Intertidal Community Differences Between the Cook Strait and Wellington Harbour
Wellington Harbour which lies near the southern tip of the North Island, New Zealand, exhibits a typical rocky intertidal shoreline with groups of species similar to those found on many temperate rocky coasts around the world. A short distance away, the Cook Strait displays a very different shoreline in community composition compared with Wellington Harbour, most notably a distinct lack of filter feeders. This thesis aims to examine how exactly the community composition is different between the two coasts at a species level and if there are any environmental factors that can explain the differing distributions. Here, a series of field and laboratory experiments aim to examine why certain filter feeders (mussels) are absent from the Cook Strait shore, yet so abundant in Wellington Harbour ... This work indicates that the Cook Strait coastline has lower filter feeder abundances and an overall different community composition than Wellington Harbour. The cause of these differences appears to be bottom up regulation through the lack of food availability (phytoplankton) during winter months in the Cook Strait. The high commercial value of coastal environments in both fisheries and tourism heightens the need to understand these habitats. Unravelling the complex relationships between the seasonal changes in the water column and onshore biota is important for conserving and protecting these essential ecosystems in New Zealand and temperate shores worldwide.