20Th February 2019 Richard Hook Acting Team Leader
Total Page：16
File Type：pdf, Size：1020Kb
20th February 2019 Ref: 1215/19 Richard Hook Acting Team Leader – Approvals Development Assessments EPA Victoria 200 Victoria Street CARLTON 3053 By email 20th February 2019 Dear Richard, We note from the Engage Victoria web site Yumbah Aquaculture’s response to EPA’s s22 Notice of 18th January 2109. As there are a number of, in our view, inaccurate assertions contained in the response, especially regarding DigsFish Services analysis, we attach, for your information, a copy of their review. The wild catch abalone fishery remains of the view that adequate protection should be afforded to the state’s natural abalone resource from the possibility of disease being introduced to the marine environment through inadequate treatment of effluent from Yumbah’s proposed land-based farm. Yumbah states that the operation ‘can sustain abalone survival for weeks, if not months on water recirculation reservoirs’. If the operation can be sustained on recirculated water for weeks or months then for added protection design should be extended to incorporate such a system, at least, for the summer months when elevated water temperatures could lead to heightened risk. We also have concerns about Yumbah’s statement that ‘relying on recirculation capabilities provides a significant opportunity to reduce the concentration of AVG entering the ocean’. This seems a blatant statement that AVG could be discharged into the ocean (albeit at reduced concentrations) with the risk that wild abalone could become infected. This reinforces industry’s opinion that the proposed effluent treatment is inadequate to provide protection to the marine environment, and in particular the wild catch abalone fishery, and is an area of Yumbah’s operation that needs to be challenged, reviewed and strengthened. _________________________________________________________________________________ DigsFish Services Pty Ltd Ph/fax +61 7 3408 8443 32 Bowsprit Cres, Banksia Beach mob 0403 773 592 Bribie Island, QLD 4507, [email protected] AUSTRALIA www.digsfish.com _________________________________________________________________________________ 14 February 2019 re: Yumbah Response to VIAC Submission Abalone Industry Committee, Dear Thanks for providing me with a copy of the letter from Yumbah Aquaculture regarding the submission made by the Victorian Abalone Industry Committee. I wish to correct some inaccurate assertions contained in their letter regarding my independent assessment of the disease risks to the wild fishery (DigsFish 2018) that accompanied the VAIC submission. Over the past 20 years I have produced biosecurity reports for many abalone farms operated by various companies in Tasmania, South Australia and New Zealand, but never in Victoria. However, in no prior instance was I asked to assess disease risks posed to wild fisheries adjacent to these farms. The Yumbah Aquaculture proposal is the first instance where I was asked to specifically consider the question of spillback infection of wild abalone. My assessment of the AVG outbreak on an abalone farm in Bicheno (Diggles 2011) suggested it was infected by intake of virus particles originating from the effluent water from an AVG outbreak in a nearby abalone processing facility. This opinion was supported by others (e.g. Ellard 2011, Ellard et al. 2011, Baulch et al. 2013). Under normal operational circumstances the risk of an AVG outbreak on a typically sized abalone farm which is not adjacent to an abalone processing plant is indeed extremely low, however biosecurity risk analyses for specific aquaculture farms are done on an individual basis taking into account the specific circumstances of each farm (such as location, water temperature, farm layout, biosecurity protocols, and so on). Furthermore, as time moves on scientific knowledge of disease processes improves, and this is particularly the case with AVG given the significant quantity of scientific information published on this disease since 2011 (see the references in DigsFish 2018). In the present case, the Yumbah Aquaculture proposal represents a very large-scale farm, much further north than Bicheno, in an area with a known history of clinical AVG in adjacent wild abalone populations, while the risk being assessed was not the disease status of the abalone inside the farm, but the disease status of wild abalone that may be exposed to effluent water from the farm. The specific circumstances discussed in DigsFish (2018) are, therefore, very different to those assessed in Diggles (2011). As was pointed out in my assessment of the Yumbah aquaculture proposal, subsequent generic risk assessments done by the Tasmanian Government, Federal Government and others since 2011 (see references cited in DigsFish 2018) have found that discharge of untreated water from abalone farms and holding facilities into the marine environment is, in general, a high risk activity with potential for high (regionally significant) to extreme consequences, including spread of AbHV into the environment adjacent to abalone farms which could result in outbreaks of AVG disease in wild abalone populations. While I did not help develop those other analyses, I concur with the assessments by others in a general sense, though of course the particular farm risk profiles will vary in each case depending on specific risk factors such as the location, water quality, size and layout of each farm and the particular biosecurity processes employed therein. I note that the letter from Yumbah Aquaculture stated that my assessment m ade “ general assertions … that treatment of intake and discharge water should be a mandatory requirement at abalone farms ” , and “ specifies that treatment of intake and outlet water shou ld be mandatory in abalone farming ” . This is incorrect . T he word mandatory was not used in my assessment except to describe “ Mand atory annual audits carried out by government Veterinary Officers ” . Inst ead, I wa s referring to the fact that treatment of efflue nt water is widely recognised as best practice for all forms of aquaculture , including abalone farming . Interestingly, the recent N ational B iosecurity Plan Guidelines developed for abalone farms in August 2018 (Spark et al. 2018) stated the following on page 20 : R46. Treat incoming water appropriately (for example, screens on intake pipes, filtration) to minimise the risk of disease/pest entry a nd R47. Treat discharge water from dedicated quarantine facilities appropriatel y to minimise the risk of disease/pest establishment in the marine environment. The document by Spark et al. (2018) was originally based upon a generic templa te produced by the Sub - Committee on Aquatic Animal Health (SCAAH 2016 ) in late 2016 . Th e templa te of SCA A H (2016) is utilised across all aquaculture industries in Australia . The gen eric document states on page 21 that “ a ppropriate discharge of water will need to be considered wher e there is a risk of spreading infection to nearby populations of wil d aquatic animals or other nearby farms ” . Th is generic document , which represents a general, nationwide approach to aquacultu re best practice , therefore does not discriminate between discharge from different parts of an aqu acu lture facilit y when discussin g the risk of spreading infection to populations of wild aquatic animals. The decision by the abalone industry to adjust this general advice to one of treatment of “ discharge water from dedicated quarantine facilities only ” , is one of convenience and th us increase s risk of spillba ck infection of wild animals in any instance where there is a disease outbreak on the growout side of a facility (and the vast majority of a nimals and water flow in any aquaculture farm are fou nd in the growout tanks). I note that the letter from Yumbah Aquaculture di sagreed with my statement that “ The prevalence and virulence of AVG and Perkinsis (sic) is likely to increase with increased temperature and climate change ” . This statement that disease s become more problematic in molluscs at high er water tempera tures is backed by abundant scientific proof in the case of almost every significant diseas e of molluscs , for not only AbHV ( the herpesvirus that causes AVG ) and P erkinsus (e.g. Cook et al. 1998) , but the agent causing withering syndrome of abalone ( Moore et al. 20 00 , Rogers - Bennett et al. 2010) , and other herpesvirus es in oysters ( P ernet et al. 2015) . The underlying problem is generally one of increased physiological stress (such as reduced oxygen availability) combined with increased rates of viral and parasitic multip lication at higher water temperatures , which precipitate s diseas e . The fact that high water temperatures activat e latent infections to cause “ summer mortalities ” is well known for molluscan herpesviruses , and f or AbHV, Corbeil et al. ( 2016 ) state d “ perhap s the Tasmanian virus variants remain sub - clinical in Tasmanian wild abalone because environmental conditions (for example, water tem perature) favour a latent or persistent infection. It would be interesting to hold a large number of wild Tasmanian abalon e in the laboratory at slightly warmer temperatures than those recorded in Tasmanian waters, and look for evidence of reactivation of possible latent infections . ” In the case of Perkinsus olseni , th e original outbreaks of P erkinsosis disease in wild abalo ne in South Australia and NSW both originated in years when water temperatures were higher than normal , probably because “ stress such as high temperature predisposed the abalone to disease ” ( Goggin and L ester 1995) . Furthermore, P . olseni has recent ly bec ome problematic in some of the a balone farms I have visit ed in N ew Zealand , but only in summer in f arm s operating in the far northern part of the country whe n water temperatures exceed 20 °C . This has been attr ibuted by the owners of the affected far m s to g r adually in creasi ng intake water temperatures and long er periods during which w a t e r temperatu res e xceed 20°C . Therefore, these links between increased temperature s and increased prevalence or virulence of AVG and Perkins os is are not speculative , but are st rongly backed by emp irical data and peer reviewed science.