Huon Estuary and D'Entrecasteaux Channel BEMP Review

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Professor Kenny Black and Professor Paul Tett, from the Scottish Association of Marine Science (SAMS), have completed their review of the Broadscale Environmental Monitoring Program (BEMP) for the Huon Estuary and D'Entrecasteaux Channel marine farming region.​

The broad aim of this review was to evaluate the suitability and efficacy of the existing BEMP and to determine whether the BEMP is adequate in detecting environmental impacts of finfish farming at regional scales. As part of the review process, SAMS were asked to provide a list of recommendations to rationalise, improve, and modernise the monitoring program.

Review Reco​​mmen​​da​​tions​​

The review is now complete and it outlines several recommendations for updating the Huon Estuary and D'Entrecasteaux Channel BEMP. These recommendations include, but are not limited to:

  1. ​rationalising monitoring sites and reviewing the location of sites to ensure detection of subtle impacts, while increasing the frequency of some monitoring

  2. expanding existing monitoring methods to include surveys of reef and seagrass habitats

  3. increasing statistical analysis to better understand the source of variation of the data collected and to improve the presentation of data in monitoring reports to show relationships between key parameters

  4. implementing further research to modernise key aspects of environmental monitoring, including the potential use of cutting-edge technologies for DNA analysis

  5. developing a report card to summarise monitoring data and to increase accessibility for the public

Overall, the Director, EPA agrees ​with the recommendations of the reviewers  - see the table below.

The EPA intends to incorporate the recommendations into a revised BEMP for the Huon Estuary and D'Entrecasteaux Channel. 

The EPA will consult with industry and key scientific experts at the Institute for Marine and Antarctic Studies (IMAS), the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Scottish As​sociation of Marine ​Science (SAMS) and Analytical Services Tasmania (AST) to develop the revised BEMP.​

​​The review will be provided to the Department of Natural Resources and Environment Tasmania for consideration during the development of the proposed Environmental Standard for Marine Finfish Farming.​​

​ ​​​

​​"We are not aware of any other fish farming country or region carrying out a broad scale environmental monitoring programme at the scale undertaken here. ​

The decision by the Tasmanian authorities to develop with industry a programme of industry-funded broad scale monitoring as the industry developed was both laudable and prescient." 

​SAMS BEMP Review 2022

 SAMS International Huon Estuary and D'Entrecasteaux Channel BEMP Review (PDF 3Mb)

​Response to the Recom​mendations​

The following table sets out the position of the Director, EPA in response to the report recommendations.

​​Recommendations from the ​BEMP Review
​​Director's Position​​​​

​​​​a) Increase the statistical analysis of BEMP data to better understand the sources of variability and potential to detect change. Such as a Generalised Additive Model of the spatial and temporal components.

b) Establish a new control site to provide a better understanding of boundary conditions that is not disturbed by human influence and is typical of conditions prior to potential growth of phytoplankton populations within more sheltered waters of the D'Entrecasteaux Channel.

c) Undertake advanced statistical analysis to consider reducing the number of pelagic broadscale monitoring stations.

d) Set up real-time monitoring using instrument moorings to increase the frequency of monitoring at a reduced number of locations (i.e. 4 locations – 3 within the system, 1 control) measuring Temp, Salinity and chlorophyll within the water column. Couple this with monthly sampling of plankton – for 'balance of organisms' approach.

e) Look at optimising the placement of benthic sampling locations. Use bathymetry and hydrodynamic models to identify potential accumulation sites. Combine this with a field program to determine the best accumulating sites using core studies to identify rates of accumulation and biogeochemical markers to detect fish farming influence.

f) Status of Thompson 2008 triggers – identify seasonal-varying reference conditions for all trigger variables and for the State of indicators in each habitat.

g) Rethink the use and presentation of data for the components of the Nitrogen system. Use TAN as local indicator and DIN as the main broad-scale variable. Routinely plot dissolved nitrogen concentrations and their molar ratios against salinity, in order to substantiate the assumption of nitrogen limitation throughout the Huon Estuary and D'Entrecasteaux Channel.

​​The Director, EPA agrees with the SAMS recommendation that further statistical analysis is required to gain a greater insight into the spatial and temporal components of the pelagic and benthic datasets available in the south-east of Tasmania. 

The EPA will look to commission a project with the Institute for Marine and Antarctic Studies (IMAS) through the SMRCA (Sustainable Marine Research Collaboration Agreement) to undertake a more rigorous statistical analysis of the extensive BEMP dataset for the south-east of Tasmania together with other relevant environmental data collected over the last two decades.

The above advanced analysis will provide the EPA with greater insight into the current state of the environment in the Huon Estuary and D'Entrecasteaux Channel and may allow the EPA to rationalise the number of pelagic and benthic sampling locations, whilst increasing the frequency of monitoring. It may also provide additional capacity to identify usage and presentation of components of the nitrogen system, and to update data presentation requirements for the BEMP report to further support the assumption that nitrogen is the key parameter that limits algal growth in the environment.

In addition, combining this new analysis together with reviewing bathymetric data and hydrodynamical models, the project agreement with IMAS will also extend to a broader strategic approach to optimise the siting of current location of sampling stations with an aim to maximise the likelihood of detecting broadscale environmental impacts.

Furthermore, exploration of the data outcomes from more rigorous statistical analysis of existing and historical datasets will enable identification of seasonal-varying reference conditions for trigger variables and for the State of Indicators in each habitat.

Undertaking a more sophisticated approach to data analysis, the EPA will engage with IMAS and/or CSIRO to investigate establishment of a trial using instrument moorings to conduct continuous real-time water quality monitoring. This trial will be undertaken alongside existing monitoring to identify whether continuous real-time water quality monitoring can provide further benefits to the BEMP and if considerations should be made to permanently establish real-time monitoring as part of the BEMP.​​


​​​Continue to use hydrodynamic and biogeochemical models developed by CSIRO for diagnosis and prognosis of BEMP program.​

​It is the Director’s intention that the use of well-established hydrodynamic and biogeochemical models developed by CSIRO will continue to be important tools used to provide diagnosis and prognosis for the BEMP program. ​


​Improve the reporting of the methodology used for measuring photosynthetic pigments by spectrophotometry and micro-algal abundance by microscopy.​

​The Director agrees that the presentation of methods within annual BEMP reports should be reflective of the work that has been undertaken and at a sufficient level of detail that allows the work to be repeated and understood by people who have not undertaken the work. 

Companies responsible for submitting Annual BEMP Reports will be informed that these requirements will apply to all BEMP reports submitted to the EPA.​


​​Modify the method of measuring chlorophyll to change the detection limit from 0.5 to 0.1 mg/L​

​The EPA is currently in discussion with AST staff to ascertain whether the current analytical method could be adapted to lower the detection limit from 0.5 mg/L to 0.1 mg/L. 

The Director will make a final recommendation on the minimum required detection limit fo​r Chlorophyll in the BEMP program following a full exploration of this issue.​


​Consideration should be given to the use of benthic indices derived from benthic survey analysis which can indicate enrichment status.​

​The Director, EPA agrees that more in-depth analysis of the data that is collected during the BEMP sampling program should be undertaken. Applying benthic indices to infauna data sets is a common method adopted in many jurisdictions. ​


​The advantages of moving towards a DNA metabarcoding methodology for infauna in terms of data richness, cost, and speed should be investigated. 

​The Director, EPA agrees that it is important to look at new methodologies to improve the accuracy, cost and speed of environmental monitoring. It is also acknowledged that research into DNA metabarcoding methodologies (i.e. eDNA) for environmental monitoring of finfish farming is underway globally.

To realise the potential of using DNA metabarcoding methodologies a significant body of work needs to be undertaken in Tasmania, to determine whether DNA metabarcoding methodologies will be appropriate for the context of monitoring benthic impacts of finfish farming in Tasmania. 

IMAS are currently undertaking research as part of their Storm Bay monitoring project to assess the potential of using these DNA metabarcoding methodologies alongside traditional benthic monitoring methods.​ 


​Epiphyte monitoring of seagrass and hard bottom reef habitats should become part of the BEMP.

​Currently the monitoring of seagrass and reef (inshore and deep reefs) habitats is a requirement of Environmental Licences issued in other finfish farming regions. 

It is the intention of the Director, EPA to update the BEMP monitoring requirements of Environmental Licences of finfish farms in the Huon Estuary and D’Entrecasteaux Channel to incorporate the monitoring of these habitat types.  


​Adoption of a ‘balance of organisms’ indicator to track year to year changes in phytoplankton floristic composition. This should take into account the seasonal cycle and group ecologically-relevant species as ‘lifeforms’. 

​The Director, EPA agrees that it is important to extract more value from environmental data that is collected as part of the BEMP to further develop indicators of ecosystem change. 

The EPA will engage further with Paul Tett at SAMS and with experts at IMAS/UTAS to further explore the benefits to the BEMP monitoring program of adopting a ‘balance of organisms’ indicator. 


​Develop a report card to summarise the current state of each main pelagic and benthic habitat that could be used to inform the public of the State of the Huon Estuary and D’Entrecasteaux Channel ecosystem.

​The Director, EPA will continue to publish BEMP reports and commits to improving accessibility for the public. The EPA will progress opportunities to synthesise BEMP report findings into a more accessible and simplified ‘report card’ format.​