Source:Auckland Council Research and Evaluation Unit, RIMU
Suspended sediment is a natural feature of Auckland’s coastal waters; however land use changes speed up the input of sediment into the marine environment resulting in unnaturally high levels. It is now recognised as one of the most significant stressors to marine life, particularly in New Zealand.
Sediment is generated predominately through forestry, urbanisation, construction and farming. The sediment enters the harbours via runoff, streams and rivers and is deposited on the coast. A portion of this sediment generally settles on the sea bed, however currents, wave action and storms, result in continual re-suspension of sediment, causing our waters to become muddy and cloudy, a state which will be familiar to many people.
Snapper are a highly valuable fish species in New Zealand both recreationally and commercially and represent a significant icon of New Zealand’s culture. They tend to breed in shallow coastal and estuarine environments where the juveniles then spend the first part of their life cycle. This is of particular relevance as these shallow coastal environments are especially susceptible to the effects of sedimentation due to their proximity to the coast and fresh water outflows. Snapper are therefore an ideal study species for investigating some of the impacts of suspended sediment.
RIMU masters student research summary
MSc thesis, University of Auckland
Effects of turbidity on the aerobic physiology and feeding behaviour of juvenile snapper (Pagrus auratus)