatiotemporal variation in shallow-water freshwater fish distribution and abundance in a large subtropical coastal lagoon(2003) Garcia, Alexandre Miranda; Raseira, Marcelo Bassols; Winemiller, Kirk; Grimm, Alice MarlenePatos Lagoon is located off the southern Brazilian coast and represents one of the largest coastal lagoons in the world. We estimated hydrological and physicochemical conditions associated with spatial variation in the abundance and diversity of freshwater fishes along the lagoon, and inter-annual variability in abundances of freshwater fishes occurring in its estuarine zone. During our study, the region experienced two periods of average rainfall and two periods with above-average rainfall. The characids Astyanax eigenmaniorum and Oligosarcus jenynsii and the siluriform Parapimelodus nigribarbis were the most abundant freshwater fishes in the estuary during wet periods when water levels were higher and salinity was lower. Increases in abundance of these species in the estuarine area, all of which members of primary-division freshwater families, apparently were associated with pulses of reproduction and passive transport from freshwater habitats located near middle and upper lagoon reaches. Abundance of species from secondary freshwater families, such as poeciliids and cichlids, were less correlated with hydrological conditions, and their patterns of occurrence in the estuary suggest active migration from nearby freshwater habitats draining into this area. Findings indicate that freshwater discharge in the basin and expansion/retraction of freshwaters in the middle-upper lagoon determined patterns of freshwater fish abundance and species richness in the estuarine zone
- ItemBiodegradation of [d-leu1 ] microcystin-lr by a bacterium isolated from sediment of patos lagoon estuary, Brazil(2015) Lemes, Gilmar Antonio Farias; Kist, Luiza Wilges; Bogo, Maurício Reis; Yunes, João SarkisBackground: Toxic cyanobacterial blooms are recurrent in Patos Lagoon, in southern Brazil. Among cyanotoxins, [D-Leu1 ] microcystin-LR is the predominant variant whose natural cycle involves water and sediment compartments. This study aimed to identify and isolate from sediment a bacterial strain capable of growing on [D-Leu1 ] microcystin-LR. Sediment and water samples were collected at two distinct aquatic spots: close to the Oceanographic Museum (P1), in Rio Grande City, and on São Lourenço Beach (P2), in São Lourenço do Sul City, southern Brazil. Methods: [D-Leu1 ] microcystin-LR was isolated and purified from batch cultures of Microcystis aeruginosa strain RST9501. Samples of water and sediment from Rio Grande and São Lourenço do Sul were collected. Bacteria from the samples were allowed to grow in flasks containing solely [D-Leu1 ] microcystin-LR. This strain named DMSX was isolated on agar MSM with 8 g L−1 glucose and further purified on a cyanotoxin basis growth. Microcystin concentration was obtained by using the ELISA immunoassay for microcystins whereas bacterial count was performed by epifluorescence microscopy. The genus Pseudomonas was identified by DNA techniques. Results: Although several bacterial strains were isolated from the samples, only one, DMXS, was capable of growing on [D-Leu1 ] microcystin-LR. The phylogenetic analysis of the 16S rRNA gene from DMXS strain classified the organism as Pseudomonas aeruginosa. DMXS strain incubated with [D-Leu1 ] microcystin-LR lowered the amount of toxin from 1 μg.L−1 to < 0.05 μg.L−1 . Besides, an increase in the bacterial count–from 71 × 105 bacteria.mL−1 to 117 × 105 bacteria.mL−1 –was observed along the incubation. Conclusions: The use of bacteria isolated from sediment for technological applications to remove toxic compounds is viable. Studies have shown that sediment plays an important role as a source of bacteria capable of degrading cyanobacterial toxins. This is the first Brazilian report on a bacterium–of the genus Pseudomonas–that can degrade [D-Leu1 ] microcystin-LR, the most frequent microcystin variant in Brazilian freshwaters.
- ItemTrophic model of the outer continental shelf and upper slope demersal community of the southeastern Brazilian Bight(2012) Nascimento, Marcela Conceição do; Canziani, Gonzalo Velasco; Okey, Thomas A.; Christensen, Villy; Amaral, Antonia Cecília ZacagniniIt is increasingly recognized that demersal communities are important for the functioning of continental shelf and slope ecosystems around the world, including tropical regions. Demersal communities are most prominent in areas of high detritus production and transport, and they link benthic and pelagic biological communities. To understand the structure and role of the demersal community on the southeastern Brazilian Bight, we constructed a trophodynamic model with 37 functional groups to represent the demersal community of the outer continental shelf and upper slope of this area, using the Ecopath with Ecosim 6 (EwE) approach and software. The model indicates high production and biomass of detritus and benthic invertebrates, and strong linkages of these components to demersal and pelagic sub-webs. The level of omnivory indexes in this ecosystem was high, forming a highly connected trophic web reminiscent of tropical land areas. Although high levels of ascendency may indicate resistance and resilience to disturbance, recent and present fisheries trends are probably degrading the biological community and related ecosystem services.
- ItemDDT in biota of Paranaguá bay, southern Brazil: recent input and rapid degradation(2011) Liebezeit, Gerd; Brepohl, Daniela Christine; Rizzi, Juliane; Guebert, Flávia Maria; Krome, Mats; Machado, Eunice da Costa; Pijanowska, UrsulaDDT in Biota of Paranaguá Bay, Southern Brazil: Recent Input and Rapid Degradation Gerd Liebezeit &Daniela Brepohl &Juliane Rizzi & Flavia Guebert &Mats Krome &Eunice Machado & Ursula Pijanowska Received: 20 December 2010 /Accepted: 14 January 2011 /Published online: 1 February 2011 # Springer Science+Business Media B.V. 2011 Abstract The presence of recent dichlorodiphenyltri-chloroethane (DDT) inputs is established for Paranaguá Bay biota, i.e. bivalves, fish and one sponge. Values ranged from 6.9 to 156.2 ng ΣDDT/g dry weight. Three fish species analysed showed ΣDDT values from 36.8 to 92.1 ng/g dry weight. The highest contents (up to 156.2 ngΣDDT/g dry weight) were found for mangrove oysters (Crassostrea rhizophorae) at locations affected by sewage discharge from Para-naguá City. Turtles as herbivores were not affected by this input with values of 0.7 and 2.2 ngΣDDT/g dry weight. The areal distribution of samples suggests that usage of DDT is widespread around the bay. Fresh DDT input is degraded to DDE and DDD within approximately 5 months.
- ItemPopulation biology of shrimp Artemesia longinaris (Crustacea: Decapoda: Penaeidae) from the southern coast of Brazil(2010) Costa, Rogério Caetano da; Branco, Joaquim Olinto; Machado, Irecê Farina; Campos, Bruno Ribeiro de; Avila, Marcelo GentilSize at morphological sexual maturity, sex-ratio, and the seasonal variation in abundance of the shrimp Artemesia longinaris Bate, 1888 were assessed off Pinheira Beach, Palhoc¸a, Santa Catarina southern Brazil. Shrimp were collected monthly from November 2003 through to October 2004, in two areas that are customarily used by local traditional fishermen (278520 – 278510S and 488330 –488290W). Of the total of 1099 specimens measured, 23.93% were males and 76.07% females. Mean size at first maturity (LM50) was estimated as 56.38 mm total length (TL) for males, and 70.34 mm TL for females. Females were significantly larger than males. Abundance of juveniles varied seasonally. A high predominance of juveniles in the areas sampled occurred in winter for both sexes, and in spring for females. In the summer and autumn, we observed a decrease in juveniles in both areas, mainly, area II. We suggest that the differential migration pattern of sexes during the reproductive cycle was the principal reason for the larger catch of females. The classical paradigm of continuous reproduction at lower latitude, with increased seasonality of the breeding period at higher latitudes, seems to apply to this species.
- ItemThe use of oxygen isotopic ratios to identify natural and anthropogenic mercury concentrations in the Lower Brazilian Pantanal(2012) Windom, Herbert; Niencheski, Luis Felipe Hax; Wells, Debbie; Brandes, JayPrevious studies in the Amazon Basin and the Upper Pantanal show widespread mercury contamination of fish and water as a result of gold mining, and subsequent volatilization of mercury during the recovery process. A study was initiated to assess whether atmospheric transport of mercury to the south has resulted in elevated levels in water and fish in the Lower Pantanal. Water samples werecollected from streams and rivers from the Pantanal (Mato Grosso do Sul) down into the southernmost state of Brazil (Rio Grande do Sul) for total Hg concentration and oxygen isotopic analyses. Based on oxygen isotopes and conductivity, surface water samples can be considered as mixtures of three endmembers: groundwater, rain and ‘‘aged’’ surface water. Lowest concentrations (\2 ng/L) of total Hg were observed in the northernmost samples, especially those associated with the groundwater sources. Further south, Hg concentrations tended to increase, but higher concentrations ([2 ng/L) likely reflect direct input from more localized watershed sources. Fish collected from streams in the Pantanal had extremely low concentrations of total Hg regardless of their size or feeding habit, although one large carnivorous fish ([2 kg) had concentrations approaching 400 ng/g wet wt. All concentrations, however, were considerably lower than those observed in similar species from the region of the Amazon Basin affected by gold mining.