DENSITY, BIOMASS AND PRODUCTIVITY OF ANIMALS IN 4 SUBTIDAL ROCKY REEFHABITATS - THE IMPORTANCE OF SMALL MOBILE INVERTEBRATES

Density, biomass and productivity of animals >0.5 mm were estimated in 4 shallow subtidal rocky reef habitats in temperate northeastern New Zealand. The main objective was to determine the relative contribution s of mobile epifauna (0.5-10 mm) and megafauna (>10 mm) to the flux of materials on the reef. The habitats surveyed were (1) Carpophyllum pl umosum var. capillifolium forest (Phaeophyceae: Fucales), (2) Ecklonia radiata forest (Phaeophyceae: Laminariales), (3) urchin barrens, and (4) articulated coralline algal turf flats. Epifauna comprised >99.5% of individuals in each habitat. Epifauna dominated biomass (>86%) in t he finely structured Carpophyllum forest and turf flats, where they co ntributed >97% of total secondary productivity. Although lower in the other 2 habitats, the epifaunal contribution to total secondary produc tivity was still similar to 78% on the scale of the entire reef. These results show that epifauna are major contributors to the flux of mate rials in rocky reef habitats, and should therefore be included in trop hic models of these systems. Consumption by fish could only account fo r similar to 26% of epifaunal production, with the fate of the remaind er unknown. Estimated annual secondary productivity within the Carpoph yllum forest and turf flats habitats (100 to 115 g AFDW m(-2) yr(-1)) was higher than Literature values for a range of soft sediment habitat s, and was exceeded only by 2 other hard-bottom communities.