Assessing Environmental Impacts of the Salmonid Aquaculture Industry on the : A Scoping Study.

Fiona M. Gavine and Brendan Larkin

January 2011 Fisheries Department of Primary Industries

Goulburn River Study Final Report

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Published: Fisheries Victoria Preferred way to cite this publication: Department of Primary Industries, Queenscliff Centre Gavine, F. M. and Larkin, B. (2011) Assessing Environmental Impacts of the Salmonid PO Box 114, Queenscliff, Victoria Aquaculture Industry on the Goulburn River: A 3225 . Scoping Study. Fisheries Victoria Internal Report Series No. 26, 19 pages. Department of Primary General disclaimer Industries, Queenscliff, Victoria, Australia. This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.

Short title ii

Executive Summary

This project was a one‐year scoping study for a which the risk associated with individual farms larger project that originally intended to could be assessed. systematically investigate the impacts of the trout The decision tree approach is a framework industry on the Goulburn River and its through which farms could be systematically tributaries. The specific objectives of the scoping categorised against key environmental factors. study were: Real data are now required to make the decision • To define the scope and data requirements of tree a useful tool for environmental management. a three‐year project to assess the ecological Three characterisation studies were carried out to impacts of trout culture on the Goulburn illustrate how the decision tree approach would River and its tributaries work in practice. This showed that there is very • To define the data required to identify little current information on the downstream constraints to industry development on the impacts of salmonid farming and so this is a key Goulburn River and its tributaries. data requirement for a larger project. In addition, the studies also showed that the level of risk The activities undertaken as part of this project attributed to a farm was directly related to the evolved over the year in response to the type of useable data available ‐ particularly the requirements of stakeholders. One key alteration proportion of the river flow that the farm used. was the widening of the scope of the larger The more data that were available from the farm project to make it relevant to the whole Victorian and relevant databases, the more reliably industry. Key activities conducted to deliver on environmental risks could be quantified. the objectives of the 2004/05 scoping study included: This information was used to build a staged proposal for a monitoring study that will • Preparation of a review on ecological impacts quantify actual impacts of the salmonid of the salmonid aquaculture industry aquaculture industry on the aquatic • Preparation of preliminary research environment. proposals for submission to potential funding bodies

• Formation of a steering committee to guide project development. The scoping study carried out in 2004/05 has provided a sound platform from which to develop the larger monitoring programme for salmonid farms. The terms of reference for future work was adjusted to accommodate a wider, more representative industry study. Specific outputs of the project included: • A review of impacts of the salmonid aquaculture industry on the aquatic environment • Preliminary research proposals submitted to various funding bodies • Two workshops with stakeholders to discuss appropriate approaches to project development. The study identified key factors that need to be measured and provided a framework through

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Table of Contents

Executive Summary...... iii

Introduction...... 1 Objectives...... 1 Deliverables ...... 1

Project Design and Methods...... 2

Results...... 3 Workshop outcomes ...... 3

Discussion...... 5 Proposed method – Year 1 ...... 5 Identification of sites to be monitored...... 5 Characterisation studies of the selected farms...... 5 Monitoring impacts downstream of the farm...... 5 Collation of on‐farm data...... 6 Evaluation of risks...... 6 Proposed method – Year 2 onwards...... 6

Acknowledgements ...... 7

References ...... 8

Appendix 1 – Literature Review...... 9 Review of ecological impacts of salmonid farms...... 9 Abstraction of water from rivers...... 9 Discharge of effluents to rivers ...... 10

Appendix II – Preliminary proposals submitted ...... 14

Appendix III – Workshop Minutes 12/4/05...... 15

Appendix IV: Workshop Minutes 22/6/05...... 17

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List of Tables Table 1: Assessment of farms against key environmental issues...... 4 Table 2: Trigger value for ammonia in freshwaters...... 11 Table 3 Default trigger values for dissolved oxygen in south east Australia (ANZECC 2000) ...... 11 Table 4 Default trigger values for turbidity in slightly disturbed ecosystems in south east Australia.(ANZECC 2000) ...... 12 Table 5: Default trigger values for total nitrogen (TN) and total phosphorus (TP) in slightly disturbed ecosystems (ANZECC 2000)...... 12

List of Figures Figure 1: Typical effects on water quality and the associated biota which may be observed downstream of a sewage outlet. A and B. Physical and chemical changes; C. Changes in micro‐organism populations; D. Changes in invertebrate populations (after Hynes, 1990)...... 10

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Introduction

The Goulburn River and its catchment supports around 40% of Victoria’s aquaculture production Objectives and 85% of the state’s rainbow trout production The specific objective of the scoping study were: (Anon 2005). A major constraint to expansion of • To define the scope and data requirements of trout farming on the Goulburn River, and indeed a three‐year project to assess the impacts of on other rivers, is the perceived impact of the trout culture on the Goulburn River. industry on the environment, particularly with respect to the contribution by aquaculture effluents to nutrient loads in the catchment. Deliverables However, there is a lack of knowledge about The three key deliverables of this study were: actual impacts of the industry on the • A literature review to identify key environment and the ability of the environment environmental concerns related to salmonid to continue to sustain activities such as farming aquaculture. • Development of preliminary research Best Practice Environmental Management proposals for consideration by funding (BPEM) guidelines for the salmonid industry, bodies were developed by Department of Primary Industries (2005). This document primarily • A fully costed 3‐year project proposal. addressed on‐farm environmental issues and identified and prioritised key issues that salmonid farmers should address using a qualitative risk assessement. It documented BPEM for salmonid farms and set targets where appropriate.

A key recommendation of the BPEM was that mass‐balance models (MBM) should be used as a tool to monitor compliance with discharge licences. Although this approach gives a reliable estimation of total nutrient loads to the environment, it is not useful in predicting levels of key parameters in effluent streams or actual impacts on the aquatic environment. Current and more complete data on nutrient inputs and effluent quality are required to validate and refine the use of the model for this purpose. This project was a one‐year scoping study for a larger project that will systematically investigate the impacts of the trout industry more broadly on the aquatic environment. As part of this process, the data requirements for such an assessment would be defined.

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Project Design and Methods

The activities undertaken as part of this project Innovation, Industry and Regional evolved over 2004/05 in response to the Development (DIIRD), River Health Strategy, requirements of stakeholders. Key activities Department of Sustainability and conducted to deliver on the objectives of this Environment (DSE) and Fisheries Victoria scoping study included: • Two workshops were held to discuss the • Preparation of a review on ecological impacts scope and level of detail required by the of the salmonid aquaculture industry project • Various meetings to assess the policy context • Three characterisation studies of selected and scope for collaborative funding farms to ground truth the proposed rationale for project development. • Preparation of preliminary research proposals for submission to potential funding bodies • Formation of a steering committee to guide project development. The steering committee was made up of representatives from the Victorian Trout Association,

Goulburn Broken Catchment Management Authority (GBCMA), Environmental Protection Authority (EPA), Goulburn Murray Water (GMW), Department of

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Results

The review of impacts of the salmonid • Conditions and history of existing EPA aquaculture industry on the aquatic environment licence. is presented in Appendix I. To test this approach, three characterisation Appendix II contains a list of the preliminary research proposals submitted to date. studies were carried out: Walnut Island Trout Farm (Goulburn River at Thornton), Yarra Valley Workshop outcomes Salmon (), and Buxton Trout Farm Workshops were held on 12 April 2005 (minutes (Little Stevenson River at Buxton). in Appendix III) and 22 June 2005 (minutes in Appendix IV). The results of the three characterisation studies The outcome of the first workshop is that a were the basis for discussion in the second decision tree approach should be used to identify workshop and may be summarised as follows: key environmental risks for salmonid farms. 1. Walnut Island Trout Farm The decision tree approach will lead to an understanding of the system that the farms • Large farm (production > 300 tonnes per operate in and the relative risks associated with annum) located on large, seasonally individual farms. It was recommended that a regulated river. This reach has been two‐phase approach be undertaken in characterised as a “poor” quality river developing the decision tree. system by the Index of Stream Condition (GBCMA 2004; DNRE 1999). PHASE 1: Characterisation and assessment of critical issues at a farm level. This will include an • Good data on flows in river and farm assessment of: discharge rates. • Nature of the receiving waters • Effluent quality sampled 6 times per year. • Flow regime of receiving waters • Quality of upstream water is available • Existing background data from Data Warehouse • Proportion of flow diverted through farm (www.vicwaterdata.net) and inflow data during low flow events (it is assumed that available from Company records. low‐flow exacerbates the impact of • Nutrient mass balance models are used aquaculture effluent on the environment as a management tool but are of limited • Current management procedures (e.g. use in predicting effluent quality. feeding strategy, stocking density, feed • No recent data on downstream impacts. quality, and solids settlement mechanisms used). 2. Yarra Valley Salmon PHASE 2: Development of a decision tree that • Medium sized farm (around 100 tonnes will be used to select farms/ rivers for monitoring per annum) located on relatively small, under this project. Key concerns include: daily regulated (as opposed to seasonally regulated) river system. This reach of • Ammonia concentration in farm effluent the river was classified as “good” quality by the Index of Stream Condition • Total phosphorous (P) concentration in farm (GBCMA 2004; DNRE 1999). effluent • Effluent quality is sampled 6 times per • Flow regime in the farm and the receiving year (mostly in high‐risk period). river • Quality of influent water is available from Data Warehouse but farm inflow • Turbidity data are not available. • Potential for dissolved oxygen deficiency

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• No recent data on downstream impacts • No data on flows for Little Stevenson although part of EPA study in 1993. River or for discharge from trout farm. • Confounding effects of power station • Only available water quality information operations (e.g. annual de‐silting, routine available is data collected by trout farm. maintenance, changes in flow rate). • No studies on river health although there • Anecdotal evidence of long‐ term drop in has been ongoing community pH in river possibly resulting from Waterwatch monitoring. sawdust heaps located adjacent to river. Results of the characterisation studies were 3. Buxton Trout Farm assessed against key environmental concerns (Table 1). Farms are deemed to have a risk • Medium sized farm (70‐90 tonnes per (denoted as √) if insufficient information is annum) located on a small, upland river. available to enable assessment and quantification This river was not classified by the Index of impacts. Where there is adequate information of Stream Condition and very little data to evaluate the environmental risk, farms are exists on background flows or ecology. deemed to be managing the risk (denoted as X). • Effluent quality is sampled 6 times per year (mostly in high‐risk period).

Table 1: Assessment of farms against key environmental issues.

Risk Factor Assumptions Walnut Yarra Buxton Island Valley Trout Salmon Flow 1. Less of an issue on some (not all) regulated rivers than X √ √ on unregulated rivers. 2. Upland rivers have a higher risk as flows are more variable. Ammonia toxicity 1. At what concentration will the ammonia in discharged X √ √ effluent cause an environmental impact? 2. ANZECC guidelines state that a concentration of 0.32 mg/l provide a 99% level of ecosystem protection. 3. Compliance with EPA licence conditions and adequate dilution should provide protection. Suspended solids/ Impacts will depend on physical factors in river including √ √ √ turbidity flow regime, type of substrate, presence of pools, and hydrodynamics near discharge point. Total Phosphorus 1. Catchment scale issue. X √ √ 2. Importance will depend on limits/caps set. 3. Total loads can be calculated. Oxygen deficiency 1. Impacts will depend on biochemical oxygen demand √ √ √ of flow.

2. Downstream sediment accumulation.

3. Dilution.

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Discussion

The scoping study carried out in 2004/05 has related to the river, flow regime, provided a sound platform from which to background water quality) on downstream develop the larger monitoring programme for impacts to be assessed salmonid farms. It has identified key factors • Ideally, monitoring sites would represent that need to be measured and provided a various environmental classifications of framework through which the risk associated stream condition (DNRE 1999). with individual farms may be assessed. The decision tree approach is a framework through The sites to be monitored in Stage 1 will be which farms may be systematically categorised finalised through consultation with industry, against key environmental factors. However, EPA, Fisheries Victoria and other co‐investors. data are now required to make the decision tree a useful tool for environmental management. Characterisation studies of the selected farms. The results of the 2004/05 study showed that If the selected farms are different from those that there is very little information on the took part in the 2004/05 study, characterisation downstream impacts of salmonid farming. This studies will be carried out to assess the farms in is a key data requirement for a future project. In the context of their environment. These studies addition, the studies showed that the level of will summarise: risk attributed to the farm was directly related to the type of useable data available ‐ particularly • Production characteristics of the farm the proportion of the river flow that the farm (annual production, standing crop; feed used. The more data that were available from types, FCR and effluent treatment) the farm and relevant databases, the more • Existing data on the quality of the reliably environmental risks could be quantified environment (Values and Threats to river and assessed. system, Index of stream condition rating) Proposed method – Year 1 and hydrology and water quality • The prototype decision tree developed during Interaction between farm and environment 2004/05 will be used to identify categories of (proportion of total river flow diverted by sites to be monitored. It was decided that farms the farm, effluent quality compared with on both regulated and unregulated rivers background water quality) should be monitored, with the number of farms • Assessment of the farm against key risk and intensity of monitoring to be determined by criteria and identification of significant data the budget available. The project will be gaps. implemented in stages. The project method for Stage 1 will be as follows: Monitoring impacts downstream of the farm. Identification of sites to be monitored. Downstream impacts of the selected salmonid The second workshop decided that the first farms will be evaluated through monitoring stage of the study should monitor three farms ‐ benthic macro invertebrates and water quality. one on a regulated river and two on unregulated Habitat quality will also be assessed. rivers. Final selection of the farms is still to be carried out; however, the criteria upon which Invertebrate and habitat monitoring farms will be selected includes: For the selected farms in Year 1, the aim of invertebrate monitoring will be simply to assess • The farms should be operating at industry whether or not significant impacts on the Best Practice levels so that the results are benthos had occurred. Monitoring will be representative of others in the industry and undertaken upstream and downstream of the may be broadly extrapolated to other farms farm over a period of 3 months when the most • The mixture of farms selected should allow severe impacts would be expected (low river the influence of site specific farm and flow periods). This period could vary between environmental characteristics (size of farm farms.

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At each site, five samples will be collected per • Diurnal monitoring of effluent quality. sampling event. Metzeling et al. (1993) argued This data will be analysed to identify key factors that this would be adequate to assess if an influencing water quality on a site‐specific basis. impact has occurred. The samples will be analysed using measures of species richness, Evaluation of risks percentage composition of major taxa, faunal The downstream monitoring and on‐site data abundance, biotic indices (SIGNAL and will be assessed to evaluate the specific risk AUSRIVAS) and multivariate analysis. posed by the selected farms. Farms that pose a Water quality monitoring low risk will not be considered further in this Water quality samples will be collected at two study. Farms that have a demonstrated impact sites upstream and two (or more) sites or are not operating at Best Practice will be downstream of the selected farms. Sampling monitored more closely from Year 2 onwards. will occur at the same time as the invertebrate The data will be used to populate the decision monitoring takes place. The distance of the tree and ultimately should provide an index of sample downstream will be determined on a pollution that can be extended over the whole site‐specific basis. Effluent samples will also be salmonid industry. This Index can be used to collected. identify farms that pose a threat to their Samples will be analysed for the following receiving environment and control measures parameters: that need to be in place. • Temperature, pH, electrical conductivity; Proposed method – Year 2 dissolved oxygen onwards. • Total nitrogen, total phosphorus, ammonia, The specific method for Year 2 onwards will be nitrite, nitrate, ortho‐phosphate determined after Year 1 monitoring has taken • Suspended solids, Biochemical Oxygen place. However, the broad rationale is as Demand (BOD). follows: In addition, chlorophyll and algal/zooplankton • Farms that have demonstrated a significant samples will be collected upstream and impact on the environment will be more downstream of the point of discharge. intensively monitored in Year 2 The results of the monitoring will be assessed • Farms that have demonstrated no significant with reference to the ANZECC trigger levels for impacts will not be considered further the river into which the farm discharges. • Additional farms will be adopted by the Collation of on‐farm data project and undergo the Year 1 assessment. The following data will be collected from the The aim is to have three farms being selected farms over the period of the study: monitored at any one time. • Total area of ponds

• Standing crop and stocking density

• Daily water use • Feeds and feed rates • Distance between inflow and outflow

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Acknowledgements

The authors would like to thank the Steering Committee for their invaluable contribution to this project. The steering committee consisted of:

• Edward Meggit, Mark Fox and Mitch Mc Rae, Victorian Trout Association • Sue Botting, Goulburn Broken Catchment Management Authority (GBCMA) • Dave Tiller and Elita Briggs, Environmental Protection Authority (EPA) • Giles Flower, Goulburn Murray Water (GMW)

• Bill Lussier, Fisheries Victoria.

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References

Alabaster, J. S. and Lloyd, R. (1980). Water quality GBCMA, (2004). Regional River Health Strategy criteria for freshwater fish. Butterworths, UK. 2004. Status of the Riverine System – Waterways in Focus. Goulburn Broken Anon. (2004). Fisheries Victoria Commercial Fish Catchment Management Authority, Production Information Bulletin 2004. 33pp. Shepparton. (Primary Industries Research Victoria (PIRVic): Queenscliff, Victoria, Australia). Loch, D., West, J. and Perlmutter, D. 1996. The effect of trout farm effluent on the taxa ANZECC, (2000). Australian and New Zealand richness of macroinvertebrates. Aquaculture, guidelines for fresh and marine water 147 (1996), 37‐55p. quality. Volume 1, The Guidelines / Australian and New Zealand Environment Markmann, P. N. 1982. Biological effects of and Conservation Council, Agriculture and effluents from Danish fish farms. In Resource Management Council of Australia Alabaster, J. S. (ed). Report on the EIFAC and New Zealand. workshop on Fish Farm Effluents. EIFAC Tech. Pap. 41: 99‐102. Carmago, J. A. (1992). Structural and trophic alterations in macrobenthic communities Metzeling, L. (1999) The impact of fish farm downstream from a fish farm effluent. effluent on stream ecosystems – some results Hydrobiologia. 242: 41‐49, 1992. from EPA studies. In Ingram, B.A. (Ed). Towards Best Practice in Land‐based Salmonid Cottingham, P. Stewardson, M., Crook, D. Farming: Options for Treatment, Re‐use and Hillman, T., Roberts, J. and Rutherford, I. Disposal of Effluent. Marine and Freshwater (2003). Environmental flow Resources Institute, Alexandra. 121 pp. recommendations for the Goulburn River below Lake Eildon. Technical Report Metzeling, L., Bibrowska, H., & Goudey, R. 01/2003. Cooperative Research Centre for (1993) The Impact of Fish Farming on the Freshwater Ecology, University of Canberra, Goulburn River. Environment Protection ACT, 2601. Authority of Victoria Report SRS 91/011 ISBN 0 7306 2891 4 DEFG, (2005). Draft Environmental Flow Guidelines. Arts, Heritage and Environment, Metzeling, L., Bibrowska, H., & Goudey, R. Australian Capital Territory, Canberra, 2005. (1996) The Effect of Fish Farming on the Water Quality and invertebrate Fauna of DNRE, (1999). An Index of Stream Condition: Two Upland Rivers. Environment Protection Reference Manual. Waterways Unit, Authority Publication 482 ISBN 0 7306 2903 1 Department of Natural Resources and Environment (Victoria). September 1999. NCC (1990). Fish Farming and the Scottish Environment. NCC Contract No. HF3‐03‐450. DNRE, (2002). The FLOWS Method. A method for Nature Conservancy Council. determining environmental water requirements in Victoria. Department of Natural Resources Pillay, T. V. R. (1992). Aquaculture and the and Environment, Feb. 2002. environment. Halsted Press. New York, NY 189 pp. Department of Primary Industries (2005). Best Practice Environmental Management Guidelines for the Salmonid Aquaculture Industry. Fisheries Victoria Management

Report Series No. 25.

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Appendix 1 – Literature Review

diversion licence stipulates the maximum rate of Review of ecological impacts of diversion (ML/day), maximum daily volume salmonid farms (ML) and total annual volume. The diversion Impacts of salmonid farms on the aquatic rate should be set relative to the capacity of the environment primarily occur as a result of two river, but many of the current licences were processes (NCC 1990): granted well before the current legislation was enacted. In addition, water use in the catchment • Abstraction of water from rivers upstream of farms has changed over the years, • Discharge of wastes to rivers. altering the flow regime. Department of Primary Industries (2005) Many methods have been developed to identified six waste streams from salmonid determine in‐stream environmental water aquaculture. This study deals exclusively with requirements to sustain river health both in wastes discharged directly to aquatic Australia and overseas. A key concept here is ecosystems particularly organic matter (mainly the environmental flow of the river. uneaten feed and fish excreta) contained in Environmental flows are defined as (DEFG effluents. 2005): Abstraction of water from rivers “the streamflow (including aquifer discharge) Salmonid farms can divert surface waters under necessary to sustain habitats (including channel a water diversion licence from the appropriate morphology and substrate), provide for spawning Rural Water Authority (RWA) under the Water and the usual migration of fauna species to Act, 1989. Salmonid farming is classed as a non‐ previously unpopulated habitats, enable the processes consumptive user of water (i.e. the amount of upon which succession and biodiversity depend and water diverted is equal to the amount maintain the desired nutrient structure within lakes, discharged back to the waterway). streams, wetlands and riparian areas. Environmental flows may comprise elements from Abstraction of water from rivers can result in the full range of flow conditions which describe long‐ physical, chemical and biological changes to term average flows, variability of flows including low aquatic habitats. If there is a depletion or loss of flows and irregular flooding events.“ flow between the intake and outflow, the following impacts can occur (NCC 1990): A method for determining environmental flows in Victorian rivers has recently been developed • Changes in channel shape and patterns of (DNRE 2002). The “FLOWS” method is aimed sedimentation at a scientific assessment of flow requirements • Loss of spawning or nursery areas for fish for river systems where some information is available on ecology, geomorphology and • Possible barriers to fish movement hydrology (DNRE 2002). This approach has • Alteration of biological communities. already been applied to the main Goulburn River channel downstream of Lake Eildon The severity of any impacts will be site specific (Cottingham et al. 2003) as part of the “Living and depend on the proportion of the total flow Murray” initiative. It is planned that this abstracted, the distance between the inflow and method will be used to develop Streamflow outfall and the duration of flow depletion. Management Plans for river systems. Impacts are likely to be most severe during low flow periods in the river, which in unregulated In summary, the impacts of salmonid farms as a Victorian rivers, tend to co‐incide with high result of water abstraction will be site specific. temperature and high water demand from Any analysis of the impacts of water diversions salmonid farms. from farms should consider environmental water requirements of the river, particularly The key unknown here is how much of the flow between influent and effluent points of the farm. of a given river can a farm abstract over long and short timeframes without causing environmental harm. The farm’s water

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Discharge of effluents to rivers The principal components of salmonid aquaculture effluent include: suspended solids, nutrients, oxygen consuming organics, nutrients and toxic metabolites (e.g. ammonia and nitrite). Factors influencing the quality of effluent from salmonid farms were discussed in the Best Practice Environmental Management Guidelines for the Salmonid Aquaculture Industry (Gavine et al. In press) and will not be further discussed here. On a broad scale fish farm, effluents are relatively harmless compared with other discharges to freshwater environments, some of which cause significant environmental harm (e.g. sewage treatment works) (Metzeling 1999). Figure 1 shows the typical effects of sewage discharge, which usually contains high levels of Figure 1: Typical effects on water quality and biodegradable organic matter, on water quality the associated biota which may be observed and biota in an aquatic ecosystem. Discharges downstream of a sewage outlet. A and B. of this nature can result in physical and Physical and chemical changes; C. Changes in chemical changes to the water and sediments (A micro‐organism populations; D. Changes in and B), changes in micro‐organism populations (C) and changes to the invertebrate population invertebrate populations (after Hynes 1990). (D).

Although fish farm effluents are more dilute in Impacts on water chemistry in surface waters terms of pollutants, the effluents can have As noted above, fish farm effluents usually broadly similar impacts to those shown in contain elevated levels of BOD, suspended Figure 1 and may impact on water chemistry, solids, nutrients and toxic metabolites and may sediment quality and the biota of aquatic have slightly lower dissolved oxygen levels. At environments. the point of discharge, levels of these parameters The impact of salmonid farms on the may change in the receiving watercourse downstream environment has been studied both compared with background levels. As the in Australia (Metzeling et al. 1993, discharge travels downstream, water quality in the river gradually returns to normal. Metzeling et al. 1996) and overseas (Loch et al. 1996, Markmann 1982). Pillay (1992) reported Downstream water chemistry can be effected by the work of Markmann (1982) who listed the effluent discharge in two ways: following downstream impacts of salmonid • Direct toxicity (e.g. ammonia) farms in Denmark: • Indirect effects (e.g. elevated nutrient levels • More fine grained and homogeneous which can stimulate algal growth and sediment organic matter which can cause • Higher concentrations of suspended solids sedimentation and deoxygenation if allowed (food for invertebrates) and dissolved to accumulate). organic materials (food for bacteria and Specific concerns related to components of fish protozoa) farm effluents include: • Reduced dissolved oxygen levels from fish Ammonia levels respiration on farm, increased BOD and Fish farm effluents contain elevated levels of sediment respiration ammoniacal nitrogen as it is an excretory • Higher concentrations of ammonia, nitrate product of fish. Several studies have recorded and phosphate increases in total ammoniacal nitrogen downstream of fish farms (Solbe 1982; Sumari • Potentially toxic concentrations of ammonia. 1982; Metzeling et al. 1993, 1996). Total

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ammoniacal nitrogen is composed of unionised • Hydrological conditions (such as effluent ammonia (which is toxic to aquatic life) and entering the stream in a pool, compared ionised ammonium. Concentrations of the toxic with a riffle section of the stream) form of ammonia increase with pH, • The temperature of the stream. temperature, and salinity (Alabaster and Lloyd 1982). ANZECC trigger levels for dissolved oxygen vary with the ecosystem type (Table 3). “Trigger levels” for ammonia in freshwater ecosystems were set by ANZECC (2000) (Table 2). “Trigger values” may be defined as: Table 3 Default trigger values for dissolved oxygen in south east Australia (ANZECC 2000) “the concentrations or loads of the key performance * indicators measured for the ecosystem, below which Ecosystem type DO (% saturation) there exists a low risk that adverse biological Lower limit Upper limit (ecological) effects will occur. They indicate a risk of Upland river 90 110 impact if exceeded should ”trigger” some action, Lowland river 85 110 either further ecosystem specific investigations or *dissolved oxygen values were derived from daytime implementation of management/remedial actions” measurements. Dissolved oxygen concentrations may The “trigger value” varies with the level of vary diurnally and with depth. Monitoring programs protection required for the specific ecosystem should assess this potential variability that the farm discharges to. The highest protection level (99%) is the value for Suspended solids and turbidity ecosystems with a high conservation value. It Suspended solid loads from flow‐through can also be used for slightly – moderately aquaculture systems are comprised mainly of disturbed systems where data is lacking uneaten feed and fish faeces. As with dissolved (ANZECC 2000). oxygen, solid loadings will also vary considerably depending upon the season, time of day, feeding Table 2: Trigger value for ammonia in rates, fish sizes and management practices such as freshwaters. pond or settlement pond cleaning. Trigger levels Trigger values for freshwater (mg/l) for suspended solids and turbidity in river systems were also developed by ANZECC (Table Level of protection (% species) 4). 99% 95% 90% 80% Ammonia 0.320 0.9 1.43 2.3 Nutrient discharge (especially phosphorus) Phosphorus and nitrogen are discharged in effluents from salmonid farms. Both nutrients Dissolved oxygen levels can result in an increase in the productivity of Dissolved oxygen levels in rivers can be reduced freshwater, but phosphorus is usually the by effluent waters in two ways: through the limiting factor in these cases. Trigger values for direct consumption by the stocked fish which nitrogen and phosphorus vary with the quality lowers levels in the effluent; and due to of the receiving environment (Table 5). consumption of oxygen during bacterial breakdown of organic matter. If the effluent has a high oxygen demand, deoxygenation of the water column may occur, creating localised deterioration in water quality. Re‐oxygenation occurs naturally in streams, with the extent of the effect dependent on: • Concentrations of plant matter • Biological activity (such as the requirement for oxygen by other organisms, including those breaking down the nutrients in the effluent) • Wind and other meteorological conditions (such as the intensity of sunlight)

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velocities are low enough to allow settlement Table 4 Default trigger values for turbidity in (NCC 1990). slightly disturbed ecosystems in south east Settled organic matter can change the physical Australia.(ANZECC 2000) properties of the sediments. For example, Ecosystem Turbidity Explanatory notes Markmann (1982) found that sediments were type (NTU) more fine grained and homogeneous Upland rivers 2‐25 Most good condition downstream of Danish fish farms. Accumulated upland streams have low sediment can also exert an oxygen demand and turbidity. High levels may lead to deoxygenated conditions at the sediment be observed during high water interface, with consequences for nutrient flow events recycling from the sediments. Lowland 6‐50 Turbidity can be extremely Ecological changes as a result of farm rivers variable. Values at the effluents high end of the scale The flora and fauna present in specific aquatic would be found in rivers ecosystems are a function of the hydrological, draining slightly distrubed physical and chemical characteristics of that catchments and in many ecosystem (Chapman 1992). Flora and faunal rivers at high flows communities can be affected by anthropogenic discharges to rivers. For example, Figure 1 shows a typical effects of sewage discharge on Table 5: Default trigger values for total the environment. nitrogen (TN) and total phosphorus (TP) in slightly disturbed ecosystems (ANZECC 2000). In running waters, major ecological issues related to the discharge of effluents include: Ecosystem TP (μg P/l) TN (μg P/l) Type • increases in algal growth as a result of nutrient discharges (discussed previously) Alpine streams 10 100 Upland river 20 250 • impacts on macroinvertebrate communities. Lowland river 50 500 The discharge of fish farm effluents to surface waters can cause changes in the local benthic The extent and magnitude of impacts on water macro‐invertebrate communities as a result of chemistry downstream of the point of discharge (adapted from NCC 1990): are related to: • Increased solid loadings can result in an • Volume and quality of the effluent released increased food supply and increase the • Dilution afforded by the receiving numbers of invertebrates. However, if watercourse solids accumulate, habitats can be smothered and there can be localised • The sensitivity of the receiving deoxygenation and the creation of abiotic environment. zones In Victoria, with the exception of farms on • Increased nutrient loadings and/or turbidity regulated rivers, salmonid farms tend to be can result in changes in invertebrate located in high quality environments which community structure often offer only limited dilution capacity • (Metzeling 1999). Metzeling et al. (1993) found Direct toxic effects can arise from the that downstream impacts on water quality were discharge of ammonia and some chemicals. clearly related to the size of the farm – the bigger The effects of fish farm effluents are similar to the farm, the further downstream elevated the impacts of other inputs of organic matter nutrient concentrations persisted. and nutrients and include (Loch et al. 1996; Physical and chemical changes to sediments Camargo 1992; NCC 1990): The release of solid particles with a density • A loss of sensitive invertebrate species greater than water means that there is a immediately below the discharge point tendency for solid matter to deposit • downstream of the discharge point, if water An increase in the biomass of pollution tolerant species

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• Return to diverse conditions at some point Oligochaete worms) were more abundant downstream of the point of discharge. downstream of farms 2 and 3. Other species tolerant of enriched conditions (e.g. gastropod Previous studies have investigated the impact of snails and the Chironomidae) did not increase in Victorian salmonid farms on invertebrate abundance downstream of the farms. Overall communities downstream of the point of the results indicated that invertebrate biota are discharge (Metzeling et al. 1993; Metzeling et al. more sensitive indicators of an impacted 1996). Metzeling et al. (1993) studied the impact ecosystem than water quality indicators taken in of three farms on benthic communities in one isolation. regulated river by taking samples upstream and downstream using two sampling methods. Metzeling et al. (1996) investigated the impact of Artificial substrate samplers (ASS) were used at two fish farms on invertebrate communities in one farm as the river stretch was made up of upland rivers. This was a more intensive study deep pools without any shallow riffles. Five of benthic impacts than the previous study with ASS were placed both upstream and 5 sites (2 upstream and 3 downstream) on each downstream of the farm for three weeks. At the river sampled. Each site was sampled 3 times other two farms, shallow riffles were present with 5 samples collected from a riffle on each allowing benthic invertebrates to be sampled occasion using a Surber sampler. directly. The results showed that there was a noticeable The study found that the impact of the fish impact on benthic communities downstream of farms on invertebrate communities in the river both farms, but these impacts were not as severe varied considerably and postulated the other pollutants. Impacts were not discernible following reasons: in a simple measure of species richness as there was often more taxa downstream of a farm than • Different habitats at each farm. At the farm upstream. This was a result of the effluent being showing greatest impacts, the river fairly good quality (non‐toxic) and not resulting consisted of a series of slow‐flowing deep in severe secondary effects. The results were pools (this could allow solid wastes to analysed using other measures including: accumulate). The other two farms showed percentage composition of major taxa, faunal less impacts and the river at the point of abundance, two biotic indices (PET and discharge was rapidly flowing with shallow SIGNAL) and multivariate analysis. This riffles. analysis showed that the quality of sites • Effluent quality. The farm showing greatest upstream were clearly distinct from those impacts had poorer effluent quality then the downstream at both sites; however, the impact other two farms. This combined with the of one site was greater than the other site. slow water flow could have resulted in accumulation in the deep pools resulting in degraded conditions. This study did not show pronounced changes to the biota downstream as overseas studies have (e.g. Jones 1990); however, some pollution tolerant species (snails Potamopyrus niger and

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Appendix II – Preliminary proposals submitted

Preliminary proposals for funding have been submitted (or will be submitted shortly) to the following sources:

Funding source Outcome Fisheries Victoria Successful for 05/06

GBCMA Partially successful 05/06 EPA Sustainability Fund Awaiting next round opening. DPI ADT Program 1 06/07 funding round to open shortly DIIRD Negotiations ongoing.

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Appendix III – Workshop Minutes 12/4/05

Goulburn River Study Technical Working ¾ Key information ‐ what is the range Group of impacts related to fish culture on this catchment and can we identify Minutes of first meeting indices to streamline monitoring. • What we wanted to achieve at the 12th April 2005, Snobs Creek. meeting? ¾ Specify the scope and detail Attendees: required to answer the questions we Fiona Gavine and Brendan Larkin, Aquaculture have to. Section, DPI Snobs Creek ¾ Identify the regulatory, policy and Hugh Meggitt, Goulburn River Trout business imperatives that the project Mark Fox and Stuart Gilmore, Yarra Valley must address. Salmon ¾ Accurately cost the monitoring Dave Tiller and Elita Briggs, Environmental component of the project. Protection Agency Mitch Macrae, Buxton Trout 3. General discussion Felicity Smith, Ecological Monitoring Specialist • Key document for this study is the Sue Botting, Goulburn Broken CMA Goulburn‐ Health Strategy Giles Flower, Goulburn Murray Water. which classifies river reaches according to Bill Lussier, Fisheries Victoria. stream health indicators. It was noted that river reaches with salmonid farms range Apologies: from “poor” to “excellent” – and would Deb Brown, River Health Program, DSE require different monitoring. • CMA and EPA data all incorporated in Meeting minutes: Victorian Data Warehouse. CMA reaches 1. Meeting opened by Brendan Larkin, are aligned with SEPP segments. River introductions and welcome. health strategy reaches up to 30 km long – 2. Fiona Gavine gave presentation of this project needs to refine the data to make background to the study including: it relevant to individual farms. • Where the proposal came from • EPA had two areas it wanted to see ¾ BPEMG development highlighted addressed under SEPP WOV: information gaps in effluent quality ¾ That enterprises were implementing from farms and actual impacts. Best Practice. ¾ EPA Licence review was a parallel ¾ That impacts of individual process that required industry to businesses were not detrimental to collect a lot of information related to the beneficial uses of the receiving their impacts. The project could environment. assist industry to collate that • The same effluent quality and quantity information. could have far different impacts depending • Overall aims and specific objectives. on the quality of the receiving environment. ¾ Overall aim was to evaluate the EPA wants to concentrate its efforts on those impact of the existing salmonid identified as having significant/unacceptable industry on the Goulburn River and impacts. its tributaries. • David Tiller suggested that in order to identify farms for monitoring under this

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project a “decision tree” approach should be used to identify key risk factors for salmonid farms. This decision tree would lead to an understanding of the system that the farms operate in and the relative risks associated with individual farms

4. Outcomes The following approach was recommended (to be completed by June 2005):

PHASE 1: Characterisation and assessment of critical issues forselected farms. All four farms represented volunteered to be part of the initial assessment. This will include an assessment of: • Nature of the receiving waters • Flow regime of receiving waters • Existing background data • Proportion of flow diverted through farm during low flow events (focus will be on low flow events as it is presently assumed that these are when the greatest impact is likely to occur) • Current management procedures (feeding strategy, stocking density, feed quality, settlement mechanisms used)

PHASE 2: Development of a decision tree that will be used to select farms/ rivers that will be monitored under this project. Key concerns on which farms will be assessed include: ‐ Ammonia ‐ Flow ‐ Turbidity ‐ DO deficiency ‐ Total P - Conditions and history of existing licence

The decision tree will take into account the receiving waterʹs ability to handle effluent input from trout farms. Farms will be categorised according to their risks.

PHASE 3: Workshop in June 05 to determine which categories of risk will be studied and develop monitoring protocols specific to each risk.

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Appendix IV: Workshop Minutes 22/6/05

Goulburn River Study Technical Working Trout Farm, Yarra Valley Salmon and Group Buxton Trout Farm that had been completed. For each site considerations Minutes of second meeting were given to farm production, river health and flow statistics, diversion data and 22 June 2005, Snobs Creek effluent quality. The characterisation studies are attached to this document and Attendees: may be summarised as follows.

Edward Meggitt, VTA and GMW Walnut Island Trout Farm Giles Flower, GMW • Large farm located on large, highly Dave Tiller, EPA Head Office seasonally regulated, “poor” quality river Cathryn Marum, EPA Regional system. Sue Botting, GBCMA • Good data on flows in river and farm Bill Lussier, Fisheries Victoria discharge rates. Fiona Gavine and Brendan Larkin, PIRVic • Effluent quality sampled 6 times per year in compliance with current EPA licence. Apologies: • Quality of upstream water is available from Data Warehouse and inflow data available Elita Briggs, EPA from Company records (?). Mitch Macrae, Buxton Trout Farm • Nutrient mass balance models are used as a Mark Fox, YVS management tool but are of limited use in Deb Brown,DSE predicting effluent quality. • No recent data on downstream impacts. Meeting minutes: Yarra Valley Salmon 1. Fiona Gavine (FG) opened meeting with • Medium sized farm located on relatively introductions and welcome. small, daily regulated, “good” quality river 2. FG gave a brief description of the outcomes system. of the first meeting held 22 April 2005 and • Effluent quality is sampled 6 times per year the presentation to the VTA (22 April 2005). (mostly in high‐risk period) ‐ complies with 3. The main action item from the first meeting licence. was to prepare Characterisation Studies for • Quality of influent water is available from three farms to investigate how the decision Data Warehouse and inflow data available tree would work. Key information required from Company records (?). from these studies is: • No recent data on downstream impacts ¾ How capable is the system of coping although part of EPA study in 1993. with the discharges. • Confounding effects of power station ¾ Which farms require mixing zones operations (e.g. annual de‐silting, routine ¾ What % of the time are flows below a maintenance). certain level. • An observed long‐ term drop in pH in river possible resulting from sawdust heaps 4. FG proceeded to describe briefly the located adjacent to river. characterization studies on Walnut Island

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Buxton Trout Farm parameter. A major finding was the lack of • Medium sized farm located on a small, data on downstream impacts at all three upland, unclassified river. farms. • Effluent quality is sampled 6 times per year (mostly in high‐risk period) ‐ complies with 6. General discussion: licence. ¾ All parties felt it was better to move • No data on flows for Little Steavenson River towards monitoring actual impacts of or for discharge from trout farm. effluent rather than “end of pipe” • Only available water quality information measurements. That is the study should available is data collected by trout farm. investigate what effects effluent from • No studies on river health although farms have on the receiving streams, although there has been ongoing and whether the different parameters community Waterwatch monitoring. within the effluent have different effects. 5. The characterisation of each farm against the ¾ Dave Tiller highlighted the need for a key risks is shown in Table 1. The level of “decision tree”and felt that a lot of the risk identified was directly related to the decisions necessary from the study data that was available. Where no data was would be decided in the formulation of available, farms were assigned a risk for that the decision tree.

Table 1: Risk assessment from characterisation studies.

Risk Factor Assumptions Walnut Yarra Buxton Island Valley Trout Salmon Flow 4. Less of an issue on some (not all) regulated rivers than X √ √ on unregulated rivers. 5. Upland rivers have a higher risk as flows are more variable. Ammonia toxicity 6. At what concentration will the ammonia in discharged X √ √ effluent cause an environmental impact? 7. ANZECC guidelines state that a concentration of 0.32 mg/l provide a 99% level of ecosystem protection. 8. Compliance with EPA licence conditions and adequate dilution should provide protection. Suspended solids/ Impacts will depend on physical factors in river including √ √ √ turbidity flow regime, type of substrate, presence of pools, and hydrodynamics near discharge point. Total Phosphorus 4. Catchment scale issue. X √ √ 5. Importance will depend on limits/caps set. 6. Total loads can be calculated. Oxygen deficiency 4. Impacts will depend on biochemical oxygen demand √ √ √ of flow.

5. Downstream sediment accumulation.

6. Dilution.

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¾ It is better to concentrate on a few farms 7. A prototype decision tree was developed to to get the decision tree right, then assist with the categorisation of farms (see overlay that result on all the farms to below). It was decided that the study test the functionality of it. should focus on farms that are ¾ It was stressed the three farms chosen representative of commercial farms and for the characterisation were not assess the effect that different river types necessarily those which will be chosen and environmental conditions has on for the study. The existing downstream impac characterisation studies are to be used in a project proposal to lever up the main study.

Salmonid licence holders

Discharging EPA Not discharging EPA

Regulated Rivers Unregulated Rivers Other

Effluent Quality and Stream Quality Quantity

Effluent Quality and Stream Quality Excellent Good Moderate Poor No Data Quantity Adequate Not Adequate

Good Moderate Poor

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