Many abalone farms are reliant on coastal water inputs which are subject to fluctuations in environmental variables such as temperature, oxygen, CO 2 and salinity. Near future climate change scenarios predict that there will be more frequent extreme weather events which can exacerbate these fluctuations and potentially be deleterious to farmed abalone where these variables remain largely uncontrolled. In this review, we have taken an in depth examination of current literature on the effects of environmental stress on abalone physiology and metabolism and how this affects their health and growth. In conjunction, we have also reviewed the effects of farm-specific stressors such as ammonia, stocking density, handling, nutrition and disease and the synergistic effects of these and environmental stressors on abalone physiology. We have identified currents gaps in our knowledge of this under-studied species and have made predictions on the effects of climate change on future abalone production with suggestions for future research. In summary, it is expected that abalone will show reduced growth rates as more energy is invested in combating stresses rather than growth. Furthermore, disease outbreaks may become more frequent with greater fluctuations in temperature and salinity, both of which have large-scale effects on immunity. The current body of knowledge is mainly on whole animal effects of stresses, but we know very little of their mechanistic foundation. Research in this area as well as investments in infrastructure will be pivotal in identifying and implementing strategic interventions to maintain a sustainable abalone industry in Australia.

Climate warming involves not only a rise of air temperature means, but also more frequent heat waves in many regions on earth, and is predicted to intensify physiological stress especially in extremely changeable habitats like the intertidal. We investigated the heat-shock response (HSR) and enzymatic antioxidant defense levels of Patagonian shallow-water limpets, adapted to distinct tidal exposure conditions in the sub-and intertidal. Limpets were sampled in the temperate Northern Patagonia and the subpolar Magellan region. Expression levels of two Hsp70 genes and activities of the antioxidants superoxide dismutase (SOD) and catalase (CAT) were measured in submerged and 2-and 12-h air-exposed specimens. Air-exposed Patagonian limpets showed a tiered HSR increasing from South to North on the latitudinal gradient and from high to low shore levels on a tidal gradient. SOD activities in the Magellan region correlated with the tidal rhythm and were higher after 2 and 12 h when the tide was low at the experimental site compared to the 6 h value taken at high tide. This pattern was observed in intertidal and subtidal specimens, although subtidal individuals are little affected by tides. Our study shows that long-term thermal adaptation shapes the HSR in limpets, while the oxidative stress response is linked to the tidal rhythm. Close to the warm border of their distribution range, energy expenses to cope with stress might become overwhelming and represent one cause why the limpets are unable to colonize the shallow intertidal zone.

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