Heatwave on land and heatwave in sea! 

Recent studies reveal the astonishing resilience of mussels, as they adapt to and endure marine heatwaves by regulating their heart rate and other physiological processes. This adaptation bodes well for their long-term survival as global temperatures continue to rise. Everything is possible as we study the world around us and how we can learn and benefit from our research facilities.

Beyond being nutritional powerhouses, rich in vitamin B12 and omega-3, and containing over nine times the amount of B-12 than beef and five times more than salmon, mussels have showcased their ability to thrive even in the face of marine heatwaves by fine-tuning their bodily functions.

In a comprehensive experiment examining the effects of a marine heatwave on mussels of various sizes, both groups emerged as resilient champions, showcasing their extraordinary capacity to withstand environmental stress, even amidst temporary physiological alterations.

Leading scientists from the Chinese University of Hong Kong and the University of South Australia conducted a comprehensive examination of mussel vital signs after subjecting them to three weeks of elevated ocean temperatures. Remarkably, while their heart and clearance rates showed temporary increases during the heatwave, within just one week of the heatwave's conclusion, the mussels' vital signs had fully recovered.

UniSA environmental lecturer Dr. Falkenberg who was involved in the study explains, “This bodes well for their survival under future marine heatwaves, with these events predicted to increase in severity, frequency and duration,” adding, “We expected to see some marked impacts of increased ocean temperature on their vital signs, including survival, heart and respiratory rates, but to our surprise they were extremely resilient, persisting through – and recovering after – the marine heatwave.”

Furthermore, their capacity to enhance clearance rates in warmer conditions could have a positive ripple effect on other organisms within coastal ecosystems, as marine heatwaves frequently trigger blooms of algae and plankton.

Mussels are vital to marine ecosystems, playing critical roles in recycling nutrients and improving water quality in coastal systems by filtering large volumes of water while feeding, which helps to keep the water clean.

The Bugle spoke to Sam Gordon, Managing Director of South Coast Mariculture, who has a large local venture - a mussel farm in the middle of Jervis Bay, which is one of the few aquaculture farms that operates in a marine park. “We are producers of one of the world's most sustainable foods with plenty of health benefits, a nice space to be!” he says.

Nika Rountree, Operations Manager from South Coast Mariculture said, “We have noticed water temperatures fluctuate from 16 degrees in winter and as high as 25 degrees in the summer in Jervis Bay.”

In collaboration with UTS South Coast Mariculture have installed a weather buoy on their Jervis Bay Marine farm to monitor weather patterns including water temperature. “Knowing and recording sea temperatures and other weather patterns helps us manage our marine farms as Marine Heatwaves and other weather-related events become more active. The warming sea water after winter each year is associated with growth in the mussels we farm,” Mr Rountree informs.

Mr Gordon recalls other studies from overseas that have demonstrated the net benefit to the environment of farming shellfish (and seaweeds), as filter feeders that remove nutrients in the environment, and create a habitat that restores the marine environment. He says, “We are in the early stages, working with researchers and the NSW Government to do a similar study of our farm in Jervis Bay.”