The tropical seascape is herein defined as a landscape made up of five ecosystems: coastal terrestrial forests, mangrove forests, seagrass beds, coral reefs and the deep sea. Previous studies have shown that men and women use the tropical seascape in different ways. If the seascape was to change as a result of anthropogenic climate change, then men and women could potentially be affected differently by those changes. The seascape is particularly vulnerable to the predicted rise in sea-level and ocean warming, but the coastal terrestrial forests and mangrove forests are in addition vulnerable to the increased storms and hurricanes a warmer climate is predicted to lead to. While men and women utilizes these ecosystems in many different ways, this study found, based on the literature reviewed, that in a worst-case scenario all parts of the seascape could potentially be destroyed and none of the activities performed there today could be performed in the future. The deep sea would not be destroyed, but the fish living there would move to higher latitudes and deeper waters, effectively ending the fishing practices in the tropical waters. To save the tropical seascape anthropogenic climate change would have to stop on a global scale, since the problem cannot be solved on a local or regional level.

Collecting sea cucumbers to supply the high value Chinese dried seafood market is a livelihood activity available to many people in the Western Indian Ocean (WIO), making it an important part of local economies. These fisheries are generally not successfully managed and tropical sea cucumber fisheries show continuing signs of decline. This thesis takes a social-ecological systems approach to guide better management of sea cucumber fisheries and aquaculture in the WIO. Papers 1 and 2 analyse the fishery situation in Zanzibar and find that in the absence of effective management institutions and income alternatives among fishers, leading to dependence, there are unsustainable expanding processes. Paper 3 compares the unmanaged fishery in Zanzibar to the highly controlled situation in Mayotte. In Mayotte, a protection effect is evident and the commercial value of stocks is significantly higher than in Zanzibar. The analysis of the situation in Mayotte demonstrates the importance of matching the fishery – management temporal scales through prepared and adaptive management to avoid processes that reinforce unsustainable expansion. Paper 4 analyses sea cucumber community spatial distribution patterns at a coastal seascape-scale in Mayotte establishing baseline patterns of habitat utilization and abundance, which can be used as reference in management. Paper 5 reviews the potential for sea cucumber aquaculture in the WIO. The review illustrates that this activity, which is currently gaining momentum, does so based on inflated promises and with significant social-ecological risks. Emphasis for improvements is, in this thesis, placed on the importance of prepared and adaptive institutions to govern and control expanding processes of the fishery. These institutional features may be achieved by increasing the level of knowledge and participation in governance and by integration of sea cucumber resources management into higher-level policy initiatives. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.</p>