Opinion – What we need to do to protect our marine mammals from the negative effects of noise in the ocean.

by Dr Deanna Clement and Dr Simon Childerhouse

16 April 2021

While we’ve known for more than 70 years that whales and dolphins use sound to communicate across the oceans, it’s only been within the last few decades that we’ve had the technology to use sound as a means of studying them within their environment.

At the same time, we are also beginning to realise just how noisy humans have made the oceans and the significant impact this has had on many marine mammal species including masking communication, displacing individuals from critical habitats and even potentially causing strandings resulting in death. This is an issue that is receiving considerable international interest with increasing calls for consistent policy and guidance.

There are two key things we need to do here in Aotearoa that will enable us to address this issue:

Firstly, we need to collect a lot more high-quality data about the level of noise in our marine environment and its impact on our marine mammals.

Unfortunately, we don’t know much about the impacts of noise on our marine mammals because we don’t have robust national data. Recently, Cawthron has been working alongside a number of partners including industry to begin monitoring and collecting data from coastal areas in Aotearoa using underwater acoustic recording devices. In particular, we are pleased to see many ports taking proactive steps to address this key conservation issue.  

The second thing we need to do is introduce consistent national guidelines for underwater noise.

Aotearoa doesn’t currently have national standards or guidelines for underwater noise. Our Resource Management Act (RMA) regulatory framework does include requirements for coastal development and marine activities to prevent harm to protected species, including marine mammals. However, this RMA process is managed at a local level by Councils and so the mitigation required by applicants to avoid any impacts varies from Council to Council, project to project. At present, some projects (e.g. dredging and piling) receive very complicated and detailed consent conditions relating to the mitigation of noise while other projects receive little or no conditions.

Because we don’t have a lot of data about noise in our marine environment, we have to rely on encouraging the application of overseas guidelines and standards during consent processes. There is no requirement on consent authorities to implement any mitigation and, in some cases, there are valid questions around the applicability of international guidelines to New Zealand. This can introduce a high degree of uncertainly into the process which translates into increased risk and also costs for ports and other users applying for consents in the marine environment. As a general rule, each individual project in the resource consent process traverses the same ground, meaning each project pays for these issues to be debated and considered, sometimes reaching different conclusions about the appropriate level of noise mitigation that should be implemented.

The development of guidelines in Aotearoa would enable a greater level of confidence for all concerned.

Our experience is that most people using the marine environment in Aotearoa care about marine mammals and want to protect them. National guidelines would support regulators and users of the marine environment in achieving better outcomes for marine mammals.

Our skills and experience in marine ecology, oceanographic modelling, biosecurity and aquaculture environmental effects research are proving valuable to industries that are operating in the marine environment and looking to understand and mitigate the effects of their activities on marine mammals.  We hope to draw on this experience and contribute to the establishment of national guidelines for noise in the marine environment, providing advice, support and leadership where we can. 

Above all else, we’ll continue to advocate for the wellbeing of our marine mammals – they are taonga species here but also globally-significant in efforts to protect the biodiversity and health of our oceans.


Deanna Clement, Marine Ecologist – Marine Mammals and Resource Management
Dr Deanna Clement – Marine Ecologist at Cawthron
Simon Childerhouse, Senior Scientist – Marine Mammals and Marine Ecology
Dr Simon Childerhouse – Marine Ecologist at Cawthron
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