Non-geniculate coralline algae
Map ID Number: Not mapped during the workshop
Location: Non-geniculate coralline algae are widespread from the intertidal to the deep subtidal. They are found throughout New Zealand, from the Kermadecs (to approximately 200m) to the subantarctic islands.
Approximate area: Not recorded during the workshop
Description of habitat type:
Coralline algae encrusts rock walls and cobbles, and other marine plants and animals (epiphytic and epizoic). It is also found in a free-living form as rhodoliths, which are also in fossil deposits.
Biological attributes:
Coralline algae are implicated in the settlement of invertebrates, particularly paua (abalone) species and kina (sea urchins). Algae release materials that result in the settling of planktonic phases. Rhodolith beds are recognised internationally as significant (and vulnerable) habitat for fish juveniles and invertebrate hot spots of diversity.
Criteria applied:
Species richness; endemism; representation; habitat complexity/diversity.
Status and management:
Rhodoliths are vulnerable to disturbance/harvest as bycatch from trawling or other fishing activities. Coralline algae are slow-growing, which makes it them vulnerable to human impacts such as modification of coastal environments through sedimentation and nutrient enrichment. Removal of particular species may have a significant impact on recruitment of particular invertebrates.
State of information:
Information on non-geniculate coralline algae is very poor, but an initial study was started in 2002 with funding from the Ministry of Fisheries. Very little is known about the distribution of rhodolith beds. Only one rhodolith bed is well identified between Kapiti Island and mainland New Zealand, although others have been recorded, predominantly from northeastern North Island sites
References and further reading:
Nelson and Farr (2001), Nelson (2002), Woelkerling and Nelson (2004).