EXECUTIVE SUMMARY

Nelson City Council requested advice and assistance in compilation and evaluation of background information required for follow up determination of the degree of modification of the condition / health of Whangamoa Inlet. This information was required as a basis for future incorporation of Whangamoa Inlet into the overall state of the environment (SOE) monitoring framework for estuaries in the region.

The present report provides:

1. A compilation of existing background information relevant to assessing the ecological condition of Whangamoa Inlet

2. A preliminary decision matrix ranking of the ecological status and values of Whangamoa Inlet

3. Identification of critical information gaps indicating the need for further investigation

4. Recommendations for follow-up baseline investigation of estuary health.

Existing information describing estuary characteristics, although limited, suggests that Whangamoa Inlet remains in a relatively pristine condition compared to other estuaries within Tasman Bay that have been more thoroughly investigated.

The present ecological state of intertidal habitats and the degree to which alteration of estuary functional integrity has occurred in response to upper estuary perturbations and catchment land use activities, although likely minor, has not been thoroughly assessed. Due to the considerable values associated with the relatively unmodified state of the intertidal environment, it is critical that a baseline be established describing the presently existing ecological state of the Inlet. Estuary-wide, broad-scale habitat mapping and fine-scale assessment of individual reference sites are recommended. These investigations should be carried out in accordance with the standardised estuary monitoring protocol previously implemented for other Tasman Bay estuaries. This would enable a regional comparison of estuary condition and serve as a point-in-time baseline for future monitoring.

Additional evaluation of estuarine water and shellfish faecal indicator bacteria concentrations would provide better understanding of the relationships with catchment inflows and potential sources of contamination.

Preliminary scoring of an estuary decision matrix spreadsheet (appended to this report) indicates a high priority for further investigation. Numerous gaps were identified in the available information required to build a better understanding of estuary health / condition and the associated risks. In conjunction with SOE monitoring, it is recommended that scoring of the estuary decision matrix be reviewed and revised with community / iwi input and periodically updated to provide a working document for prioritising estuary management requirements.

Considering the 'assumed' relatively pristine condition of the Inlet and the associated high values attached, a collaborative management approach including major stakeholders would seem highly appropriate. Historical Māori interests in the region of the Whangamoa Rivermouth suggest a potential for integration of science-based indicators with iwi cultural indicators for future monitoring of intertidal Inlet habitats.