scholarly journals HYDROELECTRIC DAMS FROM MADEIRA RIVER SEASONALLY IMPACTS THE FISHERIES PRODUCTION IN THE GUAPORÉ BASIN (RONDÔNIA, BRAZIL)

2021 ◽  
Vol 46 (4) ◽  
pp. 1-11
Author(s):  
Helen Cristina PARAZZI de Freitas ◽  
Carolina Rodrigues da Costa DORIA ◽  
Raniere Garcez Costa SOUSA
Keyword(s):  
Fish Species ◽  
Cultural Context ◽  
Hydrological Cycle ◽  
Water Levels ◽  
Fish Production ◽  
Hydroelectric Dams ◽  
Fish Stocks ◽  
Production Values ◽  
Before And After ◽  
Madeira River

In the Amazon region, fisheries play an important role in the socioeconomic and cultural context and are directly affected by changes in the hydrological cycle, which can interfere with the numbers and frequency of fish species landed. This study analyzed the variation of fishery production against the seasonality of the water level of the Guaporé River (a tributary of the Madeira River) using information contained in the records of fishery landings in the area under study. In addition, two periods pre (2000 to 2008) and post (2009 to 2019) installation of the Jirau and Santo Antônio dams in the Madeira River were considered. Fish production in the period prior to damming indicated linearity (r2 = 0.41) which was inversely proportional to the water levels of the Guaporé River, with low fish production in the flood and high production during the low water phases. However, for the period after damming, these variables showed low correlation (r2 = 0.14). Among the fish species exploited, 35.13% presented significant differences (p <0.05) between the production values for the periods before and after installation of the dams. Therefore, the results showed significant differences between the values of fishery production by species and phases of the hydrological cycle of the Guaporé River, which occurred in the periods pre and post damming of the Madeira River, which indicates that the hydroelectric dams have negatively impacted the fish stocks of this region. The information contained in this study is useful and serves as a basis for coherent decision-making, since it aids in the sustainable management and monitoring of fish stocks in the Madeira River Basin.

scholarly journals A description of mercury in fishes from the Madeira River Basin, Amazon, Brazil

2008 ◽  
Vol 38 (3) ◽  
pp. 431-438 ◽  
Author(s):  
Wanderley Rodrigues Bastos ◽  
Mauro de Freitas Rebelo ◽  
Márlon de Freitas Fonseca ◽  
Ronaldo de Almeida ◽  
Olaf Malm
Keyword(s):  
Body Weight ◽  
River Basin ◽  
Fish Species ◽  
Temporal Trends ◽  
Migratory Fish ◽  
Madeira River ◽  
Interspecies Variability ◽  
Total Hg ◽  
Madeira River Basin ◽  
Hg Accumulation

Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.

scholarly journals Transient flow between aquifers and surface water: analytically derived field-scale hydraulic heads and fluxes

2012 ◽  
Vol 16 (3) ◽  
pp. 649-669 ◽  
Author(s):  
G. H. de Rooij
Keyword(s):  
Surface Water ◽  
Transient Flow ◽  
Hydrological Cycle ◽  
Realistic Model ◽  
Water Levels ◽  
Subsurface Water ◽  
Water Model ◽  
Infinite Strip ◽  
Catchment Scale ◽  
Basin Scale

Abstract. The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.

scholarly journals KEANEKARAGAMAN DAN KEKERABATAN IKAN FAMILI CYPRINIDAE PADA EKOSISTEM BENDUNGAN COLO SUKOHARJO JAWA TENGAH

2018 ◽  
Vol 14 (2) ◽  
pp. 137
Author(s):  
Ragil Nur Cahyono ◽  
Agung Budiharjo ◽  
Sugiyarto Sugiyarto
Keyword(s):  
Fish Species ◽  
Diversity Index ◽  
Abiotic Factors ◽  
Morphological Characters ◽  
Cluster Method ◽  
Fish Diversity ◽  
Abiotic Factor ◽  
Fish Family ◽  
Water Ecosystem ◽  
Before And After

The Cyprinidae fish family is a family of freshwater fish with the largest number of species and its presence is widespread almost all of the world. The main habitat of this family is the river's ecosystem, river damming changing the environmental conditions between the ecosystems before and after the dam's watergate. Such as Colo Dam that dammed Bengawan Solo River that allegedly affects the diversity of species of Cyprinidae fish. So this study was conducted in order to determine the diversity and kinship of the Cyprinidae fish family in the ecosystem before and after the Colo Dam watergate. Sampling was conducted September-October 2017 at Sukoharjo Colo Dam by Purposive sampling method. Identify fish species used Kottelat identification books. The diversity of fish species was calculated by Shannon Wiener's diversity index. The correlation between abiotic factor and fish diversity was analyzed by a regression test. The kinship of the fish was analyzed by the Ntsys cluster method (2.02i). The results showed that the Cyprinidae fish species that live in the Colo Dam ecosystem contain 10 species, the diversity of Cyprinidae fish in the fast-water ecosystem of station I is higher (0,96) then the slow-water ecosystem of station II, III, and IV (0,47; 0,73, and 0,58). Abiotic factors of current velocity affect the level of fish diversity reaches 91%. The Cyprinidae fish kinship rate has a coefficient of resemblance between 60% - 85%, fish with the same genus and many similarities in morphological characters and their behavior is categorized as having a close kinship.

scholarly journals Fish, Marmelos Conservation Area (BX044), Madeira River basin, states of Amazonas and Rondônia, Brazil

Check List ◽  
2007 ◽  
Vol 3 (4) ◽  
pp. 291 ◽  
Author(s):  
Mauricio Camargo ◽  
Tommaso Giarrizzo
Keyword(s):  
River Basin ◽  
Fish Species ◽  
Ecological Assessment ◽  
Aquatic System ◽  
Species List ◽  
Conservation Area ◽  
Madeira River ◽  
Northern Brazil ◽  
Rapid Ecological Assessment ◽  
Madeira River Basin

The present study provides a species list of fish from the Marmelos River Area – BX044 in the states of Amazonas and Rondônia in northern Brazil. During a Rapid Ecological Assessment (REA) performed in October and November of 2003, 133 fish species from six orders and 24 families were recorded. The most diverse families were Characidae (47 species), Cichlidae (15 species), Loricariidae (12 species) and Pimelodidae (7 species). 23 fish species were common to the entire river basin and 4 were endemic to the aquatic system studied.

scholarly journals An assessment of the factors determining rotifer assemblage in river-lake systems: the effects of seasonality and habitat

2019 ◽  
Vol 36 ◽  
pp. 1-5
Author(s):  
Moacyr Serafim-Júnior ◽  
Gilmar Perbiche-Neves ◽  
Fabio Lansac-Toha
Keyword(s):  
Species Richness ◽  
Aquatic Macrophytes ◽  
Hydrological Cycle ◽  
High Water ◽  
Water Levels ◽  
Natural Environments ◽  
Ecological Attributes ◽  
Lake System ◽  
The Mean ◽  
Lake Systems

Zooplankton exhibit several trends of variation in space and time, and these trends can be more evident in natural environments without anthropic perturbations. Examples of anthropic factors are climate change, eutrophication and construction of reservoirs. This study evaluated the influence of three factors – seasonality, type of environment and the presence of aquatic macrophytes – on various ecological attributes of rotifers in a river-lake system located in the Paraná River floodplain. Monthly samplings were conducted during 1993 and 1994. The mean species richness per sample was 60 species. The seasonality and the type of environment influenced the ecological attributes of rotifer assemblages, while the presence or absence of aquatic macrophytes did not. Species richness was highest in the lake system and during the months when water levels were low. Multivariate analysis indicates a small group of species associated with the low water-level phase. In contrast, many species were associated with high water levels or increasing water levels. The seasonal variation of hydrological cycle and the type of environment are the most important factors for rotifer structure in natural conditions.

scholarly journals Opportunity for marine fisheries reform in China

2017 ◽  
Vol 114 (3) ◽  
pp. 435-442 ◽  
Author(s):  
Ling Cao ◽  
Yong Chen ◽  
Shuanglin Dong ◽  
Arthur Hanson ◽  
Bo Huang ◽  
...  
Keyword(s):  
Resource Management ◽  
Fisheries Management ◽  
Cultural Context ◽  
Scientific Data ◽  
Coastal Development ◽  
Chinese Government ◽  
Marine Fisheries ◽  
Marine Resource ◽  
Fish Stocks ◽  
Marine Resource Management

China’s 13th Five-Year Plan, launched in March 2016, provides a sound policy platform for the protection of marine ecosystems and the restoration of capture fisheries within China’s exclusive economic zone. What distinguishes China among many other countries striving for marine fisheries reform is its size—accounting for almost one-fifth of global catch volume—and the unique cultural context of its economic and resource management. In this paper, we trace the history of Chinese government priorities, policies, and outcomes related to marine fisheries since the 1978 Economic Reform, and examine how the current leadership’s agenda for “ecological civilization” could successfully transform marine resource management in the coming years. We show how China, like many other countries, has experienced a decline in the average trophic level of its capture fisheries during the past few decades, and how its policy design, implementation, and enforcement have influenced the status of its wild fish stocks. To reverse the trend in declining fish stocks, the government is introducing a series of new programs for sustainable fisheries and aquaculture, with greater traceability and accountability in marine resource management and area controls on coastal development. As impressive as these new plans are on paper, we conclude that serious institutional reforms will be needed to achieve a true paradigm shift in marine fisheries management in China. In particular, we recommend new institutions for science-based fisheries management, secure fishing access, policy consistency across provinces, educational programs for fisheries managers, and increasing public access to scientific data.

Management of evolving fish stocks

1998 ◽  
Vol 55 (8) ◽  
pp. 1971-1982 ◽  
Author(s):  
Mikko Heino
Keyword(s):  
Maximum Sustainable Yield ◽  
Evolutionary Change ◽  
Fish Stock ◽  
Sustainable Yield ◽  
Harvest Rate ◽  
Fish Stocks ◽  
Population Dynamics Model ◽  
Before And After ◽  
Age Structured ◽  
Delayed Maturation

Mortality caused by harvesting can select for life history changes in the harvested stock. Should this possibility be taken into account in the management of renewable resources? I compare the performance of different harvest strategies when evolutionary change is accounted for with the help of an age-structured population dynamics model. Assuming that age of first reproduction is the only evolving trait, harvesting of only mature individuals selects for delayed maturation and results in increased sustainable yields. Unselective harvesting of both mature and immature fish selects for earlier maturation which causes the sustainable yield to decrease. Constant stock size and constant harvest rate strategies perform equally well in terms of maximum sustainable yield, both before and after evolutionary change. The maximum sustainable yield for fixed-quota strategies is lower. All those strategies have similar evolutionary consequences given a similar average harvest rate. Coevolutionary dynamics between fish stock and the stock manager indicate that the evolutionary benefits of selective harvesting are attainable without incurring yield losses in the near future.

Change in the rocky reef fish fauna of the iconic Poor Knights Islands Marine Reserve in north-eastern New Zealand over 4 decades

2018 ◽  
Vol 69 (10) ◽  
pp. 1496
Author(s):  
David R. Schiel ◽  
Tony Ayling ◽  
Michael J. Kingsford ◽  
Christopher N. Battershill ◽  
J. Howard Choat ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Species ◽  
Marine Reserve ◽  
Fish Fauna ◽  
Rocky Reef ◽  
Long Term Effects ◽  
Before And After ◽  
Negative Effect ◽  
Reef Fish Species

Marine reserves exhibit increases in targeted fish species, but long-term effects on biodiversity are poorly understood. Factors other than reserve status may affect decadal changes, including environmental change. We examined the fish fauna at the iconic Poor Knights Islands over 4 decades (1974–2016) before and after implementation of a no-take marine reserve in 1998. We document a substantial increase in commercially and recreationally targeted Chrysophrys auratus, which was virtually absent before 1994 but by 2016 had reached up to 11 fish per 500m2 (220 per hectare). There were also large changes to the fish community, including the decline of subtropical and coastal wrasses, some species with no change and others that increased significantly. Many declines occurred >20 years before the arrival of abundant C. auratus, suggesting the changes do not represent a trophic cascade. Furthermore, this normally benthic-feeding fish has adopted a mid-water foraging behaviour targeting planktivorous fish. The increase in C. auratus appears to be linked both to reserve status and catch regulations in the wider region. Overall, the data point to long-term environmental fluctuations from the late 1970s having a negative effect on the abundance of more than half the reef fish species at these islands.

scholarly journals Assessment of the Role of Snowmelt in a Flood Event in a Gauged Catchment

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 506 ◽  
Author(s):  
Jesús Mateo-Lázaro ◽  
Jorge Castillo-Mateo ◽  
José Sánchez-Navarro ◽  
Víctor Fuertes-Rodríguez ◽  
Alejandro García-Gil ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Digital Terrain Model ◽  
Terrain Model ◽  
Rain Gauges ◽  
Digital Terrain ◽  
Before And After ◽  
Thawing Process ◽  
Rainfall Model

An actual event that happened in the Roncal valley (Spain) is investigated and the results are compared between models with and without snowmelt. A distributed rainfall model is generated with the specific data recorded by the rain gauges of the catchment during the episode. To describe the process of water routing in the hydrological cycle of the basin, a model is used based on combinations of parallel linear reservoirs (PLR model), distribution by the basin, and tip-out into its drainage network configured using a digital terrain model (DTM). This PLR model allows simulation of the different actual reservoirs of the basin, including the snow and the contribution due to its melting which, in the model, depends on the temperature. The PLR model also allows for a water budget of the episode where, in addition to the effective rainfall contribution, the water that comes from the thaw is taken into account. The PLR model also allows determination of the amount of water that exists in the basin before and after the episode, data of great interest. When comparing the simulations with and without taking into account the thawing process, it is evident that the intervention of the snow reservoir has been decisive in causing a flood to occur.

Structure and ecological production of the fish taxocene of a small floodplain system

1983 ◽  
Vol 61 (11) ◽  
pp. 2446-2464 ◽  
Author(s):  
Lawrence C. Halyk ◽  
Eugene K. Balon
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Local Extinction ◽  
Total Production ◽  
Fish Production ◽  
Resource Potential ◽  
Annulus Formation ◽  
Total Fish ◽  
Stream Pool ◽  
Pool Area

Fish species richness in floodplain pools results from species addition by spring invasion from the stream and species subtraction by local extinction throughout the summer. Local extinction is the more important of the two components. Nineteen floodplain pools (1 to 597 m2) and an adjacent section of Irvine Creek (43°44′ N, 80°25′ W), Ontario, Canada, were treated with a piscicide to test if the pools contribute significantly to the resource potential of the river basin. Altogether, 41 626 fishes of 20 species were collected. Number of days of stream connection in the spring was not significantly correlated with fish species richness in the pools (P < 0.10). A significant correlation (P < 0.05, r = 0.7413) was found between species richness and the logarithm of pool area. The total fish production for the Irvine Creek section, adjusted to account for dominant and nondominant species, was 298 kg∙ha−∙year−1. Production for this site was underestimated by 49% when weights and densities were backcalculated to time of annulus formation. Total production estimates of the floodplain pools ranged from 135 to 314 kg∙ha−1∙year−1. Stream connection duration affects pool fish production by regulating accessibility to the young of stream spawning species. Floodplain pools are beneficial to the Irvine Creek system. As nursery areas, floodplain pools produce fish biomass which can return to the stream during periods of stream–pool connection. These pools may also act as fish havens if catastrophic stream mortality occurs.

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