International Journal of Marine Science, 2026, Vol.16, No.3, 141-152 http://www.aquapublisher.com/index.php/ijms 148 7.2 Actual impacts of high/low-temperature events on growth and survival Short-term high-temperature events superimposed on seasonal warming can trigger sharp increases in mortality and physiological stress. In suspended-cage culture adjacent to a tidal-mixing front, Pacific abalone exposed to stable high summer temperatures showed elevated metabolic rates and experienced summer mortality, whereas cages experiencing semidiurnal fluctuations between 20 °C-26 °C had no summer mortality, suggesting that intermittent low-temperature periods can buffer lethal impacts. (Kang et al., 2019) In controlled trials with greenlip abalone, survival remained >95% at 18 °C-22 °C but fell by up to 50% at 26 °C when animals were fed a commercial diet, revealing that modest additional warming above 22 °C can halve survival in larger, market-sized stock over several weeks. Epidemiological analysis of commercial farms confirms that summer mortality risk is tightly linked to thermal extremes. A case-control study of greenlip and hybrid abalone in Australia showed that the risk of summer mortality doubled for every 2 °C increase in maximum weekly water temperature, with interactions involving age, previous mortality history, feed rate and post-grading mortality further modulating outcomes (Figure 2) (Bansemer et al., 2023). Continuous laboratory exposures of Haliotis discus hannai to temperatures above 26 °C likewise reduced survival, increased falling rates and caused abnormal foot structures, indicating compromised attachment and heightened mortality risk when summer peaks exceed species-specific thresholds. Figure 2 Buffering effects of short-term temperature fluctuations on summer mortality in Haliotis spp. 7.3 Evaluation of temperature control measures and farming profitability Because open coastal farms often cannot economically control temperature, management has focused on nutritional and system-design strategies to mitigate seasonal stress. In hybrid abalone reared at 12, 17 and 22 °C, higher dietary protein (up to 410 g /kg) improved weight gain, specific growth rate and feed conversion, particularly at 22 °C, and did so without compromising flesh quality, indicating that diet optimization at higher temperatures can shorten culture duration and “profit maximisation” despite seasonal warming (Hassan et al., 2023). Similarly, summermortality experiments show that providing live macroalgae (Ulva lactuca) at 26 °C maintained survival above 97%,
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