Marlborough Sounds Resource Management Plan F Marine - Inner Pelorus Sound Collective Characteristics: Mainly Sheltered Shallow and very sheltered; turbid warm waters; very tidal with extensive mudflats; cockle beds; expansive saltmarsh; birdlife common. A. The Physical Environment 1. Form/Geology Kaituna estuary dominates the head of Pelorus Sound with extensive tidal mudflats extending out to beyond Mahakipawa Arm. Mahau and Kenepuru Sounds are fringed by a very narrow cobble reef, with mud/silt habitat predominant beyond. Much of the area is tidal or very shallow. 2. Dynamic Features and Processes, Including Climate Very sheltered. 3. Water The area is strongly influenced by the Pelorus and Kaituna Rivers, resulting in a very high turbidity and sedimentation levels. Relatively poor water quality as a result of catchment management and specific discharges in the vicinity of Havelock. Relatively warm waters with reduced salinities, particularly at the head of Pelorus Sound or during floods. A moderate tidal range exposes extensive tidal flats in the inner reaches of the Sound. Tidal currents are strong along the main channel. B. The Biological Environment Distinctive Biota, Communities and Habitats Natural Biodiversity, Productivity and Biotic Patterns Kaituna Estuary, and neighbouring Mahakipawa Arm and Kaiuma Bay form a complex estuarine system supporting extensive and productive saltmarsh and invertebrate communities. Dense cockle beds (inter-tidal and sub-tidal) occur at various locations. The general area is important as a nursery and feeding ground for coastal fish, as well as habitat for various wildlife species. The introduced and invasive cord grass Spartina is a dominant feature of the Kaituna Estuary. The cobble reefs and sub-tidal mud habitats beyond the inner estuarine areas generally support a low diversity and abundance of macro-invertebrates. C. Potential for Restoration Restoration of riparian habitat. Water quality. Spartina control. App Two - 68