Marine mammals

• Ensure a comprehensive understanding of the presence, distribution, abundance and density of marine mammals in the area both pre-operation and during operation to assist to determine whether and to what extent mining operations and associated activities may be impacting on marine mammals
• Make sure all personnel on board project vessels receive training in regards to monitoring and management of any impacts on marine mammals and seabirds, such as identification and behaviour observation
• Avoid areas frequented by threatened or endangered marine species, such as Hector’s and Maui’s dolphin, Bryde’s whale and Southern right whale, as well as those listed on the ‘Species of Concern’ list within DOC’s Code of Conduct for Minimising Acoustic Disturbance to Marine Mammals for Seismic Survey Operations ³⁵³¹
  
• Use marine mammal observers
• Use of Passive Acoustic Monitoring
• Investigate options to cease operation if marine mammals are present in high use areas
• Limit unnecessary underwater sound generation and lighting
• Reduce vessel speeds in areas known to be frequented by marine mammals

Seabirds

• Limit unnecessary lighting, and ensure that lights that are required are directed vertically onto work surfaces and/or utilise green lighting
• Monitor bird strike and review mitigation measures in response to bird mortality above an identified level
• Implement measures to reduce the likelihood of oil spills that may affect seabirds

Biodiversity

• Undertake sufficient research, to identify what species are likely to be present in the area to be mined, including their distribution
• Avoid areas of high ecological value, including areas of high endemism, such as active vent sites
• Only mine a small portion of any specific habitat
• Mine in a chequerboard or strip pattern to allow re-colonisation from adjacent populations
• Adopt mining methods which minimise the amount of sediment which is released into the water column
• Consider the cumulative impacts of mining activity and other  activities such as deep-sea trawling on benthic habitats
• Consider trialling artificial hard surfaces on the seafloor to act as settlement and attachment surfaces for corals, sponges and similar organisms
• Regularly check, clean and apply antifouling paints (preferably copper-free) to infrastructure that is brought to New Zealand from overseas (see Craft Risk Management Standard discussed in Chapter 5: Marine biosecurity)
• Assess options for biodiversity offsetting, as appropriate, to protect seabed habitats

Water column

• Adopt mining methods that minimise the amount of sediment that is released into the water column ³⁵³⁵
  
• Avoid areas where the sediment plume would disrupt areas with high ecological value
• Deposit tailings close to the seafloor to minimise extent of plume

Monitoring

• Develop and undertake a robust monitoring regime –including biological and geomorphological monitoring
• Undertake rigorous baseline monitoring, prior to mining commencing, so that ongoing monitoring data can be compared to the baseline
• Undertake sufficient monitoring so any significant adverse effects on the marine environment can be identified and addressed in a timely manner
• Publicly release monitoring information in a timely fashion.
• Consider involving tangata whenua and stakeholders in overseeing monitoring programmes 

Disruption of sedimentation and coastal processes

• Monitor changes in shoreline position
• Complete beach profiles prior to mining commencing
• Minimise the area which is directly affected by mining activity

Other

• Regularly check, clean and apply antifouling paints (preferably copper-free) to infrastructure that is brought into New Zealand’s marine area from overseas. Biosecurity New Zealand has prepared a Craft Risk Management Standard  – discussed in Chapter 5: Marine biosecurity
• Avoid significant fish spawning and nursery areas, and areas of high fish density
• Avoid sand mining in closed sand systems
• Avoid mining in areas of recreational significance, including high quality surf breaks
• Undertake rigorous baseline monitoring prior to lodging application so that sufficient information is available during the hearing and so that ongoing monitoring can be compared to the baseline
• Adopt an adaptive management approach where appropriate, where the impacts of a pilot operation are monitored and assessed before considering whether expanding to full production can be allowed or whether amendments are required
• Develop and undertake a robust monitoring regime – this should include biological, geomorphological monitoring as well as baseline monitoring, so that any significant adverse effects on the marine environment can be identified and addressed in a timely manner
• Support the efficient use and recycling of minerals to minimise the need for mining activity in the marine area

Seafloor

• Setting aside part of the habitat, with representative animals, to serve as a reference areas and sources of animals to assist recolonisation of the impacted site
• Relocating of some of the representative animals
• Installing artificial substrates to help recolonisation
• Considering location, positioning and method of any subsea discharge to limit its impact
• Employing technologies/methodologies so that sediment re-suspension is minimised during cutting
• Limiting the number and/or size of sites

Mid water column

• Developing and implementing emergency response procedures in the event of accidents leading to spills that might affect water quality
• Using fully enclosed ore delivery systems

Surface

• Releasing discharge and water from dewatering plant, where possible, at least below the top 200 metres of the water column (that is, below the light zone)
• Developing and implementing environmental management plans that specifically cover waste minimisation and loss prevention, in order to reduce impacts on water quality
• Developing and implementing emergency response procedures in the event of accidents leading to spills that could affect water quality
• Adopting effective mitigation measures to minimise the risk of injury to marine animals from ship strike or collision
• Installing approved sewage treatment plant, certified through relevant international standards, to handle such normal ship discharges as treated sewage
• Maintaining deck lights on surface levels at the lowest levels needed to ensure safe working conditions
• Developing safety, health and environmental policies and plans for all offshore operations

Operational

• Developing and implementing environmental management plans that cover waste minimisation and loss prevention to minimise impacts on water quality – a working example of a management plan was prepared by the International Seabed Authority in 2012
• Developing and implementing  emergency response procedures in the event of accidents leading to spills to the environment
• Using effective mitigation measures to minimise the risk of injury to marine animals from ship strike or collision
• Installing an approved sewage treatment plant, certified to meet relevant international standards and/or other relevant regulations
• Developing and implementing safety, health and environmental policies and plans for all offshore operations

Spatial

• Setting areas aside for conservation, possibly within mine site/mine lease areas. Depending on the site, it may not be possible to find an appropriate site within the mine lease that will not be impacted by the mining (e.g., by sediment plumes), in which case a similar site nearby may be nominated as the conservation area instead. Attention should be given to the representativeness, adequacy, resilience and connectivity of a network of areas
• Establishing marine management areas, which involve zoning of different areas for different uses or intensities of use. Such an approach may designate areas that are acceptable for total mining, areas that can only be partially mined, or areas set aside for conservation
• Evaluating other generic measures, if feasible, including installation of artificial substrates to encourage more rapid colonisation by fauna impacted by mining, and animal relocation if there are populations of rare, endemic or highly endangered species
• Evaluating the location of discharges to ensure minimal impact on ecosystems
• Considering the use of diffusers to aid dispersal
• Considering animal relocation, if there are populations of rare, endemic or highly endangered species
• Employing reserve networks, such as Marine Protected Areas

Temporal

• The time scales of nodule and crust growth and faunal recovery in the abyssal deep sea almost certainly make consideration of short-time scale measures impractical
• Measures to rehabilitate degraded areas or encourage longer-term faunal recruitment are much less likely to be effective than spatial management approaches