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Overview of Marine Biosecurity Risks from Finfish Aquaculture Development in the Waikato region

TR 2011/22

Report: TR 2011/22

Author: Cawthron Institute: Barrie Forrest, Grant Hopkins, Steve Webb, Louis Tremblay.


Interest in the development of finfish aquaculture in the Firth of Thames and southern Hauraki Gulf has led to the allocation by Waikato Regional Council of c. 390 ha of water space for ‘fed aquaculture’. The primary use of this zone is expected to be the culture of yellow tail kingfish (Seriola lalandi lalandi) and hapuku (groper, Polyprion oxygeneios).

The council contracted the Cawthron Institute to undertake a preliminary desktop assessment of the marine biosecurity issues that could be associated with the culture of these species, to inform decision-making as the industry develops.

 This report presents a broad discussion of biosecurity hazards, in which our definition of biosecurity relates to any marine pest , pathogen or parasite with the potential to adversely affect the uses and values of the Waikato region. Internationally, these groups of biosecurity risk organisms have all been known to cause adverse effects on finfish culture operations or the wider environment.

Overview of Marine Biosecurity Risks from Finfish Aquaculture Development in the Waikato region [PDF, 1.5 MB]

  Executive summary i
1 Introduction 1
1.1 Background 1
1.2   Definition of terms and scope of report 1
Overview of potential developments 3
2.1  Finfish culture locations 3
2.2   Background on candidate species 5
Overview of regional values and biosecurity HAZARD PATHWAYS 6
3.1  Values of the Waikato region 6
3.2 Framework for assessing biosecurity risks to Waikato values 7
Marine pests and biosecurity risks 9
4.1  Background 9
4.2   Potentially high risk marine pests 9
4.2.1  Aquaculture-related fouling pests 11
4.2.2   Other non-indigenous or cryptogenic fouling or benthic pests 13
4.2.3 Indigenous fouling pests 14
4.2.4 Harmful algal bloom (HAB) species 15
4.3 Marine pest infection pathways for finfish culture sites. 17 
4.3.1.     Pathway overview 17
4.3.2. Finfish culture pathways for marine pests 18
4.3.3. Non-finfish culture pathways for marine pests 21
4.4.   Spread or enhancement of marine pests by finfish culture 22
4.4.1.   Spread of marine pests from infected finfish farms 22
4.4.2.    Exacerbation of marine pests 25
5.   Pathogens and parasites 28
5.1.   Background 28
5.2.    High risk pathogens 28
5.2.1.    Kingfish 28
5.2.2. Hapuku (Polyprion oxygeneios) 31
5.3.     Infection pathways for marine pathogens and parasites 32
5.3.1.   Finfish culture pathways of pathogens and parasites 34
5.3.2. Non-finfish culture sources of pathogens and parasites 36
5.4.   Spread or enhancement of marine pathogens and parasites by finfish culture 38
5.4.1. Overview 38 
5.4.2.   Direct spread by natural dispersal and fish or bird interactions 40
5.4.3.    Implications for wild fish populations 41
5.4.4.   Shellfish/finfish culture disease interactions 42 
5.4.5.   Other processes leading to the spread or exacerbation of disease agents 43
6.   Iplications for Waikato region values 44 
6.1.   Overview 44
6.2.      Approach used to assess effects on Waikato region values 45 
6.3.   Marine pest: hazards x values 46
6.4.    Pathogens and parasites: hazards x values 50
7.   Mitigation of risks to Waikato region values 51
7.1.   Overview 51
7.2.    Points of intervention for mitigation 52
7.3.   Pathway management 52
7.3.1.  Culture-related stock and feed transfers 53
7.3.2.   Culture-related transfers of equipment and vessels 53
7.3.3.   Efficacy of pathway management 54
7.4.    Surveillance and response to incursions/outbreaks 54
7.4.1.  Macroscopic marine pests 54
7.4.2.  HAB species 56
7.4.3. Pathogens and parasites 56
7.5.   Farm spacing as a mitigation tool 58
8.  Environmental implications of therepeutant use for pathogen or parasite control 61
9.   Conclusions and further considerations 65
10.   Acknowledgements 67
11.     References 67