The Marlborough District council is developing the second generation of its resource management plan for the Pelorus Sounds area. This includes, amongst other things, the identification and protection of significant marine biological sites, and the development of marine farming provisions. Pelorus Sound is a key location for both significant sites and activities This project provides a historic context for understanding how the Pelorus has changed, and will assist in the development of environmental outcomes for seabed habitats of planning provision. This project uses the Compound Specific Stable Isotope (CSSI) method developed by NIWA scientist, Max Gibbs, that can identify and apportion, by land use on a catchment scale, the sources of soil contributing to the sediment at a location of an estuary (Gibbs 2008).