Komatsu T.,University of Tokyo |
Komatsu T.,Japan Science and Technology Agency |
Noiraksar T.,Burapha University |
Sakamoto S.X.,University of Tokyo |
And 6 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
Coastal habitats having high productivity provide numerous ecological services such as foods, protection from strong waves through buffering effect, fixation of CO2 through photosynthesis, fostering biodiversity etc. However, increasing human impacts and climate change decrease or degrade coastal habitats. ASEAN region is developing most rapidly in the world. In the developing region, it is necessary to grasp present spatial distributions of habitats as a baseline data with standardized mapping methods. Remote sensing is one of the most effective methods for mapping. Japan Aerospace Exploration Agency (JAXA) provides non-commercial satellite images with ultra-high spatial resolution optical sensors (10 m), AVNIR2, similar to LANDSAT TM. Using ALOS AVNIR2 images it may be possible to make habitat map in the region. In Thailand, shrimp ponds cause degradation of coastal ecosystem through cutting mangroves and eutrophicated discharge from ponds. We examined capability of remote sesing with ALOS AVNIR2 to map seagrass beds in Khung Kraben Bay, Chanthaburi Province, Thailand, surrounded by shrimp ponds. We analyzed ALOS AVNIR2 taken on 25 January 2008. Ground truth survey was conducted in October 2010 using side scan sonar and scuba diving. The survey revealed that there were broad seagrass beds consisting of Enhalus acroides. We used a decision tree to detect seagrass beds in the bay with quite turbid seawater coupled with Depth-Invariant Index proposed by Lyzenga (1985) and bottom reflectances. We could succeed to detect seagrass beds. Thus it is concluded that ALOS AVNIR2 is practical to map seagrass beds in this region. © 2012 SPIE.
Teh L.S.L.,University of British Columbia |
Teh L.C.L.,University of British Columbia |
Hines E.,Romberg Tiburon Center for Environmental Studies |
Junchompoo C.,Eastern Marine and Coastal Resources Research Center |
Lewison R.L.,San Diego State University
Ocean and Coastal Management | Year: 2015
We apply an integrated and interdisciplinary conceptual framework to assess the potential for uptake of bycatch reduction measures by small-scale fisheries along the Andaman coast and eastern Gulf of Thailand, and in Sabah, Malaysia. Specifically, we characterize the current governance, socio-economic, ecological, and scientific context for marine megafauna bycatch, and identify the enabling and limiting factors to bycatch reduction at each location. Enabling factors are those that motivate or facilitate conservation actions among resource users, managers, and other stakeholders, while limiting factors are those that act as barriers to conservation. We conduct a comparative analysis of the strength of enabling and limiting factors at the two study locations by using a qualitative scoring system. Overall, conditions in Thailand appear to be relatively more supportive of bycatch reduction than Sabah. Many enabling factors, such as community based marine management and positive attitudes towards conservation, occur at the local scale, suggesting potential marine megafauna bycatch reduction approaches can be implemented successfully from the bottom-up. We show that intervention points for reducing marine megafauna bycatch lie within a much broader realm than conventionally considered in bycatch reduction schemes. Effective policies for reducing marine megafauna bycatch thus have to address multifaceted drivers of small-scale fishing behaviour in addition to ecological considerations. © 2015 Elsevier Ltd.