Thermal Stress Responses in Abalone Aquaculture

Abalone aquaculture faces mounting challenges from rising sea temperatures and more frequent marine heatwaves. Thermal stress can compromise growth, reproduction and survival across life stages, with smaller or sexually immature individuals often exhibiting different tolerance thresholds compared with larger, spawning animals. Acute heat exposure provokes rapid physiological adjustments such as increased heart rate until the Arrhenius breakpoint temperature is reached, beyond which cardiac performance falters. At the cellular level, misfolded proteins accumulate in the endoplasmic reticulum, triggering the heat shock response and activation of molecular chaperones, particularly heat shock proteins. Prolonged or recurrent thermal insults also generate reactive oxygen species, disrupt energy metabolism and depress immune capacity, leading to increased susceptibility to pathogens. Modern transcriptome profiling has unveiled complex regulatory networks, including protein processing in the endoplasmic reticulum, endoplasmic reticulum-associated degradation pathways and innate immune signalling cascades. These insights underpin selective breeding for thermal resilience, optimisation of husbandry regimes and the development of molecular biomarkers to predict summer mortality events, thereby enhancing the sustainability of global abalone production.

Research from Nature Portfolio

Recent studies have explored the interplay between thermal and hypoxic stress in abalone immune function. Transcriptome analysis of hemocytes revealed that simultaneous exposure to elevated temperature and low oxygen levels induces immunosuppression through coordinated regulation of PI3K-AKT, MAPK, NF-κB and p53 signalling pathways. Inhibition of key kinase genes demonstrated that temperate modulation of these pathways can attenuate pathogen resistance under stress. This work emphasises the need to consider multiple environmental stressors in abalone farming and suggests molecular targets for bolstering immune defences during peak summer temperatures.

Thermal Stress Responses in Abalone Aquaculture publication trend

The graph below shows the total number of articles in thermal stress responses in abalone aquaculture across all publications each year (not limited to Nature Index journals).

Technical terms

Critical thermal maximum (CTmax): The highest temperature at which an abalone maintains physiological function before collapse under increasing thermal load.

Heat shock proteins (HSPs): Conserved molecular chaperones upregulated by elevated temperatures to refold damaged proteins and protect cellular integrity.

Transcriptomics: The comprehensive analysis of RNA transcripts to identify gene expression changes under thermal stress conditions.

Arrhenius breakpoint temperature (ABT): The temperature at which a species’ heart rate-temperature relationship deviates from linearity, signalling impending cardiac failure.

Endoplasmic reticulum-associated degradation (ERAD): A quality control pathway that disposes of misfolded proteins in the endoplasmic reticulum, critical during heat-induced protein damage.

References

1. Size-dependent thermal limits in Australian hybrid abalone: implications for productivity shifts with ocean warming. Reviews in Fish Biology and Fisheries (2023).
2. Different Transcriptomic Responses to Thermal Stress in Heat-Tolerant and Heat-Sensitive Pacific Abalones Indicated by Cardiac Performance. Frontiers in Physiology (2019).
3. Expression of Heat Shock Proteins in Thermally Challenged Pacific Abalone Haliotis discus hannai. Genes (2019).
4. Epipodial Tentacle Gene Expression and Predetermined Resilience to Summer Mortality in the Commercially Important Greenlip Abalone, Haliotis laevigata. Marine Biotechnology (2017).
5. Immunity-related genes and signaling pathways under hypoxic stresses in Haliotis diversicolor: a transcriptome analysis. Scientific Reports (2019).
6. Transcriptomic responses to thermal stress in hybrid abalone (Haliotis discus hannai ♀ × H. fulgens ♂). Frontiers in Genetics (2022).
7. Transcriptome Sequencing Reveals the Response to Acute Thermal Stress in the Pacific Abalone, Haliotis discus hannai. Aquaculture Research (2023).