20 results

Management of bioeroding sponges in wild stocks of Pinctada maxima in Western Australia

Project number: 2005-074
Project Status:
Completed
Budget expenditure: $726,409.01
Principal Investigator: Anthony Hart
Organisation: Department of Primary Industries and Regional Development (DPIRD) WA
Project start/end date: 29 Jun 2005 - 30 Sep 2008
:

Need

Cliona sponges burrow into shell causing damage and occasionally death, rendering the half-shell, and occasionally the pearl, unsaleable. Estimates of cost to the industry from Cliona sp. run into the millions of dollars per year (Moase et al. 1999) and preliminary studies have identified the species responsible and some aspects of their reproductive cycle relevant to pest management and control (Rawlinson 2000, Fromont et al.submitted). However, there is need to understand, and then control, the recruitment/ infection rate of Cliona, and the project shall provide this knowledge. The specific knowledge sought is an understanding of the process of recruitment or transmission of sponges onto pearl oysters, and an assessment of the source of bioeroding sponges in the environment. Key areas of investigation are the distribution and abundance of Cliona sp relative to size and age of oysters, and in the fishing ground habitats, and key biological questions are: is the incidence of Cliona increasing in wild stocks over time, and what effect is the biomass of bioeroding sponges in large, unfished pearl shell having on the fished proportion of the population? Effective management of these sponges in the pearling industry requires that the recruitment issue be resolved, so remedial action can be focused correctly. Management outcomes from the project may include changes to wild-shell fishing practices, shell treatment and shell discard processes, all of which will ameliorate the economic impact of Cliona sp on the industry and maintain the health of the wild stocks.

Objectives

1. To develop a field guide for identifying bioeroding sponges present in Pinctada maxima
2. To develop sampling techniques for estimating the biomass and reproductive capacity of bioeroding sponges in pearl oyster shells and benthic substrates
3. To estimate the effect of size/age, location, and time, on infection rates of bioeroding sponges in the wild stocks of Pinctada maxima for key fishing locations.
4. To establish a sponge infestation database, including both oysters and the habitat in which they live, for representative fishing grounds
5. To evaluate management options to maintain the health of the wild stocks and ameliorate the economic impact of bioeroding sponge infestation on the industry.

Final report

ISBN: 1-921258-73-X
Authors: Sabine Daume Jane Fromont Anthony Hart
Final Report • 2010-04-08 • 1.02 MB
2005-074-DLD.pdf

Summary

Data on bioeroding sponge species that excavate shells of the pearl oyster, Pinctada maxima, was collected from the main fishing grounds in North Western Australia. Estimates on infestation rates across size/age classes of shell are provided from the main fishing grounds and over three consecutive fishing seasons. Minimal infestation occurred in smaller shells therefore lowering the minimum size provides one approach to minimizing the impact of these sponges. Estimates of infestation rates in calcareous substrates of the fishing ground are also provided and compared on an area basis with shell infestation rates, including shell density and calcareous substrate density estimates of the fishing grounds. Techniques were developed to estimate the volume of bioeroding sponge erosions in pearl oyster shells and results are compared between different sponge species and fishing grounds. A field guide was developed to demonstrate the most common visual appearances of bioeroding sponge infestations. Industry and research personnel can use this field guide for bioeroding sponges in general and as a guideline to determine grades of infestation during field surveys.

People
Industry
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Environment
Environment
PROJECT NUMBER • 1998-153
PROJECT STATUS:
COMPLETED

Mother-of-pearl (Pinctada maxima) shell: stock evaluation for management and future harvesting in Western Australia

The West Australian Pearling industry is one of Australia’s most valuable aquaculture industries, currently generating around $120 - $160 million annually. The majority of pearl shell used to culture pearls come from the pearling beds in the inshore waters near Broome. The fishery for...
ORGANISATION:
Department of Primary Industries and Regional Development (DPIRD) WA
Environment

Aquatic Animal Health Subprogram: Identification and Distribution of an intracellular ciliate in pearl oysters

Project number: 2004-086
Project Status:
Completed
Budget expenditure: $110,984.33
Principal Investigator: Shane Raidal
Organisation: Murdoch University
Project start/end date: 29 Apr 2005 - 29 Jul 2008
:

Need

One of the key objectives of the WA Dept of Fisheries Business Plan is to ensure ecological and environmental sustainability of the pearling industry. The proposed project will be of direct benefit to the Western Australian pearling industry in that it will document the existence of the ciliate and its effect on an economically very important oyster species, it will establish whether the parasite is in the wildstock oysters in Zone 1 and it will establish whether the parasite has a reservoir host. This information is required by pearling companies in assessing their level of risk of getting or transmitting the parasite, given that, for environmental reasons, translocation of infected oysters out of Zone 1 is currently not permitted.

There is an international shortage of pathologists with expertise in molluscan pathology and a National need for research projects that are suitable for the postgraduate training of aquatic animal health specialists.

The Aquatic Animal Health Committee (AAHC), National Aquatic Animal Health Technical Working Group (NAAHTWG) and the Federal Government through the Aquaplan Initiative have all recognised a need for Australian veterinary education institutions to participate in specialised postgraduate training programmes in aquatic animal health.

Objectives

1. Train a postgraduate in molluscan and aquatic animal health pathology
2. Describe what the parasite is doing to the cells in the oyster including host-ciliate interactions and host specificity.
3. Survey other species of bivalves occurring within an affected farm, i.e. determine the site of the ”index case”.
4. Survey piggyback spat collected from Zone 1 during the Department of Fisheries piggyback spat research project, for the parasite.
5. Formally describing the intracellular ciliate parasite, its ultrastructure, life cycle and giving it a scientific name.

Aquatic Animal Health Subprogram: Investigation of Chlamydiales-like organisms in pearl oysters, Pinctada maxima

Project number: 2008-031
Project Status:
Completed
Budget expenditure: $197,532.00
Principal Investigator: Brian Jones
Organisation: Department of Primary Industries and Regional Development (DPIRD) WA
Project start/end date: 30 Jun 2008 - 29 Jun 2011
:

Need

In October 2006 unexplained high mortalities of P. maxima oysters were reported. Many farms are affected and the cause is not known. The disease is termed Oyster Oedema Disease (OOD) and it is likely that an infectious agent is involved. The disease spread rapidly and there are no known control measures, no knowledge of a causative agent, no understanding of how widespread the disease was, and no way to test for it. Molecular and electron microscope research into the mortalities resulted in the discovery of two undescribed Chlamydiales-like organisms (CLO’s) associated with affected shell, and their involvement in OOD is unknown but it is considered unlikely that they are by themselves the major pathogen. However, it is possible that these organisms are contributing to the onset of OOD and further work is required to eliminate or confirm these organisms as a factor in OOD. A report detailing the OOD mortality event (AusVet Report on OOD, 2007) concludes that it is likely that more than one factor contributes to the onset of OOD. Therefore one or both of these CLO’s may play an important role in OOD. Preliminary research in WA suggests a link between OOD-affected animals and the presence of at least one of these CLO’s. The discovery of CLO’s in oysters is a new finding.

Mortalities continue to be reported and OOD still represents a high risk to surviving and young oysters. This proposal seeks to continue the work started at the Department of Fisheries WA in 2007 with the discovery of two CLO’s in P. maxima oysters. There is a need to further characterise these two organisms in relation to each other and to similar organisms worldwide, determine if they play a role in the onset of the fatal OOD, and represent a risk to surviving pearl oysters.

Objectives

1. To further develop the current conventional PCRs being used to investigate two CLO’s in pearl oysters and use these PCRs in an attempt to gain further sequence data than that available. An expansion of the current known sequence data will be used to develop a real-time PCR that is specific and sensitive enough to detect and differentiate between the two CLO’s in pearl oysters. The co-investigator’s see no reason why the development of a real-time PCR will not be successful, given the success to date with the use of conventional PCRs. The real-time PCR will be validated at two independent laboratories (QLD and NSW) using known OOD-positive and negative control samples.
2. To test healthy versus OOD-affected pearl oysters to determine if the presence of either or both CLO's play a role in the onset of OOD. The Department of Fisheries WA currently has numerous samples of OOD-infected and some non-infected P. maxima oysters that are available to test for the presence of these CLO’s using the developed and validated real-time PCR. More samples will be sought as the need arises, in particular P. maxima samples from NSW and QLD. Animals will be tested as individuals to determine the prevalence of the two CLO’s in P. maxima oysters. Prof. Whittington has experience as an epidemiologist and has completed a similar survey recently with pilchard herpesvirus in pilchards. This study will determine if there is a link between the presence of these CLO’s and the onset of OOD.
3. To survey non-maxima shellfish associated with pearl farms to determine the prevalence of these organisms in molluscs in Australian waters, and whether there is a fellow molluscan reservoir host. Sampling will include wild non-maxima shellfish, shellfish stocked in supermarkets and any other shellfish that is available. Any positive samples obtained will be confirmed by sequencing the PCR product.
4. To further develop the current conventional PCRs being used to investigate two CLO’s in pearl oysters and use these PCRs in an attempt to gain further sequence data than that available. An expansion of the current known sequence data will be used to develop a real-time PCR that is specific and sensitive enough to detect and differentiate between the two CLO’s in pearl oysters. The co-investigator’s see no reason why the development of a real-time PCR will not be successful, given the success to date with the use of conventional PCRs. The real-time PCR will be validated at two independent laboratories (QLD and NSW) using known OOD-positive and negative control samples.

Final report

ISBN: 978-1-921845-43-7
Author: Brian Jones
Environment
PROJECT NUMBER • 2013-002
PROJECT STATUS:
COMPLETED

Aquatic Animal Health Subprogram: Identifying the cause of Oyster Oedema Disease (OOD) in pearl oysters (Pinctada maxima), and developing diagnostic tests for OOD

The goal of this project was to investigate the cause of oyster oedema disease (OOD) in Australian pearl oysters so that diagnostic tests and management practices for the disease can be developed. OOD has been associated with mortalities in some pearl oyster farming areas. However, the cause of...
ORGANISATION:
Macquarie University
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