Our Marine Environment

Broad-scale habitats

Ideally, any marine classification should be based on the ecology and distribution of
marine flora and fauna. However, we simply do not have this information at the scale required nationally. So as an alternative to a biologically-driven classification, the approach of the MPA Policy is to use physical surrogates to classify the marine

Broadscale habitats

Example of broad-scale classified habitats off the Otago peninsula

environment into broad scale habitats.The main environmental factors which influence community structure (international and national literature) are considered to be depth, substrate, and exposure (wave action, tidal action and currents). These three key physical variables that influence coastal biodiversity have been used to identify habitat-types within the region. More detail on what these habitats are and how they were derived can be found [here].

Biogenic habitats

Some plants and animals grow in such a manner that they provide a unique environment and physical structure for other plants and animals. Habitats created this way are called biogenic.


Examples of biogenic habitat (Source: NIWA ‘Sensitive marine benthic habitats defined)

Biogenic habitats may offer space for attachment, hiding places from predators, and shelter from harsh environmental conditions. Examples of biogenic habitats in the Southeast Marine area include seagrass beds, kelp forests, bryozoan thickets, sponge gardens, tubeworm mats, shellfish beds,  and probably many more that are as yet unreported. These different communities develop in a range of habitats from exposed open coasts to estuaries, marine inlets and deeper offshore habitats, and may be found in a variety of sediment types and salinity regimes.Below are a few examples and some links to further information..


Bryozoans are colonial animals that live on the seafloor and feed by collecting single-celled algae from the seawater (suspension feeding). They encrust surfaces – rocks, seaweeds, other animals – and can also grow away from these substrates, forming three-dimensional structures. A summary of the science relating to Bryozoans can be found here.




Seagrasses are highly productive coastal habitats that provide a range of key ecosystem functions and services (Duarte & Chiscano 1999; Gillanders 2007). Seagrasses have been recognised to support one of the most valuable ecosystems worldwide, and represent a significant ecological and economical component of coastal habitats. A summary of the science relating to seagrass can be found here.



Macrocystis pyrifera (which forms a floating surface canopy) and other sub-canopy forming marine macroalgal species … are often prevalent on shallow, temperate, rocky coastlines and reefs. Collectively these configurations of species create ecosystems known as kelp-forests. A summary of the science relating to kelp can be found here.

Sponges, worms, shellfish & others…

Unfortunately, while we know other biogenic habitats exist in the region, we don’t have detailed information on whereabouts they all are, or how much there is of it. The links below provide some general information on these habitat types…