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EFEITO DA CONSTRUÇÃO DA RODOVIA PA-458 SOBRE AS FLORESTAS DE MANGUE DA PENÍNSULA BRAGANTINA, BRAGANÇA, PARÁ, BRASIL
Abstract and Figures
The PA-458 highway construction caused severe impact on mangrove Forest in the Ajuruteua peninsula, Bragança-PA, mainly at the Km 17. In order to better understand the effect of the highway construction on mangrove forest, it was undertaken a phytographic profile and a study on the structure of mangrove stands under three different levels of environmental destruction: Degraded Area (DA), Semi-Degraded Area (SDA), and Non-Degraded Area (NDA). Considering the three levels of destruction, mangrove stands comprise trees from 3 to 9 m of height, describing a gradient from the most impacted area till the non-impacted one, whereas values of mean DBH of these trees range from 4.2 to 10 cm. The trees dominance and density showed significant differences between the three different levels of impact (ANOVA, F=13.30; df=15; p
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... A number of authors believe that unmanaged logging in mangrove forests may cause considerable alterations to the composition of these ecosystems or even their total elimination from some areas [4]- [7]. In Brazil, the exploitation of these systems has involved even more drastic impacts, such as the installation of shrimp farms at many locations in the northeast of the country [8], deforestation and lumbering in the southeast [9], and the construction of highways in the extreme north [10]. ...
... The region's growing human population has been the primary factor determining the ongoing degradation of the mangrove forests of the Brazilian Amazon region [10]. Given this, the present study investigated the viability of the production of seedlings of the three principal local mangrove species-Rhizophora mangle L., Avicennia germinans (L.) L., and Laguncularia racemosa (L.) C.F. Gaertn.-focusing in particular on the effects of different types of soil on the growth and survival of seedlings, and the potential of this procedure for the restoration of degraded mangrove forests on the Brazilian Amazon coast. ...
... mangle, A. germinans, and L. racemosa-dominate the landscape, while Avicennia schaueriana Stapf and Leechman ex Moldenke is more sparsely distributed. It is important to note that the construction in the 1970s of the PA-458 state highway, which connects Bragança to the village of Ajuruteua, bisected 26 km of the local mangrove forest [10], and impacted an area of 3.8 km 2 of this ecosystem [19]. These authors concluded that he primary source of this impact was the obstruction of the tidal creeks on the east of the peninsula, that drain into the Caeté River. ...
The present study investigated the growth and survival of seedlings of Rhizophora, Avicennia, and Laguncularia raised in three different substrates: mangrove soil, latosol, and sand. The study was based on an entirely random factorial design (3 × 3) × 3, with three tree species, three substrates, and three replicates. The experiment was conducted in a nursery installed in the municipality of Bragança, in the northern Brazilian state of Pará. The seedlings were grown in 17 cm × 27 cm po-lyethylene containers. Survival was calculated based on the percentage of germinated propagules surviving after 270 days. Seedling heights were evaluated using an analysis of variance (ANOVA) and morphological parameters were compared using Tukey's test. All three species were ready for replanting after 270 days. The R. mangle and A. germinans seedlings presented better rates of survival and growth on the substrates tested. All three species grew well in the substrates tested, and the production of seedlings in yellow latosol would appear to be the most effective approach.
... Here, we considered land use as all human activities recorded within the mangrove, including the adjacent areas of salt flat (known as the "apicum" in Brazilian Portuguese), such as deforestation, roads, urban expansion, ports, salt works, aquaculture, and degradation. The term degradation herein refers to altered mangrove areas, with dead trees and few remaining individuals that still resist the dry and hypersaline soil exposed to high solar radiation [64]. We selected nine anthropogenic drivers, which are expressed by factors associated with anthropogenic features including human population density, urbanization, infrastructure, and their location in relation to the mangrove that have a direct and/or indirect influence on mangrove land use ( Table 1). ...
... This 26 kmlong highway was constructed in the 1970s, creating a linear corridor of disturbance that interrupts the flow of water and has caused the degradation of 6 km 2 of Avicennia forest on the left side of the road [81]. While covering only a small area, this feature is considered to represent the principal impact on the mangrove of the Brazilian Amazon coast [64]. A more general analysis also reinforces the conclusion that paved roads have the most negative impacts on the mangrove [52]. ...
Mangroves play an essential ecological role in the maintenance of the coastal zone and are extremely important for the socioeconomics of coastal communities. However, mangrove ecosystems are impacted by a range of anthropogenic pressures, and the loss of this habitat can be attributed primarily to the human occupation of the coastal zone. In the present study, we analyzed the spatial patterns of land use in the mangrove of the Brazilian Amazon coast, and evaluated the anthropogenic drivers of this impact, using a remote sensing approach. We mapped the road network using RapidEye images, and human settlements using global data. The results of these analyses indicate that the Brazilian Amazon coast has a low population density and low rates of anthropogenic impact in most of the coastal microregions investigated, factors that contribute to the maintenance and conservation of the region's mangrove. The study also revealed that the paved road network is one of the principal drivers of land use in the mangrove, whereas other factors, such as population density, urban centers, and the number of settlements are much less important. While the region has 2024 km of paved highways, unpaved roads (17,496 km) facilitate access to the mangrove, with approximately 90% of anthropogenic impact being recorded within a 3 km radius of these roads. While the network of paved highways is relatively reduced in extension, preventive measures are urgently required to impede any major shift in the current scenario, caused by the expansion of major development programs. The results of the study indicate that biophysical, economic, and political factors may also contribute to the reduction, stability, and development of one of the world's largest areas of mangrove forest.
... O problema é que, no meio do caminho, havia um mangue. O município de Bragança está inserido na região que detém uma das maiores reservas de manguezais do mundo (Fernandes, 2003) nas latitudes próximas à linha do Equador, litoral amazônico, entre a foz do rio Oiapoque (no Amapá) e a baía de São Marcos (no Maranhão), área conhecida como "costa norte". ...
... Por outro lado, a história da construção da rodovia PA-458 evidencia o lugar da natureza nos projetos de desenvolvimento desse período. Estudos sobre os impactos socioambientais do aterramento de 26km de manguezais só começaram a ser feitos a partir da década de 1990 (Maneschy, 1993a) e com maior intensidade nos anos 2000 (Carvalho, 2000;Fernandes et al., 2007;Nascimento, 2008). Com a inauguração da estrada, o fluxo de turistas na praia de Ajuruteua aumentou, mas, sendo feito de modo desordenado e sem políticas de inclusão da comunidade local, o turismo levou consigo o problema do lixo, a especulação imobiliária, o encarecimento dos produtos no comércio e o crescimento demográfico igualmente desordenado. ...
The article investigates the social and environmental impacts of construction of Highway PA-458, which turned 26km of mangrove swamp into a landfill between the municipality of Bragança and Ajuruteua beach in northeastern Pará. Working with official documents, newspapers, photographs, and oral accounts, it analyzes politicians', local residents', and crab harvesters' representations of the significance of the highway. It is concluded that officials have disregarded the environmental impact both on the mangrove swamps and on the daily lives of crab harvesters. While the latter may even view the road as positive, they have been confronted with a progressively dwindling crab population and a growing number of crab dealers.
... Around 6 to 8 tons km −2 of crabs are harvested annually in this municipality (Diele 2000;Araújo 2006;Diele et al. 2005 and this activity intensified following the construction, in the 1970s, of the PA-458 state highway, which links the town of Bragança to Ajuruteua beach crossing a large mangrove area (Alves 2014). However, despite of providing an ease access to the areas of crab exploitation and the Ajuruteua beach, the construction of this paved road led to the degradation of large mangrove areas along the Ajuruteua Peninsula (Fernandes et al. 2008). In addition, some mangrove areas have also been degraded due to the exploitation of the wood by the local fishers population. ...
The recovery of degraded mangroves may favor the reestablishment of the diversity and abundance of benthic organisms, including those of commercial importance. Here, we assessed (i) the degree of population recovery of the exploited mangrove crab Ucides cordatus in nine areas of replanted mangroves, and (ii) the influence of dominant mangrove species on density and population parameters of this species. Our results indicate that the U. cordatus population has been reestablished successfully in all replanted areas. A total of 1620 inhabited burrows (1.8 ± 0.5 burrows m−2) were counted, and 423 crabs were captured (57.7% males and 42.3% females). Almost a third (33.2%) of the male crabs was of legally harvestable size (6.4 ± 0.3 cm carapace width), while the others (66.8%; 5.0 ± 0.8 cm) can be considered for future fishery. The densities of burrows were higher in areas dominated by R. mangle and L. racemosa. Both males and females were larger in areas dominated by L. racemosa, while they were heavier at the sites dominated by R. mangle and L. racemosa. The return of the local crab population exhibiting density and structure similar to those found in preserved habitats highlights the success of the rehabilitation of impacted mangroves.
... As É possível que a estrada que delimita a área de estudo a jusante, embora disponha de uma drenagem aparentemente adequada, exerça alguma influência no regime hídrico do solo que possa estar relacionada às diferenças florísticas observadas. O impacto de estradas sobre a rede de drenagem pode resultar em danos à vegetação adjacente (Fernandes et al., 2007). No caso da área de estudo, não há indícios patentes de alterações na vegetação decorrentes da presença da estrada, tais como mortalidade acentuada ou mudanças fisionômicas. ...
A ameaça de perda da biodiversidade da fisionomia Campo Sujo Úmido,
localizada na Estação Ecológica de Itapeva, devido à contaminação biológica causada pela
invasão de Pinus elliottii Engelm., motivou a elaboração deste trabalho. Os objetivos foram
caracterizar floristicamente essa fisionomia e quantificar a existência de Pinus elliottii na
área, de modo a subsidiar propostas de manejo. Realizou-se o mapeamento da área ocupada
por Campo Sujo Úmido na Estação através da interpretação de fotografias aéreas. O estudo
florístico foi realizado através de coletas mensais de material botânico, no período de junho
de 2008 a maio de 2009, posteriormente processado e depositado no herbário SPSF. Para a
quantificação de Pinus elliottii, adotou-se o método de parcelas, utilizando-se 12 parcelas
de 3 m x 15 m. Os indivíduos a partir de 15 cm de altura foram medidos e contados para o
cálculo da densidade e frequência. A área de Campo Sujo Úmido representou 2,3% da área
total da Estação. Foram encontradas 106 espécies. As famílias mais ricas foram
Melastomataceae (11 espécies), Asteraceae (8), Cyperaceae e Poaceae (7), Myrtaceae e
Rubiaceae (5), Fabaceae, Lauraceae e Myrsinaceae (4). A densidade absoluta de Pinus
elliottii foi de 1.704 indivíduos.ha-1 e a frequência absoluta, 92%. Portanto, Pinus elliottii
apresentou duas propriedades que caracterizam espécies dominantes: grande número de
indivíduos e ampla disseminação na área. A área relativamente pequena ocupada por
Campo Sujo Úmido na Estação Ecológica, a elevada riqueza de espécies observada e o grau
de contaminação biológica constatado nessa fisionomia, indicam a possibilidade de perda
iminente de considerável parcela da biodiversidade da Unidade de Conservação. São
propostas medidas de manejo para combater o problema.
... São também importantes por representarem bens e serviços para as comunidades ribeirinhas, além de serem úteis como área de refúgio e reprodução para animais marinhos e terrestres e atuarem no controle da erosão, retenção e acúmulo de sedimentos e contaminantes, sumidouro de carbono e produção de nutrientes (FONSECA e DRUMOND, 2003). No Brasil, entre os fatores que mais infl uenciam a alteração deste ecossistema destacam-se o desenvolvimento da carcinicultura, construção civil, corte indiscriminado para a produção de carvão vegetal e retirada de madeiras para as olarias (GLASER, 2003), além de rodovias pavimentadas (FERNANDES et al., 2007). ...
Abstract Given the ecological and socioeconomic importance of the mangroves of the Brazilian Amazon coast, RapidEye satellite images were analyzed to recognize mangrove forest and salt flat changes to different land use through human activities. Results show that mangroves are still very well preserved, with less than 1% of the total converted to other uses, primarily urban areas and roads. These human activities have been the principal causes of use in the mangrove forest, driven by local anthropogenic pressures resulting from human settlements in the transition zone between the mainland and tidal flats. In contrast, aquaculture, the principal driver of the loss of mangroves in other regions of South America and in Asian countries, plays only a secondary role in habitat conversion on the Amazon coast. However, these human activities demand more attention and policies need to be supported by Brazilian legislation.
The Amazon Macrotidal Mangrove Coast contains the most extensive and continuous mangrove belt globally, occupying an area of ~6500 km2 and accounting for 4.2% of global mangroves. The tallest and densest mangrove forests in the Amazon occur on the Bragança Peninsula. However, road construction that occurred in 1973 caused significant mangrove degradation in the area. A spatial-temporal analysis (1986–2019) based on optical, Synthetic Aperture Radar (SAR), drone images, and altimetric data obtained by photogrammetry and validated by a topographic survey were carried out to understand how the construction of a road led to the death of mangroves. The topographic data suggested that this road altered the hydrodynamical flow, damming tidal waters. This process killed at least 4.3 km2 of mangrove trees. Nevertheless, due to natural mangrove recolonization, the area exhibiting degraded mangrove health decreased to ~2.8 km2 in 2003 and ~0.73 km2 in 2019. Climatic extreme events such as “El Niño” and “La Niña” had ephemeral control over the mangrove degradation/regeneration. In contrast, the relative sea-level rise during the last several decades caused long-term mangrove recolonization, expanding mangrove areas from lower to higher tidal flats. Permanently flooded depressions in the study area, created by the altered hydrodynamical flow due to the road, are unlikely to be recolonized by mangroves unless connections are re-established between these depressions with drainage on the Caeté estuary through pipes or bridges to prevent water accumulation between the road and depressions. To minimize impacts on mangroves, this road should have initially been designed to cross mangrove areas on the highest tidal flats and to skirt the channel headwaters to avoid interruption of regular tidal flow.
Sediment transport in the southeastern Amazon coastal zone (SACZ) is substantially affected by tidal asymmetry, seasonal variation of the wind and wave regime and especially rainfall (i.e., river discharge). The regional climate and geological configuration have resulted in numerous estuaries and large mangrove-covered coastal plains that partially divide the estuarine basins, which are connected by tidal channels. Based on the investigation of the Furo Grande tidal channel, we assess the relevance of connectivity on the sediment transport and evolution of the ∼8000 km² SACZ mangrove belt. Extensive sedimentologic and bathymetric surveys, as well as hydrodynamic measurements including water level, water and sediment flow, and physical-chemical characteristics of the water, were undertaken at different seasonal periods. Water-level variation along the channel shows that sediment-transport convergence (STC) tends to be formed within the connecting channel, as the tide propagates from both ends. Morphologic and sedimentologic results show the accumulation trend of fine sediments within the STC zone, and this is relevant for mud retention and further delivery to the mangrove plains, which may eventually lead to channel-connection closure. Despite the STC, results also show that there is an important net flux of suspended sediments between estuaries through the studied channel. However, the connected estuaries of Taperaçu and Caeté have substantial differences regarding riverine discharge, and thus estuarine processes, tidal propagation and sediment transport. Bottom sediments and morphology reflect long-term trends and show STC migration towards the Taperaçu as a result of substantially smaller fluvial discharge in that estuary, and therefore higher sediment accumulation rates, compared to the Caeté estuary. The migration of the STC prevents the closure of the connection, and its maintenance preserves these channels as sediment-flow conduits between estuaries. The connectivity is a key process to redistribute mainly muddy sediments along this coastal sector, which helps to explain the evolution and maintenance of the relatively homogeneous and widespread progradation of mangroves along the SACZ, with uneven mud supply.
The mangrove ecosystem is subject to the dynamics of symbiotic relationships between the social and ecological system, according to the use of the ecosystem services of this forest. However, the environmental conflicts have increased due to the social metabolism and the terms of economic development. The dwellers are environmentally responsible for the mangrove ecosystem governance on the Brazilian Amazon coast. They heavily depend on the mangrove resource, such as dewllers who live inside and in the surroundings of the Caeté-Taperaçu Marine Extractive Reserve (MER). This type of Conservation Unit (CU) aims to generate sustainable development, and users identify direct and indirect drivers of change according to the dependence of the mangroves and the handling experience of this ecosystem. Besides them, the Brazilian State, through the promulgation of laws also govern environmentally forests of mangroves in the MER, but mandatorily. The practice of environmental inspection is run by federal institutions through conservation tools ruled by the federal policy guidelines. Finally, the MER environmental governance, as a space where ecological and social dynamics occurs, is formed by networks that include some principles such as the social actors’ responsibilities, as well as the representations, the transparency and accountability of the management, and the resilience as a strategic vision for the sustainable conservation of these units.
O estudo climático do Estado do Pará visa enfatizar a classificação climática e a deficiência hídrica da região. Para isso, foram utilizados dados de estações meteorológicas, pertencentes ao Instituto Nacional de Meteorologia; a EMBRAPA-Centro Nacional de Pesquisa Agroflorestal da Amazônia Oriental; a Diretoria de Eletrônica e Proteção ao Voo; ao Departamento Nacional de Águas e Energia Elétrica; e ao Instituto do Desenvolvimento Econômico e Social do Pará. A metodologia empregada para obtenção da classificação climática utilizou uma adaptação do método de KÖPPEN, enquanto que para a determinação da deficiência hídrica media anual, foi adotado o método de THORNTHWAITE, MATHER (1955). De acordo com os resultados, verificou-se que o regime pluviométrico, no Para esta caracterizado por totais médios de precipitação anual que se acham compreendidos entre os valores de 1.000 mm a 4.500 mm, devendo-se destacar uma faixa que ocorre na direção Noroeste-Sudeste do Estado, com pluviosidade entre 1.000 mm e 2.000 mm, que constitui uma espécie de "corredor seco". Para a classificação climática, foram encontradas 10 divisões para os subtipos climáticos, sendo três em Af (AF1 - Af2 - Af3), quatro em Am (Am1 - Am2 - Am3 - Am4), e três em AW (Aw3 - Aw4 - Aw5). A deficiência hídrica media anual se apresentou bastante variável, pois foram encontradas desde áreas onde praticamente não houve deficiência, caracterizadas no intervalo de 0mm - 100mm, até áreas onde a deficiência hídrica se encontra entre 400 mm - 500mm.
The impact of restoration of the degraded areas of Pichavaram mangrove wetland was analysed by comparing TM digital data of 1986 (before restoration) and LISS III digital data of 2002 (after restoration). The analysis indicates that the area of the mangrove forest cover has increased by about 90%. A science-based, community-centred and process-oriented approach followed for the restoration of the Pichavaram mangrove wetland in collaboration with the Forest Department, Government of Tamil Nadu and participation of local mangrove user-communities is mainly responsible for success of the effort. This study indicates that remote sensing data can be used as a monitoring tool to assess the effectiveness of restoration and conservation programmes of the mangrove wetland, where direct and regular physical monitoring is difficult due to marshy nature of the soil and presence of numerous tidal creeks and canals.
In June 1990 a research project sponsored by DANIDA and AWF was carried out by botany students of Nairobi University to investigate the regeneration strategy of mangroves at Gazi bay and Mida creek. Statistical analysis of 449 quadrats (5 × 5 m) sampled along 35 line transects in 4 mangrove forests showed that mangrove seedlings follow the same distribution pattern in the intertidal zone as their parent trees. In other words, mangrove seedlings mainly develop within a well-defined species specific zone. These distribution zones for the various mangrove trees and their seedlings are defined in terms of elevation above the mean low water level of spring tides.
Through assigning mangrove seedlings in the intertidal zone to the categories (i) ‘fixed’ or ‘not-fixed’, and (ii) ‘covered’ or ‘not-covered’, evidence was found that propagule dispersal followed both the ‘self-planting’ theory and the ‘stranding’ theory. The ‘self-planting’ theory appeared to be the major mechanism of propagule dispersal in ‘undisturbed’ mangrove forests, whilst the ‘stranding theory’ proved to be predominant in colonizing ‘over-exploited’ and cleared mangrove forests.
It is concluded that re-afforestation of mangrove seedlings in the intertidal zone will be most successful when the seedlings are planted in their specific distribution zones under fixed conditions.
In June 1990 a research project sponsored by DANIDA and AWF was carried out by botany students of Nairobi University to investigate the regeneration strategy of mangroves at Gazi bay and Mida creek.
Statistical analysis of 449 quadrats (5 × 5 m) sampled along 35 line transects in 4 mangrove forests showed that mangrove seedlings follow the same distribution pattern in the intertidal zone as their parent trees. In other words, mangrove seedlings mainly develop within a well-defined species specific zone. These distribution zones for the various mangrove trees and their seedlings are defined in terms of elevation above the mean low water level of spring tides.
Through assigning mangrove seedlings in the intertidal zone to the categories (i) ‘fixed’ or ‘not-fixed’, and (ii) ‘covered’ or ‘not-covered’, evidence was found that propagule dispersal followed both the ‘self-planting’ theory and the ‘stranding’ theory. The ‘self-planting’ theory appeared to be the major mechanism of propagule dispersal in ‘undisturbed’ mangrove forests, whilst the ‘stranding theory’ proved to be predominant in colonizing ‘over-exploited’ and cleared mangrove forests.
It is concluded that re-afforestation of mangrove seedlings in the intertidal zone will be most successful when the seedlings are planted in their specific distribution zones under fixed conditions.
This report is by the Working Group on Mangrove Ecosystems of the IUCN Commission on Ecology in cooperation with the United Nations Environment Programme and the World Wildlife Fund. The review describes the mangrove resource and its value; factors which maintain the ecological processes in mangroves; and the causes and consequences of mangrove destruction. There is a section on management of the mangrove resource and 2 chapters on recommendations for those concerned with mangrove management and applied research needs. Appendices describe the mangrove reserves of the world. -K.Clayton
Mangrove restoration projects have been attempted, with mixed results, throughout the world. In this paper, I first examine goals of existing mangrove restoration projects and determine whether these goals are clear and adequate, and whether or not they account for the full range of biological diversity and ecological processes of mangrove ecosystems. Many restored mangrove forests resemble forest plantations rather than truly integrated ecosystems, but mangrove plantations can be a first step toward mangrove rehabilitation. Mangrove restoration projects that involve associated aquaculture or mariculture operations tend to be more likely to approximate the biological diversity and ecological processes of undisturbed mangrove ecosystems than are projects that focus only on the trees. These integrated restoration projects also provide a higher economic return than do silvicultural projects alone. Second, I briefly assess whether existing ecological data are sufficient to undergird successful restoration of mangal and define criteria for determining whether or not a mangrove ecosystem has been restored successfully. These criteria include characteristics of vegetation (forest) structure, levels of primary production, composition of associated animal communities, and hydrology. Finally, I suggest ways to improve mangrove restoration projects and identify key research needs required to support these efforts. Ecological theories derived from other wetland and upland systems rarely have been applied to either “basic” or “applied” mangrove forest studies, to the detriment of restoration projects, whereas lessons from restoration of the relatively species-poor mangrove ecosystems could be beneficially applied to restoration projects in other contexts. An international database of mangrove restoration projects would reduce the likelihood that unsuccessful restoration projects would be repeated elsewhere. Clear criteria for evaluating success, greater accessibility of information by managers in the developing world, intensified international cooperation, and application of relevant ecological theories will improve the success rate of mangrove restoration projects.
In the Cinaga Grande de Santa Marta, a brackish lagoon system on the Caribbean coast of Colombia, human-induced changes in the hydrological system caused hypersalinisation of the soils. As a result, 30 000 ha of originally 51 000 ha of the mangrove forests growing in the lagoon's flood plain died. Presently, efforts are being made to reestablish the original hydrological system. Reforestation of the bare areas is planned with the three dominating mangrove species Avicennia germinans, Laguncularia racemosa and Rhizophora mangle. The objective of the project presented here is to identify the regeneration patterns in the study area. Experiments under controlled conditions and measurements at bare and forested sites carried out from 1994 to 1996 showed that regeneration is possible. However, as the bare areas are large and presently very few or no propagules arrive naturally, regeneration will be slow. Therefore, reforestation is recommended to accelerate the process. In the forests, the seedling growth is mainly controlled by changes in salinity and the mortality by seasonal flooding, while in the bare areas, regeneration is aggravated by extremely high salinities, high soil temperatures and dessication of the top soil layers. The establishment of the small A. germinans and L. racemosa propagules is especially difficult, because they cannot establish themselves in flooded soils and in direct sunlight they dry out rapidly. The seedlings of both species are also very sensitive to changes in water level, wind, waves, temperatures exceeding 45 C and dry soils. In A. germinans, phytophagous insects affect the chances for survival also. Therefore, mortality in both species is extremely high. R. mangle is much more resistant to most detrimental factors observed with the exception of high salinities. However, there is one favourable factor at the open sites. When sufficient water is present and salinities as well as temperatures are low enough, the high light availability increases growth rates and survival.
Within the last decade shrimp farming in the Mekong Delta of Vietnam has increased by 3500%. Shrimp farming became un-sustainable in the early 1990's due to the un-planned development of this industry and the resulting self pollution of the farms, the destruction of mangrove forest and the outbreak of viral diseases. Historical data on fisheries, fishing effort and mangrove coverage were obtained from the province Minh Hai (lately divided in Ca Mau and Bac Lieu). Analysis of catch and effort data of marine fisheries in the Mekong Delta indicated a severe danger of over-exploitation of fish stocks and further decline can be expected if fisheries management only considers the demand for fish. The relation between the total fish catch (t/year), the mangrove area (ha), the engine capacity (HP) of the fishing fleet and the social incentive for fishing could be described with the model: Total catch=0.449*Mangrove area + 0.614 Engine capacity + 654 Social factor. One hectare of mangrove forest supports a marine catch of 450 kg/year