Macrofaunal assemblages of benthic habitat of different complexity and the proposition of a model of biogenic reef habitat regeneration in Foveaux Strait, New Zealand

Abstract

Complex biogenic reefs in Foveaux Strait have been removed by dredging for the oysters that occurred on this habitat and reduced much of the seafloor to relict pebble gravel. Biogenic habitat has regenerated in localised patches on the dredge-modified seafloor. We sampled the macrofauna on five of these habitats with differing complexity and tested the hypothesis that the macrofauna assemblage composition differed between habitats and the difference conformed to a seriation with increasing complexity. The results of multivariate analyses supported the hypothesis and allowed for the postulation of a model of macrofaunal assemblage succession and biogenic habitat regeneration in Foveaux Strait. The extent of habitat regeneration appears to largely depend both on the time since fishing ceased and on the proximity of the sources of re-colonising propagules. Oyster density rebuilt to relatively high densities in habitat that had not fully regenerated. The results of the study suggest specific habitat conservation strategies that could benefit the sustainable management of the oyster fishery of Foveaux Strait.