A Marine Mammal Mitigation Plan (MMMP) or Marine Mammal Impact Assessment (MMIA) is designed to identify and minimise any impacts (positive or negative) of any offshore activities on marine mammals, such that any disturbance to the animals is reduced. In New Zealand, a MMIA is required when applying for approval to carry out a seismic survey.
Concerns have been raised over impacts of increasing levels of ocean noise on cetaceans (whales, dolphins and porpoises), which use sound to detect and locate food sources, communicate, and navigate. Introduction of noise into the marine environment by offshore industrial activities, such as seismic surveys or pile-driving, may have negative impacts on marine mammals both at the individual and population level, leading to conservation concerns. Consequently, many countries have introduced mitigation guidelines, some of which require a MMMP for approval of offshore activities.
A Marine Mammal Mitigation Plan must consider:
- Location and timing of proposed activity;
- Mitigation options and control at the operational level; and,
- Real-time mitigation options.
The location and timing of a proposed offshore industrial activity can determine the marine mammal species likely to be encountered (including seasonal differences in distribution and migration routes) and behaviour of those species (e.g. breeding or feeding, which may make them more or less susceptible to any impacts). Data on many cetacean species are sparse, so any data collected as part of an MMMP contribute to increasing the effectiveness of future MMMPs.
Mitigation options and controls at the operational level involve ensuring that the level of entering into the marine environment by the proposed industrial activity is kept to the minimum required. For example, in the case of seismic surveys, air guns should only be fired at the power and number required to conduct the survey, rather than at maximum capacity (unless required). Other noise-producing activities, such as pile-driving, may require acoustic insulating materials.
The aim of real-time mitigation is to ensure the absence of marine mammals in the vicinity of the proposed industrial activity prior to commencement, and in some cases, whilst operations are ongoing. This is achieved through visual and acoustic observations of the area surrounding the operational area.
Real-time mitigation guidelines vary from country to country. In New Zealand, the Code of Conduct for Minimising Acoustic Disturbance to Marine Mammals from Seismic Survey Operations (referred to as the Code, available here) is specifically tailored to seismic surveys and is administered by the Department of Conservation (DOC). Guidelines on mitigation vary depending on the level of noise produced by the survey.
Implementing a Marine Mammal Mitigation Plan
Location and timing of the proposed activity and mitigation controls at the operational level are usually determined prior to operational approval, or as part of the approval process.
The real-time monitoring aspect, however, takes place during the industrial activity, and is implemented by dedicated Marine Mammal Observers (MMO) and Passive Acoustic Monitoring (PAM) operators, usually stationed on the vessel or rig from which the noise-producing activity is being conducted. Number of MMOs and PAM operators required varies between countries; in NZ, a minimum of two MMOs are required, and, depending on the seismic source operational capacity, a minimum of two PAM operators may also be required. MMOs can only conduct visual surveys for marine mammals during daylight conditions and in reasonable weather conditions. Passive Acoustic Monitoring detects vocalisations of submerged cetaceans (with some limitations) and can be carried out at night and in poor weather conditions, allowing for 24-hour implementation of a MMMP.
Ocean Science Consulting (OSC) provide trained, qualified, and experienced MMOs and PAM operators to implement Marine Mammal Mitigation Plans and monitor compliance with regulatory guidelines.
Ocean Science Consulting and Marine Mammal Mitigation Plans
Ocean Science Consulting has written Marine Mammal Mitigation Plans for a number of clients across varied offshore sectors around the world, including oil and gas and wind farm projects. OSC is able to draw on its unique depth of knowledge and experience gained from working offshore in both research and monitoring/regulatory capacities, and is aware of the realities of working in offshore conditions. Drawing on our extensive expertise, we examine all possible marine mammal mitigation options and also consider the practicalities of implementing a Marine Mammal Mitigation Plan offshore so that we deliver a quality MMMP that maximises mitigation effectiveness (thus satisfying the regulator) whilst minimising operational downtime.
Ocean Science Consulting also provide trained, qualified, and experienced MMOs and PAM operators to implement MMMPs and monitor compliance with
In New Zealand, OSC have advised the Department of Conservation (DOC) on guidelines for Passive Acoustic Monitoring (PAM) of marine mammals for their seismic survey Code of Conduct. The Code is currently under review, a process which we are once again involved in.
DOC, 2013. 2013 Code of conduct for minimising acoustic disturbance to marine mammals from seismic survey operations. p. 36. Publishing Team, Department of Conservation, Wellington, NZ.