Pāua
Pāua are one of the most sort after, and fought over, kai moana species in Aotearoa. A vigourous commercial harvesting industry is thought to be depressing stocks available for customary and recreational fishers in many places.
Pāua – Abalone (Haliotis sp.)
World wide 55 different species are known, grazing on red, green and brown seaweeds in temperate waters. In New Zealand three species - the black foot, yellow foot and virgin pāua - are known, which are most abundant on shallow reefs.
Reproduction
Pāua sexually mature at 3-5 years or 60-90mm depending on where they are found. The
size of a pāua depends on water temperature: the further south the bigger, and the greater size needed to maturity. Unlike several other mollusks, pāua are not hermaphrodites but have animals of separate sex. Males and females can be distinguished before spawning, when female gonads are dark green while male gonads are cream coloured. The mollusks spawn once a year starting in late summer through to October. Egg and sperm release through the obvious respiratory pores in the shell is probably triggered by water temperature dropping below 15°C and stormy conditions. The animals can sense when their neighbours are spawning, prompting simultaneous spat release. This increases the number of eggs (each female releases 7 million 0.2mm diameter eggs) being fertilized, hence chances for survival of larvae increase. Although not well understood, it is known that the larvae go through several developmental stages during a one to two week period. The Settling of the larvae depends on several factors, most important temperature: the warmer the water the faster larvae develop. It was found that pāua larvae settle within 5km of their release area.
Re-seeding pāua
Settlement of pāua larvae and the following early development seem to be encouraged by 
chemicals produced by different species of coralline algae. These coralline algae are well visible as pink patches forming crusts or turfs on rocks and reefs in the intertidal and shallow subtidal, but can be found at a depth of 270m. Tests in the laboratory have shown that even the species of coralline algae can matter: two species Mesophyllum sp. (relatively thick, warty) and Phymatolithon sp. (thinner, smoother) were tested for settlement preference and post-settlement survival and compared to barren rock. Both species showed significant higher numbers of pāua larvae settled compared to the barren rock. Post-settlement survival after 72 hours was much higher on the thinner, smoother Phymatolithon sp. than the thick, warty Mesophyllum sp.. 
Observations of juvenile pāua (30-70mm) in the wild found the animals mainly on an encrusting brown alga (Ralfsia) and encrusting coralline algae. Juveniles seemed to avoid the thick, warty and turf-forming coralline algae. Western research on re-seeding pāua is still in its infancy in New Zealand, hence collaborative work with communities interested in pāua re-seeding is of great importance for the sustainable management of the animal.
Research underway
Te Tiaki Mahinga Kai research on pāua management is being done by Chris Hepburn, Miles Lamare, Derek Richards, Julie Futter, John Pirker and Simon Lambert.
References:
The living Reef: The Ecology of New Zealand's Rocky reefs, editors Neil Andrew & Malcolm Francis
Acknowledgement: Thanks to Te Atiawa Manawhenua Ki Te Tau Ihu Trust for providing some great images!
