Aquaculture news

Greenshellâ„¢ Mussels breeding trials reveal varying resilience to ocean acidification
13 June 2017

Strong mussels inherit ocean acidification resilience from parents

Cawthron scientists have revealed preliminary findings from their Greenshell™ Mussel ocean acidification breeding trials. Dr Norman Ragg advised their trials indicate certain mussel families are more likely than others to survive predicted ocean acidity changes.

“We’ve been conducting ambitious breeding trials to determine how the iconic Greenshell™ Mussel species will respond to ocean acidification. I’m pleased to report these trials have been remarkably successful.

“Preliminary analysis of our trial data suggests different families have varying resilience to ocean acidification during the fragile early life stages. This means there’s genetic potential within the New Zealand mussel populations to adapt to rapid acidity changes,” said Dr Ragg.

Ocean acidification is a worldwide climate change phenomenon. As the level of carbon dioxide in the atmosphere increases, the acidity of seawater around the world is slowly increasing.

Cawthron scientists share their research into the effects of ocean acidification on coastal waters and their inhabitants, and how selective breeding may help with acidification resilience in Greenshell™ Mussels

Through their trials, Dr Ragg and his team have discovered this pH change makes it difficult for young mussels to grow their hard shells, meaning some babies will not survive the vulnerable first 48 hours of life. However, the breeding trials show some offspring are blessed with a stronger innate resilience, inherited from their parents.

Dr Ragg explained that the research team have also been studying whether the experiences of adult mussels are reflected in the resilience of their babies; interestingly there does appear to be a correlation.

In this study, adults were kept in seawater of varying relative acidity. After months in this environment, scientists induced spawning and monitored the offspring’s growth and survival.

“Results from the parent acidification trials look positive. They suggest adult mussels who experienced relatively acidic seawater have more tolerant offspring than adults without this exposure.

Taking a closer look at the Greenshell™ Mussel trials

“This is a major discovery and supports Lamarck’s evolutionary theory on inheritance,” said Dr Ragg.

This research is facilitated by industry partnership and the Greenshell™ Mussel breeding programme. Through this programme, scientists could access excellent genetic coverage, studying Greenshell™ Mussel families from populations sourced from across New Zealand. These families were then carefully reared and harvested by Sanford, providing ideal research material.

These trials are part of the wider Coastal acidification - rate, impacts and management (CARIM) project, which aims to develop ocean acidification knowledge to enhance the protection and management of New Zealand coastal ecosystems.

CARIM is a NIWA-led collaboration, which includes partners Cawthron, University of Auckland, and University of Otago. It’s a four year project, funded by the Ministry of Business, Innovation and Employment (MBIE).