Information for environmental stakeholders

Chatham Rock Phosphate is acutely aware of its responsibilities to conduct both the mineral prospecting programme and extraction of the rock phosphate, in a manner causing minimal disruption to the marine environment.

The company has undertaken extensive environmental research, prepared a comprehensive Environmental Impact Assessment and undergone a full Marine Consent application process conducted by a decision-making committee appointed by the Environmental Protection Authority. All of the proceedings can be found at:

The website contains all of the 30-plus expert reports prepared for the application process, plus all evidence, submissions and other reports prepared.

CRP has spent at least $20 million on scientific research to assess the potential impacts of our project. As a side benefit, our environmental work programme is contributing many millions of dollars worth of new data about the environment, which will be of the public benefit.


Specifically CRPL wants to:

  • Understand which baseline information currently exists
  • Understand which additional information should be collected to critically evaluate the potential impact of exploration and extraction
  • Utilise the information collected, including these initial baseline reports and subsequent impact assessments, to develop any required mitigation strategies.

The reports cover biological and commercial fishing considerations, epifaunal and infaunal communities, distributions of cetaceans, physical oceanographic data, oceanographic models for sediment dispersal estimates and simulations of sediment plume behaviour. NIWA has previously conducted several environmental investigations on the Chatham Rise as a whole, albeit not connected to CRP’s potential extraction activity, including the mapping of various habitats and sea state conditions.
CRP has stationed environmental baseline monitoring equipment within the licence area on the Chatham Rise to monitor currents, water temperatures and water turbidity to create baseline environmental records for the area. Some rock phosphate and sediment samples were also gathered.  CRP has also undertaken additional environmental data collection as part of survey cruises.  


Summaries of each of the reports follow:

Phosphorite Prospecting on the Chatham Rise – Biological and Commercial Fishing Consideration:

This report details currently available knowledge of fishing activity and benthic communities on the Chatham Rise, including our project’s area of interest. The area is located on the mid-slope of the Chatham Rise in an area where there is very little trawling compared with the rest of the Chatham Rise. Approximately 80% of the project area lies within a Benthic Protected Area that has been closed to bottom trawling since 2007. Long line activity in the area has been inconsistent in recent years, which suggests that catches are poor. The macro-benthic fauna on the Chatham Rise have been relatively well sampled compared with many areas of the deep sea. However, only limited data are available from within the licence area and these data are mostly qualitative and patchily distributed.



The Chatham Rise Benthos – Epifaunal and Infaunal Communities:

This report expands on the initial work described above and places the benthos of the  area in the context of the wider Chatham Rise to determine if the  area encompasses benthic habitats and/or species that are not present elsewhere. Abundance and species diversity for a range of taxa were determined from a geographic information system (GIS) analysis of the NIWA databases. Based on the qualitative baseline data currently available, it appears the area does not contain any epifaunal or infaunal taxa not present elsewhere on the Chatham Rise.


Distribution Patterns of Cetaceans on the Chatham Rise:

Cetaceans are highly mobile and dynamic animals that travel quickly between areas in search of prey and preferred habitat. Two datasets of opportunistic sightings of cetacean species were used to describe their distribution patterns along the Chatham Rise:

  1. The Department of Conservation (DOC) cetacean sightings data
  2. A dataset provided by Martin Cawthorn of incidental cetacean sightings by transiting ships.

These two datasets provide 57 records of 8 different cetacean species sighted between July 1981 and November 2007 on the Chatham Rise.

The majority of sightings were of sperm and pilot whales; sightings were concentrated on shelf breaks in areas of high slope where whales are known to feed on squid. Additionally, sightings of various species of migratory whales were made in the Chatham Rise area, likely as the animals travelled between their summer feeding grounds toward the south and their northern breeding grounds during winter months. Three species of dolphin have also been sighted on the Chatham Rise (bottlenose, common, and dusky).


Physical Oceanographic Data Available on the Chatham Rise:

This report provides a brief overview of the available physical oceanography databases around the Chatham Rise, and provides a list of available data for future analyses. The metersse data include sea surface temperatures from satellites, vertical profiles of temperature and salinity, current measurements (current meters, shipboard measurements and acoustic Doppler current profilers (ADCP), sea surface heights, sea surface colour, and ocean winds. The main oceanographic feature along the Chatham Rise is the convergence of several eastward flowing currents or ‘jets’ on the northern and southern flanks of the Rise:

  • The northern jet comprises salty subtropical water (STW) and originates in the  East Cape Current
  • The southern jet comprises fresh sub-Antarctic water (SAW) and is sourced from the Southland Current.

Waters directly over the crest of the rise can be STW, SAW, or a mixture of the two; currents on the crest are variable in direction and weaker than the jets on the flanks of the rise. There is significant seasonal variability in seawater composition. Wintertime mixed layers can extend to 300 m (comparable with the crest of the rise) while summer mixed layers are shallow (typically less than 50 m).


Oceanographic Models of Chatham Rise for Sediment Dispersal Estimates:

This report documents the oceanographic modelling of the Chatham Rise. The lack of observations of this dynamic region makes detailed testing of the models difficult; however, representative estimates of sediment dispersal for several scenarios, associated with a possible extraction operation within the project area, are provided. The effect of bathymetry is considered with a simplified model. Evidence from in-situ observations related to existing natural material fluxes and sediment concentrations is also presented.


Ocean Model Simulations of Sediment Plume Behaviour:

Building on previous NIWA work in the area, a three-dimensional, hydrodynamic model (ROMS), has been set up for a 500 km by 440 km domain over central Chatham Rise with a 2 km horizontal resolution. The model is forced by currents, temperature and salinity at its lateral boundaries from a larger-scale ocean model of the New Zealand region and by surface stresses and heat fluxes from a global atmospheric model (the NCEP Reanalysis). A base simulation was run for two model years, producing time-varying temperature, salinity, and velocity fields. There was also a series of sediment plume simulations. These were run for shorter periods, initialised from the base simulation and exposed to the same forcing, plus tidal fluctuations in velocity and sea surface height from a New Zealand region tidal model, also applied at the lateral boundaries.