Climate change and its risk reduction by mangrove ecosystem of Bangladesh

Climate change is amongst the most dreaded problems of the new millennium. Bangladesh is a coastal country bounded by Bay of Bengal on its southern part and here natural disasters are an ongoing part of human life. This paper discusses about the possible impact of climate change through tropical cyclones, storm surges, coastal erosion and sea level rise in the coastal community of Bangladesh and how they cope with these extreme events by the help of mangrove ecosystem. Both qualitative and quantitative discussions are made by collected data from different research work those are conducted in Bangladesh. Mangrove ecosystem provides both goods and services for coastal community, helps to improve livelihood options and protect them from natural disaster by providing variety of environmental support

Distribuição espacial dos foraminíferos no perfil transversal ao manguezal da margem da baía de Sepetiba-RJ: habitat e paleoambiente

Os foraminíferos de zona entre-marés são amplamente utilizados como na reconstituição paleoambiental holocênica. Entretanto, a despeito dos manguezais, estudos com foraminíferos são relativamente escassos. A estrutura do habitat e seu grau de exposição atuam na distribuição espacial das espécies de zona entre-marés. Em um perfil transversal ao manguezal que margeia a baía de Sepetiba (RJ), foi investigada a influência parâmetros estruturais do habitat e da riqueza na distribuição espacial dos foraminíferos do manguezal. Os parâmetros escolhidos neste estudo foram serapilheira, litologia, matéria orgânica total, microtopografia, zonação botânica, espécies botânicas, altura média das árvores e densidade de árvores. Um testemunho de 144 cm também foi descrito em termos da sua litologia, matéria orgânica total, composição biogênica, incluído foraminíferos. O perfil apresentou textura silte argilosa, matéria orgânica total concentrada por todo manguezal e a serapilheira acumulada principalmente no mangue superior. Os forminíferos (24) ocorreram apenas no manguezal, com predomínio de aglutinantes e presença significativa de formas calcárias. A densidade de testas se concentrou no mangue superior. A. beccarii f. tepida, E. excavatum, A. mexicana, Q. seminulum e T. inflata foram as espécies mais constantes. A diversidade não apresentou variabilidade espacial significativa e foi marcada pela baixa dominância e alta equitabilidade. Notou-se diferença significativa da riqueza de foraminíferos entre habitats expostos e protegidos. A riqueza específica apresentou moderada correlação com a serapilheira e densidade de árvores. A. mexicana e H. wilberti apresentaram moderada correlação com a riqueza. Q. seminulum apresentou significativa correlação com a matéria orgânica total e altura média das árvores. T. inflata apresentou significativa correlação com a riqueza e serapilheira. Em relação ao testemunho, foi possível identificar três paleoambientes de baía restrita: infralitoral, mesolitoral e supralitoral. O manguezal este presente entre o nível 124 62 cm e a planície hipersalina a partir do nível 24 cm.

Concentrations en métaux toxiques chez Crassostrea gasar (huître de mangrove) en zone urbaine lagunaire d'Abidjan (Côte d'Ivoire)

This paper presents results related to a study of toxic heavy metals concentrations (Cd, Cu, Hg and Zn) in Crassostrea gasar (mangrove oyster). A comparative study is made between samples collected in urban region (Abidjan) and those from rural areas (Assinie-Mafia and Assouindé). Toxic metals concentrations in oyster samples collected in urban zone are higher than those in rural samples, as a result of chemical pollution due to urban and industrial wastes. Correlations between pollutants-weight of organisms and pollutants are good.

Bioconversion efficiency and growth in the white shrimp Penaeus indicus (Milne Edwards), fed with decomposed mangrove leaves

Food conversion efficiency and growth in the white shrimp Penaeus indicus fed with decomposed mangrove leaves of Avicennia marina and A. officinalis were monitored under laboratory conditions. It was observed that test animals fed with the decomposed leaves of A. marina had higher assimilation efficiency (87.96%), gross growth efficiency (10.82%), net growth efficiency (12.3%) and relative growth rate (0.0603 g/day) than those fed with A. officinalis. The relatively higher growth registered in the animals fed with decomposed leaves of A. marina was attributed to its high calorific and protein content.

Small-scale fishery of Pichavaram mangrove swamp, Southeast India

A description of the small-scale fishery of Pichavaram mangrove, southeast India is given, with emphasis on catch composition, catch per effort and deployment of various gear types.

Management of mangrove areas in Calauag Bay, Quezon Province, Philippines

The findings are presented of a study conducted in Calauag Bay, Quezon Province, Philippines in order to estimate resource rent of mangrove areas converted to fishpond production. The rents were calculated based on the technology practised by the farmers and the prices of inputs and outputs that prevailed during the study period. The major causes of mangrove depletion are cutting of mangroves for fuelwood and charcoal and clearing for fishpond development. It was concluded that there is justification for the government to increase the feed which could be used to rehabilitate the inland-coastal fisheries to improve productivity and ensure sustainability of the ecosystem for future generations.

The relationship of shell dimensions and shell volume to live weight and soft tissue weight in the mangrove clam, Polymesoda erosa (Solander, 1786) from northern Australia

Shell dimensions (length, height, width) and shell volume were evaluated as estimators of growth for Polymesoda erosa in northern Australia. Each parameter was a good estimator when applied to live weight (r2 values of 76-96 percent), but not to soft tissue weight (wet, dry, or ash-free dry weight) (r2 values of 13-32 percent). The b value for shell volume to weight relationship of clams collected during the dry season (June to October) was signifi cantly different than for those collected in the wet season (February to April).

Mangrove rehabilitation in the west coast of Aceh: issues and perspectives

The condition of mangroves pre- and post- tsunami and the socioeconomic role of mangrove forests in the livelihoods of coastal communities along the west coast of Aceh province, Indonesia are examined. The findings indicate that community livelihoods are significantly linked to the mangrove ecosystem. However, most of the mangrove rehabilitation programs are conservation orientated, aimed primarily at land conservation, and are not necessarily linked with livelihood options for local people or integrated resource management. This is a cause for concern as rehabilitation will only succeed when conservation measures are balanced with local community needs to obtain sustainable benefits from the rehabilitated systems. The rehabilitation efforts do involve the communities to a certain extent, but a more holistic and integrated approach needs to be adopted to ensure better management and sustainability of the rehabilitated mangrove forests.

Mangrove rehabilitation and coastal resource management: a case study of Cogtong Bay, Philippines

The Cogtong Bay experience represents a bold attempt to pursue a shared responsibility between the government and local residents for rehabilitating coastal resources. Some of the factors that provided the impetus to co-management arrangements were the recognition of resource management problems, dependence on coastal resources for livelihood and the desire for more sustainable resource use. This paper draws attention to the importance of legitimate user/property rights, vigilant law enforcement efforts, common commitment among stakeholders and continuing support from local leadership in viable co-management arrangements.

Mangrove forests and shrimp culture in Ngoc Hien District, Minh Hai Province, Vietnam

As a result of increased population growth, the attraction of high profits from shrimp culture and ineffective mangrove forest management, a number of serious environmental problems exist in Ngoc Hien District, Minh Hai Province, Vietnam. These environmental problems are highlighted in this article.