Oyster breakwater reefs promote adjacent mudflat stability and salt marsh growth in a monsoon dominated subtropical coast
Chowdhury, Mohammed Shah Nawaz ; Walles, Brenda ; Sharifuzzaman, Sm ; Shahadat Hossain, M. ; Ysebaert, Tom ; Smaal, Aad C. - \ 2019
Scientific Reports 9 (2019)1. - ISSN 2045-2322
Oyster reefs have the potential as eco-engineers to improve coastal protection. A field experiment was undertaken to assess the benefit of oyster breakwater reefs to mitigate shoreline erosion in a monsoon-dominated subtropical system. Three breakwater reefs with recruited oysters were deployed on an eroding intertidal mudflat at Kutubdia Island, the southeast Bangladesh coast. Data were collected on wave dissipation by the reef structures, changes in shoreline profile, erosion-accretion patterns, and lateral saltmarsh movement and related growth. This was done over four seasons, including the rainy monsoon period. The observed wave heights in the study area ranged 0.1–0.5 m. The reefs were able to dissipate wave energy and act as breakwaters for tidal water levels between 0.5–1.0 m. Waves were totally blocked by the vertical relief of the reefs at water levels <0.5 m. On the lee side of the reefs, there was accretion of 29 cm clayey sediments with erosion reduction of 54% as compared to control sites. The changes caused by the deployed reefs also facilitated seaward expansion of the salt marsh. This study showed that breakwater oyster reefs can reduce erosion, trap suspended sediment, and support seaward saltmarsh expansion demonstrating the potential as a nature-based solution for protecting the subtropical coastlines.
Elements of fishing community resilience to climate change in the coastal zone of Bangladesh
Sharifuzzaman, S.M. ; Hossain, M.S. ; Chowdhury, Sayedur Rahman ; Sarker, Subrata ; Chowdhury, M.S.N. ; Chowdhury, M.Z.R. - \ 2018
Journal of Coastal Conservation 22 (2018)6. - ISSN 1400-0350 - p. 1167 - 1176.
Analytic hierarchy process (AHP) - Fishing community - Hatiya Island - Livelihood assets - Resilience
Resilience has been conceptualized in various ways by anthropologists, ecologists, systems scientists and engineers; the boundaries of resilience are subjective and context dependent. Consequently, choosing the standards and metrics for assessing resilience remains key challenges for policy makers. In this study, using multicriteria evaluation of 40 basic criteria of human, physical, financial, natural and social assets, we have identified several elements, such as experienced fishermen, natural abundance of hilsa (Tenualosa ilisha), ability to assert decision on fish selling, nets and boats ownership, social harmony and capacity of buying food as essential livelihood assets for the fishermen at Hatiya Island, Bangladesh. These assets may enhance the relative resilience of the fishing community of the island to climate change by as much as 20–40%. The results of this study will improve our understanding of the elements that lead to resilience at the community level.
First Record of Porpita porpita (Cnidaria: Hydrozoa) from the coral reef ecosystem, Bangladesh
Shah Nawaz Chowdhury, M. ; Sharifuzzaman, S.M. ; Chowdhury, Sayedur Rahman ; Rashed-Un-Nabi, Md ; Hossain, M.S. - \ 2016
Ocean Science Journal 51 (2016)2. - ISSN 1738-5261 - p. 293 - 297.
Bangladesh - Bay of Bengal - Hydrozoa - Porpita - Saint Martin’s Island
The occurrence of Porpita porpita is reported, for the first time, in the coral island of St. Martin’s located in the southeastern coastal region of Bangladesh. P. porpita was found to occur in the lower littoral zone and beach rock pools, together with molluscan species, and collected during the pre-monsoon season when both water temperature (> 30°C) and salinity (> 30‰) tend to reach a maximum. This study recounts some details on the discovery and description of the species, and thus extends the global distribution and range limits of the genus Porpita.