International Journal of Aquaculture, 2025, Vol.15, No.3, 135-148 http://www.aquapublisher.com/index.php/ija 138 found that tilapia can reduce the metabolic rate and enter a metabolic inhibitory state under long-term hypoxia exposure, thereby reducing oxygen demand and increasing survival time. This is reflected in the field and in breeding practice: tilapia are often observed to gather on the water surface at night or in the early morning when dissolved oxygen is low, so as to pass the low oxygen period in the fish pond. In order to further enhance the anti-oxidant properties of tilapia, breeding experts have also carried out relevant breeding work. Chinese scientific researchers have successfully cultivated tilapia families with stronger hypoxia resistance, and screened individuals with higher survival rates for seed selection through the hypoxia-reoxygen alternating stress experiment. At the molecular level, tilapia activates hypoxia-inducing factor pathways such as HIF-1α under hypoxia stress, regulates the expression of a series of anti-stress genes, thereby enhancing the cell's tolerance to the hypoxia environment (Ma et al., 2023). 3 Analysis of Climate Change and Geographical Suitability 3.1 Changes in the breeding area in the context of global warming Global warming is profoundly affecting the spatial pattern of aquaculture, especially for tropical fish such as tilapia. As the average temperature rises, high-latitude areas that are traditionally too cold to be suitable for tilapia to overwinter may become new breeding suitable areas in the future. In recent years, there have been reports of experimental overwintering tilapia in coastal provinces such as Zhejiang and Fujian in China. The success rate has gradually increased, which is a reflection of the reduction of local extreme low-temperature events in winter due to the warming. In addition to China, some previously marginalized areas in southern Japan and southern United States may have the conditions for seasonal breeding of tilapia in the future. Northward migration of distribution has become one of the trends of global expansion of tilapia: A study on the invasion potential of tilapia shows that climate warming will cause the centroid of high-risk invasion areas of tilapia to migrate to high latitudes, and temperate areas with strong climate restrictions may have an outbreak of alien tilapia populations under warm winter conditions. However, global warming is not unilaterally beneficial to tilapia farming. Excessive water temperatures may exceed the optimal range of tilapia, thereby inhibiting its growth and reproductive efficiency. Especially in tropical areas, the temperature of many aquaculture water bodies is close to the upper limit of tilapia tolerate in summer. Further heating may lead to enhanced stress response and decreased immune function, thereby increasing the risk of disease outbreaks. Studies have found that when the water temperature rises from 28 ℃ to 34 ℃, the gill tissue structure of tilapia is damaged, and its tolerance to hypoxia is significantly reduced (Zhou et al., 2022). 3.2 Prospects of aquaculture expansion in tropical and subtropical regions Tropical and subtropical regions have always been the areas with the most concentrated tilapia farming, and these regions will still be the main force of industrial growth in the future. In Africa, many countries are actively expanding their breeding scale due to the rich local resources and strong market demand. For example, Egypt, as Africa's largest producer of tilapia, relies on the water resources and high temperature climate in the Nile River Basin to expand its breeding to a wider range of waters, including the use of drainage ditches and reservoirs to develop high-density cage farming. Other sub-Saharan African countries, such as Nigeria and Kenya, have suitable climatic conditions, and have also regarded tilapia as an important way to improve protein supply and promote agricultural development, and there is a lot of room for improvement in future output. In Southeast Asia, tilapia farming has become very popular. Countries such as the Philippines, Indonesia, Thailand and other countries will continue to optimize varieties and breeding models to improve unit yield and product quality. Especially in monsoon areas with abundant rainfall, by developing flood-resistant cage farming, tilapia can continue to produce in water-stalk areas and reservoirs in the rainy season. For example, the Haor wetlands in northeastern Bangladesh are flooding year by year. The local government is trying to raise tilapia in floating cages during the flood season to explore new models of livelihoods in floodplain areas. The experimental results show that the survival rate of cage tilapia under different densities is above 90%, and the unit water output can reach 25 kg per cubic meter, showing good climate adaptability potential (Burggren et al., 2019). Subtropical areas such as Brazil and Mexico in Latin America have developed rapidly in recent years. These areas have sufficient sunshine and a large number of reservoirs are available. The Brazilian state of São Paulo and other places use reservoirs to
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