12 results
Environment

Tactical Research Fund: Assessment of heavy metals in tropical rock oysters (blacklip and milky) and implications for placement into the Australian seafood market and for Indigenous enterprise development in the NT.

Project number: 2012-223
Project Status:
Completed
Budget expenditure: $37,796.00
Principal Investigator: Ann Fleming
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 12 May 2013 - 12 Dec 2014
Contact:
FRDC

Need

The aim of the project is to manage an unforeseen event that has arisen in the early staged of facilitating Indigenous tropical edible oyster enterprises in the NT (both wild harvest and farmed). Samples taken in December 2011 from two sites had high levels of some heavy metals in the flesh. Specifically, levels of cadmium and arsenic were above the Food Standards Code MRL’s. The implications of these results for Indigenous organisations planning to sell tropical oysters into Australian markets are unknown. An additional small, but more extensive, sampling program is needed to assess the extent (spatially and temporally) to which heavy metals peck above MRL's in NT tropical oysters.

The project's Industry partner, Mr Ziko Ilac of Darwin Fish Markets, sees this as a high priority issue. He is currently liaising with top-end Darwin restaurants to develop a niche market in Indigenous-produced, fair-trade seafood. His intention is to develop a niche market for small volumes of shellfish and fish, flown in weekly from remote communities when seasonally available. Restaurateurs see great potential in developing an 'NT seafood cuisine experience' for national and international visitors to Darwin using an 'Indigenous produced, fair-trade' marketing strategy.

Professor Karen Gibb, Leader Environmental Analytical Chemistry Unit (EACU), Charles Darwin University has advised that their own data and those of Peerzada et al. (1993) (Env. Monitoring & Assessment 28: 101-107) also showed elevated cadmium and arsenic in oysters collected along the northern coastline. However not all sites were elevated and Peerzada et al. implicated phytoplankton as a source of elevated metals. Before we can make informed decisions about the future of this very promising enterprise we critically need to gain an accurate measure of metals in replicated samples over two seasons and determine if there is an association with metal levels in water and/or phytoplankton.

Objectives

1. Conduct a sampling survey of the spatial and temporal variability of heavy metals in tropical oysters (blacklip and milky) in the West Arnhem region
2. Assess the implications of results on the development strategy of the oyster enterprise and the sale of tropical oysters into the Australian seafood market
3. Employ Indigenous partners to conduct the shellfish monitoring outlined in this project to develop Indigenous capacity in fisheries sciences and an additional employment steam for Indigenous people

Final report

ISBN: 978-0-9943311-1-3
Authors: Ann Fleming Karen Gibb Dylan Campbell Niels Munksgaard Julia Fortune Andrea Birch Mirjam Kaestli
Final Report • 2015-09-01 • 3.55 MB
2012-223-DLD.pdf

Summary

This small, but extensive, sampling survey was conducted on South Goulburn Island, located off West Arnhem Land in the Northern Territory (NT) to assess the occurrence of heavy metals (both spatially and temporally) in tropical blacklip (Saccostrea mytiloides) and milky (Saccostrea mordax) oysters. Heavy metals tested where those identified by the Australian Shellfish Quality Assurance Program

Results were used to determine whether heavy metal levels exceeded the Maximum Residue Levels (MRLs - or MLs as the more commonly used terminology) set by Food Standards Australia New Zealand (FSANZ) within the Australia New Zealand Food Standards Code (ANZFSC). The range of metals tested were chosen based on previous national residue surveys in seafood across the NT (and our preliminary screening of the study site) that indicated likely contaminants. For example, in this study mercury was not tested as the preliminary screening test done on South Goulburn Island indicated mercury to be low (0.005-0.007 mg/kg; ML 0.5mg/kg) and previous extensive heavy metal testing done by various national surveys along the NT coastline over the last few decades reported consistently low levels of mercury in various seafood products.

This sampling survey was initiated in response to an unforeseen event that arose in the early development phase of the Indigenous oyster enterprise program of the NT Government’s Aquaculture Unit. In December 2011 opportunistic samples of oyster flesh taken at two sites on Goulburn Island showed high levels of cadmium and arsenic, both at levels above the MLs for these elements. The implication of these results for Indigenous organisations planning to sell tropical oysters into Australian seafood markets was unknown at the time.

A more extensive assessment of the occurrence of heavy metals in potential growout areas was needed to assess the risk to human health and identify possible management strategies to ensure oyster product met the food safety standards set by the FSANZ. To assess the risk to human health from heavy metals in tropical oysters the following objectives were addressed:

1 Conduct a sampling survey of the spatial and temporal variability of heavy metals in tropical oysters (blacklip and milky) in the West Arnhem region.
2 Assess the implications of results on the development strategy of the oyster enterprise and the sale of tropical oysters into the Australian seafood market.
3 Employ Indigenous partners to conduct the shellfish monitoring outlined in this project to develop Indigenous capacity in fisheries sciences and an additional employment steam for Indigenous people.

The Aquaculture Unit of the Department of Primary Industry and Fisheries, the Goulburn Island Indigenous Aquaculture Team and Charles Darwin University (CDU) researchers collaborated to measure trace elements (metals) in blacklip and milky oysters collected from four sites around South Goulburn Island. Sampling (of oysters and seawater) was conducted during the dry season in September 2012, the wet season in February 2013, and again during the dry in September 2013. Samples were collected from the shore within a 24-hour period during extreme low daytime tides, flown to CDU’s Environmental Chemistry and Microbiology Unit (ECMU), where they were analysed for heavy metal content. A suite of heavy metals were analysed but of prime interest were arsenic (As) (note - FSANZ considers arsenic as a metal for the purposes of the Food Standards Code), cadmium (Cd) and lead (Pb) as MLs are set by FSANZ for these elements only. Oyster product must conform with MLs set for these metals to allow placement of product in the Australian seafood market.

The results
Ideally, oyster sampling would target market sized animals within a narrow size range (10-15 cm length), as the heavy metal content of these aniamls would be assumed to reflect heavy metal contect of harvestable animals from commercial operations. However this was not possible as the oyster sampling program conducted in this study was done on a remote island, at remote sites across the breadth of the island that were accessably only during dry weather conditions, and during a small window of opportunity when oyster beds were exposed during extreme low tides. As a result, the data is compromised due to the small sample size for some sampling sites and times. Every effort was made to meet the targeted sample size and number, but final oyster samples were limited to those that were available.. An initial collection trip failed to collect sufficient samples at most sites and so was not included in the dataset. Farmed blacklip oysters were deployed during the project to increase sample availability. Subsequent collections were sometimes done at night-time low tides to ensure all sites were sampled. It must be noted that accumulation of heavy metals may differ between oyster age classes (and size), most likely due to different exposure times. Thus the smaller size range of oysters collected in this study may be an underrepresenation of heavy metal content of marketable oysters.

Our analysis of trace elements in milky and blacklip oysters in the West Arnhem region showed that the heavy metal content of oysters differed between sites and sampling times and that the two species accumulated heavy metals differently. Farmed blacklip oysters showed different heavy metal accumulations than wild caught blacklips at some sites.

Wild harvest blacklip oysters accumulated Cd levels that exceeded the food safety standards at all sites and on each of the three sampling events (two during the wet season and one during the dry) over the 12-month survey period.
Farmed blacklip deployed for up to 12 months repeatedly exceeded Cd at only one site (site 2) for the three sampling event. There were no other exceedences of Cd by farmed blacklip at any other sites or sampling events.
Wild harvest milky oysters also exceeded Cd levels at site 2 for each of the three sampling events. They also exceeded Cd at one site (site 1b) on the first sampling event.
We also tested total arsenic in the two oyster species. Levels of total As recorded in this study suggests that the inorganic component to which the guidelines relate are not likely to have been exceeded. Further As speciation analysis would be needed to confirm this.
The lead content of oysters was below MLs for all sites and at all sampling events.

Industry
PROJECT NUMBER • 2000-210
PROJECT STATUS:
COMPLETED

Development of commercial production systems for mud crab (Scylla serrata) aquaculture in Australia: hatchery & nursery

Commercially viable techniques for rearing Scylla serrata larvae through to megalops stage have been developed at both the centres involved in the project, the Darwin Aquaculture Centre (DAC) and the Bribie Island Aquaculture Research Centre (BIARC). The methods developed in an earlier ACIAR project...
ORGANISATION:
Department of Agriculture and Fisheries (NT)
SPECIES
People
Environment
Communities
PROJECT NUMBER • 2018-115
PROJECT STATUS:
COMPLETED

National tropical oyster aquaculture workshop - Darwin 2018

The first national workshop on tropical oyster aquaculture was held in Darwin on 22 to 23 October, 2018 at the Waterfront Campus of Charles Darwin University (CDU). The workshop brought together representatives from Aboriginal communities, industry, government agencies, and Australian and...
ORGANISATION:
Department of Agriculture and Fisheries (NT)
SPECIES
People

People Development Program: FRDC indigenous development scholarship - Robert Carne

Project number: 2008-326.33
Project Status:
Completed
Budget expenditure: $9,999.99
Principal Investigator: Bo Carne
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 11 Jan 2012 - 11 Jul 2013
Contact:
FRDC

Need

The indigenous development scholarship is part of the suite of professional development opportunities developed and managed through the FRDC people development program. This particular scholarship addresses the following objectives of the people development program 2008-2013:

Objective 1 Enhance industry leadership within all sectors
and; Objective 3 Provide opportunities for knowledge transfer and R&D adoption

The significant drivers identified in the FRDC people development program, addressed by this project
are:
- There is a shortage of industry leaders in all sectors of the fishing industry.
- There is an urgent need to develop people within all sectors who have the skills to effectively contribute to debate and policy development for significant challenges, including access to fish resources.
-Early career researchers and emerging industry leaders lack opportunities for formal mentoring and
professional development.
-There is a shortage of opportunities for people in industry to develop skills that are going to directly
improve business profitability and sustainability.
-The industry is geographically dispersed and fragmented, and needs opportunities to learn within and
across sectors.

Objectives

1. To provide one annual scholarship for an indigenous person
4. See manual application for development activities specific to this award

People development program: 2010 FRDC International Travel Bursary – Helen Cribb – 17th International Conference on Aquatic Invasive Species.

Project number: 2008-314.21
Project Status:
Completed
Budget expenditure: $6,000.00
Principal Investigator: Helen Cribb
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 30 Jun 2010 - 22 Dec 2010
Contact:
FRDC

Need

The introduction and spread of aquatic invasive species in freshwater and marine environments is a worldwide problem that is increasing in frequency. There are various pathways by which non-indigenous species are introduced and cause significant damage to coastal and freshwater ecosystems, and to the economies that depend upon them.

With increased development, population growth, and vessel traffic, opportunities for the introduction and establishment of invasive species to Northern Territory waterways are increasing. Industries threatened include commercial and recreational fishing, aquaculture, port services, shipping and tourism. Challenges associated with addressing these risks include the need to respond to changing risk factors; unregulated or illegal vessel activity; and remote locations.

The International Conference on Aquatic Invasive Species is held annually and is the most comprehensive international forum for the review of scientific knowledge; presentation of research; introduction of technological developments for prevention, monitoring and control; and discussion of policy, legislation and outreach initiatives to raise awareness of the impacts of aquatic invasive species and prevent new introductions.

Attendance at the conference will provide opportunities for cooperation and collaboration, and allow the Territory to benefit from the latest knowledge and experience of researchers and managers worldwide in the development and implementation of local programs to address emerging risks.

It is also intended to visit the Great Lakes region to learn from local experiences with the invasive Zebra mussel (Dreissena polymorpha), and the management, control and monitoring of this species.

Objectives

1. Gather information about invasive species prevention, management and emergency response strategies overseas.
2. Learn from experiences with the zebra mussel establishment and spread in the Great Lakes region.
3. Apply the knowledge gained from objectives 1 and 2 to aquatic biosecurity strategies in the Northern Territory.
4. Disseminate knowledge gained from objectives 1 and 2 to national committees including the National Introduced Marine Pest Coordination Group and the Consultative Committee on Introduced Marine Pest Emergencies.
5. Present a paper to the ICAIS conference on marine pest threats, vectors and management strategies in the Northern Territory (if abstract is accepted).

Factors affecting the profitability of the Northern Territory Demersal fishery

Project number: 1999-371
Project Status:
Completed
Budget expenditure: $12,860.00
Principal Investigator: Ray Clarke
Organisation: Department of Agriculture and Fisheries (NT)
Project start/end date: 29 Jun 1999 - 14 Nov 2005
Contact:
FRDC

Need

In October 1998, key demersal fishers and NT Fisheries Division officers held a meeting to review the current knowledge and understanding of the Demersal Fishery and the areas of knowledge that are still required to assure its viable development. Participants identified two impediments to the expansion of the demersal fishery:

1. the inability to consistently supply fish to the market; and
2. catching fish at a profitable rate.

The variation in catch rates are substantial enough make the difference between profit and significant loss. Sensitivity analysis on projected catch rates and cost structures support the view that there is potential to achieve an adequate, if not attractive, level of profitability in the fishery with passive fishing methods (Cann, 1996). This work has shown that profitability is quite sensitive to catch rates and market prices, with a marginal increase in either prices or landings, making the difference between a profitable or uneconomical fishing operation.

There is no long-term trend apparent in the CPUE data, and fishers have presented a number of reasons why both seasonal and inter-annual catch rates are so variable. These include water temperature changes in concert with El Nino events, seismic surveys conducted by oil exploration companies and limited experimentation with a wider range of gear types. Further, there are other factors, which may affect profitability such as vessels used, operating costs, debt structure and training/skill of industry members. The meeting agreed that these and other issues must be formally addressed if the fishery is to develop further. It also identified a number of specific research projects (see B14).

Industry and government agreed that the best way address issues affecting profitability would be to employ relevant specialists to participate in a workshop with industry, researchers and managers. This was seen as the most effective way to exchange ideas, share experience, reach agreement on how to best improve profitability and identify what research is needed to improve industry viability.

Objectives

1. To examine factors affecting profitability in the Demersal Fishery
2. To increase industry awareness about how profitability in fishing operations may be improved
and
3. Determine and prioritise the principal areas for further research.
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