190 results
Industry
PROJECT NUMBER • 2004-237
PROJECT STATUS:
COMPLETED

Aquaculture Nutrition Subprogram: assessment of growth performance under limiting environmental conditions

This research has advanced our understanding of how fish growth is influenced by nutrition, by environment and by the interaction between nutritional and environmental factors. When the research started the majority of nutrition research considered the performance of feeds under optimum...
ORGANISATION:
University of Tasmania (UTAS)
TAGS
Nutrition
Environment
PROJECT NUMBER • 2013-025
PROJECT STATUS:
COMPLETED

Assessing post-release survival of Southern Bluefin Tuna from recreational fishing

Southern Bluefin Tuna (SBT) are an important component of the recreational game fishery in Australia. Recreational fishers in waters around South Australia, Victoria, Tasmania and New South Wales catch this species seasonally. Each state respectively is responsible for the management of this...
ORGANISATION:
University of Tasmania (UTAS)
TAGS
Wild Catch
SPECIES
Southern Bluefin Tuna
Industry
Environment

Aquafin CRC - Atlantic Salmon Aquaculture Subprogram: use of immunomodulation to improve fish performance in Australian temperate water finfish aquaculture

Project number: 2004-210
Project Status:
Completed
Budget expenditure: $288,959.00
Principal Investigator: Barbara Nowak
Organisation: University of Tasmania (UTAS)
Project start/end date: 16 Jun 2004 - 30 Jun 2008
:
TAGS
Vaccine
Stock Assessment
Physiology
Disease
Aquaculture
SPECIES
Atlantic Salmon

Need

Strategic plan
This proposal is part of FRDC Industry Development Program, Strategy - Aquaculture development - production and production systems. However, it also has strong capacity building elements, including training of at least one PhD student in the area of fish health/immunology and providing workshops for industry and researchers (Use of immunostimulants in finfish culture, Immune response in fish). It provides leadership development by having a full time young researcher (CI - Dr Richard Morrison) working on this project. Thus, this proposal will significantly contribute to Human Capital Development Program, Leadership and Vocational Development. Improved knowledge of immune response and immunomodulators was identified as one of the key research areas for aquatic animal health in Research and Development Plan Aquatic Animal Health Subprogram. Priorities covered by this key research area included immunology in aquatic vertebrates (nature of disease and host-pathogen interactions), immunomodulators (aquatic animal health management) and development of tools for immune status monitoring as a means of implementing health management strategies (surveillance and monitoring). All three elements are included in this proposal. This proposal is consistent with R&D plans for Atlantic Salmon Aquaculture Subprogram and with Aquafin CRC AGD research program. It also addresses targeted priority: fish health, within Program 2: Industry Development, Key R&D issues for fisheries and aquaculture in SA, South Australia's Fisheries and Aquaculutre Research and Development Strategy 2002-2007. The research focus is within Tasmanian Fisheries and Aquaculture, Aquaculture Strategic Research Plan 1999-2004. This proposal fits well into Aquafin CRC strategy and mission by significant contribution of its outcomes to achieving sustainable aquaculture in Australia through reduction of economic impact of diseases in farmed fish, development of environmentally friendly approaches to disease management and training aquaculture industry and researchers in the fields of fish immunology.

Need for research
It is impossible to prevent the presence of pathogens in aquaculture systems, particularly in sea-cage grow-out. Most disease outbreaks occur when there is an interaction between pathogens and susceptible fish (for example immunocompromised fish due to stress). This will result in lowering the performance of the fish and possibly mortalities. Sustainable aquaculture of finfish requires lowering the risk of disease outbreaks and replacing disease treatment with control strategies. The use of immunomodulators is essential to achieve these goals, in particular in times of increased disease risk or reduced immunocompetence. Our understanding of host-pathogen interactions and immune response allows for the use of appropriate immunomodulators. For example, if a disease is caused by overreaction of the inflammatory response, traditional immunostimulants will not improve the outcomes. Similarly, there is a need to determine correct timing and dose for immunomodulation in mariculture. Improved immune response would improve fish performance during grow-out.

Importantly immunomodulators are natural products that are derived from microbes, thus avoiding the use of chemical products. Commerical immunomodulators have been successfully used in aquaculture worldwide however only experimentally in Australia. For example oral immunomodulators MicroVital significantly increases survival rates of Atlantic salmon following Vibrosis challenge and 32% gain in survival rates of salmon fed natural immunomodulators (ß glucans and nucleotides) following exposure to IPN (exotic viral disease) challenge has been achieved in trials in Norway. However, there is little information available for fish species other than salmon or diseases other than commercially important in Northern Hemisphere. There is a need to develop immunomodulation strategies that are directly applicable to Australian mariculture, either specific for our species or diseases affecting Australian aquaculture industry (for example Amoebic Gill Disease) or unique conditions such as water temperatures.

Benefits
For Atlantic salmon we will address AGD management by investigation of immunomodulators. AGD is the main health problem for salmon industry and successful use of immunomodulation could provide an answer, particularly in combination with other management strategies.
This project is generic and the benefits are not limited to the species we will use as a model in our investigation. Other finfish aquaculture industries will also benefit from training and workshops provided by this project.

Objectives

1. Evaluate use of immunostimulants for control of AGD of Atlantic salmon.
2. Investigate role of inflammation in AGD of Atlantic salmon.
3. Test effectiveness of vaccination against AGD using crude or partially purified antigens.

Final report

ISBN: 978-1-86295-436-6
Author: Barbara Nowak
Final Report • 2008-04-14 • 1.03 MB
2004-210-DLD.pdf

Summary

Before this project our knowledge of immune response in Amoebic Gill Disease (AGD) was fundamentally limited and more  information was required to assess the potential for immunomodulators in the management of AGD.

We confirmed that injection of bacterial DNA motif (CpG oligonucleotides) six days before AGD challenge can offer signficant protection to Atlantic salmon (relative percent survival up to 52.5%).  However, there was no effect if the fish were challenged immediately post injection with bacterial DNA.  This suggests that while there is a potential benefit from the use of immunostimulants, their application is limited because their efficacy is directly linked to the timing of an outbreak, which can be unpredictable in the field. While fish which survived an initial AGD episode show increased resistance to subsequent AGD infection, in contrast to some diseases this effect cannot be simply explained by the presence of antibodies.   The duration of exposure (or number of exposures) appears to be important for the development of serum antibodies.  Mucus antibodies could not be detected in Atlantic salmon that survived AGD challenge.  Microarray experiments and further gene expression studies suggested that there is a loss of cell-cycle control in AGD lesions.  Furthermore, immune pathways are affected since the down-stream effect(s) of the initial inflammatory signals were not detectable.  It is possible that this significantly contributes to the extremely high rate of mortality in unmitigated AGD epizootics.

While we have achieved our objectives and answered many of the original questions, new issues have emerged from our research.  These include a lack of understanding of the mechanisms of inhibition of inflammatory and immune pathways, significance of antibody response (if any) in AGD, and the potential for vaccine antigen discovery through the use of anti-peptide antibody.  The presence and role of a more localised antibody response in the gill mucus or epithelium (currently undetectable) warrants further investigation.  

In conclusion, we now have a better understanding of AGD pathogenesis and the reasons why the host immune response is ineffective in this disease.  In particular, we have shown that immune pathways are inhibited in Atlantic salmon affected by AGD. 

Keywords: Amoebic Gill Disease, salmon, aquaculture, immunostimulants, inflamation, gene expression, transcriptome analysis.

Industry
PROJECT NUMBER • 2016-208
PROJECT STATUS:
COMPLETED

Waste to profit in urchin fisheries: developing business opportunities to ensure fishery sustainability and safeguard reef dependent fisheries from destructive urchin grazing

This report examines two potential applications of Longspined Sea Urchin (Centrostephanus rodgersii) via pitot scale trials; processing waste as an agricultural fertiliser and use as Southern Rock Lobster bait. The biochemical composition of Longspined Sea Urchin waste products was analysed, and the...
ORGANISATION:
University of Tasmania (UTAS)
TAGS
Rac Vic
SPECIES
Sea Urchins
Blank
Industry
PROJECT NUMBER • 2023-005
PROJECT STATUS:
CURRENT

Research to support the development of a Tasmanian Sardine Fishery

This study documents the first comprehensive evaluation of the spawning biomass of the South Eastern Stock of Australian Sardine (Sardinops sagax). This stock occupies continental shelf waters from the Victorian-South Australian border, east through Bass Strait and along the north-western and...
ORGANISATION:
University of Tasmania (UTAS)
TAGS
Rac Tas
SPECIES
Sardines
Industry

Aquafin CRC - Atlantic Salmon Aquaculture Subprogram: establishment of challenge for AGD

Project number: 2004-215
Project Status:
Completed
Budget expenditure: $652,222.00
Principal Investigator: Barbara Nowak
Organisation: University of Tasmania (UTAS)
Project start/end date: 16 Jun 2004 - 31 Jul 2008
:
TAGS
Vaccine
Stock Assessment
Disease
Aquaculture
Animal Health
SPECIES
Atlantic Salmon

Need

Strategic plan
This proposal is part of the FRDC Industry Development Program, Strategy – Aquaculture Development – Production and Production Systems. The project includes a technician and a postdoctoral research fellow (Dr Philip Crosbie) as co-investigator and they will both be provided with suitable professional development opportunities through the Education Program of the Aquafin CRC. Later in the project it may be possible to adopt a PhD student with an independent scholarship or include Honours and Masters projects as they are required and become available. Thus, the project will contribute to the Human Capital Development Program, Leadership and Vocational Development. This proposal includes several key research areas outlined in the Aquatic Animal Health Subprogram Strategic R&D Plan, namely the Nature of disease and host-pathogen interactions and Training and capacity building. Relevant priorities being: to provide improved knowledge of the biology of disease agents (in this case the AGD-causing organism), and an improved knowledge of host responses to disease agents which will be partially addressed by monitoring the specific antibody response to N. pemaquidensis antigens (Nature of disease and host-pathogen interactions). Both the research and service components of this proposal will expand the technical skill base in aquatic animal health and facilitate R&D knowledge transfer (Training and capacity building). This project will underpin other projects that contribute to the Aquafin CRC Health Program Outcomes ie. reduced economic impact of disease (AGD) in finfish (Atlantic salmon) farming.

Need for this research
The continued existence of Atlantic salmon farming in Tasmania is threatened by AGD. Production is expected to increase over the next few years and this will undoubtedly lead to an increase in the incidence of AGD. The AGD control method of freshwater bathing has increased in frequency with the growth in production over the past few years and this trend is expected to continue. This will present a growing cost burden to salmon growers, it is therefore imperative that the impact of AGD on the industry be reduced so as to maintain viability for the future. Multidisciplinary teams have been assembled to achieve this outcome via a number of projects. The projects are complementary and in some cases interdependent where progress in one area is dependent on progress in another area. This is particularly the case with the service component of the current proposal and the vaccine development program, where supply of infective material and a means of controlled testing of candidate vaccines are integral to success. Vaccine development requires identification of specific antigens from the pathogen that will elicit a protective immune response in the host, hence the need for significant quantities of infective material. Similarly, success of the treatment of AGD investigation is dependent on supply of cells for initial screening of a battery of potential therapeutants in vitro before attempting field trials. The research component of the proposal, which is the development of a standard AGD challenge method that can be used in experimental tanks, is essential for the success of these projects. We need to be able to consistently induce AGD in fish to economically appraise alternative treatments and candidate vaccines before moving onto costly field trials. Inducing experimental infections is widely recognised as one of the cornerstones of vaccine development (Nordmo, 1996).

Benefits
The major benefit will be enabling progress in the vaccine development and alternative treatment projects to be made. We will have in place a model to economically appraise novel treatments, experimental vaccines and other less specific means of prophylaxis such as immunomodulation. Ultimately the project will contribute to a collective outcome of lessening the impact of AGD on salmon producers and reducing the estimated 10-20% of production costs that is currently spent controlling the disease. Other benefits include a better understanding of risk factors contributing to AGD, and the opportunity to investigate the virulence mechanisms of the organism. Overall the project will contribute to research output and service. The systematic development and subsequent use of challenge models will yield publishable material. The service aspect will be in the supply of amoebae to collaborators and provision of a means to test novel therapeutants, experimental vaccines and immunomodulatory compounds.

References
Nordmo, R., 1996. Strengths and Weaknesses of Different Challenge Methods. In: Fish Vaccinology (ed. By Gudding, R., Lillehaug, A., Midtlyng, P.J. and Brown, F.) Developments in Biological Standardisation. Basel, Karger p 303-309

Objectives

1. Standardisation of AGD challenge models (research)
2. Use of challenge to appraise trial vaccines developed in the vaccine development project (essential service)
3. Provision of gill-associated and cultured amoebae to collaborators (essential service)
4. Cryopreservation of virulent amoebae (research)
5. Maintenance of infection tank (essential service)
6. Provision of freshwater salmon for experiments in other projects (essential service)

Final report

ISBN: 978-1-86295-460-1
Author: Barbara Nowak
Final Report • 2008-10-20 • 1.35 MB
2004-215-DLD.pdf

Summary

This project has increased our knowledge of Amoebic Gill Disease, in particular about the pathogen and the dynamics of infection.  We have described a new species of neoparamoeba, Neoparamoeba perurans, and showed that it has been consistently associated with AGD worldwide.  Stocking density, acclimation to sea water and amoeba batch variability affected AGD infections.  During this project challenge protocols were developed, which have been successfully used and their results correlated well with field challenge.  This project provided crucial support for all AGD research through provision of amoebae and salmon for all AGD projects and running experimental challenges for trial vaccines.

The main objectives of this project were to provide essential service for AGD research.  During this project we standardised existing AGD challenge protocol and developed a new in vivo gill attachment challenge assay.  Both challenge protocols have been successfully applied in AGD research.  Research on virulent amoebae resulted in a description of a new species, which consequently has been shown to be involved in all AGD cases worldwide.  This discovery led to the development of new diagnostic tests, which are now available for confirmation of AGD infections and further research.

In conclusion, this project has not only provided essential support for all AGD research by supplying amoebae and salmon and running AGD challenges for the experimental vaccines, but also increased our knowledge and understanding of AGD.

Keywords: Amoebic Gill Disease, salmon, aquaculture.

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