SCRC: Business Plan for a Collaborative Seafood Processing Hub in South Australia
Seafood CRC: chilled pre packaged seafood category development (CRC Syndicate Project)
SCRC: SCRC RTG 3.12: Micromon recombinant DNA techniques course (Dr James Harris: Students Paula Lima and Celeste Knowles)
Final report
This research travel grant allowed two PhD students: Paula Lima and Celeste Knowles to travel to Melbourne to undertake the Micromon Recombinant DNA Course conducted by Monash University. This course taught essential techniques and skills which may be used by both students in the course of the PhD studies and throughout their careers.
The Monash Recombinant DNA Techniques Course is widely recognised as the leading course of its type in Australia, which consists of a series of tutorials, lectures and hands on laboratory work.
These students aimed to use the techniques learned to investigate amoebic gill disease in Atlantic Salmon which costs the industry $20-25 million annually. Both students have reported that the techniques learned during the course have been used on a regular basis since returning from Melbourne.
SCRC: SCRC Honours Scholarship - H3.3 Impact of fish oil replacement on the expression of antioxidant genes and genes involved in the synthesis of highly unsaturated omega-3 fatty acids in YTK liver and muscle tissue (Dr Kathy Schuller: Student Nathan Rout-Pitt)
SCRC: SCRC Honours Scholarship H 3.4 - Development of Near-Infra Red method to detect and control microbial spoilage (Dr Shane Powell: Student Ms Nthabiseng Tito)
Final report
Spoilage of fresh fish products by the action of bacteria is one of the main causes of the short shelf-life of these products. A range of bacteria are responsible for this and are referred to collectively as "spoilage bacteria". Currently methods to detect both spoilage of the product and the presence of number of bacteria are time-consuming, for example requiring 24-hour incubation periods, or require specialised labour such as tasting panels. Near infra-red spectroscopy (NIR) is widely used in the food industry to monitor factors such as fat and moisture content in a range of foods. Although it has been used to distinguish different types of bacteria and, in a few cases, to quantify the number of bacteria in different materials, there is a lack of information on the ability of the method to quantify bacteria directly on food products. The aim of this project was to determine whether NIR had the potential to be used as a method to detect and predict microbial spoilage of fresh fish products.
NIR was easily able to distinguish between fresh Atlantic Salmon fillets and those stored for nine days at 4°C indicating that NIR can detect spoilage. Partial least squares regression prediction models for the number of total bacteria and the number of Enterobacteriaceae present were developed. These models used the NIR spectra collected when the fish was fresh to predict the number of bacteria that would be present nine days later. There are many factors (protein and fat content of the salmon itself for example) that contribute to the differences in the NIR spectra that are unrelated to the numbers of bacteria. Hence for any model to be useful it needs to include as many of these variables as possible. In conclusion, the results of this project show that NIR has potential to be a useful method for detecting and predicting bacterial levels on fish but much more work is required to develop a suitably robust model.
SCRC: Masters M3.1 Nutritional Genomics and its Application to Aquaculture (Prof Abigail Elizur; Student Linda Moss)
The project aims to address the question: Can different aquaculture diets be assessed and evaluated by examining the expression profiles on known (or newly discovered) candidate genes that are responsible for, or associated with, the digestion and absorption of diet components.
Nutrition is a key significant consideration in aquaculture operations and absorption of molecular components of feed is the main factor contributing to nutrition in fish. An innovative alternative to feed trials is the use of nutritional genomics, where the specific response to the various diet at a gene expression level can potentially predict the quality of the diet and its suitabilty for optimum aquaculture use.
Candidate genes for such studies include genes associated with the digestion and absorption of nutrients i.e. trypsin, aminopeptidase, bile salt-activated lipase, insulin, glucagon and cholecstokinin. This project is expected to also lead to the discovery of a novel suite of genes whose expression is diet dependant, leading to the discovery of suitable markers for diet effectiveness, reducing the necessity and costs of feed trials.
The research done during the project is expected to greatly enhance our knowledge of the molecular processes with feed digestion, absorption and feed development, thus not only offereing an attractive testing alternative to diet development, but also explore the animal's response to different diets.
SCRC: SCRC Honours Scholarship H3.2 -Impact of acid sulphate soils on the survival of adult Pacific Oysters challenged by bacterial extracellular products (Dr James Harris: Student Joel Kellam-Stock)
Final report
This study investigated the impact of short-term exposure to acid sulphate soil leachate on the biochemical condition of the Pacific Oyster Crassostrea gigas. Oysters were exposed to artificially acidified seawater, aluminium and iron treatments for a period of six hours and assessed for changes in mantle glycogen, mantle protein and haemolymph protein between treatments.
An additional challenge using Vibrio harveyi extracellular products was conducted to reduce oyster condition and make them more vulnerable to impacts of acidified treatments. Despite depressed mantle protein levels, no significant differences in biochemical condition were found between control treatments and acidified water treatments indicating that short periods of exposure to acid leachate in the field would be unlikely to have significant impacts on general oyster condition.
SCRC: SCRC Honours Scholarship H3.1– Impact of commercial hatchery practices on the contribution of broodstock to offspring and genetic diversity in the Yellowtail Kingfish breeding program (Dr Alex Safari: Student Daniel Tan)
Final report
Using small numbers of broodstock for breeding often leads to random drift in gene frequencies between generations. Effective population size (Ne) is used as an indicator to assess the rate of inbreeding and loss of genetic variation in small populations. In this study we used six microsatellites, coupled with DNA parentage analyses, to determine the relative contributions from two commercial Yellowtail Kingfish hatchery broodstock groups over four pooled spawning events (two for each group).
Initial broodstock contributions from the dams was found to be highly skewed, with one dominant dam contributing more than 70% of the offspring (1-day post hatch, dph) in three of the pooled spawning events, while two dams contributed fairly equally to the offspring in the fourth pooled spawning event. Two sires were found to be contributing more that 78% of the offspring in one pooled spawning event, while contributions between the sires were fairly equal in the other three spawning events. The student then examined the differential survival of family size through the hatchery production (from 1 to 25 dph) during which time mortality averaged 80%. Parentage analyses indicated that through the process some maternal and paternal contributions that had been initially represented in the 1-dph offspring 3 were lost. There were also significant changes in the frequencies of progeny from individual dams and sires from day 1 to day 25.
These results indicate that hatchery breeding practices and high mortality during early larvae culture would result in poor retention of genetic variability across generations. With the actual Ne being less than half of the census Ne inbreeding rates would be relatively high if the current broodstock population was closed and future broodstock were derived from existing hatchery systems.
SCRC: PhD 5.04 Assessing the costs and benefits of changing fishing practices in the southern rock lobster fishery (Dr Bridget Green; Student Tim Emery)
There currently is concern in SRL fisheries about the status of inshore stocks. Catch has declined in a number of areas, despite improvements in catch rates. For example, in Northeastern Tasmania, catch is at record lows, yet CPUE has failed to climb. Inshore stocks on western Tasmania are now receiving historically high levels of effort, due in part to change in shot rotation practices. Further, it is unclear whether the extra effort in these practices is adequately recorded in estimates of CPUE. There has been a recent increase in potting effort, commonly referred to as double night fishing, whereby fishers set and haul their pots twice a night, compared to the standard practice of emptying pots once at dusk and/or once during the day. Currently we have no data on the composition of the catch in double night shots, and what proportion of captured lobsters are handled and released, and what consequence this handling has on production from the fishery.
Final report
The specific aim of this thesis was to assess the effectiveness of individual transferable quota (ITQ) systems of management in meeting economic, ecological and social objective(s) through quantitatively analysing changing fishing practices and behaviour of fishers in the Tasmanian Southern Rocklobster (TSRL) fishery to inform management decision-making. Understanding how fishers behave and make decisions is critical in determining how best to manage fisheries. If the response of fishers to management measures can be predicted, unexpected and undesirable outcomes can be avoided.
ITQ management has been introduced in many international fisheries, with the purpose of accounting for human behaviour, as it theoretically generates behavioural incentives that are aligned with management objectives (e.g. reducing fishing costs). The ability of ITQ systems to meet continuing economic, ecological and social objectives therefore is centred on ensuring fisher behavioural incentives remain aligned with those objectives.