Rahui And Marine Construction: Potential For Enhancement of Taonga species

Abstract

The aims of my study were to investigate whether marine reserves enhance intertidal species used by Māori in a traditional or contemporary sense, and whether artificial structures in the intertidal region (such as wharf and bridge pilings) provide suitable habitats for traditionally harvested species. Further, I investigated whether non-indigenous species were found in these habitats, which may affect traditionally used species. The abundance of ataata (cat's eyes; Turbo smaragdus) and kina (sea urchin; Evechinus chloroticus) were quantified in three marine protected areas and nearby unprotected reference beaches. Results from Mann-Whitney U comparisons suggested that kina were significantly enhanced inside the two marine reserves with total protection. Kina are released from harvest pressure inside these reserves and possibly from the effects of predation and competition. In one reserve ataata abundance was significantly lower and no difference was found for ataata in the second reserve. This species is not as heavily harvested as kina and may even be negatively affected by trampling inside reserves. Both kina and ataata showed no response to a partially protected marine park. Abundance of both non-indigenous species was not sufficient enough to be sampled and statistically quantified at the marine reserve sites. Biotic resistance may restrict the proliferation of non-indigenous species in rocky intertidal marine reserves. Intertidal fauna were scraped from concrete and wooden structures and were compared with fauna inhabiting nearby natural rocky reefs. Multi-dimensional scaling and ANOSIM was used to explore trends in the community composition of different study sites, and to illustrate which habitat types are more associated with traditionally used and non-indigenous species. The main results conclude that diverse communities are associated with natural habitats whereas constructed structures have limited fauna. Of the traditionally used species, the native rock oyster (Saccostrea glomerata) was found in relatively equal frequencies on artificial habitats and rocky reefs, and the non-indigenous oyster (Crassostrea gigas) was predominantly recorded on artificial structures and rare on natural substrates. The construction of artificial structures around New Zealand's coastline may assist in the spread of non-indigenous species, to the detriment of species traditionally used by Māori.