A feasibility study of coastal acidification mitigation strategies for the mussel industry (innovation fund)
With coastal waters becoming more acidic, this project is testing two techniques to alleviate local acidification around mussel farms. The results from these trials will then be used in hydrodynamic models to predict their effects on mussel farm pH in the top of the South Island and the Firth of Thames.
Project leader: Cliff Law, NIWA/University of Otago
Protecting mussel farms from ocean acidification
Coastal waters are becoming more acidic due to increasing atmospheric CO2 and local processes such as microbial respiration. This is a threat to New Zealand’s shellfish aquaculture industry, because mussels are less healthy and don’t grow as well at a lower pH.
We are testing two techniques to see how effective they are at alleviating local acidification around mussel farms. The first involves returning waste mussel shell, which could raise pH and dissolved carbonate, as it dissolves. The second is strategic aeration to oxygenate farm waters during the night, when oxygen and pH are naturally lower.
The results from trials of the two methods will be compared, and then used in hydrodynamic models to predict their effects on pH in mussel farms in the top of the South Island and the Firth of Thames. The impact of these methods will also be assessed on the survival and condition of mussel spat and juveniles. We are working in collaboration with Sanford, with fieldwork at their EcoFarm in May 2018 that will provide useful information to guide this project.
As well as providing recommendations for shellfish aquaculture, this research may help efforts to mitigate acidification in coastal ecosystems.
Green-lipped mussels contribute more than $240 million to New Zealand’s economy in food exports, biopharmaceuticals and health supplements; the majority are farmed.
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