Shallow rock-wall biological associations of some southern fiords of New Zealand

Abstract

Rich invertebrate faunas on the upper 50 m of the steep rock walls of some southern fiords of New Zealand are described from scuba observations and collections. A layer of low-salinity water, derived from land runoff, forms a light-absorbing band up to 4 m deep, reducing light to such an extent that algae (other than enorusting Lithothamnion) are restricted to the top few metres. The biota below this layer is dominated by brachiopods, antipatharians, gorgonians, and serpulid polychaetes, many of which are similar to those reported from other areas of New Zealand, but usually from depths greater than 40 m. Distributions of the major species of algae and invertebrates with depth in Preservation Inlet are given and briefly compared with observations in Dusky, Nancy, Caswell, and Milford sounds.