Among the services NIWA provides the Shellfish Industry are real-time harvest restriction reports. The day-to-day opening and/or closure of the harvesting areas are based on either rainfall, river flows or changes in salinity – all of which are used as proxies for coliform contamination. We operate a network of telemetered raingauges, river level recorders and salinity buoys which allows real-time harvest area reports to be either broadcast-faxed out to the required clients or updated to a NIWA Faxback system.

Our new salinity monitoring buoys incorporate leading-edge technology to monitor and report (via cell phone telemetry) on the salinity conditions used to govern shellfish harvesting. Several of these buoys have been deployed in the Nelson/Marlborough region at areas where the harvest criteria were originally based on either rainfall or outflows from a nearby river catchment. The result of the change to a salinity based harvest criteria has been that the harvest areas are now open for harvesting for longer periods because only true impact events close the areas.

With the use of the cell phone technology the placement of the buoys can be local, national or even international. The buoys can operate either at sea, as for a mussel farm, or on a beach in the inter-tidal zone as required in cockle-harvesting areas.

Contact

Ralph Dickson [ r.dickson@niwa.co.nz ]