Compliance monitoring by the salmon companies is a requirement of the marine farming environmental licence. The companies undertake regular benthic visual surveys using a remote underwater video camera, and these survey reports along with the video footage are sent to the EPA.
Data collected since 2014 has confirmed a decline in dissolved oxygen (DO) levels in the bottom waters of Macquarie Harbour, while routine benthic monitoring since 2013 has indicated an increase in the abundance and distribution of opportunistic polychaetes. A range of actions have been undertaken in response to the monitoring, including immediately beginning targeted research and increasing levels of environmental monitoring in the Harbour on a spatial and temporal scale.
Environmental Licence Conditions relating to environmental management of fish farming in Macquarie Harbour require compliance with environmental standards. One requirement is that there must be no significant visual impacts at, or extending beyond, 35 metres from the boundary of the lease area. Visual impacts from farming outside of marine farm lease areas are monitored by remotely operated vehicles with cameras surveying for benthic bacterial mats (Beggiatoa spp.) at these compliance points around lease areas 35 m from the boundary.
In November 2016, the EPA completed its first assessment of monitoring data since the Tasmanian Government's announcement that environmental regulation would be transferred to the EPA on 1 July 2016. The benthic monitoring undertaken by the companies is complemented by independent research undertaken by the Institute of Marine and Antarctic Studies (IMAS), research commissioned by the companies themselves, and water quality monitoring data collected by the EPA, industry, IMAS, and the CSIRO through separate monitoring programs.
Compliance Monitoring Results
The September 2020 round of regular benthic monitoring undertaken by the three salmon companies in Macquarie Harbour has now been assessed. A summary table of results from September 2016 to September 2020 at 35 metre compliance survey points at all lease sites is provided below. The results from the May 2020 and September 2020 benthic surveys (three non-compliances for both surveys) demonstrate a sustained improvement in compliance compared to the September 2019 and January 2020 surveys (seven and thirteen non-compliances). Companies discuss on-going management responses with the EPA to maintain progress towards full lease compliance. The next benthic compliance survey is scheduled for January 2021.
Table 1. Macquarie Harbour Lease Boundary Compliance Summary - non-compliant (NC) survey points for
Beggiatoa from total compliance points surveyed for each lease survey conducted since September 2016
* Lease #213 first stocked in 2016. First compliance survey required in January 2017.
HAC = Huon Aquaculture