IN THE MATTER of the Resource Management Act 1991

Transcription

1 IN THE MATTER of the Resource Management Act 1991 AND IN THE MATTER of a Board of Inquiry appointed under section 149J of the Resource Management Act 1991 to consider The New Zealand King Salmon Co Limited's private plan change requests to the Marlborough Sounds Resource Management Plan and resource consent applications for marine farming at nine sites located in the Marlborough Sounds STATEMENT OF EVIDENCE OF BENJAMIN KEITH DIGGLES IN RELATION TO RISKS FROM DISEASE FOR THE NEW ZEALAND KING SALMON CO LIMITED JUNE 2012 D A Nolan / J D K Gardner-Hopkins Phone Fax PO Box DX SX11189 Wellington

2 CONTENTS ABBREVIATIONS AND ACRONYMS 2 EXECUTIVE SUMMARY 3 QUALIFICATIONS AND EXPERIENCE 6 SCOPE OF EVIDENCE 8 METHODOLOGY 8 SUMMARY OF EVIDENCE 10 APPENDIX 1 List of New Zealand salmon diseases 34 APPENDIX 2 Risk Assessment Methodology used in the Disease Assessment Report 35 Hazard identification 35 Release assessment 36 Exposure assessment 37 Risk estimation 41 Risk mitigation 42 Option evaluation 42 APPENDIX 3 Curriculum Vitae Dr Ben Diggles 43 ABBREVIATIONS AND ACRONYMS AGD ALOP IPN IPNV ISA ISAV OIE Amoebic Gill Disease Appropriate Level of Protection Infectious Pancreatic Necrosis Infectious Pancreatic Necrosis Virus Infectious Salmon Anaemia Infectious Salmon Anaemia Virus World Organisation for Animal Health (formerly Office International des Epizooties) wwwdigsfishcom 2

3 EXECUTIVE SUMMARY A This document outlines the statement of evidence by Dr Ben Diggles in relation to assessment of the fish disease risks potentially associated with expansion of salmon farming in the Marlborough Sounds, as described in the planning and resource consent applications presented by the New Zealand King Salmon Company s Sustainably Growing King Salmon Proposal B A detailed assessment of the fish disease risks posed by the proposed development was presented in the Disease Assessment Report That report presented the results of a qualitative risk analysis undertaken using internationally recognised methodology for assessment of the risks of transfer of aquatic disease agents After an extensive literature review, the risk assessment found that 4 infectious disease agents (Aquatic birnavirus, amoebic/nodular gill disease caused by amoebae (Neoparamoeba perurans and Cochliopodia spp), sea lice (Caligus and Lepeophtheirus spp), and whirling disease cased by the myxozoan Myxobolus cerebralis) should be considered as diseases of concern that required detailed risk assessment However, based on the outcomes of these detailed risk assessments, I found that none of the 4 diseases of concern were likely to cause significant disease in wild fishes or other aquatic animals under the conditions experienced in the Marlborough Sounds The risk analysis therefore indicated that these 4 disease agents posed no negative or cumulative threat to the health of wild aquatic animals in the Marlborough Sounds, and because of this, I considered that no additional risk management measures were necessary if the proposed development went ahead C Several of the public submissions raised to the proposal suggested that the proposed development could increase the risk of introduction of unknown or unspecified infectious diseases into wild fish populations However, none of the submissions presented any new information or evidence that I considered would require me to modify the outcomes of the risk wwwdigsfishcom 3

4 assessment The risk assessment was, by necessity, limited to consideration of disease agents of salmon that are known to occur in New Zealand While emergence of new (ie unknown ) infectious diseases is always a possibility, the risk assessment recognised that the main threat in this regard in the New Zealand context relates to biosecurity breakdowns at the border, which could potentially allow introduction of exotic disease agents into the country Several biosecurity leaks in New Zealand in recent times demonstrate this possibility, but the risk that biosecurity leaks could allow exotic diseases to be introduced into New Zealand s salmon farming industry remains largely unquantified at this time Because of this, I considered that the salmon farming industry in New Zealand needs to be able to effectively manage any new disease problems that may emerge if biosecurity leaks occur at the border in the future D In my opinion, the proposed planning changes, if approved, would allow New Zealand King Salmon to expand without increasing stocking densities on individual farms, while permitting establishment of 3 independent farm management areas separated by ideal buffer zones Because the proposed planning change would allow expansion of salmon farming in the Marlborough Sounds without increasing stocking density of fish in cages at each site, this represents best practice and would minimise the risk of emergence of new endemic diseases because the dynamics of infectious diseases are often related to the density of host populations I consider that the ability to establish independent farm management areas separated by ideal buffer zones of at least 18 km (and preferably > 30 km as the fish swims, as is the case for the proposed development) represents world s best practice in salmonid seacage farming This is because such an arrangement would allow best practice biosecurity principles to be utilised (such as integrated pest management strategies including site fallowing and year class farming) if a biosecurity lapse at the border allowed entry of an exotic salmon pathogen in the future E In my opinion, the ability to utilise best practice biosecurity principles and integrated pest management strategies, if required, would greatly increase wwwdigsfishcom 4

5 the chances of containment, management and eradication of any exotic disease agents or new endemic disease agents that may emerge in the future, to the benefit of the salmon farming industry, New Zealands fisheries, and the marine environment of the Marlborough Sounds and New Zealand wwwdigsfishcom 5

6 STATEMENT OF EVIDENCE OF DR BEN DIGGLES FOR NEW ZEALAND KING SALMON QUALIFICATIONS AND EXPERIENCE 1 My full name is Benjamin Keith Diggles 2 I hold a Bachelor of Science (with first class Honours) from 1992 and a PhD from 1995 from the University of Queensland, specialising in parasitology of aquatic animals (fishes) 3 I am currently Managing Director and principal consultant for DigsFish Services Pty Ltd, a private aquatic animal health consultancy which I established in 2003 The company provides an independent aquatic animal health consulting service for the fisheries and aquaculture industries in New Zealand, Australia, Asia and the South Pacific Prior to this position I spent 7 years as a marine pathologist in the Fish Health Unit of the National Institute of Water and Atmospheric Research (NIWA), in Wellington, New Zealand, and one year as a manager of recreational fisheries for the South Australian Government department Primary Industries and Resources of South Australia 4 Since the completion of my undergraduate degree in 1991 I have accumulated 20 years experience conducting a wide range of basic and applied science related to the prevention, diagnosis, epidemiology and control of diseases of aquatic organisms including fish (both marine and freshwater species), crustaceans and molluscs During this time I have worked on projects for local, State and Federal Governments of New Zealand, Australia, the Cook Islands and Brunei-Darussalam, as well as various fisheries and aquaculture industries throughout Australasia, in core business areas that include disease risk analysis, environmental risk assessments, biosecurity assessments, disease diagnosis, and disease control I have presented invited keynote presentations on risk analysis for aquatic animal diseases at international conferences and published 30 wwwdigsfishcom 6

7 scientific papers in the field of aquatic animal health in peer reviewed scientific journals as well as hundreds of other chapters, reports and articles I also regularly conduct peer reviews for a number of scientific journals, including Diseases of Aquatic Organisms, Journal of Aquatic Animal Health, and Aquaculture, as well as occasional reviews for several other journals and scientific publications See Appendix 3 for more details 5 In the recent past I have been asked several times in Australia and Brunei Darussalam to provide advice, professional opinion and recommendations to parliamentary inquiries, government inquiries and court proceedings I have not, however, until now been required to present evidence to boards of inquiry in New Zealand 6 This evidence is given to inform the board of inquiry on matters relating to fish disease risks associated with the various planning changes and resource consent applications required as part of the New Zealand King Salmon Company s Sustainably Growing King Salmon Proposal for the Marlborough Sounds 7 I have been involved with the Sustainably Growing King Salmon Proposal through my company s development of the Environmental Assessment Report Disease Risks, and will refer to that report in these documents as the risk analysis in the Disease Assessment Report 8 I have read the Code of Conduct for Expert Witnesses and agree to comply with it My qualifications as an expert are set out above I confirm that the issues addressed in this brief of evidence are within my area of expertise I have not omitted to consider material facts known to me that might alter or detract from the opinions expressed wwwdigsfishcom 7

8 SCOPE OF EVIDENCE 9 My evidence will focus on matters within the areas of my expertise relating to assessment of the types and magnitude of fish disease risks (including positive, adverse and cumulative effects) associated with expansion of salmon farming in the Marlborough Sounds, as prescribed in the various planning changes and resource consent applications presented by the New Zealand King Salmon Company s Sustainably Growing King Salmon Proposal A detailed assessment of the fish disease risks posed by the proposed development was presented in the Disease Assessment Report The methodology used in the Disease Assessment Report is described in more detail below METHODOLOGY 10 I undertook a review of the peer reviewed scientific literature dealing with disease agents of seacage cultured salmonid fishes in both New Zealand and worldwide using several databases and abstracting engines, such as Scirius, Scopus, ISI Web of Knowledge, Cambridge Scientific Abstracts, Medline, and IngentaConnect as well as internet databases such as Google and Google Scholar I also consulted experts in the field from New Zealand and around the world, and using this information I developed a reference list of viral, bacterial, fungal, protozoan and metazoan disease agents of sea cage cultured salmonids 11 I then briefly reviewed the various different groups of pathogens occurring in seacage farming of salmon in an international context, summarised their environmental impacts (if any), and identified the best practice management measures currently used for their avoidance and control wwwdigsfishcom 8

9 12 Then, to develop a description of the existing environment in relation to the proposed expansion of salmon farming in the Marlborough Sounds, I conducted a comprehensive review of the literature relating to the diseases and parasites of salmon in New Zealand by examining historical papers on diseases of salmonids in New Zealand together with various checklists of parasites and pathogens of New Zealand fishes as well as New Zealand s National List of Reportable Diseases of Finfish I then cross referenced the scientific papers cited within the checklists using citation lists in electronic databases including Cambridge Scientific Abstracts, Scirius, Scopus and Web of Knowledge I also included unpublished data relating to the infectious and non-infectious diseases of King salmon encountered by NZ King Salmon veterinarians, in order to develop an updated and complete list of known pathogens of salmon in New Zealand 13 The final list of known diseases and parasites of wild and cultured salmon in New Zealand (see Appendix 1) contained 20 infectious disease agents of wild and cultured salmon, including 1 virus (aquatic birnavirus), 4 bacterial diseases, 1 fungal disease, 3 protozoan disease agents and 11 metazoan disease agents The list also contained 13 noninfectious diseases that have been reported mainly from cultured salmon (Appendix 1) 14 I then assessed the updated list of known pathogens of New Zealand salmon using the standard qualitative pathogen risk analysis methodology that was outlined in Appendix 1 of the Disease Assessment Report (see Appendix 2 of this statement) The qualitative methodology used in the risk analysis was consistent with that recommended by international authorities such as the OIE (Office International des Epizooties, the world organisation for animal health), Biosecurity Australia and Biosecurity New Zealand for assessment of risks of transfer of aquatic disease agents wwwdigsfishcom 9

10 SUMMARY OF EVIDENCE Literature review 15 My review of the literature, presented in the Disease Assessment Report, found that King salmon Oncorhynchus tshawytscha (also known as Quinnat or Chinook salmon) were introduced into New Zealand by acclimatization societies as ova only between 1875 and 1907, eliminating the risk of introduction of many diseases that have since emerged in northern hemisphere salmon in recent years and been spread with salmonid farming The literature review also found that King Salmon also appear to be innately resistant to many of the disease agents that have been problematic in salmon culture overseas 16 Nevertheless, my review showed that vigilance is required when planning for expansion of a successful salmonid aquaculture industry, because new diseases continue to emerge in aquaculture and the dynamics of infectious diseases are often related to the density of host populations 17 Furthermore, even New Zealand s world leading biosecurity arrangements are not perfect, as demonstrated by biosecurity leaks that have resulted in the introduction and establishment of several aquatic pest species in New Zealand waters such as the seaweed Undaria pinnatifida in 1987, swimming crab Charybdis japonica in 2000, the diatom Didymosphenia geminate in Because of these reasons, I consider that it is important that any expansion of the salmon farming industry should be well planned in order to firstly avoid known disease problems, and in a worse case scenario, to be able to effectively manage any new problems that may emerge if biosecurity leaks occurred at the border at some time in the future wwwdigsfishcom 10

11 19 As outlined in Section 20 of the Disease Assessment Report, I briefly reviewed the important diseases in seacage farming of salmon in an international context, to identify the various types of significant diseases that have occurred overseas, summarise their environmental impacts, and identify the best practice management measures currently used for their avoidance and control 20 I found that seacage farming of salmon can be associated with a range of diseases, including microparasites such as viruses, bacteria and protozoa, metazoan macroparasites such as monogeneans and crustaceans, as well as several non-infectious diseases The results of my review can be summarised as follows 21 Several viral diseases have caused problems in seacage aquaculture of salmonids in the northern hemisphere, particularly Infectious Pancreatic Necrosis (IPN), and Infectious Salmon Anaemia (ISA) However, the literature showed that viruses originating from cultured salmonids appear to have minimal impacts on wild populations of finfish 22 The birnaviruses that cause IPN have been described from at least 65 species of fish, including King salmon, and also from bivalve molluscs and crustaceans King salmon in New Zealand that return from the sea are known to be infected by a birnavirus from time to time, however the local strain of the virus appears to be of low virulence (or non-virulent) to adult salmon Birnaviruses are known to occur naturally in wild marine fish at low prevalences in many parts of the world, including Australia and New Zealand 23 In contrast, ISA has been recorded in Atlantic salmon only from Europe, Canada, USA, Faroe Islands and Chile ISA has never been recorded from New Zealand or Australia, and it appears that King salmon are wwwdigsfishcom 11

12 resistant to ISA virus, although new evidence from Canada 1 suggests that King salmon may harbour ISA-like viruses in the carrier state 24 Because salmon farming is done in seacages in areas where wild fishes occur, it is impossible to fully control the presence of viral disease agents in the rearing environment There are no effective treatments for viral diseases and prevention through avoidance is the key form of management, while vaccination will be possible once vaccines become commercially available 25 Several bacterial and fungal diseases have caused problems in seacage aquaculture of salmonids Many of these disease agents are ubiquitous in aquatic environments, including the Flavobacterium/ Cytophaga /Tenacibaculum and Vibrio sp bacteria, and Saprolegnia spp fungi, which act mainly as facultative pathogens in aquatic animals that are stressed, injured and/or exposed to adverse environmental conditions However there are also some bacterial and fungal pathogens that are limited in their distribution, including typical and atypical strains of Aeromonas salmonicida, which can cause Furunculosis and goldfish ulcer disease, and the fungus like protistan Ichthyophonus hoferi 26 Bacteria and fungi originating from cultured salmonids generally have minimal impact on wild populations of finfish or other aquatic animals, because these disease agents already occur naturally in the wild, and optimisation of the environment and absence of stressors associated with captivity are usually sufficient to prevent most infections from progressing in wild fish As bacterial and fungal disease agents are usually opportunistic pathogens, good husbandry and water quality can markedly reduce the prevalence and severity of disease in aquacultured fish populations as well Furthermore, vaccination is being increasingly used to reduce or eliminate bacterial diseases in seacage growout of salmonids and other marine fishes 1 FirstNationsCoalitionpdf wwwdigsfishcom 12

13 27 A variety of diseases caused by protozoan agents have been recorded from salmonids cultured in seacages, including infections by amoebae, microsporidians, flagellates and ciliates However, my review found that there is no evidence that protozoans harboured by cultured salmonids can result in increased disease in wild fish 28 Amoebic gill disease (AGD) caused by infection of the gills with free living amoebae, predominantly Neoparamoeba perurans is problematic in salmon culture in many parts of the world However, N perurans has been recorded in King salmon in New Zealand in the absence of disease, and King salmon appear relatively resistant to this disease agent Amoebae and other protozoa such as Ichthyophthirius multifiliis (causative agent of white spot disease in freshwater fish) and ciliates of the genus Trichodina are ubiquitous with worldwide distributions, however some protozoans such as microsporidians Loma salmonae, and flagellates such as Hexamita salmonis have limited distributions restricted to the northern hemisphere 29 Protozoan infections in fish cultured in marine waters can be reduced by bathing fish in freshwater, hydrogen peroxide or formalin baths, though this is a laborious process that increases production costs Vaccines are theoretically capable of providing protection against protozoan diseases but none are commercially available at this time 30 Salmonids in seacages can be infected by a wide range of metazoan disease agents, including myxosporeans, copepods, monogeneans, digeneans, cestodes, and nematodes Helminths (Monogeneans, digeneans, cestodes and nematodes) have generally not been problematic in cultured salmon In contrast, caligid copepods (also known as sea lice) and several species of myxosporean parasites, (including Kudoa thyrsites, Chloromyxum truttae, Myxobolus spp and Parvicapsula spp) have been problematic in seacage cultured salmonids in other parts of the world wwwdigsfishcom 13

14 31 Sea lice infections have caused significant problems in seacage culture of salmonids in the Northern hemisphere and Chile The environmental impacts of the majority of metazoan disease agents of salmonids are negligible, however there is evidence in some regions of the world where intensive salmon farming occurs in seacages and salmonids are native fishes that occur naturally in the wild, that farmed salmon can act as reservoirs of sea lice (mainly Lepeophtheirus salmonis, but also other species including Caligus elongatus) which can result in increased infection of wild salmonids that must swim past seacage sites during their migrations 32 Sea lice have been controlled in salmon cultured in the northern hemisphere through oral administration of drugs such as emamectin benzoate (SLICE) There are no drugs commercially available to control myxosporean infections, however regular cleaning of nets may help remove a range of invertebrates that are potential intermediate hosts for myxosporeans such as K thyrsites Most helminth infections can be reduced by oral treatment with anthelmintics, while many types of ectoparasitic metazoans can also be managed by bathing seacaged fish in freshwater, formalin or hydrogen peroxide baths, though this is a laborious process that increases production costs Again, vaccines are theoretically capable of providing protection against metazoan diseases but none are commercially available at this time 33 I also reviewed best practice biosecurity strategies that have been used at an industry planning level overseas to minimize the risk of outbreaks of viral, protozoan and metazoan diseases (including sea lice) in cultured salmon These have included use of moderate stocking densities and implementation of independent farm management areas where production from several farming sites can be co-ordinated and synchronised, and where integrated disease management procedures, including site fallowing, can be implemented, if necessary Separation of independent farm management areas by buffer zones of sufficient wwwdigsfishcom 14

15 distance (>5 km) to reduce the risk of horizontal disease transmission via movements of water and wild fishes was also found to be useful to avoid and/or control outbreaks of disease due to viruses and sea lice Risk analysis 34 The risk analysis I presented in Sections 4 and 5 of the Disease Assessment Report included a qualitative risk assessment of the likelihood of any changes to the existing disease status of King salmon, native fishes and other aquatic animals within the Marlborough Sounds and assessed the consequences of disease spread (should it occur) 35 I found that the 13 non-infectious diseases of cultured salmon in New Zealand identified during the hazard identification process of the risk analysis (Section 4 of the Disease Assessment Report) would not pose any additional negative or cumulative threat to the health of wild aquatic animals in the Marlborough Sounds, and hence these were not considered further This is because as a general rule, non-infectious diseases do not pose a threat to the natural environment, as by definition they are non-infectious and cannot be transmitted to other marine fishes or other aquatic animals However, one exception to this rule is algal blooms The risk of harmful algal blooms is addressed in the evidence of Lincoln MacKenzie 36 Of the infectious diseases I identified as occurring in cultured salmon in New Zealand, I do not consider that the bacterial disease agents that cause vibriosis and fin and gill rot (genera Vibrio, Flexibacter, Tenacibaculum, Flavobacterium, and Cytophaga) pose a risk to the health of wild aquatic animals in the Marlborough Sounds This is because these bacteria are already ubiquitous in the marine environment and only cause disease in cultured fish held in stressful conditions at high densities I do not consider that the bacterium Yersinia ruckeri and the fungus Saprolegnia spp pose a risk to the health of wild aquatic animals in the Marlborough Sounds, because they are both considered wwwdigsfishcom 15

16 opportunistic pathogens that almost exclusively cause disease in salmon cultured in freshwater, and only when they are injured or held in high densities under poor conditions Similarly, in my opinion, the ciliate protozoans Chilodonella spp and Ichthyophthirius multifiliis do not pose a risk to the health of wild aquatic animals in the Marlborough Sounds because they do not tolerate salt and cannot survive in seawater 37 Cultured salmon become infected with endoparasitic digenean, nematode and cestode worms through consumption of intermediate hosts or exposure to infective stages in natural food items, but because cultured salmon are fed artificial feeds, they are not regularly exposed to these parasites and hence I do not consider these parasites pose any significant risk to the health of wild aquatic animals in the Marlborough Sounds The copepod Paenodes nemaformis, only infects salmonids in freshwater, while the isopod Cirolana spp was found in the mouth of returning sea run King salmon Other free living isopods can sometimes be ingested by salmon in seacages, survive being swallowed and damage the stomach and internal organs, causing death In my opinion, all of these crustacean ectoparasites do not pose a significant risk to the health of wild aquatic animals in the Marlborough Sounds because they either cannot survive in seawater (P nemaformis), or they are already ubiquitous in the marine environment 38 From the remaining potential hazards identified in cultured salmon in New Zealand that were due to infectious disease agents, I determined that 4 agents (Aquatic birnavirus, amoebic/nodular gill disease caused by amoebae (Neoparamoeba perurans and Cochliopodia spp), sea lice (Caligus and Lepeophtheirus spp), and whirling disease cased by the myxozoan Myxobolus cerebralis) should be considered as diseases of concern that required detailed risk assessment 39 Aquatic birnavirus: My detailed risk assessment found that aquatic birnaviruses are known to occur in the marine waters adjacent to the South Island of New Zealand at low prevalences in sea run salmon, wwwdigsfishcom 16

17 though the required surveys have not been conducted to determine the complete range of host species or prevalence of infection Given that returning sea run King salmon in New Zealand are occasionally positive for birnavirus, but that the vast majority of broodstock King salmon used by NZ King Salmon are held over in freshwater for their entire lives, I considered the likelihood estimations for the release of salmon infected by aquatic birnavirus into seacages in the Marlborough Sounds to be Extremely Low 40 Data from Scotland showed that prevalence of birnavirus infection was increased slightly above background levels (from 015% prevalence to 058% prevalence) in wild fishes within 5 km of salmon farms that contained clinically diseased fish infected with birnavirus However, because marine teleosts and invertebrates in New Zealand are already at risk of exposure to the local strain of aquatic birnavirus, and the birnavirus isolates recorded to date in New Zealand are not known to cause disease in salmon, I considered the likelihood of exposure and establishment of aquatic birnavirus in new fish and molluscs populations to be Very Low Even in the unlikely instance that the disease became established in cultured salmon, in my opinion, it would have mild biological consequences, which would be amenable to control, and would not cause any noticeable environmental effects 41 I therefore estimate that the consequences of introduction of birnavirus strains into New Zealand s environment via salmon in sea cages in the Marlborough Sounds would likely be Very Low, meaning that the unrestricted risk associated with aquatic birnavirus did not exceed the Appropriate Level of Protection (ALOP), and that no additional risk management was required for this disease agent 42 Amoebic/nodular gill disease: My detailed risk assessment found that the agents that cause amoebic gill disease (AGD) and nodular gill disease in cultured salmon in New Zealand (Neoparamoeba perurans and wwwdigsfishcom 17

18 Cochliopodia spp, respectively) are free-living amoebae that occur naturally in the rearing environment 43 Cochliopodia spp are only problematic for salmon reared in freshwater, and these do not tolerate salt, hence I do not consider Cochliopodia app to pose a risk to the health of wild aquatic animals in the Marlborough Sounds because they cannot survive in seawater 44 In New Zealand, AGD due to infection with Neoparamoeba perurans is not considered a significant problem because King salmon appear to be resistant to this disease, being often infected but rarely experiencing any mortality in marine seacages So even though I consider the likelihood estimations for the release of amoebae from seacaged salmon into the Marlborough Sounds to be High, marine teleosts in New Zealand are already at risk of exposure to these amoebae, and the likelihood of additional exposure of wild fish to amoebae from cultured salmon is Low 45 In Australia, studies of wild fishes near seacage farms containing AGD infected salmon have found that they are not a significant reservoir of infection for amoebae Because of this, in my opinion, from my risk assessment, the consequences of exposure of wild aquatic animals in the Marlborough Sounds to amoebae originating from cultured salmon is likely to be negligible, meaning that the unrestricted risk associated with amoebae did not exceed the Appropriate Level of Protection (ALOP), and that no additional risk management was required for these disease agents 46 Sea Lice: My detailed risk assessment found that several different species of the genera Lepeophtheirus and Caligus (Family Caligidae) occur on a wide variety of wild fishes throughout New Zealand Caligus elongatus is a host generalist which has been found on over 80 different hosts and has been problematic in salmonid aquaculture in the northern hemisphere Caligus elongatus has been found in the South Island of NZ wwwdigsfishcom 18

19 in the Heathcote Estuary, Christchurch on flounder Rhombosolea spp, but has not been problematic in the culture of King salmon either in New Zealand or elsewhere 47 Another species of Caligus that is present in New Zealand is Caligus epidemicus, which has been recorded on flounder (Rhombosolea leporina) in northern New Zealand Neither C elongatus or C epidemicus have been reported to infect cultured salmon in New Zealand to date, and Caligus elongatus has not been problematic in culture of King salmon elsewhere 48 Another species, Caligus longicaudatus, was found on sockeye salmon (O nerka) reared in seacages in New Zealand, but King salmon in nearby seacages were not affected Indeed, overseas data shows that King salmon are relatively resistant to sea lice infection compared to other salmon species I consider that the lack of evidence of sea lice infection in King salmon in New Zealand after many years of culturing these fish at high densities demonstrates that King salmon are resistant to infection by those species of sea lice endemic to New Zealand 49 However, host switching by caligids onto new hosts is known to occur, and one possible mechanism that could encourage this process is increased use of artificial lighting to delay onset of maturation of seacaged salmon The copepodid infective stage of caligid copepods is photopositive, hence use of artificial lighting would tend to attract them towards seacages This would therefore tend to increase the number of encounters between copepodids and caged salmon Because of this, the likelihood estimation for salmon becoming infected by sea lice in seacages in the Marlborough Sounds was considered to be Low 50 Nevertheless, if King salmon in seacages did become infected with sea lice via host switching, sea lice infective stages originating from infected salmon could enter the marine environment and infect wild fishes up to wwwdigsfishcom 19

20 30 km away, hence the likelihood of exposure of wild fish populations to sea lice was considered to be Moderate 51 I considered that if a worst case scenario occurred and sea lice infections became established on cultured King salmon, this could result in interactions with migrations of wild salmon through the Marlborough Sounds region, although the extent of these potential interactions would be difficult to quantify However, because sea lice only tend to occur at subclinical levels in wild non-salmonids, I considered that transmission of sea lice infections into wild marine fish near affected salmon farms was unlikely to have significant impacts on wild fish populations 52 Because of these reasons, from my risk assessment I considered that the consequences of exposure of wild aquatic animals in the Marlborough Sounds to sea lice originating from cultured salmon are likely to be Low, meaning that the unrestricted risk associated with sea lice did not exceed the Appropriate Level of Protection (ALOP), and that no additional risk management was required for these disease agents 53 Whirling disease: My detailed risk assessment found that the myxosporean parasite Myxobolus cerebralis has been reported from King salmon and several other species of salmonids in the South Island of New Zealand, including rainbow trout, brown trout, brook trout and Sockeye salmon 54 The intermediate hosts for M cerebralis are ubiquitous in the aquatic freshwater environment, and because of this the disease agent occurs naturally in freshwater aquatic environments in several places in the South Island Juvenile King salmon reared in freshwater can be exposed to infective stages of the parasite via their water supply and some have become infected at very low prevalences and intensities, but despite this, clinical whirling disease has never been recorded in this species in New Zealand, so I considered that the likelihood of the disease agent being released into seacages in the Marlborough Sounds was Low wwwdigsfishcom 20

21 55 Marine fishes are not susceptible to M cerebralis, nor are the freshwater tubificid intermediate hosts required to complete the lifecycle likely to be present in the marine environment under salmon farms Nevertheless, a potential pathway exists which could allow completion of the lifecycle of M cerebralis if infected fish were released into seacages and subsequently escaped and swam up local rivers 56 However because of the various steps involved in this process, I considered that the likelihood of this pathway being successfully completed would be Extremely Low Furthermore, the likelihood of this pathway being completed must also be measured against the significant risks of transfer of M cerebralis spores or other infective stages of the parasite via angling activity 57 Because of these reasons, I considered that the consequences of exposure of wild aquatic animals in the Marlborough Sounds to whirling disease originating from cultured salmon were likely to be Very Low, meaning that the unrestricted risk associated with whirling disease did not exceed the Appropriate Level of Protection (ALOP), and that no additional risk management was required for this disease agent Outcomes from the detailed risk assessments 58 Based on the outcomes of these detailed risk assessments, I found that none of the 4 diseases of concern are likely to cause significant disease in wild fishes or other aquatic animals under the conditions experienced in the Marlborough Sounds The risk analysis therefore indicated that these 4 disease agents posed no negative or cumulative threat to the health of wild aquatic animals in the Marlborough Sounds, and because of this, I consider that no additional risk management measures are necessary at this time wwwdigsfishcom 21

22 59 However, the risk analysis did determine that there was an unquantifiable risk that biosecurity leaks could allow exotic diseases to be introduced, and/or that new endemic diseases could emerge in salmon aquaculture in New Zealand at some time in the future 60 In my opinion, the proposed planning changes, if approved, will allow New Zealand King Salmon to expand without increasing stocking densities on individual farms, while permitting establishment of 3 independent farm management areas separated by buffer zones of at least 30 km as the fish swims 61 It is evident to me that the farms proposed for Kaitapeha, Ruaomoko and Ngamahau could be managed with existing farms at Clay Point, Te Pangu, Ruakaka Bay and Otanerau Bay as one individual farm management area (Queen Charlotte Sound/Tory Channel Management Area) 62 The farms proposed for Waitata, Tapipi, Richmond and Kaitira could be managed with existing farms at Waihinau Bay and Forsyth Bay as another individual farm management area (Waitata Reach Management Area), and; 63 The proposed farms located at Papatua and Melville Cove would represent a third individual farm management area (Port Gore Management Area) 64 Because the proposed planning change would allow expansion of salmon farming in the Marlborough Sounds without increasing stocking density of fish in cages at each site, this represents best practice and would minimise the risk of emergence of new endemic diseases because the dynamics of infectious diseases are often related to the density of host populations wwwdigsfishcom 22

23 65 I consider that the ability to establish independent farm management areas separated by ideal buffer zones of at least 18 km (and preferably > 30 km as the fish swims ) represents world s best practice in salmonid seacage farming This is because such an arrangement would allow best practice biosecurity principles to be utilised (such as integrated pest management strategies including site fallowing and year class farming) if a biosecurity lapse at the border allowed entry of an exotic salmon pathogen in the future 66 In my opinion, the ability to utilise best practice biosecurity principles and integrated pest management strategies, if required, would greatly increase the chances of containment, management and eradication of any exotic disease agents or new endemic disease agents that may emerge in the future, to the benefit of the salmon farming industry, New Zealands fisheries, and the marine environment of the Marlborough Sounds and New Zealand Submissions 67 The NZ King Salmon application attracted over 1200 public submissions While I have not read all of the submissions, my attention has been drawn to several of them that are relevant to the topic of fish diseases The key relevant submissions were as follows: wwwdigsfishcom 23

24 Ref # File number Submitter Relevant point of evidence McGuinness Institute Area based management and year class farming are examples of worlds best practice in salmon farming that prevent disease occurrence Sustain our Sounds 1 Seeks explanation of cause of significant mortality event at Waihinau Bay, Bulwer, in March Point 17 - Suggests there was no assessment of impact of disease outbreaks, harmful algal blooms, biosecurity problems or unexplained fish deaths Greater Whatamango Bay Residents Assoc Seeks explanation of cause of mortality events in salmon Concerned about diseases in salmon and transfer of disease to other wild fish species M Pinder Increased numbers of seagulls may act as non point source faecal water contamination and vectors of disease to humans and wildlife Global Alliance against Industrial Aquaculture 1 Salmon farming spreads disease into wild fish populations 2 ISA infects Chinook salmon GE Free for the Environment 1 Increased levels of faecal matter from fish may result in increased prevalence of Bonamia exitiosa in flat oysters 2 Increased salmon densities increases risk of spread of disease including ISA, Furunculosis D & L Boulton Point 9 the proposal will increase biosecurity and other disease risks via intensification of monoculture R Rice Salmon farms could act as high density, nutrient rich nursery areas for diseases and parasites which could intensify and spread to wild fish R Crum L Lomas A Parr E Parr J Bullock P Bailey D Boyce P Trotman Salmon farming increases prevalence of diseases that can spread into wild fish populations wwwdigsfishcom 24

25 Ref # File number Submitter Relevant point of evidence SOS Inc If the cause of the significant mortality event at Waihinau Bay, Bulwer, in March 2012 remains undetermined, the industry should not be allowed to expand D Mitchell, Marlborough Rec Increased rates of disease and mortality in wild fish due to increased concentrations of cultured salmon Fishers Assoc Residents of Torea Bay Concern regarding use of antibiotics and disease based on precedents in Norway and Canada 700 tonnes of salmon already dumped by NZKS in Dr N Elliot Point 22 - potential risk of introduction of disease to consumers and into wild fish stocks Point 24 impacts of sea lice treatments if they become problematic wwwdigsfishcom 25

26 68 Many of the submissions (Refs # 2, 3, 5, 6, 7, 8, 9-16, and 18-20) raised a perception of increased risk of introduction of unknown or unspecified infectious diseases into wild fish populations that could be initiated by the proposed development Assessment of the risk of introduction of known significant diseases of New Zealand salmon into wild fish populations was the core objective of the disease risk assessment I have undertaken for this proposal, hence the issues raised in these submissions have already been covered in sufficient detail in my evidence at points 15 to 68 above While emergence of new (ie unknown ) infectious diseases is always a possibility, New Zealand King Salmon have been operating on a commercial scale for a significant period of time in the Marlborough Sounds environment without new infectious disease problems emerging, probably because good husbandry, feed quality and best practice management arrangements greatly reduce the likelihood of disease emergence Furthermore, non infectious diseases (eg those associated with nutritional inadequacies and toxicities, and environmental issues such as jellyfish strike, algal blooms, and so on, see Appendix 1) are more common in cultured finfish in the majority of circumstances, and while these may occur from time to time, by definition (because they are non-infectious) they pose no threat to populations of wild fishes, even though they may still pose some threat to the welfare of the farmed salmon 69 Some submissions have raised new or slightly different issues, and I address these below Issue 1 The submission by The McGuinness Institute (Ref #1) suggested that international standards for worlds best practice in salmon farming that have been developed by certain NGOs should be adhered to, including area based management and year class farming As was pointed out in both my original disease risk assessment and my wwwdigsfishcom 26

27 evidence above, the proposed expansion would allow New Zealand King Salmon to expand without increasing fish density in the seacages, as well as permit implementation of both area based management strategies (with ideal buffer zones) and year class farming, if required These are acknowledged to be best practice management arrangements known to assist salmon farming industries in other countries to avoid emergence of new infectious diseases and better manage existing diseases Issue 2 The submission by the Global Alliance against Industrial Aquaculture (Ref #5) suggested that Chinook (king) salmon can be infected by ISA virus and that this poses a risk to both cultured salmon and wild fish populations These statements were based on new evidence from Canada 2 that suggests that king salmon in that country may harbour ISA-like viruses in the carrier state Given that king salmon are resistant to ISAV (Rolland and Winton 2003), the detection of ISA-like virus sequences by PCR in asymptomatic king salmon does not confirm that these fish can transmit ISA disease to other species Furthermore, given that ISA is exotic to New Zealand, the new information is of only academic interest, and does not change any of the outcomes of the disease risk assessment in any way This is especially so given that Atlantic salmon are the only species known to be susceptible to clinical disease due to ISA, and in New Zealand this species is only represented by remnant introduced populations in the freshwater sections of the upper Waiau River catchment, in the South Island (McDowall 1994) 2 FirstNationsCoalitionpdf wwwdigsfishcom 27

28 Issue 3 Submissions by Sustain our Sounds (Ref #2) and SOS (Ref #17) pointed out that the cause of a significant mortality event at Waihinau Bay, Bulwer in March 2012 was not determined and that if the cause remains unresolved, that it would be unwise to expand the industry until such time as its disease status is known While a certain background level of mortalities are considered a normal part of aquaculture production, increases above this level are detrimental to both fish welfare and profitability and are hence very closely studied and investigated thoroughly by company staff and veterinarians so that the underlying cause can be identified and rectified to avoid similar problems in the future Information regarding mortalities is considered proprietary information by industry, however reporting of significant disease events to relevant government authorities (the Ministry for Primary Industries via the MAF Biosecurity NZ Investigation and Diagnostic Centre at Wallaceville) is mandatory in New Zealand Because of this, NZKS is currently working with MAF Biosecurity to determine the cause of the problems at Waihinau Bay, and the relevant samples have been sent to MAF Biosecurity as well as specialist overseas laboratories to assist with the diagnosis To date no contagious disease agents have been identified in any of the samples, and NZKS internal biosecurity protocols appear adequate to prevent disease spread to other farms if a contagious disease agent is present If the public interest extends to perusal of the outcomes of such diagnostic investigations, it may be worthwhile for the NZ government to consider wider reporting of the processes involved with investigating and diagnosing disease outbreaks in cultured salmon, in order to better inform the public on these matters if and when they arise wwwdigsfishcom 28

29 Issue 4 The submission by M Pinder (Ref #4) suggested that increased numbers of seagulls may act as non-point sources of faecal water contamination as well as vectors of disease into humans as well as wild fish populations, citing a paper to that effect by Lu et al (2008) Certainly the quality of coastal waters and filter feeding shellfish can be influenced by faecal pollution containing bacteria, viruses and other chemicals from both animal and human sources (Gourmelon et al 2010, Roslev and Bukh 2011, Kirs et al 2011) Seagull numbers worldwide have increased dramatically in recent decades due to increased food availability arising directly or indirectly from human activity (Hatch 1996) Even though water fowl are known to contribute to faecal water pollution, human waste and agricultural runoff containing faecal contamination from terrestrial farm animals are still the major sources of faecal pollution of coastal waters in most parts of the developed world (Gourmelon et al 2010), including New Zealand (Anderson et al 1997, Kirs et al 2011) Nevertheless, faecal contamination by birds was found in all the lowerriver sites near Nelson studied by Kirs et al (2011) Seagull faeces may carry several known human bacterial pathogens including Salmonella spp, Campylobacter spp, Listeria spp and Yersinia spp, as well as protozoan pathogens such as Cryptosporidium and Giardia (see Hatch 1996, Fallacara et al 2001, Jeter et al 2009) However, the presence or absence of these bacteria depends on the food source being utilized by the gulls, with many of the human enteric pathogens (eg Salmonella) being acquired by seagulls when they are feeding at landfills and sewerage outfalls (Fenlon 1983, Hatch 1996, Ferns and Mudge 2000) The greatest threat to public health arises when gulls feed at these contaminated sites and then visit reservoirs of potable wwwdigsfishcom 29

30 water (Hatch 1996) Very little is known regarding the relative contribution of seagulls to water contamination around fish farms, including in the Marlborough Sounds Nevertheless, as the vast majority of the fish feed used is consumed by the cultured fish, it appears likely that seagulls would contribute very little to overall water contamination around fish farms, especially compared to the existing background levels of faecal water pollution arising from other human and agricultural sources Issue 5 The submission by Dr N Elliot (Ref #20) pointed out (her point #24) that it was unclear if treatments would be applied to sea lice if they were to become problematic in the future This question, and similar ones regarding antibiotic use (eg Ref # 5, 19) will be answered by Mark Preece who will be discussing the biosecurity and disease control strategies applied by New Zealand King Salmon together with New Zealand government authorities under various disease outbreak scenarios Issue 6 The submission by GE Free for the Environment (Ref #6) suggested that increased levels of faecal matter from cultured salmon may result in increased prevalence of infection by Bonamia exitiosa in wild flat oysters Flat oyster (Tiostrea chilensis) populations throughout the South Island, including those in Tasman Bay and the Marlborough Sounds, are known to naturally harbour low level infections of B exitiosa without expression of disease (Hine 1997) In New Zealand, the disease Bonamiosis has only been problematic in flat oysters aquacultured at high density, as well as in the wild oyster beds in Fouveaux Strait where high oyster densities combined with stress due to mechanical disturbance and alteration of benthic habitat wwwdigsfishcom 30