Best management practice guidelines for salmon farms in the Marlborough Sounds: Part 2: Water quality standards and monitoring protocol (Version 1.0)

Content Partner: Lincoln University. The New Zealand King Salmon Co. Limited (NZKS) were granted resource consent for three new salmon farms in the Marlborough Sounds by the Environmental Protection Authority (EPA) in 2012. The consent conditions were determined by the EPA’s Board of Inquiry (BoI) which required NZKS to monitor broader scale effects in the water column of their nitrogen discharge. The conditions also required the setting of numerical thresholds, or ‘interim water quality standards’ (WQS) for ecologically important water column attributes: chlorophyll-a, total nitrogen and dissolved oxygen. The consents required the interim WQS to be reviewed by the end of 2018. Two additional farms which had been separately re-consented following the BoI also required the interim WQS to be reviewed by the end of 2018. These farms are all sited in locations of high current flows (high-flow) within the Marlborough Sounds. A working group was set up to provide advice to The New Zealand King Salmon Co. Limited (NZ King Salmon) and Marlborough District Council (MDC); the group included representatives from Fisheries New Zealand, Department of Conservation (DoC), Cawthron Institute, National Institute of Water & Atmospheric Research (NIWA) and the Sounds Advisory Group to MDC (SAG). The working group was tasked with reviewing and recommending ‘best practice1 guidelines’ detailing WQS, a monitoring protocol, and a management response framework for these high-flow farms to follow. The review was to be informed by international examples of best practice and customised to the biophysical conditions of the Marlborough Sounds. The primary purpose of these guidelines is therefore to provide a central set of WQS, and requirements for monitoring and managing potential water column nutrient enrichment from salmon farms in the Marlborough Sounds. The overall framework will provide the regulator and consent holder with early detection, or warning signs, of a deterioration in water quality from nutrient enrichment, at a regional-scale. The review also acknowledged the importance of the wider environmental context, because dissolved nutrient inputs come from a range of other sources (e.g., upwelling from Cook Strait, catchment run-off). Aspects of this framework may also be broadly applicable to other fin-fish farms or feed-added aquaculture, and/or existing salmon farms in low-flow locations. However, these were not a specific consideration in the review. The guidelines defi