Biogenic carbonate/bryozoan habitats
Map ID Number: 16, 4, 21, for example.
Location: Chief areas are the Three Kings Shelf and Snares Plateau for extensive bryomol (Bryozoan-Mollusca) shell gravel. Large bryozoan colonies forming habitat occur in Tasman Bay, Otago Shelf, and parts of Foveaux Strait. Smaller areas include Mernoo Bank on the eastern Chatham Rise, Stephens Hole in Cook Strait, Otago Shelf, and parts of Foveaux Strait and the Campbell Plateau.
Approximate area: 10,000km2
Description of habitat type:
Bryomol gravel environments are rich in three-dimensionality created by erect bryozoans, corals, hydroids, sponges, and ascidians. This three-dimensionality is coassociated with high diversity of mobile epibiota and fish. The highest macrobenthos diversities are found in these habitats, with nurseries for commercial fish associated with at least some of them.
Biological attributes:
New Zealand’s currently known marine biodiversity hot spot, Spirits Bay, is associated with bryomol habitat. Of all known bryozoan localities in the world, Spirits Bay has the highest bryozoan diversity per unit area. The 300 species found in just the 200km2 region of the bay are equivalent to the diversity of the entire bryozoan fauna of the British Isles. Spirits Bay, and other areas in the world, can have high local endemism at species and even genus level.
One habitat-forming bryozoan species, Cinctipora elegans, and the related northrestricted Attinopora zealandica, are the only living species of the endemic family Cinctiporidae. This family has giant zooids – the largest in the entire Stenolaemata class.
The endemic, habitat forming bryozoan corals of Tasman Bay, Celleporaria agglutinans and Hippomenella vellicata, have existed in the northwest region of the South Island since the early Miocene period.
Criteria applied:
Species diversity; species richness; endemism; representation; unusual degree/ proportion of biomass; habitat complexity/ diversity.
Status and management:
One small area off Spirits Bay is protected from bottom trawling.
State of information:
See references below. The state of information for bryozoan taxonomy is good, but the “ecology” is only partially described (i.e. for places like Spirits Bay).
References and further reading:
Battershill et al. (1998), Bradstock and Gordon (1983), Carter et al. (1985), Head (1985), Nelson et al. (1982, 1988a, 1988b), Probert et al. (1979).