Carolina Rodrigues da Costa Doria

A pesca comercial na bacia do rio Madeira no estado de Rondônia, Amazônia brasileira

abstRact This study presents qualitative and quantitative information about commercial fishery in the basin of the Madeira River, tributary of the amazon River, describing the fishing activity in the segment between Guajara-Mirim and Porto Velho, in Rondonia State. from january to December/2004, 219 fishermen and 935 trips were registered, corresponding to the capture of 460 t of fish. Data from fish landings demonstrate that fisheries in the region are small-scaled and point to a higher participation of small motorized canoes (130 units) than of fishing boats (45 units; average capacity: 3000 kg) in the fishing fleet. Migratory species like jaraqui ( Semaprochilodus spp.), dourada ( Brachyplatystoma rousseauxii ), sardinha ( Triportheus spp.), jatuarana/matrinxa ( Brycon amazonicus e B. cephalus) , curimata ( Prochilodus nigricans ) and filhote ( Brachyplatystoma filamentosum ) were the most important in terms of landings. The technical information produced are very important in order to subsidize fishery management, as well as to assess future variations that might happen due to the hydro-electric enterprises under construction in the region.

Avaliação espermática pós-descongelamento em tambaqui, Colossoma macropomum (Cuvier, 1818)

This work tests freezing procedures of tambaqui, Colossoma macropomum, and efficiency in egg fertilizing. Sperm of a hormonally induced reproducer was collected and stored in assay pipes. The material was diluted in cryoprotectant solutions (dimetilacetamida [DMA], dimetilsulfoxido [DMSO], metanol, propilenoglicol e etilenoglicol) (1:3 ratio: sperm:diluting), and subjected to routine freezing procedures. The motility was evaluated before and after this procedure. Fertilization tests were made with cryopreserved sperm. The motility was evaluated before and after these tests. Fertilization tests were made with the cryopreserved semen. The pre-freezing motility was 80%, and after freezing, it was 20-25% for propilenoglicol and etilenoglicol, 5-10% for DMSO and 5% for DMA and methanol. The fertilization was 76% and 88% for propilenoglicol and etilenoglicol, respectively.

Temporal and spatial distribution of young Brachyplatystoma spp. (Siluriformes: Pimelodidae) along the rapids stretch of the Madeira River (Brazil) before the construction of two hydroelectric dams

Monthly (April 2009 to May 2010) bottom-trawl sampling for Brachyplatystoma species along the rapids stretch of the Madeira River in Brazil revealed that Brachyplatystoma rousseauxii larvae and juveniles were present in low abundances in all areas and during all hydrological periods. The presence of larvae and juveniles throughout the hydrological cycle suggests asynchronous spawning in the headwaters of the Madeira River.

Mercury in muscle and brain of catfish from the Madeira river, Amazon, Brazil.

The central nervous system is a critical target for Hg toxicity in all living organisms. Total Hg (THg) was determined in brain and muscle samples of 165 specimens of eight species of catfish (Brachyplatystoma filamentosum; Brachyplatystoma platynemum; Brachyplatystoma rousseauxii; Brachyplatystoma vaillantii; Phractocephalus hemiliopterus; Pseudoplatystoma punctifer; Pseudoplatystoma tigrinum; Zungaro zungaro) from the Madeira River, Brazilian Amazon. Despite the narrow range of Fishbase trophic level (4.2-4.6) the median THg concentrations ranged from 0.39 to 1.99mg/kg and from 0.03 to 0.29mg/kg respectively in muscle and brain from the studied species. Overall, the median concentration for all samples analyzed was 0.93mg/kg and 0.16mg/kg respectively in muscle and brain; most samples (76%) showed muscle Hg concentrations >0.5mg/kg. There were statistically significant THg differences between sex (female>males). The correlation between THg concentrations in muscle and brain was statistically significant (r=0.9170; p<0.0001). In the studied specimens, fish total length was significantly correlated with muscle (r=0.3163; p=0.0001) and brain (r=0.3039; p=0.0003) THg; however, fish age was negatively and significantly correlated (r=-0.2991; p=0.0012) with THg in muscle but not with THg in brain (r=-0.0190; p=0.8492). Amazonian catfish accumulate high levels of Hg in muscle and brain; however, brain-THg concentrations can be predicted from muscle-THg. Muscle-Hg in catfish can be a tool to detect brain-Hg concentrations associated with environmental Hg.

Fishes of Cuniã Lake, Madeira River Basin, Brazil

This study presents an inventory of the ichthyofauna of Cunia Lake, situated in the floodplain of the Madeira River in Rondonia State, Brazil. A total of 11,949 specimens representing eight orders, 34 families, and 189 species were sampled with gill, seine, and hand nets during the dry and wet seasons between 2008 and 2012. Most of the species recorded in Cunia Lake are commonly found in other locations in the central Amazonian floodplains, although some are rare in collections (e.g. Acestrorhynchus minimus , Triportheus culter , Oxybrycon parvulus , Tyttocharax madeirae , Trachycorystes trachycorystes and Scorpiodoras lyophisus ) or represent new distributional records.

Pescarias artesanais em comunidades ribeirinhas na amazônia brasileira: perfil socioeconômico, conflitos e cenário da atividade

Las comunidades tradicionales localizadas al margen del Rio Madeira son influenciadas por su estrecha relacion con la naturaleza y um conocimiento profundo de sus ciclos. El pescado es uno de los principales recursos explotados para la subsistencia y la comercializacion. Esta investigacion analizo el perfil socio-economico y la actividad pesquera de dos comunidades riberenas del medio rio Madeira, Sao Carlos e Calama. Fueron realizadas 189 entrevistas con cuestionarios semi-estructurados en familias de pescadores de estas comunidades, entre abril y agosto de 2009. Las preguntas incluyeron el numero de pescadores por familia, la escolaridad, edad, tempo que actua en la pesca asociativismo, forma de comercializacion, actividades complementares e ingreso mensual por actividad productiva. A traves de reuniones colectivas con los pescadores se levantaron informaciones sobre el Conocimiento Ecologico Local (CEL) de las especies y del ambiente, conflictos pesqueros y escenarios actuales. Los resultados indicaron que los pescadores de estas localidades tiene una edad promedio de 39 anos y ejercen la actividad hace mas de 20 anos y que mas de 60% no han concluido el curso primario. Los principales conflictos estan relacionados con la fiscalizacion considerada inadecuada y la falta de area de pesca. La construccion de mapas de escenarios reflejo la expectativa de aumento de los conflictos atribuyendo la reduccion de las areas de pesca e todavia posibles migraciones de pescadores dislocados relocalizados por la construccion de las presas hidroelectricas Jirau e Santo Antonio. El conocimiento generado constituye un marco cero sobre aspectos sociales que incluye la practica pesquera y que podra subsidiar la gestion de los recursos pesqueros para garantir la sostenibilidad.

Temporal fish community responses to two cascade run‐of‐river dams in the Madeira River, Amazon basin

We examined responses from shore fish assemblages and bottom channel fish assemblages before and after two cascade run-of-river dams in the Madeira River, in the Amazon. Those dams were installed in a river corridor where historical factors, represented by the presence of the Teotonio and Jirau falls, were the best predictors of the fish fauna assemblage composition. Jirau and Santo Antonio were the first dams constructed with Kaplan horizontal bulb turbines in the Amazon. These bulb turbines have the ability to operate by forming small reservoirs known as run-of-river, which should minimize impacts on fish assemblages. Overall, there were major short-term impacts in shore fish assemblages by increasing species richness, abundance and biomass in experimental catches. Shore fish assemblages dissimilarities before and after the dams’ closure were also noticed and were related to an increase in water temperature and dissolved oxygen. However, the historical factor represented by Teotonio Fall is still the best predictor of fish assemblage dissimilarities, combined with effects of dams’ closure. Bottom channel fish assemblage dissimilarities can be explained only by dams closure and are related especially to changes in fish species abundance inside the reservoirs. Our study revealed an increase in native opportunistic fish species and changes in fish assemblage structure at local scale. Kaplan horizontal bulb turbines employed in run-of-river dams seem to be less deleterious than vertical axis turbines typically used in accumulation reservoirs, and should be preferred in the face of burgeoning new hydroelectricity development plans for rivers across the Amazon basin.

The invisibility of fisheries in the process of hydropower development across the Amazon

We analyze the invisibility of fisheries and inadequacy of fishers’ participation in the process of hydropower development in the Amazon, focusing on gaps between legally mandated and actual outcomes. Using Ostrom’s institutional design principles for assessing common-pool resource management, we selected five case studies from Brazilian Amazonian watersheds to conduct an exploratory comparative case-study analysis. We identify similar problems across basins, including deficiencies in the dam licensing process; critical data gaps; inadequate stakeholder participation; violation of human rights; neglect of fishers’ knowledge; lack of organization and representation by fishers’ groups; and lack of governmental structure and capacity to manage dam construction activities or support fishers after dam construction. Fishers have generally been marginalized or excluded from decision-making regarding planning, construction, mitigation, compensation, and monitoring of the social–ecological impacts of hydroelectric dams. Addressing these deficiencies will require concerted investments and efforts by dam developers, government agencies and civil society, and the promotion of inter-sectorial dialogue and cross-scale participatory planning and decision-making that includes fishers and their associations.

Review of Fisheries Resource Use and Status in the Madeira River Basin (Brazil, Bolivia, and Peru) Before Hydroelectric Dam Completion

ABSTRACT The Madeira River, which drains one of the major tributary river basins of the upper Amazon, contributes to small-scale fisheries in Peru, Bolivia, and Brazil. This paper provides a base-line of fisheries resources and their status in six sub-basins of the Madeira River: upper Madre de Dios River basin (Peru), Beni and Mamoré River basins (Bolivia), Iténez or Guaporé River basin (Bolivia and Brazil), middle Madeira, and (two sections of the) lower Madeira River (Brazil). Data were collected between 2009 and 2011, before the completion of two hydroelectric dams in the Brazilian portion of the basin. Biophysical, social, and biological indicators were used to characterize the fisheries. The results show an overall small-scale multispecies fisheries pattern but with notorious differences between the Madeira sub-basins. The Beni and Mamoré sub-basin shows the largest flooded area, with associated higher total fisheries yields. Trophic level of the catch, diversity, and mean weight of fish caught were shown to be very sensitive to exploitation level, river water type (white or clear water), flooded area, and the introduction of Arapaima gigas in Bolivia. The Bolivian fisheries are characterized by less exploited stocks, whereas stocks in Peru and Brazil show signs of intensive exploitation, resulting in fisheries of smaller bodied, lower trophic-level species. Landing data in the upper basin show a predominant reliance on migrating fish resources, which might be vulnerable to the construction of dams. These data serve as a baseline to evaluate anthropogenic impacts on the Madeira River basin fisheries in the future.

Age and growth of the Amazonian migratory catfish Brachyplatystoma rousseauxii in the Madeira River basin before the construction of dams

The goliath catfish Brachyplatystoma rousseauxii has crucial economical and ecological functions in the Amazon basin. Although its life history characteristics have been studied in the Amazon, there is little information in the Madeira River basin, which holds genetically distinct populations and where dams were recently built. Using fish collected in Bolivia, Brazil and Peru, this study provides a validation of growth rings deposition and details the growth patterns of B. rousseauxii in the Madeira before the dams’ construction. Age structure and growth parameters were determined from 497 otolith readings. The species exhibits two growth rings per year and sampled fish were between 0 and 16 years old. In the Brazilian portion of the basin, mainly young individuals below 5 years old were found, whereas older fish (> 5 years) were caught only in the Bolivian and Peruvian stretches, indicating that after migrating upstream to reproduce, adults remain in the headwaters of the Madeira River. Comparing with previous publications, B. rousseauxii had a slower growth and 20 cm lower maximum standard length in the Madeira River than in the Amazon River. This study provides a baseline for future evaluation of changes in population dynamics of the species following dams closure.