39 REVIEW OF THE TASMANIAN ABALONE COUNCIL REPORT ON RISKS TO THE ABALONE FISHERY FROM FURTHER EXPANSION OF THE SALMONID INDUSTRY

While the impact on reefs is less well understood, the recent review of the Broadscale Environmental Monitoring Program BEMP found no evidence of any major broadscale impacts of salmon f

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/283257123

REVIEW OF THE TASMANIAN ABALONE COUNCIL REPORT ON RISKS TO THEABALONE FISHERY FROM FURTHER EXPANSION OF THE SALMONID

All content following this page was uploaded by Colin Buxton on 27 October 2015.

The user has requested enhancement of the downloaded file.

REVIEW OF THE TASMANIAN ABALONE

COUNCIL REPORT ON RISKS TO THE ABALONE FISHERY FROM FURTHER EXPANSION OF THE SALMONID INDUSTRY

COLIN BUXTON

Colin Buxton & Associates

July 2015

ii

Title

REVIEW OF THE TASMANIAN ABALONE COUNCIL REPORT ON RISKS

TO THE ABALONE FISHERY FROM FURTHER EXPANSION OF THE SALMONID INDUSTRY

Copyright

This work is copyright Except as permitted under the Copyright Act 1968 (Cth),

no part of this report may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owner Information may not be stored electronically in any form whatsoever without such permission

 Colin Buxton & Associates

Enquires should be directed to:

Prof Colin Buxton

Colin Buxton & Associates

27 Wandella Ave, Taroona 7053

colin.buxton@utas.edu.au

1

Executive Summary

On 3 December 2014 the Department of Primary Industries, Parks, Water and Environment (DPIPWE), with the endorsement of the Minister for Primary Industries and Water

commissioned a review of a report by the Tasmanian Abalone Council Ltd (TAC) entitled:

Risks to the Tasmanian Abalone Fishery from further expansion of the Salmonid Industry

(TAC 2014)

After consultation with Tassal Group Ltd (Tassal), Huon Aquaculture Group Ltd (Huon Aquaculture) and the TAC, the Terms of Reference (TOR) determined for the review were:

1 Against current scientific knowledge, assess and report on the veracity of the

assertions listed in the TAC Ltd report that relate to the potential impacts of salmonid farming on the abalone sector in Tasmania

2 Review the statutory monitoring requirements implemented for soluble and solid waste from salmonid farming and report on its adequacy for assessing impacts of salmonid farming in relation to the detection of impacts on rocky reef habitats

3 Assess the status and productivity of fishing blocks 14b, 14c and 15 in SE Tasmania and report on possible salmon farming impacts on abalone productivity

4 Review the planned salmon industry amendments and expansion and report on the potential risks to abalone and rock lobster fisheries, including harmful algal blooms and disease transmission

5 Assess the potential impacts of sediment from salmon farming on the abalone biology and ecology

In the preparation of this review the consultant interviewed the key stakeholders: TAC, Tassal, Huon Aquaculture and researchers from the Institute for Marine and Antarctic Studies

at the University of Tasmania The Tasmanian Rock Lobster Fisherman’s Association was also consulted who indicated that they had resolved their concerns over the proposed

amendments with the salmon industry

The structure of the review includes a section on each of the Terms of Reference

The major findings are summarised as follows:

1 An analysis of changes to the marine farming zones and lease areas for each of the recently approved and proposed marine farming development plan amendments shows that, while there has been an overall increase in zone area (597.67ha), the changes to the lease areas, i.e where the farming occurs, have been relatively small (105.57ha) The net effect has been an increase in leasable area for salmon marine farming of 19.94ha, which is 1.86% of the total lease area (1073ha) The data do not support the argument that there has been a significant expansion of salmon farming operations in SE Tasmania as an outcome of the marine farming development plan amendments in question

2

2 An extensive literature exists on the near field impacts of salmon farming on the marine environment in Tasmania Research shows that while salmon farming may have significant near field impacts below the cages, there is a gradient of impacts such that effects beyond 35m from the lease boundary are minor While the impact on reefs

is less well understood, the recent review of the Broadscale Environmental

Monitoring Program (BEMP) found no evidence of any major broadscale impacts of salmon farming at present in the Huon / D’Entrecasteaux Channel region This

suggests that MFDP amendments to salmon farming activities in the Channel will not pose an unacceptable risk to the key abalone fishing areas to the south of this region

3 Salmon farming has the ability to alter the environment, but the research and

monitoring conducted to date demonstrates that changes arising from the impacts of solid wastes attributable to salmon farming are localised in relation to impact on sediments below cages Since the onset of salmon farming parts of the Huon and D’Entrecasteaux system have changed from being oligotrophic (low nutrient) to mesotrophic (moderate nutrient) However, within the limits of the imposed Total Permissible Dissolved Nitrogen Output (TPDNO), these changes do not pose a

significant or unacceptable broadscale risk to the environment

4 The impacts of salmon farming on exposed oceanic environments such as Storm Bay are likely to be similar to those in sheltered waters elsewhere in SE Tasmania, with one major difference that the impacts are likely to be dispersed more widely and diluted more quickly The current lack of understanding of the impact of salmonid farming in open ocean exposed sites has been recognised and there are a number of studies underway to improve our knowledge in this area However, there are no data

to support the argument that future expansion should feature cages located four or more nautical miles from inshore reef habitat

5 DPIPWE uses an adaptive management approach to both fisheries and marine

farming, but this is clearly sector by sector Given the concerns expressed by the abalone sector, an opportunity exists for greater engagement Such an approach to adaptive management in the D’Entrecasteaux would seem appropriate and would

build on the planning provisions of the Marine Farming Planning Act 1995 which

enable the concerns and aspirations of competing interests to be identified, considered and responded to in the statutory marine farming planning processes

6 Evidence for a direct cause and effect relationship between loss of abalone

productivity and salmon farming is not clearly apparent from catch and effort data This analysis points to depletion in the fishery itself to be the most likely cause for a loss of productivity in the Southeast and the Eastern zones in general However, a combination of factors, including salmon farming, may have a localised effect in some places, especially where salmon farming occurs over an area of reef that is currently or was historically suitable abalone habitat Port Esperance is likely such an example

3

7 While abalone reef is found in proximity to salmon farms throughout the Channel, and while some areas may have produced significant yields historically, most of these areas are now minor to the fishery The key fishing areas for abalone are at least 11kms from the nearest lease at Lippies Point and thus well outside of the detectable impacts of salmon farming

8 Recent amendments to MFDPs do not constitute a major expansion of marine salmon farming in the Huon and D’Entrecasteaux regions and the industry operates within prescribed TPDNO limits determined to ensure that there are no unacceptable

broadscale impacts to the environment from salmonid farming Elevated nutrients levels are mostly in the northern parts of the system while the main abalone fishing areas occur in the south and are located well beyond the detectable limits of impact from salmon farming These factors suggest that recent and proposed amendments to marine farming development plans will not increase the risk of Harmful Algal Blooms (HABs) to the abalone industry

9 While there is the potential for disease transfer from escaped fish, the low level of disease

in farmed Tasmanian salmonids combined with relatively low loss rates from recent years means that such a risk is very low More generally, pathogens do not cross phylum barriers hence the risk of disease transmission between salmon and other species such

as abalone and rock lobster would appear to be low

10 Inshore marine environments receive inputs from a number of sources including upstream activities that include agriculture and forestry, marine farming, industrial outfall and waste treatment plants, as well as numerous natural sedimentation

processes No evidence supports the claim that the ‘milky dust’ on macroalgae in parts of the system is derived from salmon farming Until such time that the sediments can be properly sampled and analysed it is premature to attribute the source, or a portion of the source, to any sector

Esperance area 121.9 How is the Precautionary Principle used in the making of decisions relating

environmentally sustainable development in an adaptive management context? 12

2 Review the statutory monitoring requirements implemented for soluble and solid waste from the salmonid farming and report on its adequacy for assessing impacts of salmonid farming in relation to the detection of impacts on rocky reef habitats 152.1 Introduction 152.2 Monitoring and reporting requirements – D’Entrecasteaux Channel, Huon River and Port Esperance MFDP areas 162.3 Evaluating the BEMP 172.4 Detecting impacts on rocky reefs 20

3 Assess the status and productivity of fishing blocks 14B, 14C and 15 in SE Tasmania and report on possible salmon farming impacts on abalone productivity 23

4 Review the planned salmon industry amendments and expansion and report on the potential risks to abalone and rock lobster fisheries, including harmful algal blooms and disease transmission 344.1 Introduction 344.2 Planned expansion of the salmon industry 344.3 Recent amendments to salmon farming in the Huon and D’Entrecasteaux Channel 35

5

4.4 Risks to abalone and other reef fisheries 38

5 Assess the potential impacts of sediment from salmon farming on the abalone biology and ecology 43

5.1 Organic sedimentation from salmon farming 43

5.2 Organic and inorganic sedimentation in the marine environment 44

5.3 In situ net cleaning as a potential source of sediments 45

6 References 47

7 Appendices 51

Appendix 1 - Environmental monitoring and reporting requirements of salmonid licence holders in the D’Entrecasteaux Channel and Huon River and Port Esperance marine farming development plan areas 51

Appendix 2 – Schedule 3 BEMP 56

Appendix 3: Current and planned research aimed at improving the understanding of the broadscale, far-field and reef impacts of salmonid farming in Tasmania 72

6

1 Against current scientific knowledge, assess and report on the veracity

of the assertions listed in the TAC report that relate to the potential

impacts of salmonid farming on the abalone sector in Tasmania

Concerns relating to the potential impacts of salmon farming on the abalone wild fishing

sector in Tasmania have been made in a report entitled “Risks to the Tasmanian Abalone

Fishery from further expansion of the Salmonid Industry” (TAC 2014) The major assertions listed in the report are examined through a series of questions:

- Do the proposed amendments in the lower D’Entrecasteaux Channel represent a

significant expansion of salmon farming operations in the area?

- Does salmon farming impact the water quality and substrate characteristics?

- What localised amenity impacts from salmon farming may impact the abalone

fishery?

- How well are near field and far field impacts of salmon farming on the environment

understood?

- What is known about the impacts of salmon farming in “oceanic” environments?

- Does the current environmental monitoring of near-farm and/or broadscale effects

represent a conflict of interest or lack of independence?

- What is the risk of eutrophication of the system arising from salmon farming?

- What is the origin of the fine sediment observed on macroalgae in the Port Esperance

area?

- How is the Precautionary Principle used in the making of decisions relating

environmentally sustainable development in an adaptive management context?

A summarised answer to each of these key questions is presented below, while more detailed consideration and referencing is found in subsequent sections that relate to Terms of

Reference 2-5

1.1 Do the proposed amendments in the lower D’Entrecasteaux Channel represent a significant expansion of salmon farming operations in the area?

Page 7 of the TAC Report outlines plans for the expansion of farming operations in the

southern part D’Entrecasteaux Channel (Tassal) and north Bruny Is (Huon Aquaculture)

This question relates to the suggestion that salmon farming has expanded significantly in the D’Entrecasteaux Channel (Channel) and that this represents a risk to the abalone fishery, particularly in the southern part of the Channel which is adjacent to the key abalone fishing area of Block 13 These concerns are addressed in more detail under Section 2 and Section 4

An analysis of changes to the marine farming zones and lease areas for each of the recently approved and proposed amendments shows that, while there has been an overall increase in zone area (597.67ha), the changes to the lease areas, i.e where the farming occurs, have been relatively small (105.57ha) (see Table 4.2) In two cases, Flathead Bay and Lippies Point,

7

increases in the Channel have been offset by similar decreases in lease area in the Huon River and Channel respectively The net effect of all of these amendments has been an increase in leasable area for salmon marine farming of 19.94ha, which is 1.86% of the total lease area (1073ha) in the Huon River and Port Esperance Marine Farming Development Plan (MFDP) and D’Entrecasteaux Channel MFDP areas

The increase in lease area in the Channel are of primary concern to TAC, however, as a percentage of the total lease area in the D’Entrecasteaux Channel MFDP this still only

represents a 3.11% increase

The data do not support the argument that there has been a significant expansion of salmon farming operations in the area

1.2 Does salmon farming impact the water quality and substrate characteristics?

The TAC Report states (pg 7): “It is a widely acknowledged fact that salmon farming (as

previously and currently practised in Tasmania) has a detrimental effect on water quality and substrate characteristics in close proximity to farming operations”

Page 8 of the TAC Report states: “The principal ongoing risk to the abalone industry is

degradation of the marine environment upon which the resource and the industry depend”

and “Salmon farming is one anthropogenic activity that poses a risk to the Tasmanian wild

abalone fishery This risk increases when salmon farming is conducted in close proximity to the benthic reef communities that abalone inhabit”

This question addressed the potential environmental impact of salmon farming in the

D’Entrecasteaux Channel and the risk that this might pose to reef communities and hence the abalone fishery It is discussed in more detail below under Section 2 and Section 4

Since 2009 nitrogen released into the marine environment by fish farms in the Huon River and Port Esperance MFDP and the D’Entrecasteaux Channel MFDP has been regulated via limits or caps on total permissible dissolved nitrogen output (TPDNO) The cap for the

D’Entrecasteaux Channel MFDP area is 1,190.421 tonnes in any 12 month period Ross & Macleod (2013) show that in the D’Entrecasteaux Channel MFDP area inputs have increased from 709 tonnes in 2009 to 849 tonnes in 2011 Despite this increase, the data show that farms were operating well within the TPDNO limits set for the MFDP area (see Table 4.1)

An extensive literature exists on the near field impacts of salmon farming on the marine environment in Tasmania These studies show that nutrient enrichment from uneaten food and faecal material may have a considerable impact on the benthos immediately below the cage and within lease boundaries, but that there is a gradient of impact that diminishes with

1

This figure was increased from 1140.67 tonnes in March 2015

8

distance from the cage and that impacts of salmon farming were minor at distances of 35m

from the lease boundary (see Edgar et al 2005 and references therein)

Early studies of the broadscale impacts of effluent from marine farming on rocky reef

communities found no apparent patterns of change in macroalgal community composition

over a10 year time period between 1992 and 2002 (Crawford et al 2006) However, more

recent work on the macroalgal composition in the Huon and D’Entrecasteaux Channel (Oh 2009) has shown that macroalgal composition at sites located 100m from farms was clearly different from reference sites 5km away in both exposed and sheltered areas While

differences were apparent at the sites situated 400m metres away from fish farms, these were not significantly different from sites 5km away

Analogous to the results elsewhere in the world, Oh (2009) showed that the effect of

salmonid marine fish farms in SE Tasmania was characterised by increases in the cover of epiphytes and total opportunistic algae (which included opportunistic green algae,

filamentous algae and algal turf) In particular, opportunistic green alga of the genera

Chaetomorpha , Ulva and Cladophora (the main constituent of filamentous green algae in this

region) were collectively responsive to the proximity of fish farms Despite limitations in study design (including the re-analysis of reef survey data not specifically designed to test the effects of salmon farming), her findings appear to support anecdotal observations of changes

in the Channel

However, Oh (2009) found that there was no apparent decline of canopy algae close to fish farms (as has been reported for other cases of eutrophication), and, although average diversity and species richness were lowest at sites 100m from fish farms, they were not significantly different from reference sites This suggested that while variations in the detectable effects of fish farms could be anticipated at scales of several hundreds of metres from fish farms, they rarely reached distances of several kilometres away from farming areas

While abalone reef is found in close proximity to some salmon farms throughout the

Channel, and while some of these areas may have produced significant yields historically, most of these areas are now insignificant to the fishery (see Section 3) The key fishing areas for abalone in Block 13 are at least 11kms from the nearest salmon marine farming leases at Browns Point and Lippies Point and thus well outside of the near field impacts of salmon farming

Research shows that while salmon farming may have significant near field impacts below the cages, there is a gradient of impacts such that effects beyond 35m from the lease boundary

are minor (Edgar et al 2005) While the impact on reefs is less well understood, the recent

review of the Broadscale Environmental Monitoring Program (BEMP) found no evidence of any major broadscale impacts of salmon farming at present in the Huon / D’Entrecasteaux Channel region (Ross & Macleod 2013)

This suggests that proposed MFDP amendments to salmon farming activities the Channel will not pose an unacceptable risk to the key abalone fishing areas to the south of this

9

Modelling (Wild-Allen et al 2005; Volkman et al 2009) has demonstrated that the Huon and

D’Entrecasteaux region are hydrodynamically well connected (to the Southern Ocean in the south and Storm Bay in the north), with a residual circulation from south to north which flushes the whole region (a full exchange of water) over about two and a half weeks This disperses local nutrient sources widely, however, there has been a regional elevation of

nutrient and phytoplankton biomass to a modest degree As a consequence, Volkman et al

(2009) conclude that since the onset of salmon farming the system has changed from being oligotrophic (low nutrient) to mid band mesotrophic (moderate nutrient)

Ross and Macleod (2013) concluded that despite the changes in ammonium and oxygen concentration in the Huon River there was no evidence of a change in water column

productivity There was, however, some evidence to support a change in phytoplankton composition in the system

It is clear that salmon farming has the ability to alter the environment, but the research and monitoring conducted to date demonstrates that these changes are localised in relation to impact on sediments below cages and that, within the limits of the TPDNO, nutrients from salmon farming do not pose a significant or unacceptable broadscale risk to the ecosystem in the Huon River and Port Esperance and D’Entrecasteaux Channel MFDP areas

1.3 What localised amenity impacts from salmon farming may impact the abalone fishery?

The TAC Report states (pg 7): “Salmon farming generates localised amenity impacts such as

noise and visual pollution, boating & navigational hazards and reduces waterway area available for general unrestricted use”

The local amenity impacts from salmon farming are discussed in detail in each of the

Environmental Impact Statements relating to proposed amendments to MFPDs in the Huon River and D’Entrecasteaux Channel

Apart from simply noting the concerns expressed by TAC in relation to these issues, it is hard

to understand how abalone fisheries are impacted by reduction in waterway area, visual pollution and noise Major abalone fishing grounds are located for the most part well away from salmon leases

Sharks are an ever present OH&S risk to commercial diving operations, however, the

salmonid industry reports very limited shark interactions with any of their dive teams

working on a full time basis around the State There is no data to suggest sharks are attracted

to salmon farming operations and no data to suggest that interactions are increasing

Navigational hazards around marine farming lease areas exist but are explicitly managed and mitigated by Marine and Safety Tasmania regulations

10

1.4 How well are near field and far field impacts of salmon farming on the environment understood?

The TAC Report states (pg 7): “The salmonid industry and State and Federal Governments

have invested significant resources into understanding the near-farm environmental effects of salmonid production The broadscale and long-term environmental impacts of salmonid farming on the marine environment are less well understood”

This question relates to possible near field and far field risks of salmon farming to abalone fisheries and is discussed in more detail under Section 2 and Section 4

The near-farm (i.e within the marine farming zone) environmental effects of salmon farming

in Tasmania have indeed been well studied, but there is also a considerable body of research into the broadscale effects of salmon farming on the environment in SE Tasmania What is less well understood are what is termed far field effects, i.e those that occur beyond the boundary of the farm zone, and particularly the impacts on reefs This deficiency has been recognised and there are a number of studies underway to improve our knowledge in this area These are listed under Section 4

Understanding the potential long term environmental impacts is the aim of the ongoing BEMP The recent review of the BEMP data found that to date there is no evidence of any significant or unacceptable broadscale impacts of salmon farming at present in the Huon / D’Entrecasteaux Channel region

1.5 What is known about the impacts of salmon farming in “oceanic” environments?

The TAC Report states (pg 7): “There is a general lack of research regarding the

environmental impacts of salmonid farming on inshore Tasmanian oceanic benthic flora and fauna communities”

Page 22 of the TAC Report recommends: “….future expansion….should feature the use of

offshore cage systems that are located four (4) nautical miles away from inshore oceanic reef habitat”

Salmon farming in SE Tasmania MFDP areas has to date occurred in the relatively sheltered waters of the Huon River estuary, Port Esperance and the D’Entrecasteaux Channel,

however, Huon Aquaculture has recently commenced farming on the open ocean exposed north eastern shore of Bruny Island outside of these areas

The impacts of this farming on this environment are likely to be similar to those elsewhere, with one major difference being that the area is more exposed and thus the waste products of

farming (uneaten feed and faecal material) as well as products of in situ net cleaning are

likely to be dispersed more widely

The current lack of understanding of the impact of salmonid farming in open ocean exposed sites has been recognised and there are a number of studies underway to improve our

11

knowledge in this area (see Appendix 3) While research will need to be undertaken to better understand these effects, the dilution effect of more open water farming is likely to mitigate these risks to the marine environment However, there are no data to support the argument that future expansion should feature cages located four or more nautical miles from inshore reef habitat

1.6 Does the current environmental monitoring of near-farm and/or broadscale effects represent a conflict of interest or lack of independence?

Pg 7 of the TAC Report lists the environmental monitoring of broadscale effects undertaken

by the salmon industry as “…raising concerns regarding conflict of interest/lack of

independence”.

License holders must comply with environmental management standards in carrying out operations on the marine farming lease area Companies and/or consultants undertake this work according to specifications prescribed by DPIPWE and the data is reviewed by

DPIPWE

The BEMP sample collection for the years 2009-2012 was undertaken by Aquenal, an

independent environmental consultancy employed by the industry peak body, the Tasmanian Salmonid Growers Association (TSGA) and authorised by the Secretary DPIPWE to

undertake such work

Aquenal Pty Ltd is an environmental consulting company based in Hobart with offices in Perth that provides services in the areas of biological and environmental assessment of

marine, estuarine and coastal habitats

Consultants operate under strict requirements set by DPIPWE for the collection of monitoring data and may be audited by DPIPWE

1.7 What is the risk of eutrophication of the system arising from salmon farming?

The TAC Report states (pg 10): “Artificial salmon feed residues and salmon excreta in high

concentrations can lead to eutrophication within the water column – i.e nutrient overload which in turn can lead to hypoxia (oxygen depletion) and phytoplankton blooms”

This question is examined in more detail in Section 4

Studies show that phytoplankton biomass in the Channel is higher in the warmer summer months with peaks in spring and autumn The timing and intensity of blooms is highly

variable as are their appearance at different sites within the system Fish farm discharges impact the biogeochemistry of the Huon River and D’Entrecasteaux Channel by increasing the supply of nitrogen and phosphorous available for phytoplankton growth particularly in summer when nutrients are limiting Biogeochemical modelling has demonstrated that the

12

region is hydrodynamically well connected with a residual circulation from south to north which flushes the whole region over about two and a half weeks This disperses local nutrient sources widely and results in regional elevation of nutrient and phytoplankton biomass to a

modest degree (Wild Allen et al 2005) Since the onset of salmon farming parts of the

system have changed from being oligotrophic (low nutrient) to mesotrophic (moderate

nutrient) Volkman et al (2009) showed that within the nutrient limits imposed by the

TPDNO the proportion of the system classified as mesotrophic would increase from

approximately 10% (no salmon farming) to around 54% This was insufficient to produce eutrophication and therefore considered an acceptable risk of marine salmonid farming to the environment

1.8 What is the origin of the fine sediment observed on macroalgae in the Port

- Riverine inputs including upstream activities that include agriculture and forestry

- Salmon and mussel farming

- The outfall of a fish processing factory

- The Dover Wastewater Treatment Plant

- Natural sedimentation via the faecal products of zooplankton and phytoplankton Salmon farming is a source of sediments derived from excess feed, faecal material and more

recently through in situ net cleaning – these topics are covered in more detail in Section 5

Contrary to statements in the TAC report (pg 10), mussels and other bivalves may also be a significant source of sedimentation through the production of psuedofaeces, which arise when there are either excess or unwanted material filtered from the environment

No evidence is provided to support the TAC claim and until such time that the sediments can

be properly sampled and analysed it is premature to attribute the source, or a portion of the source, to the salmon industry

1.9 How is the Precautionary Principle used in the making of decisions relating

environmentally sustainable development in an adaptive management context?

The TAC Report calls for the adoption of the Precautionary Principle in Government decision

making (pg 4) It quotes the Wikipedia definition of the principle as: “The precautionary

principle or precautionary approach states that if an action or policy has a suspected risk of

13

causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is not harmful, the burden of proof that it is not harmful falls on those taking an action”

The Precautionary Principle rose to prominence following its inclusion in the Rio Declaration

on Environmental Development (Principle 15) which describes the precautionary approach and its use in the context of environmental conservation as, “[w]here there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation”

This description substantially differs from the Wikipedia definition used by the TAC in that it

is explicit that the risk must be one of serious or irreversible damage Recent reviews of the precautionary principle confirm that identification of a threat, and determination that that threat is significant, should be key prerequisite steps in accepting the application of the

Principle (Kearney et al 2012)

In the application of the precautionary principle, public and private decisions should be guided by:

- Careful evaluation to avoid, wherever practicable, serious or irreversible damage to the environment; and

- An assessment of the risk-weighted consequences of various options

A major characteristic of the precautionary principle is that it specifies that measures must be taken if there are threats of serious or irreversible environmental damage and these measures should be relaxed only if research demonstrates that they are not needed

It is not consistent with the Principle to allow scientific uncertainty to negate the necessity to assess whether any particular action or event is a threat Nor is it appropriate to assume that a threat, once identified, is sufficiently significant to uncritically trigger precautionary action The need for precaution should not be used to provoke or justify an assumption that

something is a threat without sufficient evidence UNESCO 2005 states, “Some form of

scientific analysis is mandatory; a mere fantasy or crude speculation is not enough to trigger the Precautionary Principle”

The National Strategy for Ecologically Sustainable Development (ESD) has three core

objectives: to enhance individual and community well-being and welfare by following a path

of economic development that safeguards the welfare of future generations; to provide for equity within and between generations; and to protect biological diversity and maintain ecological processes and life support systems

The strategy is implemented under the guidance of a number of ecological and development principles The ecological principles are:

- Decision making processes should effectively integrate both long and short-term economic, environmental, social and equity considerations,

14

- Where there are threats of serious or irreversible environmental damage, lack of full scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation, and

- The global dimension of environmental impacts of actions and policies should be recognised and considered

The developmental principles are:

- The need to develop a strong, growing and diversified economy which can enhance the capacity for environmental protection should be recognised,

- The need to maintain and enhance international competitiveness in an environmentally sound manner should be recognised, and

- Cost effective and flexible policy instruments should be adopted, such as improved valuation, pricing, and incentive mechanisms, and decisions and actions should provide for broad community involvement on issues which affect them

The strategy emphasises that a balanced approach is required for ESD and these guiding principles and core objectives need to be considered as a package No objective or principle should predominate over the others

Management judgements have to be based on the available scientific evidence of the risk being undertaken, and the levels of short and long-term impacts that are acceptable in the socio-economic as well as ecological areas

Adaptive management is an approach for simultaneously managing and learning about

natural resources (Williams 2011), and is an approach used by DPIPWE in the management

of abalone and other wild fisheries as well as salmon farming A key step in the adaptive management process is to engage appropriate stakeholders and to ensure their involvement in

the process This has been the motivation behind projects such as Your Marine Values (Ogier

& Macleod 2013) and underpins the Fisheries Advisory Committee (FAC) process which includes stakeholders in the co-management of all Tasmanian fisheries resources Clearly, to date, adaptive management has proceeded sector by sector and it is probably appropriate, in the context of concerns expressed by the abalone industry over the potential impacts of salmon farming on the environment, to seek ways of integrating this response To achieve this each sector would have to articulate common objectives that accounted for the

aspirations of each other Such an approach to adaptive management in the D’Entrecasteaux

would seem appropriate and would build on the planning provisions of the Marine Farming

Planning Act 1995 which enable the concerns and aspirations of competing interests to be identified, considered and responded to in the review of draft MFDP’s and draft amendments

to MFDP’s

15

2 Review the statutory monitoring requirements implemented for soluble and solid waste from the salmonid farming and report on its adequacy for assessing impacts of salmonid farming in relation to the detection of impacts on rocky reef habitats

2.1 Introduction

Open cage salmon aquaculture is a significant point source of nutrients to the marine

environment Volkman et al (2009) estimate that approximately 30% of the nutrients added

through fish feed are removed from the marine ecosystem as fish at salmon harvest, but the remainder are released to the environment as metabolic wastes and uneaten feed Of this an estimated 80% of the total nutrient losses from fish farming are dissolved and in a form that

is readily available to macroalgae, microalgae and plants such as seaweeds

To date most of the research and monitoring of the nutrient impacts of salmon farming on the environment has focussed on understanding and measuring impacts on benthic soft sediment

habitats below and adjacent to the cages (Crawford et al 2002; Macleod et al 2002;

MacLeod et al 2004; Edgar et al 2005), and understanding the broadscale impacts of

nutrient enrichment on primary production, predominantly phytoplankton (CSIRO 2000,

Volkman et al 2009)

Studies have shown that nutrient enrichment from uneaten food and faecal material may have

a considerable impact on the benthos immediately below the cage (Macleod 2004b and references therein), but that there is a gradient of impact that diminishes with distance from

the cage (Edgar et al 2005 and refs therein) Benthic impacts of salmon farming were minor

at distances of 35m from the lease boundary (Edgar et al 2005) although local conditions greatly influenced the level of impact at the level of individual farm leases (Macleod et al

2004b)

Building on the Huon Estuary Study (CSIRO 2000), Volkman et al (2009) showed that

eutrophication will become a problem if the assimilation capacity of a salmon-growing area for nutrients is exceeded This could lead to phytoplankton blooms, which may include harmful species that produce harmful algal blooms (HABs) (see commentary on HABs in Section 4), or be manifested as increased production of benthic microalgae, macroalgae or epiphytic algae The released nutrients may change ambient nitrogen/phosphorus (N/P) ratios and can alter the ratio of key phytoplankton species (e.g from diatoms to dinoflagellates) Effects of increased nutrients may also be seen at higher trophic levels, by altering the

abundance and species composition of zooplankton, which in turn can affect fish

16

Coastal nutrient enrichment due to human activities has been shown to result in a decline of perennial species and the growth and dominance of annual filamentous and sheet like algae

on temperate rocky reefs (Kraufvelin et al and references therein) Boris and Lotze (2006)

showed that grazers were important in structuring rocky reefs as they were able to keep bloom forming species in check, however, grazing could not override the effects of increased eutrophication

2.2 Monitoring and reporting requirements – D’Entrecasteaux Channel, Huon River and Port Esperance MFDP areas

Marine farming operations in Tasmania are managed under the provisions of Marine

Farming Planning Act 1995 (MFPA) and the Living Marine Resources Management Act

1995 (LMRMA)

The MFPA provides for the preparation of marine farming development plans (MFDP) which contain management controls to manage and mitigate negative effects of marine farming operations Management controls include provisions relating to environmental monitoring and management of marine farming operations

Management controls contained within the Huon River and Port Esperance and

D’Entrecasteaux Channel marine farming development plans cover a range of issues

specific provisions in relation to environmental monitoring and management of marine farming operations In many cases license conditions contain specific requirements to

expand and support the provisions of MFPP management controls

A summary of the environmental monitoring and reporting requirements of salmonid licence holders in the D’Entrecasteaux Channel and Huon River and Port Esperance MFDP areas is

17

provided in Appendix 1 The information presented is derived from salmonid marine farming schedules, the statutory instruments used to mandate monitoring and reporting requirements

2.3 Evaluating the BEMP

The Broadscale Environmental Monitoring Program (BEMP) was initiated in 2009 to assess water and sediment quality and is a regulatory compliance requirement, in accordance with salmonid marine farming licence conditions The aim of the BEMP is to provide data to enable a comprehensive assessment of the ecological condition in the D’Entrecasteaux

Channel and the Huon River estuary

The BEMP was initiated following an extended period of scientific research funded through the Fisheries Research and Development Corporation (FRDC) and the Finfish Aquaculture Cooperative Research Centre (Aquafin CRC) between 1996 and 2009 It was based primarily

on recommendations of research undertaken by Thompson et al (2008) and Volkman et al

(2009), which looked at the effects of salmonid aquaculture on the environment

The key elements of the BEMP are:

- to assess water and sediment quality and benthic infaunal condition at a specified number of sites throughout the region (see Figure 2.1),

- that all licence holders in the MFPD must participate in the monitoring,

- that monitoring is undertaken by an independent and appropriately qualified

consultant,

- that all data and reports are lodged with the DPIPWE and

- that assessment and review of the resultant data be undertaken at regular intervals with a view to ensuring that both the water column and sedimentary environment remain in a satisfactory condition and that the monitoring program is relevant and effective

The BEMP sample collection is undertaken by Aquenal, an independent environmental consultancy employed by the industry peak body, the Tasmanian Salmonid Growers

Association (TSGA)

18

Figure 2.1 Map showing the location of monitoring sites in the D’Entrecasteaux Channel and Huon Estuary Sediment assessment sites are shown as red circles (B1-B15) and water quality monitoring sites as green squares (M1-M15) The control site at Recherche Bay is located in the bottom left corner of the map (B15/M15) (after Ross & Macleod 2013)

The most recent assessment of the BEMP data was undertaken by the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania and is summarised in a report by Ross and Macleod (2013) The aim of this report was to provide an evaluation of the

observed monitoring data and to assess the outputs against ecosystem performance measures Specifically this included:

- Analysis and interpretation of the environmental data collected as part of the BEMP assessments between 2009 and 2012 in the context of other available information (including catchment input data and other historical environmental data available from the Huon Estuary, D'Entrecasteaux Channel and elsewhere)

- Provision of advice to the DPIPWE regarding the relationship between the monitoring data, relevant CSIRO model outputs and recommended trigger levels

19

- Identification of any significant gaps in the monitoring data and making

recommendations regarding data collection and analysis

Key findings of the BEMP review may be summarised as follows (Ross & Macleod 2013):

o Waste Water Treatment Plants (WWTP) and industrial inputs are relatively small at the whole of system level, yet their loads are predominately in the form of ammonia which may be significant with respect to the local receiving environment

o Nitrogen inputs from fish farms are based on feed data Inputs of dissolved nitrogen in the Huon River and Port Esperance MFDP Area have remained relatively stable at ~ 1000 tonnes p.a across the calendar years (i.e 2009,

2010 & 2011) that incorporated this BEMP monitoring period In the D’Entrecasteaux Channel MFDP area, however, inputs have increased from

709 tonnes in 2009 to 849 tonnes in 2011 Seasonally, feed inputs are at their lowest in late summer before increasing through winter to a maximum in spring each year This trend is more defined in the Huon than the Channel where autumn seems to be the period whee feed inputs are lowest

o Ammonium is one of the most labile forms of N and is readily taken up by plankton and algae

o There is a considerable exchange of D’Entrecasteaux Channel and Huon Estuary waters with oceanic waters across the northern and southern boundaries of the system, predominantly in winter Oceanic inputs are the major source of nitrate and nitrite and represent approximately 60% of the nitrogen load to the system

- Biological uptake of nutrients occurs predominantly in spring and autumn which is reflected in peak phytoplankton growth Blooms typically occur between spring and autumn

- Ammonium concentrations are higher in the Huon Estuary and the northern parts of the Channel which is consistent with the understanding of regional circulation that would accumulate nutrient inputs in these areas

- A comparison of the BEMP data collected from 2009-12 with historical data sets from the Huon Estuary (HES: 1996-1998 and Aquafin CRC: 2002-2005) and the

D’Entrecasteaux Study (Aquafin CRC: 2002-2005) suggested that, despite

considerable spatial and temporal variability in data, there was evidence of decadal system wide changes that were consistent with the increased inputs of organic matter and nutrients They included an increase in ammonium concentrations in bottom and

20

surface waters and a decrease in bottom water oxygen concentrations in the Huon Although variability in the region’s hydrodynamics may have contributed to these changes it seemed likely that they were due to a combination of increased organic load to sediments and subsequent remineralisation as well as increased inputs via fish excretion A lack of comparable data in the Channel pre BEMP obfuscated a

meaningful assessment in the Channel

- Despite the changes in ammonium and oxygen concentration in the Huon there was

no evidence of a change in water column productivity There was however, some evidence to support a change in phytoplankton composition in the system

- Spatial patterns were very similar to those observed in previous studies (Macleod &

Forbes 2004a,b; Edgar et al 2005; Macleod et al 2008)

- There was no evidence in the infaunal community composition of any significant organic enrichment or change in the community or function

2.4 Detecting impacts on rocky reefs

Research and monitoring of the impacts of salmon farming on the environment has been focussed on near field impacts close to the cages and broadscale impacts on other, closely connected, aspects of the ecosystem Few studies have assessed the impacts on rocky reefs This approach has been justified because salmon farms, with few exceptions, are usually located over soft sediments (Table 2.3) with more recent amendments deliberately avoiding proximity to reefs (DPIPWE 2015)

In recent decades anthropogenic eutrophication has been shown to change the structure and diversity of marine benthic communities (Pearson & Rosenberg 1978, Lotze & Schramm

2000, Kraufvelin et al 2010) with opportunistic fast-growing species frequently occurring in

eutrophic coastal waters (Cederwall & Elmgren 1990) These macroalgal blooms are

generally explained by increased nutrient loads which selectively favour filamentous and foliose macroalgae

Several studies have found significant differences in the macrobenthic assemblages near fish farms and there has been a growing awareness of the potential far-field impacts of salmon farming on the system (see Oh 2009 and references therein) A study of the macroalgal composition in the Huon River and D’Entrecasteaux Channel showed that macroalgal

composition at sites located 100m from farms were different from reference sites 5000m away in both exposed and sheltered areas Sites situated 400m away from fish farms were, however, not significantly different from sites 5000m away (Oh 2009)

FROM REEF (meters)

by increases in the cover of epiphytes and total opportunistic algae (which included

opportunistic green algae, filamentous algae and algal turf) In particular, opportunistic green

alga of the genera Chaetomorpha, Ulva and Cladophora (the main constituent of filamentous

green algae in this region) were collectively responsive to the proximity of fish farms

Oh (2009) also found that there was no apparent decline of canopy algae close to fish farms,

as has been reported for other cases of eutrophication The study suggested that while

variations in the detectable effects of fish farms could be anticipated at scales of hundreds of metres, they rarely reached distances of several kilometres away from farming areas

However, Crawford et al (2006) undertook an analysis of a 10 year dataset from two small

marine protected areas (Ninepin Point at the mouth of the Huon estuary and Tinderbox near North West Bay) for changes in abundance of the seven most abundant macroalgal species This study was aimed at assessing whether broadscale impacts of effluent from marine farming activities could be detected at rocky reef communities and found no apparent

patterns of change in macroalgal community composition over the 10 year time period From this it would appear that although nutrient impacts have been detected some distance from salmon farms the nutrient load has been insufficient to result in significant changes to macroalgal communities on rocky reef habitats

The relative lack of information on the far-field impact of salmon farming on temperate reefs

in the D’Entrecasteaux Channel and perceived inadequacies in the BEMP have been

22

highlighted in several submissions to the Marine Farming Planning Review Panel (the Panel)

in relation to the most recent amendments to the Huon River and Port Esperance and the D’Entrecasteaux Channel MFPDs The Panel in making its decision on these amendments has recognised this deficiency stating for example:

“The Panel noted concerns that the BEMP did not adequately address impacts of marine

farming on reef fauna and macroalgae, but also noted the current research being undertaken

by IMAS to examine possible relationships”

“The Panel concluded that the BEMP provided an adequate monitoring framework for the

adaptive management of marine farming in the MFDP in terms of local (benthic sediments within the farm zone) and broadscale nutrient inputs The Panel was, however, concerned that the amendments to the Huon and Channel plans could result in alterations to the

distribution of nutrient inputs to the system which could have impacts which would probably not be identified by the current monitoring regime” (MFPRP Zuidpool Decision Report)

In response to these concerns, several research projects are underway or planned to further improve the understanding of the impact of salmon farming, especially on temperate reefs

(Dr Catriona Macleod IMAS pers comm.) They are listed below and summarised in

Appendix 3:

FRDC 2011/042: Atlantic Salmon Aquaculture Subprogram: clarifying the relationship

between salmon farm nutrient loads and changes in macroalgal community structure/ distribution

FRDC 2012/024: INFORMD Stage 2: Risk-based tools supporting consultation,

planning and adaptive management for aquaculture and other multiple-uses of the coastal waters of southern Tasmania.

Seafood CRC Project 2011/735 - An evaluation of the options for the expansion of salmonid aquaculture in Tasmanian waters Phase III: Information Assessment/

Decision Support Framework (Pilot Study-Storm Bay)

FRDC 2015/024 Managing ecosystem interactions across differing environments:

building flexibility and risk assurance into environmental management strategies.

FRDC CC035 Reassessment of intertidal macroalgal communities near to and distant

from salmon farms and an evaluation of using drones to survey macroalgal distribution

FRDC TRF (submitted) Understanding broadscale impacts of salmonid farming on

rocky reef communities

23

3 Assess the status and productivity of fishing blocks 14B, 14C and 15 in

SE Tasmania and report on possible salmon farming impacts on abalone productivity

The abalone fishery in Tasmania consists of a number of zones (Figure 3.1), each of which is

assessed and managed separately (Tarbath et al 2014) The interaction between the abalone

fishery and salmon farming occurs in the south-eastern corner of Tasmania within the Eastern zone

Figure 3.1 Zones and statistical blocks used in the Tasmanian abalone fishery in 2013 Zone boundaries are shown as dotted lines

A more detailed map of SE Tasmania showing the areas of interest (Blocks 14B, 14C and 15)

is shown in Figure 3.2

The blocks in question are part of two regions used for blacklip fishery assessment Block 14B belongs to the Actaeons and Lower Channel region that includes sub-blocks 13C, 13D, 13E, 14A and 14B Blocks 14C and 15 are part of the Bruny Island region that includes sub-blocks 14D, 14E and 16

24

Figure 3.2 Statistical blocks used in the Tasmanian abalone fishery in south east Tasmania

Total blacklip abalone landed in 2013 was 2,008.3t, of which 2.7t, 0.0t & 0.02t were taken in blocks 14B, 14C and 15 respectively, representing less than 0.13% of the Tasmanian catch or 0.5% of the Eastern Zone TAC

The catch histories for fishing blocks 14B, 14C and 15 are shown in Figure 3.3a&b Annual catch is shown as the sum of catch in each quarter whereas CPUE is illustrated as the median with the 25th and 75th percentile represented as the box and the 5th and 95th percentile

represented by the whisker Outliers are shown as orange dots Annual catch records for blocks 14B and 14C are only available from 2000, whereas catch records for block 15 are available from 1985

sub-In sub-block 14B the average annual catch for the period 2000-2014 was 9.1t Catches were relatively high (above 10t per annum) for the period 2000-2006 before declining sharply Catches between 2007 and 2010 averaged 4.8t with a low in 2011 as a result of the Paralytic Shellfish Toxin (PST) closure in this region

21B

21A 20C 20B 20A

19B 19A

18

17B 17A

16D

16C

16B

16A 15

14E 14D

14C 14B

14A 13E 13D

13C 13B

SubBlockNo 14B

0 50 100 150 200

SubBlockNo 14C

0 50 100 150 200

BlockNo 15

0 50 100 150 200

27

In sub-block 14C the average annual catch for the period 2000-2014 was 5.3t Similar to block 14B, catches were relatively high, averaging 7.1t per annum for the period 2000-2006 before declining Catch picked up again in 2009 and 2010 before the PST closure affected catches in 2011

In block 15 the average annual catch for the period 1985-2013 was 3t For the entire period

of available catch records (1975-2013), the average was 5t The latter was due mainly to relatively large catches (all above 10t) between 1981 and 1986, with the highest annual landing being in 1986 when 22t were recorded from this block

The following extract is taken from Frusher et al (2009):

Block 14 was a key part of the abalone fishery from its earliest times, producing between 200 tonnes and

300 tonnes during the 1970s and 1980s Block 14 consists of the lower D’Entrecasteaux Channel (including Port Esperance, Southport and Great Taylors Bay), the southern shores of Bruny Island east to Boreel Head (including Cloudy Bay, the Friars and the southern shore of the Labillardiere Peninsula) and the northern parts of the Actaeons reef systems (including Southport Island, Blanche and George III Rocks) During the earliest years, much of the catch was caught in the Channel, particularly Port Esperance (Dover) or nearby Planing hulls were uncommon and divers who day fished using small timber dinghies were effectively restricted to a range less than 10 nautical miles It was reported that in early 1964, daily catches of up to 600 kilograms were taken from Port Esperance (Hope Island, southern shore between Hawkers and Lomas Points), Blubber Head north to Roaring Beach, the coast south of Dover, including Scotts Point, Tower Bay, Lady Bay and Sisters Bay, and Partridge Island and the Pineapples Ten years later, abalone populations in the area had become depleted (Witherspoon, 1975), but were still heavily fished In 1975, a resident diver said it was common to see half a dozen divers fishing the Port Esperance southern shore in south-westerly weather, with catches typically 100 kilograms per day A fish farm was established in Port Esperance during the late 1980, after which divers said that the kelp along Stringers Creek shore became covered in sediment, the clarity of the water decreased, and abalone became very depleted In 2004, some recovery of populations had occurred, and isolated catches of up to 200 kilograms per day were landed from the southern shore and Hope Island

The southern shores of Bruny Island and the northern parts of the Actaeons continue to provide high levels

of catch and were not considered to have been depleted by any divers In contrast the D’Entrecasteaux Channel (which was said to have contributed approximately half of the Block 14 annual catch during the 1970s and 1980s) became too depleted to warrant fishing The average annual catch between 2000 and 2006 for the western shore between Port Esperance and Southport was 15 tonnes, while on the Bruny Island shore the catch had declines to seven tonnes for that period The Bruny Island shore is now said to be mostly depleted, although divers occasionally take good catches from the Quarries.

This information suggests that depletion had occurred in the Channel area well before the start of the salmon industry and that fishing (if not overfishing) was the major factor

contributing to the loss of productivity in the area That said it is interesting that fishers thought that salmon farming was maintaining this condition, despite evidence that catch had improved in the 1980s, 1990s and to a lesser extent in the early 2000s Recognising that catches are a function of a variety of factors including market preference, changes in

management and biology, if the impacts of salmon farming were cumulative one might not expected these improvements

Block: 13

0 100 200

Block: 15

0 30 60 90 120

Block: 16

30

A comparison of four blocks in south east Tasmania is presented in Figure 3.4a&b Two are either distant from the main area of salmon production (Block 13) or physically isolated by landmass (Block 16), whereas Block 15 and the northern parts of Block 14 are within or adjacent to the main salmon production areas

Several trends are evident in the data which spans the period 1985 to 2014:

- Total catch taken from each block has been markedly different In block 15 catches were generally less than 5t per annum, whereas in block 13 catches were up to two orders of magnitude higher, averaging 281t Blocks 14 and 16 fell between these with

an average catch of 130t and 68t respectively

- There is some evidence of a modality in the catch, in block 15 for example, peaks were recorded in 1986 (22t), 1994 (10t) and 2005 (8t) which may be related to

recruitment, management change, market preference, fishing pattern or a combination

of these and other factors The peaks did not occur in the same years in each block, suggesting that fleet behaviour might be an important factor

- Block 13 had sustained high catches over the entire period, whereas blocks 14 and 16 show a decline over time which is most notable post 2000

- There is evidence of serial depletion across the southern blocks (13 – 16) during the recovery in the mid-1990s and again, but less clear in the mid-2000s Catch peaked in Blocks 15 and 16 in 1993/1994, Block 14 in 1995/1996 and Block 13 in 1997-1999 CPUE follows a similar trend, but is less clear In the most recent recovery, catch in Block 16 peaks two years before Block 13, but no recovery in terms of catch is

evident in Block 14 However, CPUE in Block 14 does recover during this period, and is largely aligned with Block 13

In the past four years the Eastern Zone (except Block 31) has been closed to fishing between

January and March of each year (Tarbath et al 2014) This period of closure spans the

important Chinese New Year festivities, and live abalone sourced for this period is now taken from the Western Zone, whereas prior to the closure much of the catch would have been sourced from the Eastern Zone This closure has distorted the within year pattern of harvest

in southern Tasmania, but is unlikely to have affected overall productivity

The Eastern Zone minimum legal length (MLL) was increased in 2002 from 132mm to

136mm, and increased again in 2006 from 136mm to 138mm (Tarbath et al 2014) In the

first four years at a MLL of 136mm, the reported catch in sub-blocks 14B and 14C was of a similar magnitude to that reported in 2000 and 2001, and at comparable CPUE (Figure 3.3a)

In the first year of fishing at a MLL of 138mm, the previous level of catch reported from Block 14B was maintained, but not thereafter The pattern of annual catch and CPUE

sub-reported from 14C differed, however, the largest catch and the highest CPUE recorded in sub-block 14C occurred in 2009 at a MLL of 138mm (Figure 3.3a) In sub-block 15, the 3rd

and 4th largest catches since the introduction of the quota management system were taken in

2004 and 2005, at a MLL of 136mm (Figure 3.3b) This pattern suggests that increasing LML from 132mm to 138mm has not been a primary factor in the long-term decline in production of these fishing grounds

Block: 30

0 50 100 150 200

Block: 25/26

0 50 100 150 200

32

Analysis further afield on the East Coast shows a similar pattern (Blocks 25, 26 & 30) Catches in all blocks were highest in the early stages of the fishery (Figure 3.5), then declined past a point and have not recovered This was particularly evident in Block 30 where prior to

1986 catches above 100t per annum were common (average between 1975-1986 was 136t; average between 1987-2002 was 27t; average between 2003-2013 was 3t) Blocks 25&26, Swansea and Coles Bay, provides patchy, marginal habitat interspersed with sandy beaches The early high catches reported from here may indicate that early landing reports are

unreliable, although given the fractured nature of the habitat; it is feasible that many

populations have been effectively removed from the fishery at the 127mm MLL However, post 1984 they are reliable and the same general pattern exists

The impact of fishing on inshore reef ecosystems was investigated by Frusher et al (2009)

who made the following observations:

- Divers recognised that abalone populations that they were fishing had been severely depleted over the course of the fishery (40-50yrs)

- In parts of south-east Tasmania, abalone stocks were reduced from virgin levels to an extensively depleted state within the first 15 years of the fishery (Witherspoon, 1975

in Frusher et al 2009)

- The removal of abalone from an area had the potential to alter the structure of the reef from a ‘preferred habitat’ which was crustose coralline algal dominated, to a ‘less preferred’ habitat which was dominated by sessile invertebrates and foliose algae

- Abundance of emergent abalone were negatively correlated with predator abundance, especially large rock lobsters – abalone leaving cryptic habitat at smaller sizes in fished areas compared to MPAs

In summary, evidence for a direct cause and effect relationship between loss of abalone productivity and salmon farming is not clearly apparent from catch and effort data in the fishery based on multiple lines of evidence:

- Declines in catch have been observed throughout the eastern zone (Tarbath 2014), while average daily catch in blocks 13 and 14 reduced significantly between the start

of the fishery (1966) and the period prior to the start of salmon farming (1987)

(Frusher et al 2009)

- Catches in blocks 14B, 14C and 15, those closest to the salmon farms have not

exhibited a loss in productivity that is consistent with an increasing impact of salmon farming

- The pattern of decline in catch and catch rate in blocks 14B, 14C and 15 mirrors the pattern observed in nearby blocks that are unlikely to be affected by salmon farming activities

- Catches in these blocks have gone up and down since the onset of salmon farming

- Much of the loss of production, especially in block 14 can be ascribed to depletion by the fishery itself, with catches prior to the 1970’s being significantly higher than those

at present

33

- The onset of the live abalone trade in the 1990’s has seen a significant shift of effort

to the east coast in order to meet market demand Serendipitously the recovery on the east coast associated with low TAC coincides with a strong recruitment pulse that entered the fishery in the mid 1990’s and which led to a confidence in the rebuilding process and TAC increases that, with hindsight, appears to have been unsustainable This information suggests that depletion from the fishery is most likely the major cause for a loss of productivity in the Southeast and the Eastern zones in general, although a combination

of factors, including salmon farming may have a local effect in some places, especially where the lease is over reef area that is currently or was historically suitable abalone habitat, for example in the case of lease 244 at Port Esperance

surrounding areas and increasing pressures from both commercial and recreational activities (Parsons 2012)

Salmon farming commenced in Tasmania in the mid-1980s after a report to the Tasmanian Fisheries Development Authority concluded that a salmon farming industry could be

successfully developed in Tasmania.The first commercial harvest of 53 tonnes was in the summer of 1986/87 Since then the most recent production figures show that the sector has increased to around 43,000t valued at close to $500 million in 2013 This makes farmed salmonids the largest aquaculture species group produced and also the most valuable fisheries product in Australia In the most recent ABARES statistics salmonids accounted for 48 per cent of the total value of Australian aquaculture production and 21 per cent of the total value

of fisheries and aquaculture production (Stephan & Hobsbawn 2014)

4.2 Planned expansion of the salmon industry

The salmonid industry in Tasmania has an aspirational growth target of $1billion in sales by

2030, effectively a doubling the present value of the industry (Figure 4.1 Dr Adam Main,

Tasmanian Salmonid Growers Association pers comm.)

Figure 4.1 Projected growth of the Tasmanian Salmonid industry

35

For example, Huon Aquaculture is addressing the growth currently being experienced

domestically and internationally by expanding its marine farming operations, consolidating existing lease space and changing the way it farms (DPIPWE 2014a)

Similarly, Tassal in 2013 embarked on a South East Region Site Optimization Plan, which aims to deliver sustainable growth, improved fish health and performance and improved environmental management This is focussed on delivering better returns economically and socially, and at the same time, minimising impacts to the environment (DPIPWE 2014b)

4.3 Recent amendments to salmon farming in the Huon and D’Entrecasteaux Channel

The expansion of salmon farming in the D’Entrecasteaux Channel and Huon Estuary has seen

a concomitant increase in total dissolved nitrogen (TDN) inputs to the system since the mid 1990’s Data provided by DPIPWE for 2000-2012 (Figure 4.2) shows an increase in farming post 2004 with the average TDN value rising from 760 tonnes (2002-05) to 1795 tonnes (2009-12) In the Channel MFDP area there was a 4-fold increase in TDN values between

2005 and 2011

Figure 4.2 Annual dissolved nitrogen inputs (tonnes) by year Licence holder reporting from 2005 allowed input data to be displayed by MFDP area (after Ross & Macleod 2013)

Since 2009 nitrogen released into the environment by fish farms has been regulated via limits

or caps on total permissible dissolved nitrogen output (TPDNO) Separate caps exist for the D’Entrecasteaux Channel MFDP area (1,190.42 tonnes in any 12 month period.) and the Huon River and Port Esperance MFDP area (1,084.63 tonnes in any 12 month period)

DPIPWE 2011)2 Ross & Macleod (2013) showed that farm inputs of dissolved nitrogen in the Huon River and Port Esperance MFDP Area have remained relatively stable at ~ 1000 tonnes p.a (Table 4.1) across the calendar years (i.e 2009, 2010 & 2011) that incorporate the

2

Due to improvements in diet formulation, notably the protein and nitrogen content of feed, nitrogen emissions values are now (since early 2009) calculated based on measured protein and N content in feed

1 200

2 200

3 200

4 200

5 200

6 200

7 200

8 200

9 201

0 201 1

0 500 1000 1500

2000

total Huon Channel

36

BEMP monitoring period In the D’Entrecasteaux Channel MFDP area inputs have increased from 709 tonnes in 2009 to 849 tonnes in 2011 (Table 4.1) Within the Channel this data shows that in 2011 the farms were operating well within the TPDNO limits set for the MFDP

Table 4.1 Total dissolved nitrogen inputs from fish farms for the calendar years 2009, 2010 and 2011 in the two MFDP areas (after Ross & Macleod 2013) Note the TPDNO for the Channel was increased from 1140.7 to 1190.4 in 2015

Since the implementation of the Total Permissible Dissolved Nitrogen Output (TPDNO) caps

in 2009, proposed amendments to the Huon River & Port Esperance and the D’Entracasteaux Channel MFDPs include3:

- Amendment No.3 to Huon River and Port Esperance MFDP February 2002 at

Flathead Bay (approved)

- Amendment No.4 to D’Entrecasteaux Channel MFDP February 2002 at Butlers Point (approved)

- Amendment No.5 to D’Entrecasteaux Channel MFDP February 2002 at Zuidpool Rock (approved)

- Amendment No.6 to D’Entrecasteaux Channel MFDP February 2002 at Lippies Point (not yet approved)

The changes to the zone and lease areas for each of these amendments are summarized in Table 4.2 These data show that while there has been an overall increase to the area of the marine farm zones (597.67ha), the changes to the lease areas have been relatively minor (105.57ha) In two cases, Flathead Bay and Lippies Point, increases in lease area have been offset by similar decreases in the Huon River and D’Entrecasteaux Channel areas

respectively The net effect of all of these amendments has been an increase in lease area of 19.94ha, which is 1.86% of the total combined lease area (1073ha) in the Huon River and Port Esperance MFDP (433ha) and D’Entrecasteaux Channel MFDP (640ha) As a

percentage of the total lease area in the D’Entrecasteaux Channel MFDP this represents a 3.11% increase

3

This does not include proposed Amendment No 3 to the D’Entrecasteaux Channel MFDP at Soldiers Point which was rejected by the MFPRP in 2011