Has the Threat of Ocean Warming/Acidification Been Even Considered?

Thames-Coromandel District Council has identified aquaculture as “a key activity of focus and is working hard to ensure the industry can grow on the Coromandel”.  But is the Council paying any attention to the potential looming threats to the mussel and oyster farming industry of warming and acidification of the ocean due to climate change?

Is TCDC falling into the trap of looking at the significant contribution the aquaculture is currently making to the Coromandel economy, and then simply projecting substantial future growth into the future without taking account of the cascading risks climate change/acidification poses to that industry?

It does seem that way.  The Council has relied heavily on an economic modelling report from NZEIR which paints a rosy picture of 50% increased shellfish production.  But when NZEIR lists “Limitations and caveats” on its modelling, the report fails even once to mention “climate change”, “acidification”, or “sea level rise”.

It’s obvious both the Council and its consultants have a massive blindspot around climate change/acidification and the potential threat this could mean for the mussel and oyster  industry.

Aquaculture Industry Warned of Climate Change Risks

NIWA scientist Petra Pearce laid out the threat that a warming ocean and acidification poses to the industry in stark detail at a recent aquaculture conference where she said: –

• “the world’s oceans are seeing their fastest rate of acidic change in 25 million years, with the rate of decline about to snowball if greenhouse gas emissions are not checked.” 
• “this could impact the shells of paua, mussels and oysters, reducing their larval growth, and the shells of plankton, reducing their growth rates. A drop in plankton numbers could lead to a reduction in the amount of food available for paua, mussels and oysters.”
• “the western parts of the Tasman Sea, near Australia, were projected to increase by about 4C, which would then push along to New Zealand on the Tasman Front.”
• “ocean warming could create heat stress for mussels, provoke algae blooms and encourage more water-based pests and diseases. This could lead to serious health impacts for aquaculture species, leading to a reduction in productivity and an increase in costs for marine farmers”
• “sea level rise could create a “nuisance” for aquaculture farmers due to more frequent coastal flooding.”
• “coastal flooding could cause the flooding of wastewater systems, which could contaminate coastal waters and impact aquatic animals,”
• “an increase in rainfall could create more slips, more coastal erosion and larger floods, which would lead to damaged aquaculture infrastructure and a decrease in the clearness of coastal waters.”

These represent a potentially disastrous set of cascading threats to the mussel and oyster farming industry in Thames Coromandel.  Before the Council commits further limited ratepayer funds for promotion of the mussel and oyster industry, surely it must revisit the research, and engage consultants who understand the potential threats from climate change and ocean acidification.

Footnote:

Pare Hauraki iwi authorised to apply for fish farming

Waikato Regional Council has granted Pare Hauraki Kaimoana authority to apply for resource consents to occupy 240 hectares of finfish farming space in the Firth of Thames following a tender process.

The space, known as the Coromandel Marine Farming Zone, is located about 10 kilometres offshore of Coromandel Town.

Pare Hauraki Kaimoana propose farming kingfish in the space and the authorisation means they now have two years to prepare and submit an application for the necessary resource consents.

It will be interesting to see how climate change and ocean acidification, as well as other serious environmental impacts, are dealt with in these upcoming resource consents.

Radio NZ interview with NIWA scientist –