Habitat Modification and Destruction
In general, this is much less of a problem in New Zealand than in more heavily populated countries. Nevertheless, substantial parts of the local marine environment have been changed dramatically through port developments, reclamations and other uses like aquaculture.

Sand mining is another activity that could threaten New Zealand marine mammals. For example, there are plans for sand mining throughout the range of the North Island Hector's dolphin or Maui's dolphin. Typically, it takes between one and three years for the plants and animals that live in and on the sand to recover to the same distribution and total numbers after a sand mining operation. However, it can take much longer for the community composition to recover. For example, the removal of some organisms and crushing of others tends to attract scavengers into the area, changing the local ecology.

Publications and reports

• Slooten, E., Battersby, Z. and Battersby, L. Potential effects of mussel farming on Hector’s dolphins in Queen Charlotte Sound. Report for Marlborough District Council (2001).
• Slooten, E., Dawson, S.M. and DuFresne, S. Report on interactions between Hector’s dolphins (Cephalorhynchus hectori) and a Golden Bay mussel farm. Report for Environment Canterbury (2001).
• Slooten, E., DuFresne, S. and Clement, D. Potential effects of mussel farming on Hector’s dolphins in the Banks Peninsula region. Report for Environment Canterbury (2000).
• Slooten, E., Rayment, W., Clement, D. Jones, G. and DuFresne, S. Report on the potential effects on Hector’s dolphins of proposed mussel farming in Akaroa Harbour. Report for National Institute of Water and Atmosphere (2000).
• Clement, D., Jones, G. and Slooten, E. Report on the potential effects of mussel farming in Clifford Bay on the Hector’s dolphin population in the area. Report for Clifford Bay Marine Farms Ltd (1999)

For a list of general Trust associated publications and reports on marine mammals and marine mammal ecology, click here. To find out about the people involved in this research, see the University of Otago Marine Mammal Research Group web site.