Aspectos limnológicos do lago Grande do Jutaí (Amazônia Central), face as alterações químicas do meio hídrico da região ()

Santos, Umberto de Menezes

doi:10.1590/1809-43921980104797

Cited by 8 publications

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“…The highest alkalinity recorded was in the low-water period in Lake Cujubim, which may be the result of the contribution of mineral salts from the waters of the Madeira River during the flood period, due to the presence of bicarbonates, carbonates and hydroxides present in the aquatic environment (Leira et al, 2017). When the water level decreases in periods of drought, there is an increase in the concentration of salts, according to the chemical alterations cited by Santos (1980).…”

Section: Resultsmentioning

confidence: 97%

Support capacity of a floodplain lake for intensive fish production (Rondônia, Brazil)

et al. 2023

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The Amazon Basin stands out mainly for its large floodplain’s areas, which during the period of high water become important environments for the maintenance of the life cycle of many fish species. These floodplains act as a source of food and an area for growth and reproduction for the fish assemblages. However, there are few studies on the use of floodplain lakes for breeding fish in confinement. Therefore, we analyzed the support capacity and environmental parameters of Lake Cujubim, in the Madeira River Basin, regarding its use for the implementation of intensive fish farming (net tank system). From 2019 to 2020, bathymetric profiles and limnological data were collected, considering the seasonality of the water level and the shape of the Lake Cujubim. The bathymetry data were primarily used to verify the parameters of depth, area and volume of the lake, while limnological data contributed to statistical analyses for the evaluation of health status and support capacity of the lake for fish farming in an intensive production system. The data collected from the limnological analyses and the depth and profile indicate that Lake Cujubim is suitable for the cultivation of fish, and has an estimated support capacity for an annual production of up to 468.31 tonnes of fish. Herein, we propose a viable alternative for the social and productive development of intensive fish farming in an area of floodplain lake in the state of Rondônia, Brazil. Keywords: Amazon basin, net tanks, pisciculture.

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Section: Resultsmentioning

confidence: 97%

Support capacity of a floodplain lake for intensive fish production (Rondônia, Brazil)

et al. 2023

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Fisheries ecololgy and management of the Jaraqui (Semaprochilodus Taeniurus, S. Insignis) in central Amazonia

Ribeiro

Petrere

1990

Regul. Rivers: Res. Mgmt.

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The decline of heavily exploited stocks of large, high quality, food fishes in central Amazonia has led to increasing fishing pressure on smaller taxa, especially the jaraqui (Semiprochilodus spp.). The Prochilodontids, now the most important species to the fisheries, are seined by commercial fishermen during three distinct periods. At the beginning of the annual floods, schools of mature jaraquis in poor-water tributaries migrate downstream to spawn in the nutrient rich whitewater rivers. During these rapid spawning runs, fishing effort is concentrated in the lowermost reaches of the tributaries. After spawning, they return in small groups to feed intensively in the flooded forest of the same tributaries from which they had migrated. This period, of approximately three months, may be considered as a natural closed season to the fisheries. The dispersal migration is most complex and requires distinct fishing strategies. In the middle of the floods large schools of fat jaraqui descend from the tributaries to the white-water rivers again. From there, they move upstream to different poor-water tributaries. As downstream movements are more difficult to observe, fishermen remain at fixed fishing grounds. This contrasts with the dynamic strategies of the subsequent upstream fishing period which contributes 60 per cent of the annual catches.Fluctuations in catch are shown to reflect year to year variations in abundance, which are linked to the hydrological cycle. Considering that fishing intensity over the stocks of jaraqui has already more than compensated for the deficit in catch of larger species, a combination of increased effort and environmental problems could lead, in a short period to a depletion of one of the most profitable fisheries of central Amazonia. Regulation of the fisheries could benefit from a more reasonable distribution of effort among other migratory illiophagous species which remain unexploited, if the goal of sustainable yield and conservation of these stocks is to be achieved. Reserved waters in large strategic units of at least 300 km along white-water rivers (which is equivalent to the maximum upstream displacement of jaraqui during their dispersal migrations) could also be useful to compensate for the loss of floodplain areas due to deforestation, river regulation, use of pesticides, and mining. River impoundments in tributaries in central Amazonia may have little effect on jaraqui stocks, as spawning movements are unlikely to be directly interrupted by dams. However, alterations of the hydrological regime may also benefit from simulation of the flood cycle to mitigate potential negative impacts.

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Ecology of the várzea, floodplain of Amazonian whitewater rivers

Junk¹

1984

The Amazon

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Aspectos limnológicos do lago Grande do Jutaí (Amazônia Central), face as alterações químicas do meio hídrico da região ()

Cited by 8 publications

References 0 publications

Support capacity of a floodplain lake for intensive fish production (Rondônia, Brazil)

Support capacity of a floodplain lake for intensive fish production (Rondônia, Brazil)

Fisheries ecololgy and management of the Jaraqui (Semaprochilodus Taeniurus, S. Insignis) in central Amazonia

Ecology of the várzea, floodplain of Amazonian whitewater rivers

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