Native Fish: Development and Application of the River Values Assessment System (RiVAS and RiVAS+) Method to the Gisborne District Council Region

Abstract

The first application of the River Values Assessment System (RiVAS and RiVAS+) was made to the native fisheries value in Gisborne District. A modified approach involving national (to develop the system) and local (to fully implement it) expertise applied RiVAS and RiVAS+. The method was applied to differentiate native fish sites of national significance from those of regional significance or local significance. Of 13 rivers or river clusters evaluated four were considered of national significance, namely Awatere, Coastal 1, Waiapu and Wharekahika; the remainder are of regional significance. Data were modelled by Cawthron Institute based on a variety of databases including the NZFFDB and FENZ; the expert panel then checked the modelling results and adjusted where appropriate based on local knowledge. The RiVAS+ methodology was also applied (its first application to native fisheries) to assess future potential value. Of the 13 clusters, 10 altered their sum total score, all in a positive direction. The Uawa River shifted most but still remains regionally important. In total, 10 rivers were identified as having potential to improve river conditions in a way that would enhance native fishlife value. The interventions most frequently identified for enhancing native fishlife value (with the number of times it was identified across all rivers given in brackets) were: Enhance Water Quality – reduce sediment input (8), and Enhance Water Quality – remove/fence out stock (4).