International Journal of Aquaculture, 2024, Vol.14, No.4, 221-231 http://www.aquapublisher.com/index.php/ija 226 6 Case Studies on Climate Change Adaptation 6.1 Successful adaptation in coastal ecosystems Coastal ecosystems are particularly vulnerable to the impacts of climate change, including sea level rise, increased storm intensity, and changing ocean temperatures. However, several successful adaptation strategies have been documented. For instance, in Bangladesh, coastal communities have adapted by diversifying their aquaculture practices, such as incorporating crab fattening and improving pond infrastructure, which has helped sustain livelihoods despite the adverse effects of climate change (Hossain et al., 2018). Similarly, the proliferation of sargassum seaweed across the tropical Atlantic has led to the development of national management strategies, open-access knowledge hubs, and innovative clean-up and harvesting equipment, demonstrating effective adaptation to emergent risks (Almela et al., 2023). The incorporation of climate change adaptation into marine protected area (MPA) planning has shown promise, with strategies focusing on climate refugia and adaptive management approaches to ensure the resilience of these critical habitats (Wilson et al., 2020). 6.2 Challenges in river and lake systems River and lake systems face unique challenges in adapting to climate change. These freshwater ecosystems are experiencing shorter ice cover periods, longer summer stratified seasons, and warmer water temperatures, leading to a cascade of ecological consequences such as reduced dissolved oxygen levels and increased likelihood of harmful algal blooms (Figure 2) (Woolway et al., 2022). The biodiversity crisis in freshwater systems is exacerbated by emerging threats like microplastic pollution, invasive species, and declining calcium levels, which disproportionately impact these ecosystems. Despite these challenges, there are opportunities for conservation gains through novel management tools like environmental DNA and habitat protection policies. However, the implementation of these strategies is often hindered by a lack of comprehensive scientific studies and governance structures that support adaptive management (Reid et al., 2018). The decline in dissolved oxygen levels is primarily due to the inhibition of vertical water mixing caused by the stratification of warmer water layers during the summer. This leads to the gradual depletion of oxygen in the deeper water layers. This phenomenon is particularly severe in deeper lakes, where the bottom water layers typically rely on seasonal mixing to replenish oxygen. However, as the stratification period lengthens, oxygen replenishment becomes increasingly difficult, and in some extreme cases, lakes may completely lose the ability to replenish oxygen in deep waters. The rise in water temperature also creates more favorable conditions for the outbreak of harmful algal blooms. The frequent occurrence of harmful algal blooms not only severely impacts water quality but also poses a threat to the survival of aquatic organisms. For example, as water temperatures rise, some algae can reproduce more rapidly and form large-scale blooms, which release toxins that further degrade the water environment and reduce dissolved oxygen levels. This situation not only affects fish and other aquatic organisms but also adversely impacts human communities that rely on these freshwater resources. 6.3 Lessons learned from global practices Global practices in climate change adaptation offer valuable lessons for improving the resilience of aquatic ecosystems. A key finding from studies across multiple coastal communities is the importance of strong, self-organized local institutions in facilitating effective adaptation. Communities with robust local governance structures that set and enforce rules locally and communicate across scales are better able to adapt without substantial loss of well-being (Berman et al., 2019). Additionally, the need for multi-level, multi-sectorial responses is emphasized, particularly in highly vulnerable regions like small tropical islands, where cumulative and synergistic impacts of climate change pose significant challenges. The integration of scientific knowledge into policy and management, as seen in the adaptation strategies for Australian fisheries, highlights the necessity of using evidence-based approaches to inform decision-making processes and ensure the sustainability of these resources (Fogarty et al., 2019; Jiang and Xu, 2024). Successful adaptation in coastal ecosystems, the challenges faced by river and lake systems, and the lessons learned from global practices underscore the complexity and urgency of addressing climate change impacts on aquatic ecosystems. By leveraging local governance, innovative management tools, and evidence-based policies, it is possible to enhance the resilience of these vital ecosystems and the communities that depend on them.
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