Past monitoring review
Data collected by DPIPWE since 2014 has confirmed a decline in dissolved oxygen (DO) levels in the bottom waters of Macquarie Harbour and routine benthic monitoring since 2013 indicated an increase in the abundance and distribution of opportunistic polychaetes. A range of actions were undertaken in response to the monitoring, including the immediate progression of targeted research and increased levels of environmental monitoring in the Harbour on a spatial and temporal scale.
Copies of these reports are available from the DPIPWE website at www.dpipwe.tas.gov.au/Sea-Fishing-and-Aquaculture/Marine-Farming-Aquaculture/Macquarie-Harbour-Environmental-and-Fish-Health-Monitoring-Review
In November 2016, the EPA completed its first assessment of monitoring data since the Tasmanian Government announced the transfer of environmental regulation to the EPA on 1 July 2016. The benthic monitoring undertaken by the companies is validated against independent research undertaken by the Institute of Marine and Antarctic Studies (IMAS), and against research commissioned by the companies themselves, and water quality monitoring data is collected by the EPA, industry, IMAS, and the CSIRO through separate monitoring programs.
Marine Farming Licence Conditions relating to environmental management of finfish farms 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 compliance points located around lease areas at 35 metres from the boundary of the lease.
September 2016 Monitoring Results
The Spring 2016 round of regular benthic monitoring undertaken by the three salmon companies in Macquarie Harbour has now been assessed. A summary table of the September 2016 information collected by the companies at 35 metre compliance survey points at various lease sites, is attached in the
Macquarie Harbour Lease Boundary Compliance Summary, September 2016. The benthic surveys indicated non-compliance at several of the lease sites, and water quality monitoring showed that the low levels of dissolved oxygen in the deeper parts of the harbour have continued for much of the year, reaching a record low.
Following consideration of the current dissolved oxygen levels in the deeper waters of Macquarie Harbour and the extent of the presence of
Beggiatoa species in the harbour over the past six months, the EPA Director has advised the companies of his intent to reduce the biomass limit for the Harbour to below the biomass cap for 2013 of 15,437 tonnes. In addition, management controls will be aimed at reducing the impact of nutrient waste on the benthic environment in proximity to the non-compliant sites require; and will require non-compliant areas to be fallowed, and to be re-assessed prior to any restocking.
Notice of Determination, January 2017
On 16 January 2017, the EPA Director lowered the maximum permissible biomass to 14,000 tonnes of finfish in Macquarie Harbour for the period from 14 February to 30 April 2017 and made a set of new determinations for the three salmon aquaculture companies. These new determinations were based on a range of information, including on a review of the most recent research findings provided by the Institute of Marine and Antarctic Studies (IMAS). They were set in response to environmental indicators including very low levels of dissolved oxygen (DO) in the deeper waters of Macquarie Harbour, the extent of the presence of
Beggiatoa species in the harbour currently, and its increase over the past six months, as well as a decline in benthic fauna in the vicinity of the marine farms. The new determinations, along with the letters sent to the three companies operating in the harbour, can be viewed
here. The Director has deferred making the biomass determination for the period from 1 May 2017 to 30 April 2020 until the January 2017 benthic sampling data has been reviewed and after further consultation with the companies.
Public Release of the Technical Report prepared by the Institute of Marine and Antartic Studies (IMAS)
The attached Institute of Marine and Antarctic Studies (IMAS) Technical Report, Environmental Research in Macquarie Harbour- Interim Synopsis of Benthic and Water Column Conditions January 2017, was prepared by Dr Ross and Associate Professor MacLeod at the EPA Director’s request in November 2016.
The three salmon companies were advised that this report would be made publically available as the earliest opportunity once it had been finalised and cleared by the University of Tasmania.
The report is both comprehensive and technical. As such, prior to it being made publically available the University of Tasmania has an internal review process that ensures reports and publications meet appropriate research and academic standards. In addition, the report references externally funded research projects and therefore other research organisations needed to sign off on certain aspects of the report. These are important steps in the preparation of scientific material, and do take time to complete.
This report forms part of the information that the Director considered when making the biomass determination for the period from 14 February to 30 April 2017.
IMAS Technical Report on Macquarie Harbour Condition
Salmon Regulation Section
134 Macquarie Street
Hobart TAS 7000
Phone: 03 6165 4599
Fax: 03 6173 0254