Friday, October 18, 2024

Heat hardening: a boost for abalone in warmer waters

October 18, 2024 - Climate change is leading to increased ocean temperatures, which will place mollusc aquaculture under increasing pressure to adapt. New research from the University of Plymouth offers promising insights into how molluscs can be conditioned to better withstand warming waters through a process called 'heat hardening'.

The research, published in the Journal of Thermal Biology, focused on the European abalone Haliotis tuberculata, to test how a period of exposure to different temperature treatments affected their ability to later survive rapidly rising sea temperatures. Heat hardening involves exposing animals to repeated, short bursts of heat stress, a strategy that could make them more resilient to rapidly increasing temperatures without the negative effects seen under long term heat exposure. The study explored how different thermal treatments impacted abalone over a six-month period. Researchers compared abalone kept at a stable, cool temperature (15°C), those exposed to long-term, mild warming (20°C) and those subjected to repeated acute heat shocks (23-25°C for a few hours) followed by recovery periods.

The results were striking: while both long-term warming and repeated heat shocks increased the abalone's thermal tolerance during a later heat challenge, those that underwent heat hardening showed better overall health. They maintained higher body condition indices, indicating that heat hardening allowed the abalone to build heat resilience without the usual trade-offs, such as reduced growth or performance, seen in animals exposed to milder, but longer-term warming.

This ending is particularly significant for mollusc aquaculture. Heat hardening could be an effective tool for improving thermal performance, helping them adapt to fluctuating temperatures while maintaining good health. Applied in a hatchery context, this technique could also benefit efforts to restore wild populations, which are under threat from rising temperatures and overfishing. While the study was conducted on abalone, the authors suggest that heat hardening could be a valuable strategy for other species.

The team at the University of Plymouth are now exploring the universality of heat hardening across a range of commercial species with consequences measured both in breeding stock and their offspring. If successful, heat hardening could offer a practical solution to bolster resilience against climate change, under both commercial and conservation settings, allowing molluscs to thrive in warmer, more unpredictable oceans.

For more information, visit HERE.

The Aquaculturists

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