Risk analysis to identify and minimise biosecurity risks arising from recycling bivalve mollusc shell waste during shellfish reef restoration projects in Australia
Understanding Ostreid herpesvirus type 1 risk: alternative hosts and in situ hybridisation
Risk from Diarrhetic Shellfish Toxins and Dinophysis to the Australian Shellfish Industry
Sentinel sensors: revolutionising our understanding and management of the estuarine environment
Assessing occurrence of pathogenic species of the marine bacteria Vibrio in Tasmanian oysters from St Helens
This is the first time that an illness associated with Vibrio has been traced-back to Tasmanian oysters. Regrettably, this incident occurred in the only major harvesting area in Tasmania that has not been impacted by the current Pacific oyster mortality event.
In Australia the control of Vibrio is currently limited to temperature controls during storage or transport. Pre-harvest controls used by the shellfish quality assurance programs are predicated on controlling risk posed by faecal contamination and biotoxins and are not suitable for controlling risk from these naturally occurring bacteria. Although the recent implementation of the Codex Standard for pathogenic marine vibrios suggests risk in bivalve growing areas should be assessed to ascertain the risk to public health, there has been limited research undertaken in Australia. The studies undertaken to date have generally been short in nature with no comprehensive longitudinal studies being undertaken and methodologies have now progressed significantly, whereas New Zealand has been undertaking a long-term survey to understand the risk posed by these pathogens (Cruz, Hedderley & Fletcher 2015). This issue may become a risk in accessing key markets that are active in monitoring or who regulate for these pathogens.
There is an immediate need to collect information on prevalence for the remainder of the summer period to understand the risk and evaluate if there is a relationship to salinity, temperature and toxic strains. This information will be immediately useful for developing appropriate management plans in this growing region.
This illness outbreak will likely result in Tasmanian Shellfish Quality Assurance Program and the other state programs having to consider how to manage risk in the growing areas and establish what is an acceptable level. The work proposed here could be used as a framework for future work that assesses risk across the bivalve industry Australia-wide.
Final report
Improved understanding of Tasmanian harmful algal blooms and biotoxin events to support seafood risk management
The 2012 Tasmanian biotoxin event represents a paradigm shift for seafood risk management in Tasmania and Australia as a whole. The causative dinoflagellates are extremely difficult to identify by routine plankton monitoring, and are toxic at very low cell concentrations (50-100 cells/L) . Sampling the extensive Tasmanian coast line poses a major logistical challenge, with early hints that the blooms originate offshore. The precise pathway of toxin transfer to rock lobster is unclear. The presence of cyst beds suggest that problems will persist .
Final report
The 2012 Tasmanian biotoxin event represents a paradigm shift for seafood risk management in Tasmania and Australia as a whole. The causative dinoflagellates are extremely difficult to identify by routine plankton monitoring, and are toxic at very low cell concentrations (50-100 cells/L). Sampling the extensive Tasmanian coast line poses a major logistical challenge. This project sought to improve the understanding of Tasmanian harmful algal bloom biology, ecology and toxicology to support seafood biotoxin risk management.
Seafood CRC: new opportunities for seafood processing waste
Tackling a critical industry bottleneck: developing methods to avoid, prevent and treat biofouling on mussel farms
Biofouling has emerged as the main bottleneck to production in the mussel farming industry. For example, since 2003, mussel production has declined by approximately 50% in Victoria. Concurrent with this decline has been the rise of several problematic biofouling species, including the invasive hydroid (Ectopleura crocea), the invasive sea star (Asterias amurensis), and several ascidian and algal species. Many of these biofouling taxa are common across Victorian, South Australian, Western Australian, Tasmanian and New South Wales mussel farms. Combined, these biofouling species are believed to have had a range of effects on production, including: 1) reducing natural mussel spat settlement rates; 2) preying upon mussel spat and juveniles; 3) competing for food with mussels; and 4) smothering established mussels.
A clear need exists to develop methods to avoid, prevent and treat biofouling to reduce costs and improve production. Typically, biofouling management accounts for 30-40% of production costs. Current biofouling removal methods (stripping of lines or fresh-water baths) are time consuming and labour-intensive. As a consequence, biofouling often develops to damaging levels before farmers are able to remove it.
Farmers require knowledge of the timing, location and depth of key fouling species so biofouling outbreaks can be avoided. Further, there is a need to test whether the type of equipment used (e.g., rope type and colour) or its arrangement (dropper spacing and dropper depth) may reduce biofouling. As some biofouling will inevitably develop on mussel lines, new biofouling treatments that are cheap, easy to use and effective must be tested. These include acetic acid, hot water baths, high pressure hot air and their combinations. Acetic acid has proved promising against many biofouling species in the New Zealand mussel industry, but has not been trialled on key biofouling species in southern Australian waters (e.g. hydroids).
Final report
Biofouling negatively affects shellfish production through several pathways, including: 1) reducing natural mussel spat settlement rates; 2) preying upon mussel spat and juveniles; 3) competing for food with mussels; and 4) smothering established mussels. These problems are well documented in the culture of other bivalves such as oysters and scallops, where water flow is restricted to such an extent by fouling organisms that the availability of food and growth of stock are impeded (Claereboudt et al. 1994; Taylor et al. 1997). However, the effects of fouling organisms in long-line mussel culture remain poorly known (LeBlanc et al. 2003). Various native ascidians, hydroids, tunicates, macroalgae and seastars are common biofoulers across the mussel farming industry in Australia’s southern waters. In Victoria, as in other parts of the world, introduced species are also emerging as key pests.
At present, Australian farmers deal with biofouling reactively, with treatment strategies implemented only after outbreaks have occurred. Current treatment protocols are largely based on a 2001 study in Victoria investigating measures to reduce the risk of moving noxious aquatic species via aquaculture stock or equipment (Gunthorpe 2001). Individual farmers have tried several methods on an ad-hoc basis to try to manage their fouling loads but they do not have the time or resources to carry out rigorous scientific testing and trials. Similarly, they are not aware of the basic biology or life history of the fouling species they are dealing with, and have no documented monitoring program in place to assess when fouling episodes are to be expected, and what species to be on the lookout for. Effective strategies to control biofouling must integrate information over the complex of biofouling species and their various effects. As fouling will always develop on mussel lines, it is important to develop and test cheap, easy to implement on-farm treatments that are effective against a range of biofouling species that do not affect mussel production.
Seafood CRC: overseas market access for shellfish
The potential reduction of regulatory thresholds for marine biotoxins in the EU will have significant negative economic consequences for the Australian oyster, mussel, scallop and abalone industries (and pipi’s if domestic regulatory thresholds also changed).
The scallop, oyster and mussel industry currently export product to the EU. Total scallop exports to the EU in 2006/2007 were valued at around $4,551,000 AUD (187 t). Other mollusc (including oysters and mussels) exports to the EU in 2006/2007 were around $1,084,000 AUD (255 t). Due to the periodic occurrence of okadaic acid toxins and saxitoxins in Australian shellfish the implementation of reduced regulatory levels would reduce the amount of product eligible for export to the EU.
Exports of Australian abalone to the EU ceased in 2007, this was in part due to the enforcement of marine biotoxin regulatory limits by the EC. The wild caught abalone industry is attempting to regain market access to the EU through determining alternate risk management procedures for marine biotoxins in abalone. The reduction of regulatory levels for marine biotoxins may impinge on future EU access arrangements for Australian abalone.
Experience has repeatedly demonstrated that European decisions can impact on other more commercially significant markets, including Asia and the domestic market. Codex may also be prompted to change marine biotoxin guidance levels in response to EU changes. Wide spread adoption of reduced regulatory levels for marine biotoxins would result in increased growing area closures in Australia and less product eligible for sale. This proposal aims to assist in maintaining the current EU regulatory limits for marine biotoxins which will allow the current amount of shellfish to be exported to the EU and avoid other markets being influenced.
Final report
The oyster, scallop and mussel industries currently export product to the EU. Due to the periodic occurrence of Okadaic Acid (OA) and Saxitoxin (STX) group toxins in Australian shellfish the implementation of reduced regulatory levels would reduce the amount of product eligible for EU export. Exports of Australian abalone to the EU ceased in 2007, due in part to the enforcement of marine biotoxin regulatory limits set by the EC. The wild caught abalone industry is attempting to regain EU market access through determining alternate risk management procedures for marine biotoxins in abalone.
The European Commission (EC) requested the European Food Safety Authority (EFSA) to assess the current European Union (EU) limits for shellfish regarding human health and methods of analysis for various marine biotoxins, including newly emerging toxins. A critical recommendation of the ‘EFSA Opinions’ is that the regulatory limits should be significantly lower (more stringent) for both OA and STX.
The objectives of this study were to:
- Undertake a robust technical review of the EFSA risk assessments on STX and OA group toxins.
- Submit the technical review and a rationale for maintaining current marine biotoxin regulatory limits to the EC.
- Convene a working group to determine future steps required to mitigate potential lowering of marine biotoxin regulatory limits.
Australian Mussel Association - formation and levy setup
Aquaculturists, fishers and seafood producers must be increasingly sophisticated to secure and manage their access rights to natural resources, positively respond to community interest in their activities, and viably compete in domestic and overseas markets. As a small emerging sector mussel growers currently have no aggregate capacity to address these risks relevant to their industry. Resolution of these challenges is increasingly beyond the scope of any single mussel enterprise or regional / state based group of interests.
A national industry body is a critical first step to promote effective industry and stakeholder communication, enable representation of grower and stakeholder views, develop knowledge and strategic direction and related action plans, enable cost effective investment in and management of reserch and development funds, and facilitate industry's growth. As an emerging sector, the mussel industry currently has no formal plans or development strategies.
Emerging sectors also suffer from lack of funds to grow their businesses and conduct critical research that will deliver market competitive advantages. They also need to overcome the market failure that accompanies early stage investment in shared research outcomes. By working with groups of national producers, the FRDC can provide and / or facilitate very cost effective pools of R&D funding, and a secure and pragmatic platform for industry members to jointly invest in, manage, and share the benefits of critical R&D.
Final report
Towards reliable hatchery-produced quality blue mussels: an integrated approach to optimising supply
Tasmania in 2005/06 was the largest producer of mussels in Australia; 31% of production and 42% of dollar value. This represents a three-fold increase in production and value of mussels in Tasmania over the past three years. Further to this, Spring Bay Seafoods is Australia largest mussel producer and processor; with consider capital investment into mussel production and processing. This project will directly address the issues of high and unpredictable mortality rates of blue mussel seed during the early nursery phase. There is a need in the hatcheries to develop techniques and approaches that maximise production of quality mussel seed, through informed decisions about how physical and biological conditions in the hatchery affect the health and growth of spat.
World-wide, mussel aquaculture ventures are largely supported by collection of wild juveniles. Several commercial shellfish hatcheries, in USA and Australia, produce small numbers of juvenile mussels to supplement wild collections. Until recently the demand and value of mussels has been too poor to warrant large scale hatchery production, and most shellfish hatcheries focus on higher value species, or species for which wild collection of juveniles is not possible, eg introduced oysters. Collection of spat from the wild imposes critical limits to the capacity of the mussel aquaculture industry to increase production and to control product quality and timing of supply to markets. Reliance on wild spat leaves the industry vulnerable to recruitment failure and restricts production to seasonal availability. In recent years there has been insufficient wild spat settlement to meet the demands of the expanding Tasmanian aquaculture mussel industry. The only way that the mussel industry can begin to compete against imported products and allow Australian consumers access to Australian product is through reliable hatchery production of quality-assured spat.
Final report
Aquatic Animal Health Subprogram: enhancement of the emergency disease management capability in Victoria - developing a Victorian Control Centres Management Manual
Improving Post Harvest Handling to add value to farmed mussels
There is a number of mussel farmers who have little knowledge on size grading and grading of mussels in relation to a condition index so that only good mussels with a satisfactory quality and shelf life are forwarded to market.
There is a need to identify the key quality and marketing parameters to prepare product specification for premium and standard grade mussels as a prerequisite for the development of a Code of Practice to guide growers, packers and marketers. This Code needs to cover handling, grading, packing, storage and transport of mussels to maximise quality and safety, shelf life and value of the mussels for industry and consumers benefit. This would reduce the amount of poor quality mussels going to market and thereby help raise overall prices for producers and reduce the wastage experienced today with poor mussels.
Wholesalers, retailers and restaurateurs need reliable information on how they should handle and store mussels to maximise quality and consumer benefit.
Final report
The post harvest handling of farmed blue mussels, from the sea farm through to the retail store and restaurant was examined in 2003 in a national study funded by Seafood Services Australia and the Australian mussel farming industry.
The Objectives of the study were to: (a) Identify the key quality and marketing parameters for chilled mussels and prepare product specifications for “premium” and “standard” mussels (b) Develop a Code Of Practice which takes account of product labelling, uniform size grading, shell fouling and cleanliness, condition index and any mandatory food safety requirements for the guidance of all industry sectors and (c) prepare a product Trade Users Guide for wholesalers, retailers and restaurateurs.
The project was designed to reduce the volume of poor quality mussels going to market and thereby help raise overall prices for producers and to reduce the wastage experienced by the industry and consumers with poor quality mussels.
Desk research was also carried out to explore the basis of the advice commonly given by cookery writers to discard mussels which do not open after cooking. This warning has led to the waste of many mussels and generated much confusion amongst many trade users and consumers. Cooking tests were undertaken to examine the validity of this advice and to develop a simple method for assessing the “meat content” or Mussel Condition Index.