Appendix 2: Detailed Explanation of Draft Marine Environments Classification Maps at 4-class, 9-class and 20-class levels
The maps at the end of section 1.3 of this report show the draft Marine Environments Classification at the Exclusive Economic Zone scale at three different hierarchical levels: 4-class, 9-class and 20-class levels. The following text further explains the environmental variation at these successive hierarchical levels of the classification. It has been adapted from text supplied by Ton Snelder of the National Institute of Water and Atmospheric Research (NIWA), who is project manager for the Marine Environments Classification development.
4-class map
The main subdivision shown in this map is between the relatively 'coastal' environments and the deeper 'oceanic' environments. Within the oceanic environments, further divisions are associated with differences in the mean annual solar radiation and sea surface temperature (winter). These subdivisions approximately define the subtropical, shelf and subtropical front, and subantarctic waters.
9-class map
The 9-class level further subdivides the subtropical waters into deep and abyssal, the shelf and subtropical front waters into the deep subtropical front, and central continental shelf and southern continental shelf. The 9-class level also subdivides the coastal environment into three classes that are associated with differences in the mean annual solar radiation and sea surface temperature winter; northern, central and southern continental shelf.
20-class map
The 20-class level further defines variation in the shallow coastal environments. The following environments are discriminated:
- class 58 - high tidal current
- class 60 - middle mid-depths
- class 64 - middle shallows
- class 124 - high wave energy coastlines
- class 130 - Marlborough Sounds
- class 169 - Southland Current
- class 190 - Southland front.
This series of subdivisions is summarised in Table A below.
Table A: The average value of each of the eight defining environmental variables in each class of the 20-class level of the EEZ classification
