The effects of climate change on aquaculture in the Western Cape of South Africa
Date
2024-12
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Stellenbosch : Stellenbosch University
Abstract
This thesis investigates the impacts of climate change on the aquaculture sector in the Western Cape, South Africa, focusing on both marine and freshwater systems. With global wild fish stocks under significant pressure due to overfishing and climate change, aquaculture has emerged as a critical sector for ensuring food security. However, aquaculture itself is not immune to climate-related challenges, including in regions like the Western Cape, where rising temperatures, erratic rainfall, and shifts in marine conditions are becoming more frequent. The study's primary objectives are to evaluate the effects of climate change on aquaculture production, explore the perceptions of climate change among aquaculture farmers, and assess their adaptive capacity. The thesis is divided into three key chapters: an introduction to the Western Cape's aquaculture sector and climate challenges, a literature review of climate trends and their effects on aquaculture, and a detailed results-discussion based on primary data collected from aquaculture farms. Chapter 1 provides a comprehensive overview of aquaculture in the Western Cape, tracing its origins from early attempts at cultivating oysters in the 17th century to the present-day operations. It outlines the historical context, the current state of the sector, and highlights some of the pressing environmental challenges that threaten its sustainability. Various production systems and value chains associated with each cultured species are discussed, emphasizing the sector's economic importance. Chapter 2 reviews existing literature on climate change's effects on aquaculture, particularly in the context of the Western Cape. Key climate change risks include rising temperatures, shifting rainfall patterns, and the growing occurrence of harmful algal blooms. These changes have adverse impacts on fish growth, mortality rates, feed requirements, and the sustainability of aquaculture operations. The review also examines potential adaptation strategies, including selective breeding for thermal tolerance, changes in feed management, and infrastructure modifications to mitigate environmental stressors, among others. Chapter 3 presents the findings of a survey conducted among 32 aquaculture sector participants across the Western Cape. The survey captures farmers' perceptions of climate change, its impacts on their operations, and the strategies they are adopting to cope with climate variability. Marine farmers, particularly those involved in mussel, oyster, and abalone farming, report significant impacts from ocean warming, increased acidity, and harmful algal blooms. Freshwater farmers, including those cultivating trout and tilapia, face challenges related to droughts, water scarcity, and rising temperatures. While many farmers have taken adaptive measures-such as water conservation, changing feed practices, and
diversifying production, among others- some of these strategies may be standard operating procedures rather than direct responses to climate change. Additionally, there remain considerable barriers to further adaptation, including financial constraints and socio-economic issues like load shedding which may overshadow the gradual effects of climate change. This thesis concludes that the aquaculture sector in the Western Cape is vulnerable to climate change yet holds significant potential for adaptation and growth. With targeted support, innovative technologies, and a focus on building resilience, the sector can continue to contribute to food security and economic development in the province. The study emphasizes the importance of strong coordination among all stakeholders and fostering collaboration between government, sector participants, and academia to ensure the sector's sustainability. By addressing these challenges, the Western Cape can position itself as a leader in climate-resilient aquaculture, contributing to both local food security and global sustainability efforts.
Description
Thesis (MScConsEcol)--Stellenbosch University, 2024.