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 64 4 499 9555
Fax 64 4 499 9556 PO Box 10-214 DX SX11189 Wellington
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 Amoebic Gill Disease ALOP Appropriate Level of Protection IPN Infectious Pancreatic Necrosis IPNV Infectious Pancreatic Necrosis Virus ISA Infectious Salmon Anaemia ISAV Infectious Salmon Anaemia Virus OIE World Organisation for Animal Health (formerly Office International des Epizooties).
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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
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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 (i.e. “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
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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.
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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
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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.
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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.
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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 non- infectious 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.
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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 2004.
18. 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.
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19. As outlined in Section 2.0 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
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resistant to ISA virus, although new evidence from Canada1 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 http://www.cohencommission.ca/en/pdf/FinalSubmissions/InitialISASubmissions/16-InitialISASubmission- FirstNationsCoalition.pdf
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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.
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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
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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
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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,
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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 0.15% prevalence to 0.58% 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
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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
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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
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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.
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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.
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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.
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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:
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Ref File number Submitter Relevant point of evidence # 1 24087141106 McGuinness Area based management and year class farming are examples of worlds best practice Institute in salmon farming that prevent disease occurrence 2 24046420061 Sustain our Sounds 1. Seeks explanation of cause of significant mortality event at Waihinau Bay, Bulwer, in March 2012 2. Point 17 - Suggests there was no assessment of impact of disease outbreaks, harmful algal blooms, biosecurity problems or unexplained fish deaths. 3 24060510303 Greater Seeks explanation of cause of mortality events in salmon Whatamango Bay Concerned about diseases in salmon and transfer of disease to other wild fish species Residents Assoc. 4 24072060645 M Pinder Increased numbers of seagulls may act as non point source faecal water contamination and vectors of disease to humans and wildlife 5 24075441092 Global Alliance 1. Salmon farming spreads disease into wild fish populations against Industrial 2. ISA infects Chinook salmon Aquaculture 6 24086611205 GE Free for the 1. Increased levels of faecal matter from fish may result in increased prevalence of Environment Bonamia exitiosa in flat oysters 2. Increased salmon densities increases risk of spread of disease including ISA, Furunculosis. 7 0702 D & L Boulton Point 9 – the proposal will increase biosecurity and other disease risks via intensification of monoculture 8 2408693106 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 9 24037810125 R Crum 10 24057730424 L Lomas 11 2406680282 A Parr 12 24066770372 E Parr Salmon farming increases prevalence of diseases that can spread into wild fish 13 24067140533 J Bullock populations 14 24067150554 P Bailey 15 24072040454 D Boyce 16 24083220924 P. Trotman
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Ref File number Submitter Relevant point of evidence # 17 24066900491 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 18 24064460345 D. Mitchell, Increased rates of disease and mortality in wild fish due to increased concentrations Marlborough Rec. of cultured salmon Fishers Assoc. 19 24057570432 Residents of Torea Concern regarding use of antibiotics and disease – based on precedents in Norway Bay and Canada. 700 tonnes of salmon already dumped by NZKS in 2012. 20 24051040225 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.
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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 (i.e. “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 (e.g. 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
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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 Canada2 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 http://www.cohencommission.ca/en/pdf/FinalSubmissions/InitialISASubmissions/16-InitialISASubmission- FirstNationsCoalition.pdf
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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.
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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 lower- river 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 (e.g. 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
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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 (e.g. 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
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by dredging may predispose oysters to Bonamiosis (Hine 1997, Hine et al. 2002, Cranfield et al 2005). Studies of the dynamics of Bonamiosis in flat oysters have shown that stressors such as mechanical disturbance, and rapid temperature changes can elevate B. exitiosa infections (Hine et al. 2002). Furthermore, alteration of benthic habitat including loss of biogenic reef has been associated with increased mortality due to B. exitiosa in the Fouveaux Strait oyster fishery (Cranfield et al. 2005). These data suggest that any reduced water quality or loss of benthic habitat complexity immediately under or adjacent to salmon seacages in the Marlborough Sounds (i.e. within the „footprint” of the farms) may also have detrimental effects on flat oyster populations in these areas by predisposing them to Bonamiosis. However, these impacts would be minimal, given that no large populations of flat oysters have been reported in the areas immediately under the farms, and even then, any impacts are likely be reversible if farm sites were fallowed or salmon farming was halted. The fact that B. exitiosa only infects flat oysters (Hine 1997, 2002) means that other shellfish in the region will not be affected by Bonamiosis.
The same submission also suggested that increased salmon densities increase the risk of spread of diseases including ISA and Furunculosis caused by the bacterium Aeromonas salmonicida subspecies salmonicida. These latter claims are not applicable to the New Zealand King Salmon proposal given that fish density in each cage will remain similar to current stocking levels (i.e. no increase in salmon densities above existing levels will occur on a per farm basis), and both ISA and A. salmonicida ssp. salmonicida are exotic to New Zealand.
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Conclusions
70. I conclude that development of additional salmon farms, as proposed in the Sustainably Growing King Salmon Proposal, would minimise disease risks to New Zealand‟s salmon farming industry and the environment that may be presented by expansion of salmon farming in the Marlborough Sounds. This is because it would allow expansion of salmon farming whilst keeping stocking densities at existing levels, in locations which would allow the development of 3 independent farm management areas, and establish ideal on-water buffer zones that will allow independent management of farm areas in the event of disease outbreaks.
71. In my opinion, this would be consistent with current world‟s best practice for seacage aquaculture farm management, as it would minimise the potential for negative and cumulative effects on the environment and industry that may be presented by disease agents of salmon during the planned expansion of salmon farming in the Marlborough Sound
Date: 20 June 2012
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References Anderson SA, Turner SJ, Lewis GD (1997). Enterococci in the New Zealand environment: implications for water quality monitoring. Water Science and Technology 35: 325-331. Cranfield HJ, Dunn A, Doonan IJ, Michael KP (2005). Bonamia exitiosa epizootic in Ostrea chilensis from Foveaux Strait, southern New Zealand between 1986 and 1992. ICES Journal of Marine Science 62: 3-13. Fallacara DM, Monahan CM, Morishita TY, Wack RF (2001). Fecal shedding and antimicrobial susceptibility of selected bacterial pathogens and a survey of intestinal parasites in free-living waterfowl. Avian Diseases 45: 128-135 Fenlon DR (1983). A comparison of Salmonella serotypes found in the faeces of gulls feeding at a sewage works with serotypes present in the sewage. Journal of Hygiene 91: 47-52. Ferns PN, Mudge GP (2000). Abundance, diet, and Salmonella contamination of gulls feeding at sewage outfalls. Water Research 34: 2653-2660. Gourmelon M, Caprais MP, Mieszkin S, Marti R, Wéry N, Jardé E, Derrien M, Jadas-Hécart A, Communal PY, Jaffrezic A, Pourcher AM (2010). Development of microbial and chemical MST tools to identify the origin of the faecal pollution in bathing and shellfish harvesting waters in France. Water Research 44: 4812-4824. Hatch JJ (1996). Threats to public health from gulls (Laridae). International Journal of Environmental Health Research 6: 5-16. Hine PM (1997). Health status of commercially important molluscs in New Zealand. Surveillance 24(1): 25-28. Hine PM (2002). Results of a survey on shellfish health in New Zealand in 2000. Surveillance 29(1): 3-7. Hine PM, Diggles BK, Parsons MJD, Pringle A, Bull B (2002). The effects of stressors on the dynamics of Bonamia exitiosus Hine, Cochennec-Laureau & Berthe, infections in flat oysters Ostrea chilensis (Philippi). Journal of Fish Diseases 25: 545-554. Jeter SN, McDermott CM, Bower PA, Kinzelman JL, Bootsma MJ, Goetz GW, McLellan SL (2009). Bacteroidales diversity in ring-billed gulls (Laurus delawarensis) residing at Lake Michigan Beaches. Applied and Environmental Microbiology 75: 1525–1533
Kirs M, Harwood VJ, Fidler AE, Gillespie PA, Fyfe WR, Blackwood AD, Cornelisen CD (2011). Source tracking faecal contamination in an urbanised and a rural waterway in the Nelson-Tasman region, New Zealand. New Zealand Journal of Marine and Freshwater Research 45: 43-58
Lu J, Santo Domingo JW, Lamendella R, Edge T, Hill S (2008). Phylogenetic diversity and molecular detection of bacteria in gull faeces. Applied and Environmental Microbiology 74: 3969–3976. McDowall RM (1994). Gamekeepers for the nation. The story of New Zealand‟s acclimatisation societies. Canterbury University Press. 508 pgs. Roslev P, Bukh AS (2011). State of the art molecular markers for faecal pollution source tracking in water. Applied Microbiology and Biotechnology 89: 1341-1355.
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APPENDIX 1 – List of New Zealand salmon diseases Disease Under Occurs in May cause May cause official cultured significant disease significant disease control salmon in NZ in wild marine fish in seacaged fish INFECTIOUS AGENTS VIRUSES Aquatic Birnavirus Yes No No Yes BACTERIA Flexibacter spp./ Tenacibaculum spp. No Yes No Yes Bacterial gill disease No Yes No No Vibrio spp. No Yes No Yes Yersinia ruckeri (Yersinosis) No Yes No No FUNGI Saprolegnia spp. No Yes No No PROTOZOA Chilodonella sp. No Yes No No Ichthyophthirius multifiliis No Yes No No Neoparamoeba perurans / Cochliopodida sp. No Yes No No METAZOA Digenea Derogenes varicus No No No No Lecithocladium seriolellae No No No No Parahemiurus sp. No No No No Tubovesicula angusticauda No No No No Cestoda Hepatoxylin trichiuri No No No No Phyllobothrium sp. No No No No Nematoda Heduris spinigera No No No No Hysterothylacium sp. No Yes No No Crustacea Caligus spp. No Yes No Yes Cirolana sp. No Yes No No Paeonodes nemaformis No No No No Myxozoa Myxobolus cerebralis Yes Yes No No NON-INFECTIOUS AGENTS Algal blooms No Yes No Yes Cardiomyopathy No Yes No No Gas Bubble Disease No Yes No No Gastric Dilation and Air Sacculitis (GDAS) No Yes No Yes Isopod invasion No Yes No Yes Jellyfish strike No Yes No Yes Neoplasia No Yes No No Nephrocalcinosis No Yes No No Pinhead syndrome No Yes No No Runting No Yes No No Seal predation No Yes No No Skin lesions/sunburn No Yes No No Spinal deformity No Yes No No
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APPENDIX 2 – Risk Assessment Methodology used in the Disease Assessment Report
Hazard identification
Develop list of diseases of
salmon in New Zealand
Is the disease infectious ?
No Yes
Could seacaged King salmon Exclude from further carry the disease agent ? examination in RA No
Yes
Potential hazard identified
Is the disease agent listed No in New Zealands national reportable disease list as under “official control” (see next page)
Could the disease agent cause a distinct pathological effect in No affected populations, and/or economic harm, and/or Yes damage to the environment ?
Identified as a disease of Yes concern requiring detailed risk assessment
Figure 2. Flow chart showing the decision making process used to identify diseases of concern in the hazard identification step.
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Table 2. New Zealand’s national list of reportable diseases of finfish (ie. diseases under official control).
New Zealand’s National List of Listed in the Exotic to New Found in Reportable Diseases of Finfish OIE Aquatic Zealand salmon in Animal New Zealand Health Code (2010)
1. Bacterial kidney disease (Renibacterium salmoninarum) 2. Enteric redmouth disease (Yersinia ruckeri – Hagerman strain) 3. Epizootic haematopoietic necrosis – EHN virus 4. Epizootic ulcerative syndrome (Aphanomyces invadans) 5. Furunculosis (Aeromonas salmonicida subsp. salmonicida) 6. Gyrodactylosis (Gyrodactylus salaris) 7. Infectious haematopoietic necrosis 8. Infectious pancreatic necrosis (exotic strains) * 9. Infectious salmon anaemia 10. Koi herpesvirus disease 11. Oncorhynchus masou virus 12. Red sea bream iridoviral disease 13. Spring viraemia of carp 14. Viral haemorrhagic septicaemia 15. Whirling disease (Myxobolus cerebralis)
* A birnavirus within IPNV Genogroup 5 has been found in returning sea run salmon in New Zealand (Davies et al. 2010).
Release assessment
The likelihood that a hazard would be translocated into the environment is determined through the release assessment stage of the process. The only hosts considered in the risk analysis component of this document are King salmon (Oncorhynchus tshawytscha) cultured in seacages. The release pathway for spread of disease from the host into the New Zealand marine environment is direct via faeces, urine, blood, mucus and other fluids shed by cultured
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salmon into the water. The risk assessment for a particular hazard was concluded if the release assessment determined that the likelihood of release of that hazard was negligible.
Table 4. Nomenclature for the qualitative likelihood estimations used in this RA.
Likelihood Definition
High The event would be very likely to occur
Moderate The event would occur with an even probability
Low The event would be unlikely to occur
Very Low The event would be very unlikely to occur
Extremely low The event would be extremely unlikely to occur
Negligible The event would almost certainly not occur
Exposure assessment
The exposure assessment examines the likelihood of wild aquatic animals in an uninfected jurisdiction being exposed to the hazards via infected seacaged salmon and determines the likelihood of the establishment of the hazard. The likelihood of exposure will depend on several factors relating to the capacity of the disease agent to survive in the environment in an infective form, the availability of susceptible hosts, the ease of infection of susceptible hosts, and the likelihood of subsequent transmission of infection to others within a population. In determining the likelihood of exposure of susceptible hosts to disease agents carried by salmon, the following key factors were considered relevant:
1. Route of Infection (Oral/Contact): Viable infective stages must be ingested by a susceptible host or otherwise come into contact with susceptible fish or invertebrate species. Infection may occur via the digestive tract, or through direct contact with contaminated water via the skin and gills or integument.
2. Infective Dose: There must be sufficient quantities of viable infective stages to induce an infection following ingestion or contact via the skin and gills or integument.
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Once a hazard is released into the environment, the likelihood of whether the disease agent would survive, infect susceptible hosts, and become established within a population was expressed qualitatively using the likelihood estimations in Table 4, based on information available in the scientific (and other) literature, unpublished data, as well as the professional judgment of the analyst. The likelihoods for the release and exposure assessments were combined using the matrix of „rules‟ for combining descriptive likelihoods, as shown in Table 5.
Table 5. Matrix of rules for combining descriptive likelihoods for the release and exposure assessments.
Likelihood of exposure
High Moderate Low Very Low Extremely low Negligible
High High Moderate Low Very Low Extremely low Negligible
Moderate Low Low Very Low Extremely low Negligible
release Low Very Low Very Low Extremely low Negligible
Very Low Extremely low Extremely low Negligible
Extremely low Negligible Negligible Likelihood of Negligible Negligible
The risk assessment for a particular hazard was concluded if the exposure assessment determined that the probability of establishment was negligible.
Consequence assessment
The consequence assessment estimates the likely magnitude of the consequences of establishment and/or spread of a disease agent into the environment and the possible effects of the disease agent on aquatic animals, the environment, industry and the economy. The qualitative terms used to describe the consequences of establishment of an unwanted disease agent in this RA are defined in Table 6. These descriptions are based on information available in other RAs, the scientific literature, unpublished data, as well as the professional judgment of the analyst. For each disease of concern, the consequence assessment determined the
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likelihood of occurrence and the associated impact for each of two main outbreak scenarios. Either:
1. The disease agent becomes established and spreads throughout populations of susceptible species in Marlborough Sounds and beyond. This scenario assumes that if a disease agent were to establish in a local population it would eventually spread to its natural geographical limits, or;
2. An index case occurs and infection may even spread to co-habiting animals, but the agent does not persist in the environment.
Only the first scenario was considered to represent establishment of the disease agent, because the second scenario would go undetected.
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Table 6. Definition of terms used to describe consequences of establishment of disease agents.
Consequence Definition
Extreme Establishment of disease would cause substantial biological and economic harm at a regional or national level, and/or cause serious and irreversible environmental harm.
High Establishment of disease would have serious biological consequences (high mortality or morbidity) and would not be amenable to control or eradication. Such diseases would significantly harm economic performance at a regional level and/or cause serious environmental harm which is most likely irreversible.
Moderate Establishment of disease would cause significant biological consequences (significant mortality or morbidity) and may not be amenable to control or eradication. Such diseases could harm economic performance at a regional level on an ongoing basis and/or may cause significant environmental effects, which may or may not be irreversible.
Low Establishment of disease would have moderate biological consequences and would normally be amenable to control or eradication. Such diseases may harm economic performance at a local level for some period and/or may cause some environmental effects, which would not be serious or irreversible.
Very Low Establishment of disease would have mild biological consequences and would be amenable to control or eradication. Such diseases may harm economic performance at a local level for a short period and/or may cause some minor environmental effects, which would not be serious or irreversible.
Negligible Establishment of disease would have no significant biological consequences and would require no management. The disease would not affect economic performance at any level and would not cause any detectable environmental effects.
The risk assessment for a particular hazard was concluded if the consequence assessment determined that the consequences of introduction were negligible.
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Risk estimation
Risk estimation is the final step involved with each assessment and would be used to determine whether the extent of the unrestricted risk presented by each disease agent to the environment and aquatic animals of New Zealand was sufficient to require risk management. „Unrestricted risk‟ means the estimated risk if the current industry practices remain unchanged. Risk was assessed using the risk estimation matrix in Table 7 which uses a combination of the qualitative answers given for the combined likelihoods of release and exposure and the significance of the consequences of establishment of a disease agent to provide an estimate of the risk involved, ranging from „negligible‟ through to „extreme‟. The appropriate level of protection (ALOP) for the environment adopted in this RA is expressed in qualitative terms. The ALOP is expressed as providing a high level of sanitary or phytosanitary protection whereby risk is reduced to a very low level, but not to zero. This definition of ALOP, and its illustration by way of a risk estimation matrix is shown below in Table 7.
Table 7. Risk estimation matrix showing the ALOP utilized for this RA (white squares = very low risk). Any diseases which fall to the right of the ALOP during the RA will require additional risk management (red font).
Negligible Very low Low risk Moderate High risk Extreme High risk risk risk risk
Moderate Negligible Very low Low risk Moderate High risk Extreme risk risk risk risk
Low Negligible Negligible Very low Low risk Moderate High risk risk risk risk risk
Negligible Negligible Negligible Very low Low risk Moderate Very low risk risk risk risk risk establishment and spread establishment
Negligible Negligible Negligible Negligible Very low Low risk Ext. Low risk risk risk risk risk
Negligible Negligible Negligible Negligible Negligible Very low Likelihood of Negligible risk risk risk risk risk risk
Negligible Very Low Low Moderate High Extreme
Consequences of establishment and spread
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If either the likelihood of establishment and spread, or the significance of the consequences of establishment and spread were considered to be negligible, it was considered the unrestricted risk posed by the disease agent was negligible (rising to very low for extreme consequences of establishment), and there would be no need to implement any additional risk management steps (Table 7). If the consequences of establishment and spread were considered to be very low, even a high probability of establishment and spread was tolerable without the need for risk management. If the likelihood of establishment and spread were considered to be very low, even high consequences of establishment and spread were tolerated without the need for risk management, but extreme consequences of establishment and spread were considered to exceed the ALOP, and risk management would be required (Table 7). Alternatively, if the likelihood of establishment and spread was high, even if the consequences of establishment and spread were considered to be low, this scenario would exceeded the ALOP and require risk management (Table 7).
Risk mitigation
If the unrestricted risk estimation for any disease agent is determined to be unacceptable (that is above very low), the threats posed by the disease agent will be ranked (high, medium, low) based on the likelihood that it would pose a disease risk when introduced into the Marlborough Sounds with cultured salmon. The ranking process will take into account not only the types of disease agents harboured by cultured salmon, but also the quantity of the salmon being cultured. For any diseases with risk estimation rankings that exceed the ALOP, risk mitigation measures may be necessary to reduce the risk estimate back to within the ALOP. The risk mitigation processes examined as part of this RA process related only to option evaluation.
Option evaluation
The RA will identify the options available for managing any risks that may exceed the ALOP.
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APPENDIX 3 – Curriculum Vitae – Dr Ben Diggles Full name: Benjamin Keith Diggles
Date of Birth: 5-Aug-1971
Position: Managing Director, DigsFish Services Pty Ltd.
Address: Brisbane, QLD, AUSTRALIA, [email protected]
Academic qualifications: PhD. B.Sci (Hons. 1st class)
Years post graduate experience: 20
Patents: 4
Professional positions held:
Dec. 2003 - present
Managing Director, DigsFish Services Pty Ltd. http://www.digsfish.com/
Job description: Provision of an independent aquatic animal health consulting service for the fisheries and aquaculture industries in New Zealand, Australia, Asia and the South Pacific. Core business includes import risk analysis, development of environmental risk assessments and environmental management systems, disease diagnosis in a wide range of aquatic animals, development of feeding attractants for aquaculture and recreational fishing, and development of medicated feeds for aquacultured finfish.
Sept. 1997 – Nov. 2003 Marine pathologist/parasitologist, Fish Health Unit, National Institute of Water and Atmospheric Research, Wellington, New Zealand. http://www.niwa.cri.nz/
Job description: Provision of a pathology and disease diagnostic service for the New Zealand aquaculture industry, including commercial consulting work as well as government and industry funded research. Clients included private citizens, aquaculture and fishing companies, Regional Councils and the Governments of New Zealand, South Australia, and the Cook Islands. A significant proportion of
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my time was spent designing experiments, research programmes, and disease surveys, as well as providing disease related advice for FRDC and FRST funded research projects. In this job I was required to perform all aspects of basic and applied science related to the prevention, diagnosis, epidemiology and control of diseases of aquatic organisms including fish (marine and freshwater species), lobsters, Macrobrachium, rock oysters, flat oysters, pearl oysters, mussels, abalone, scallops and sea urchins.
Sept. 1996 - Sept. 1997 Manager, Recreational Fisheries, Primary Industries South Australia, Fisheries Department, Adelaide, South Australia. http://www.pir.sa.gov.au/sector7.shtml
Job description: I was responsible for the preparation and formulation of fisheries resource management policies and options for ecologically sustainable development of recreational fishing opportunities in South Australia. I was required to attend national recreational fisheries management meetings and co- ordinate my work with other State fisheries managers. I also produced discussion papers on the management, development and funding of recreational fishing in South Australia; established a consultative process between government and the recreational fishing sector; managed a recreational fishing fund; and reported to the Director of Fisheries and the Minister for Primary Industries on issues related to recreational fishing legislation.
Jan. 1993-Sept. 1996 Ph.D candidate, Department of Parasitology, The University of Queensland. http://www.uq.edu.au/departments/index.phtml?menu=2&ID=87 Studies of the biology, ecology, taxonomy and control of Cryptocaryon irritans (Ciliata), the cause of whitespot disease in cultured marine fishes.
Job description: I was responsible for production of a PhD dissertation on the biology and control of C. irritans, an important pathogen of marine fish. The project required extensive fieldwork utilising linefishing, anaesthetics, cast nets, drag nets, and inshore trawlers for collecting various species of fish and shellfish from sites in impoundments, enclosed ponds, estuarine, coastal bar and coral reef environments in Queensland. Laboratory skills required included molecular biology (sequencing, PCR), electron microscopy (SEM, TEM), microscopy, and parasitological dissection. Awarded Doctor of Philosophy 25/2/97.
Jan. 1992-Dec. 1992 Honours candidate, Department of Parasitology, The University of Queensland. http://www.uq.edu.au/departments/index.phtml?menu=2&ID=87
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Studies of the development and chemotherapy of Polylabroides multispinosus (Monogenea), a gill parasite of cultured Yellowfin Bream, Acanthopagrus australis.
Job description: I was responsible for production of an Honours dissertation on the development and chemotherapy of P. multispinosus, an monogenean parasite of bream. The project required fieldwork and collaboration with the Port of Brisbane Authority and Seaworld on the Gold Coast, where sea cage experiments were carried out. Laboratory skills required included microscopy and parasitological dissection. First class honours awarded 18/12/92.
B. Sc. (1991). University of Queensland, Brisbane, Queensland, Australia. http://www.uq.edu.au/ Majors in Zoology, Environmental Science, Marine Biology, Aquaculture and Parasitology. Final year grade point average 6.1 (out of 7). Awarded Bachelor of Science 17/12/91.
Keynote presentations
June 2008. Pathogen risk analysis: experiences from 9 case studies – applications and limitations
Conference: Diseases in Asian Aquaculture 7 Venue: Taipei.
In 2008 I presented a keynote address on risk analysis in relation to national and international movements of aquatic animals and their related products. The presentation drew upon experience obtained from several biosecurity risk analyses conducted by Dr Ben Diggles and DigsFish Services Pty Ltd over the previous 8 years.
Further Education
November-December 2002. Asia-Pacific Regional Program on Molluscan Health Management Phase II. University of Queensland. Training workshop on diseases of molluscs in the Asia-Pacific region. Lecturers included Dr Mike Hine, Dr Judith Handlinger, Dr Brian Jones, Dr Bob Lester, Dr Sarah Kleeman and Dr Franck Berthe. http://www.enaca.org/MolluscProject.pdf
July - August 2000. Shrimp Pathology Short Course, The University of Arizona. An intensive 2 week shrimp aquaculture pathology short course run by Prof. Donald Lightner. The course outlined the history of disease in shrimp farming, the diseases, and contained practical diagnostic sessions covering histology, bacteriology, antibody assays (Fluorescent antibody tests, ELISA, Immunoblot, immunohistochemistry) and molecular diagnostic techniques (PCR, RT-PCR, ISH).
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http://microvet.arizona.edu/research/aquapath/index.htm
June 2000. Mollusc Histopathology Workshop, University of Tasmania. A 1 day intensive workshop focusing on histopathology of molluscan organs and tissues. Lecturer Dr Judith Handlinger.
June 2000. Crustacean Histopathology Workshop, University of Tasmania. A 1 day intensive workshop focusing on histopathology of crustacean organs and tissues. Lecturers included Dr Danielle Johnston and Dr Barbara Nowak.
May 2000. Fish Histopathology Workshop, University of Tasmania. A 2 day intensive workshop focusing on histopathology of fish organs and tissues. Lecturers included Dr Judith Handlinger, Dr Barry Munday, Dr Barbara Nowak, Dr Tish Pankhurst and Dr Mark Powell.
Scientific Referee
Dr Diggles conducts regular scientific 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.
Books, chapters in books, management papers, workshops, IRAs:
Diggles BK, Landos M (2012). Biosecurity Workshop. Diseases of Crustaceans in Brunei Darussalam. Training course prepared for the Government of Brunei Darussalam. May 2012.
Diggles BK (2012). Literature Review: Best practice in humane dispatch of finfish caught by recreational fishers. DigsFish Services Client Report DF12-01. Prepared for the Commonwealth of Australia, Department of Agriculture, Fisheries and Forestry, February 2012. 20 pgs.
Gordon DP, Diggles BK, Meisterfeld R, Hollis CJ, Buchanan PK (2012). Chapter 15. Phylum Cercozoa. Cercomonads, filose testate amoebae, Phaeodaria, plasmodiophoras, Gromia, haplosporidians, and kin. In: Gordon DP (Ed). New Zealand Inventory of Biodiversity. Volume 3. Kingdoms Bacteria, Protozoa, Chromista, Plantae, Fungi. Canterbury University Press.
Diggles BK, Sawynok W, Olyott LJH (2011). Development of an environmental standard for recreational fishing tournaments. In: Beard TD et al. (2011). The angler in the environment. Proceedings of the 5th World Recreational Fishing Conference. American Fisheries Society Symposium 75: 251-261.
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Diggles BK, Landos M (2011). Revision of National Water Quality Management Strategy Document 4: Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Task 2: Assessment of how aquatic guidelines (section 9.4) are used by resource managers and the aquaculture industry and investigate microbiological criteria for management of pathogens in waters for aquaculture. DigsFish Services Client Report DF11-01. Prepared for the NEPC Service Corporation May 2011. 92 pgs.
Diggles BK (2011). Risk Analysis. Aquatic animal diseases associated with domestic bait translocation. Final report prepared for the Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, FRDC Project No. 2009/072. 296 pgs.
Diggles BK (2010). Draft Risk Analysis. Hazard identification – aquatic animal diseases associated with domestic bait translocation. Draft prepared for the Australian Government Department of Agriculture, Fisheries and Forestry, Canberra, FRDC Project No. 2009/072. 119 pgs.
Aquavetplan (2010). Australian Aquatic Veterinary Emergency Plan. Viral Haemorrhagic Septicaemia. Version 2.0, 2010. 71 pgs. A revision conducted by DigsFish Services for the Office of the Chief Veterinary Officer, Australian Government Department of Agriculture, Fisheries and Forestry, Canberra.
Landos M, Diggles BK, Landos J (2010). Crustacean and disease identification and sampling manual for Brunei Darussalam. DigsFish Services Client Report DF09-10a. Prepared for the Government of Brunei Darussalam. February 2010. 116 pgs.
Diggles BK, Landos J, Landos M (2009). Import Risk Analysis – Shrimp and Other Crustacean Products. DigsFish Services Client Report DF09-10. Prepared for the Government of Brunei Darussalam December 2009. 155 pgs.
Diggles BK, Olyott L (2009). Implementation of the NEATFish environmental standard for fishing tournaments. Report published by DigsFish Services Pty Ltd, September 2009, for FRDC project no. 2008/215. 25 pgs.
Aquavetplan (2009). Australian Aquatic Veterinary Emergency Plan. Enterprise Manual. Version 2.0, 2009. 170 pgs. A revision conducted by DigsFish Services for the Office of the Chief Veterinary Officer, Australian Government Department of Agriculture, Fisheries and Forestry, Canberra.
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Diggles BK, Landos J, Landos M (2009). Assessment of Aquatic Animal Biosecurity Capacity in Brunei Darussalam - March 2009. DigsFish Services Client Report DF09-01. March 2009. 26 pgs.
Aquavetplan (2008). Australian Aquatic Veterinary Emergency Plan. Operations Procedures Manual: Disposal. Version 2.0, 2008. 50 pgs. A revision conducted by DigsFish Services for the Office of the Chief Veterinary Officer, Australian Government Department of Agriculture, Fisheries and Forestry, Canberra.
Sawynok W, Diggles BK, Harrison J (2008). Development of a national environmental management and accreditation system for business/public recreational fishing competitions . Report published by Recfish Australia , March 2008, for FRDC project no. 2006/057.
Corfield J, Diggles BK, Jubb C, McDowall RM, Moore A, Richards A, Rowe DK (2007). Draft final report for public comment to the Australian government Department of the Environment and Water Resources. Review of the impacts of introduced aquarium fish species that have established wild populations in Australia. NIWA Client Report: HAM2006-082; NIWA Project: NAU05917 http://www.environment.gov.au/biodiversity/invasive/publications/wild-aquarium- fish.html
Diggles B. K., Hine P.M. and Carson J (2007). The Cook Islands Experience. Pearl oyster health investigations. In: Bondad-Reantaso MG. et al. Pearl Oyster Health Management: A manual. FAO Fisheries Technical Paper 503. FAO, Rome 2007. pgs 71-85.
Sawynok W., Diggles B., Harrison J. (2006). A national environmental management and accreditation system for recreational fishing tournaments: Concept Development. Report published by Recfish Australia , February 2006, for FRDC project no. 2005/235.
Biosecurity NZ (2006). Import Risk Analysis: Freshwater Prawns Macrobrachium rosenbergii from Hawaii. Biosecurity NZ, Ministry of Agriculture and Forestry. 63 pgs. IRA prepared by Ben Diggles for NZ Government. http://www.biosecurity.govt.nz/pests-diseases/animals/risk/prawns-ra.htm
Biosecurity NZ (2005). Import Risk Analysis: Ornamental fish. Biosecurity NZ, Ministry of Agriculture and Forestry. 264 pgs. IRA prepared by Ben Diggles for NZ Government.
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Diggles, B. K. (2002). Import Risk Assessment: Juvenile yellowtail kingfish (Seriola lalandi) from Spencer Gulf Aquaculture, South Australia. NIWA Client report WLG 2001/03, July 2002. Prepared for Island Aquafarms Ltd. 54 p. http://www.maf.govt.nz/biosecurity/pests- diseases/animals/risk/yellowtail-kingfish-ra.pdf
Diggles, B. K., Hine, P. M., Handley, S. and Boustead, N. C. (2002). A handbook of diseases of importance to aquaculture in New Zealand. NIWA Science and Technology Series No. 49, ISSN 1173-0382. 200 pages. http://www.niwa.co.nz/pubs/st/
Hine, P. M., Jones, J. B. and Diggles, B. K. (2000). A checklist of the parasites of New Zealand fishes, including previously unpublished records. NIWA Technical Report 75. ISSN 1174-2631. 94 pages. http://www.niwa.co.nz/pubs/tr/
Diggles, B.K. (2000). Diseases of spiny lobsters in New Zealand. Proceedings of the International Symposium on Lobster Health Management, L. Evans (ed.). Curtin University of Technology. http://www.curtin.edu.au/curtin/muresk/publica/others/lhm/
Diggles, B. K. and Simpson, D. (1998). A discussion paper on the regulation of recreational fishing in South Australia. South Australian Fisheries Management Series, Paper No. 33 (May 1998). Outcomes summarised at http://www.fishresearch.sa.gov.au/download/rrr.pdf
Diggles, B. K. and Hall, D. (1997). A discussion paper on the management and development of recreational fishing in South Australia. South Australian Fisheries Management Series, Paper No. 23 (May 1997). Outcomes summarized at http://www.fishresearch.sa.gov.au/download/rrr.pdf
Dr Diggles also writes monthly educational columns on fish biology for the Australian Anglers Fishing World Magazine www.yaffa.com.au/fw/index.htm (since 1995) and contributes to a fish identification column in the USA Sport Fishing Magazine www.sportfishingmag.com/index.jsp (since March 2003).
Number of peer reviewed scientific papers: 30
Diggles BK (submitted). Saddleback deformities in yellowfin bream Acanthopagrus australis (Gunther) from South east Queensland. Journal of Fish Diseases
Diggles BK (submitted). Declines of rock oysters in Moreton Bay Marine Park – overfishing, disease or declining water quality ? Estuaries and Coasts
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Rose JD, Arlinghaus R, Cooke SJ, Diggles BK, Sawynok W, Stevens ED, Wynne CDL (submitted). Can fish really feel pain ? Fish and Fisheries
Diggles BK, Cooke SJ, Rose JD, Sawynok W (2011). Ecology and welfare of aquatic animals in wild capture fisheries. Reviews in Fish Biology and Fisheries 21(4): 739-765.
Dungan CF, Reece KS, Moss JA, Hamilton RM, Diggles BK (2007). Perkinsus olseni in vitro isolates from the New Zealand clam Austrovenus stutchburyi. Journal of Eukaryotic Microbiology 54: 263-270.
Corbeil S., Arzul I., Diggles B.K., Heasman M., Chollet B., Berthe FCJ., Crane MJ. (2006). Development of a TaqMan PCR assay for the detection of Bonamia species . Diseases of Aquatic Organisms 71: 75-80.
Whipps C.M.,Diggles B.K. (2006). Kudoa alliaria in flesh of Argentine hoki, Macruronus magellanicus (Gadiformes: Merlucciidae). Diseases of Aquatic Organisms 69: 259-263.
Diggles B.K., Oliver, M. (2005). Diseases of cultured paua (Haliotis iris) in New Zealand. Proceedings of the 5th Symposium on Diseases in Asian Aquaculture. Fish Health Section, Asian Fisheries Society, Quezon City, Philippines.
Tubbs L.A., Poortenaar, C.W., Sewell M.A., Diggles B.K. (2005). Effects of temperature on fecundity in vitro, egg hatching and reproductive development of Benedenia seriolae and Zeuxapta seriolae (Monogenea) parasitic on yellowtail kingfish Seriola lalandi. International Journal for Parasitology 35 315-327.
Sharp, N. J., Diggles, B. K., Poortenaar, C. W and Willis T. J. (2004). Efficacy of Aqui-S, formalin and praziquantel against the monogeneans, Benedenia seriolae and Zeuxapta seriolae, infecting yellowtail kingfish, Seriola lalandi lalandi, in New Zealand. Aquaculture 236: 67-83. http://www.elsevier.com/wps/find/journaldescription.cws_home/503302/description - description
Diggles B.K. (2003). Some pathological abnormalities of New Zealand Fishes. New Zealand Journal of Marine and Freshwater Research. 37: 705-713. http:/www.rsnz.govt.nz/publish/nzjmfr/2003/062.php
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Sharp, N. J., Poortenaar, C. W., Diggles, B. K. and Willis T. J. (2003). Metazoan parasites of yellowtail kingfish, Seriola lalandi lalandi, in New Zealand. Prevalence, intensity and site specificity. New Zealand Journal of Marine and Freshwater Research 37: 273-282. http://www.rsnz.govt.nz/publish/nzjmfr/2003/026.php
Diggles, B.K., Cochennec-Laureau, N., Hine, P.M. (2003). Comparison of diagnostic techniques for Bonamia exitiosus from flat oysters Ostrea chilensis in New Zealand. Aquaculture: 220: 145-156. http://www.elsevier.com/wps/find/journaldescription.cws_home/503302/description - description
Diggles, B.K., Nichol, J., Hine, P.M., Wakefield, S., Cochennec-Laureau, N., Roberts, R.D., Friedman, C.S. (2002): Pathology of cultured paua (Haliotis iris Martyn, 1784) infected by a novel haplosporidian parasite, with some observations on the course of disease. Diseases of Aquatic Organisms 50: 219-231. http://www.int-res.com/abstracts/dao/v50/n3/p219-231.html
Hine, P.M., Diggles, B.K., Parsons, M.J.D., Pringles, A., Bull B. (2002). The effects of stressors on the dynamics of Bonamia exitiosus Hine, Cochennec-Laureau & Berthe, infections in flat oysters Ostrea chilensis (Philippi). Journal of Fish Diseases 25: 545-554. http://www.blackwell-synergy.com/rd.asp?code=JFD&goto=journal
Hine, P.M., Diggles, B.K. (2002). The distribution of Perkinsus olseni in New Zealand bivalve molluscs. Surveillance 29: 8-11. http://www.maf.govt.nz/biosecurity/publications/surveillance/surveillance-29-1.pdf
Hine, P.M., Diggles, B.K. (2002). Prokaryote infections in the New Zealand scallops Pecten novaezelandiae and Chlamys delicatula. Diseases of Aquatic Organisms 50: 137-144. http://www.int-res.com/abstracts/dao/v50/n2/p137-144.html
Hine PM, Wakefield S, Diggles BK, Webb VL, Maas EW (2002). The ultrastructure of a haplosporidian containing Rickettsiae, associated with mortalities among cultured paua Haliotis iris. Diseases of Aquatic Organisms 49: 207-219. http://www.int-res.com/abstracts/dao/v49/n3/p207-219.html
Diggles, B.K. (2001). A mycosis of juvenile spiny rock lobster Jasus edwardsii (Hutton, 1875) caused by Haliphthoros sp., and possible methods of chemical control. Journal of Fish Diseases 24: 99- 110. http://www.blackwell-synergy.com/rd.asp?code=JFD&goto=journal
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Diggles, B.K., Moss, G. A., Carson, J. and Anderson, C. D. (2000). Luminous vibriosis in rock lobster Jasus verreauxi (Decapoda: Palinuridae) phyllosoma larvae associated with infection by Vibrio harveyi. Diseases of Aquatic Organisms 43: 127-137. http://www.int-res.com/abstracts/dao/v43/n2/p127-137.html
Diggles, B. K. (2000). Chemotherapy of the ciliate Trichodina sp. on juvenile turbot (Colistium nudipinnis) with notes on the susceptibility of fish with abnormal pigmentation. New Zealand Journal of Marine and Freshwater Research 34: 645 - 652. http://www.rsnz.org/publish/nzjmfr/2000/54.php
Diggles B. K., J. Carson, P. M. Hine and M. Tait (2000). Vibrio species associated with mortalities in hatchery reared turbot (Colistium nudipinnis) and brill (C. guntheri) in New Zealand. Aquaculture 183: 1-12. . http://www.elsevier.com/wps/find/journaldescription.cws_home/503302/description - description
Diggles, B. K. and Ernst, I. (1997). Hooking mortality of two species of shallow water reef fish caught by recreational angling methods. Marine and Freshwater Research 48: 479-483. http://www.publish.csiro.au/nid/126/paper/MF96108.htm
Diggles, B. K. (1997). Some information on the morphology of Cryptocaryon irritans from South-East Queensland, Australia. European Journal of Protistology 33: 200-210. http://www.urbanfischer.de/journals/frame_template.htm?/journals/ejp/e-protis.htm
Diggles, B. K. and Adlard, R. D. (1997). Intra-specific variation in Cryptocaryon irritans. Journal of Eukaryotic Microbiology 44: 25-32. http://www.jeukmic.org/Current_Issue.html
Diggles, B. K. and Lester, R. J. G. (1996a). Influence of temperature and host species on the development of Cryptocaryon irritans. Journal of Parasitology 82: 45-51.
Diggles, B. K and Lester, R. J. G. (1996b). Variation in the development of two isolates of Cryptocaryon irritans. Journal of Parasitology 82: 384-388.
Diggles, B. K. and Lester, R. J. G. (1996c). Infections of Cryptocaryon irritans on wild fish from South-East Queensland. Diseases of Aquatic Organisms 25: 159-167. http://www.int-res.com/abstracts/dao/v25/n3/index.html
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Diggles, B. K. and Adlard, R. D. (1995). Taxonomic affinities of Cryptocaryon irritans and Ichthyophthirius multifiliis inferred from ribosomal RNA sequence data. Diseases of Aquatic Organisms 22: 39-43. http://www.int-res.com/abstracts/dao/v22/n1/index.html
Roubal, F. R. and Diggles, B. K. (1993). The rate of development of Polylabroides multispinosus (Monogenea : Microcotylidae) parasitic on the gills of Acanthopagrus australis (Pisces : Sparidae). International Journal for Parasitology 23: 871-875. http://www.sciencedirect.com/science
Diggles, B. K., Roubal, F. R. and Lester, R. J. G. (1993). The influence of formalin, benzocaine and hyposalinity on the fecundity and viability of Polylabroides multispinosus (Monogenea : Microcotylidae) parasitic on the gills of Acanthopagrus australis (Pisces : Sparidae). International Journal for Parasitology 23: 877-884. http://www.sciencedirect.com/science
Client reports, popular articles and other work related outputs (selected recent publications listed chronologically from 2000 to provide examples of the range of work experience)
Diggles BK, Landos M (2012). Literature Review. Best practice in humane dispatch of finfish caught by recreational anglers. DigsFish Services Client Report DF12-01. Prepared for Commonwealth of Australia , Department of Agriculture, Fisheries and Forestry. February 2012. 20 pgs.
Diggles BK (2011). Water quality testing: Gladstone Harbour, QLD, October- Nov 2011. DigsFish Services Client Report DF11-06. December 2011, 14 pgs.
Diggles BK (2011). Abalone Farms Australia Biosecurity Assessment and Disease Risk Analysis. DigsFish Services Client Report DF11-05. December 2011, 58 pgs.
Diggles BK (2011). Biosecurity Assessment – Cawthron Aquaculture Research Facility. Phase 2, Risk management plan for shellfish diseases. DigsFish Services Client Report DF11-04. December 2011, 113 pgs.
Diggles BK (2011). Biosecurity Assessment – Cawthron Aquaculture Research Facility. Phase 1, OsHV-1 of Pacific Oysters. DigsFish Services Client Report DF11-03. October 2011, 43 pgs.
Diggles BK (2011). Declines of bivalve molluscs in Australian estuaries – disease or declining water quality ? Paper presented at the 1st Australasian Scientific Conference on Aquatic Animal
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Health 5 - 8 July, 2011, Pullman Reef Hotel, Cairns, Queensland, Australia. http://www.digsfish.com/digsfish%20oyster%20talk.pps
Diggles BK (2011). The case for moderation of marine bioregional planning processes in Australia. A submission to the Parliamentary Inquiry into the Environment Protection and Biodiversity Conservation Amendment (Bioregional Plans) Bill 2011. https://senate.aph.gov.au/submissions/comittees/viewdocument.aspx?id=a13cb113-cc9b-4bec- 998d-e10f16bf397a
Diggles BK (2010). Pathological assessment of groper from Mahanga Bay, February 2010. DigsFish Services Client Report DF10-02. February 2010, 13 pgs.
Diggles BK (2010). Review of the literature used by DEWHA to underpin declaration of the Coral Sea Conservation Zone. DigsFish Services Client Report DF10-01. Prepared for Marine QLD. 28 January 2010. 30 pgs. . http://www.marineqld.com.au/sites/default/files/DigsFish%20Services%20Report%20for%20Mar ine%20Qld.pdf
Diggles BK (2009). Fish Kill, Biggs Ave , Beachmere QLD 24-25 November 2009. DigsFish Services Client Report DF09-11. 30 November 2009, 26 pgs.
Diggles BK (2009). East Quarry Hard Rock Project – Assessment of Potential Fish Health interactions with Hebden Fish Farm. DigsFish Services Client Report DF09-04. June 2009, 33 pgs
Diggles BK (2008). Histopathological assessment of paua from Southern Marine Farms, January 2008. DigsFish Services Client Report DF08-01. February 2008, 8 pgs.
Diggles BK (2007). Risk assessment for translocation of Pacific oyster (Crassostrea gigas) seed spat from Shellfish Culture sites in Tasmania into NSW. DigsFish Services Client Report DF07-09. August 2007, 37 pgs
Diggles BK (2007). Scientific submission to AQIS supporting an application for an import permit allowing entry of whole, round menhaden (Brevoortia tyrannus) for use as lobster bait. DigsFish Services Client Report DF07-01. January 2007. 39 pgs.
Diggles BK (2006). Methods for health assessment of sand crabs. DigsFish Services Client Report DF06-08. April 2006. 18 pgs.
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Diggles BK (2006). Pathology of Salmon subjected to PIT tagging – trial 2. DigsFish Services Client Report DF06-06. March 2006. 8 pgs
Diggles BK (2006). Pathology report for Sydney Rock Oyster spat from Port Stephens. DigsFish Services Client Report DF06-04. February 2006. 7 pgs
Diggles BK (2005). Investigations into mortalities of scallop (Amusium balloti) spat. DigsFish Services Client Report DF05-17. September 2005. 6 pgs
Diggles BK (2005). Scuticociliate infection of kingfish and hapuku. DigsFish Services Client Report DF05-13. July 2005. 9 pgs
Diggles BK (2005). Testing of Pacific oyster spat for herpesvirus. DigsFish Services Client Report DF05-10. May 2005. 7 pgs
Diggles BK (2004). Assessment of liver pathology of Chinook salmon (Oncorhynchus tshawytscha) fed two diets. DigsFish Services Client Report DF04-36. September 2004, 10 pgs.
Diggles BK (2004). CASE REPORT: Histopathology of internal organs of juvenile salmon (Oncorhynchus tshawytscha) from Kaituna. DigsFish Pathology Services Pathology Report. DF04- 32. August 2004. 4 pgs
Diggles BK, Maas E (2004). Cook Islands Pearl Oyster and Lagoon Health Monitoring Programme, December 2003. NIWA Client Report WLG2004-24. April 2004, 48 pgs.
Diggles BK (2004). Parasites as potential stock discriminators of kingfish (Seriola lalandi). DigsFish Pathology Services Client Report DF04/13. April 2004, 12 pgs.
Diggles BK (2004). Design and costing of a survey for OIE List diseases in commercially important shellfish (Mollusca) in New Zealand. DigsFish Pathology Services Client Report DF04/12. March 2004, 27 pgs.
Diggles BK (2004). Survey of dredge oysters (Ostrea chilensis) from Foveaux Strait for Bonamiosis, oyster condition and other concurrent infections. DigsFish Pathology Services Client Report DF04/11. March 2004, 15 pgs.
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Diggles BK (2004). Parasites as potential stock discriminators of blue mackerel (Scomber australasicus). DigsFish Pathology Services Client Report DF04/10. March 2003, 12 pgs.
Diggles BK (2004). Health assessment of cultured kingfish (Seriola lalandi) from Crail Bay, January 2004. DigsFish Pathology Services Client Report DF04/ 03. January 2004, 17 pgs.
Diggles BK (2004). Identification of nematodes from seacaged Chinook salmon (Oncorhynchus tshawytscha). DigsFish Pathology Services Client Report DF04/ 02. January 2004, 6 pgs.
Diggles BK (2003). Histopathological assessment of paua from Stewart Island. DigsFish Pathology Services Client Report DF03/ 03. December 2003, 7 pgs.
Diggles BK (2003). Histopathological assessment of paua from NIWA Mahanga Bay, November 2003. DigsFish Pathology Services Client Report DF03/ 01. November 2003, 6 pgs.
Diggles B.K. (2003). Parasitological and pathological inspection of Macrobrachium rosenbergii from NZ Prawns Ltd. Pathology report prepared for NZ Prawns Ltd, Taupo, June 2003. 4 pgs.
Diggles B. K. (2003). NSW flat oyster (Ostrea angasi) disease survey. Final report - November 2003. NIWA Client Report AUS 2003 - 01, November 2003, Prepared for NSW Fisheries, NIWA Project NAU 04906, 19 pgs.
Diggles B. K. (2003). Shellfish Disease Surveillance Programme - Final Report June 2003. NIWA Client Report AUS 2002 - 018, June 2003, Prepared for PIRSA, NIWA Project NAU 03911, 24 pgs.
Diggles B. K. (2003). Shellfish Disease Surveillance Programme - Preliminary Report May 2003. NIWA Client Report AUS 2002 - 014, May 2003, Prepared for PIRSA, NIWA Project NAU 03911, 13 pgs.
Diggles B. K. (2003). Shellfish Disease Surveillance Programme - Preliminary Report March 2003. NIWA Client Report AUS 2002 - 010, March 2003, Prepared for Primary Industries and Resources, South Australia, NIWA Project NAU 03911, 8 p.
Dunn, A., Michael, K. P., Forman, J. S. and Diggles B. K. (2003). Estimates of intensity and prevalence of infection by Bonamia exitiosus in oysters for selected sites in Foveaux Strait in February 2003. Final Research report no. WLG2003-10, for BOM 03301, March 2003. 25 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
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Bruce, M., Diggles, B., Herbert, N. and Jeffs, A. (2003). The potential use of bovine colostrum in aquaculture. NIWA Client report AKL 2003-016, February 2003, Prepared for Fonterra Tech, NIWA project KTL 02101. 18 p.
Macaulay, G., Hart, A., Grimes, P., Diggles, B. K., Bull, B. (2002). Target strength estimates of hoki and associated species. Final research report for Ministry of Fisheries Research Project HOK2000/03, Objective 3. November 2002. 33 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Diggles, B. K. (2002). Import Risk Assessment: Juvenile yellowtail kingfish (Seriola lalandi) from Spencer Gulf Aquaculture, South Australia. NIWA Client report WLG 2001/03, July 2002. Prepared for Island Aquafarms Ltd. 54 p. http://www.maf.govt.nz/biosecurity/pests- diseases/animals/risk/yellowtail-kingfish-ra.pdf
Hickman B, Tait M, Redfearn P, Moss G, Allen S, Poortenaar C, Diggles B, Maas E, Carton G (2002). Progress towards kingfish farming in New Zealand: a report on the kingfish larval rearing programme 2001/02. NIWA Client report AK02088, July 2002, prepared for Moana Pacific Fisheries Ltd. 20 p.
Diggles, B. K. and Oliver, M. (2002). Investigation of the epidemiology of a haplosporidian parasite infecting cultured paua Haliotis iris. Final research report for Ministry of Fisheries Research Project MOF 2001/03, Objective 1. June 2002. 12 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Diggles, B. K. and Hine, P. M. (2002). Bonamia epidemiology in Foveaux Strait oysters. Final Research Report for Ministry of Fisheries Research Project OYS 1999/01/other services. June 2002. 52 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Dunn A., Michael, K. P., Parsons, M., Diggles, B. K. (2002a). Updated estimates of the commercial population size, yields and estimates of the intensity and prevalence of infection by Bonamia exitiosus in Foveaux Strait oysters for selected sites in Foveaux Strait in March 2002. Final research report for Ministry of Fisheries Research Project MOF 2001/03L Objectives 1 and 2, July 2002. 20 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Dunn A., Michael, K. P., Parsons, M., Diggles, B. K. (2002b). Estimates of prevalence and intensity of infection of Foveaux Strait oysters by Bonamia exitiosus for selected sites in Foveaux Strait in
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January 2002. Final research report for Ministry of Fisheries Research Project MOF 2001/03I, February 2002. 16 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Michael K, Dunn A, Diggles B (2002). Foveaux Strait: Bonamia is back - a setback for the rebuilding Bluff oyster fishery. Seafood New Zealand August 2002: 44.
Smith, P, Diggles, B. K., Bull, B. and Benson, P. (2001). Stock relationships of alfonsino and cardinalfish in New Zealand waters. Final Research report for Ministry of Fisheries Research Project DEE1999/03, objective 2. September 2001. 50 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Diggles, B. K. and Tait, M. (2001). Mortality of eels (Anguilla australis) in a water recirculation system. NIWA Client report WLG 2001/92 prepared for Wiptec Aquaculture Ltd, December 2001. 8 p.
Oliver M, and Diggles BK (2001). Condition assessment of CRA8 lobsters from Bluff Holding facility. NIWA Client report WLG 2001/95 prepared for Ngai Tahu Fisheries Ltd. December 2001. 12 p.
Michael, K. P., Dunn, A., Parsons, M., Diggles, B. K. Cranfield, H. J. (2001). Preliminary analysis of Foveaux Strait oysters and associated infection by Bonamia exitiosus. Final Research report for Ministry of Fisheries Research Project OYS 2000/01. 25 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Diggles, B. K and P. M. Hine (2001). Mortality of black-lip pearl oysters (Pinctada margaritifera) in Manihiki Lagoon. NIWA client report no. WLG 01/5 prepared for The Ministry of Marine Resources, Government of the Cook Islands. 36 p.
Diggles BK and Hine PM (2001). The distribution of Perkinsus olseni in New Zealand bivalve molluscs. NIWA Client Report: WLG 01/46 prepared for The Ministry of Agriculture and Forestry Biosecurity Authority, July 2001, 15 p.
Diggles, B. K. (2001). A paua parasite problem ? Aquaculture Update 28: 3.
Dunn, A., Hine, P. M., Diggles, B. K., and Andrew, N. L. (2001). The oyster and the parasite. Seafood New Zealand, June 2001. 9(5): 46-47.
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Smith, P., Proctor, C., Robertson, S., McMillan, P., Bull, B. and Diggles, B. (2000). Stock relationships of black oreo in New Zealand waters. Final Research Report for the Ministry of Fisheries Research Project DEE9801 Objective 1 (Part two). November 2000. 40 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
Dunn, A, Michael, K. P., Hine, P. M., Andrew, N. L., Diggles, B. K. and Cranfield, H. J. (2000). Analysis of a survey of the prevalence and intensity of Bonamia sp. in Foveaux Strait oysters. New Zealand Fisheries Assessment Report 2000/32, September 2000.
Diggles, B. K. (2000). Final report on the parasites and pathological lesions of yellowbelly flounder Rhombosolea leporina and their relationship with contamination in Manukau Harbour. NIWA Client Report WLG 2000/29 prepared for the Auckland Regional Council. 14 p.
Diggles, B. K., Chang, H., Smith, P., Uddstrom, M. and Zeldis, J. (2000). A discolouration syndrome of commercial bivalve molluscs in the waters surrounding the Coromandel Peninsula. Final report for the Ministry of Fisheries Research Project MOF 1999/04B, January 2000. 30 p. (Unpublished report held by the Ministry of Fisheries, Wellington).
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