Guide to the sharks and rays of Australia
Analysis of Taiwanese gill net data
Final report
The effects of cyclones on the seagrass communities and penaeid prawn stocks of the Gulf of Carpentaria
Determination of the migration patterns of juvenile southern bluefin tuna and jackass morwong
Final report
This project reports on:
1) our detailed evaluation of current methodologies for otolith chemical analysis, and our recommended procedures when electron probe microanalysis is used for stock delineation in finfish
2) our assessment of the accuracy and precision of otolith probe microanalysis relative to the scales of natural variability in otolith composition, and an evaluation of the extent to which such variability reflects changing environment conditions
3) a direct test of the hypothesis that SE Tasmanian bays are the sole nursery area for Jackass Morwong
4) an evaluation of the likelihood of more than one spawning area/migration route for southern Bluefin Tuna.
Diseases of abalone
Final report
In 1985 and 1986 many greenlip abalone Haliotis laevigata near Edithburg in the St Vincent Gulf died. The protozoan parasite, Perkinsus olseni, was suspected to be the cause. We showed that Perkinsus olseni was seasonally abundant in greenlip from the edge of the die-back area. It was also common in three other species of abalone, H. rubra, H. cyclobates and H. scalaris, and was recovered from 4 species of bivalves from the same area (Barbatia pistachio, Chlamys bifrons, Katylesia rhytiphora and Pinna bicolor).
In July 1987, 140 healthy abalone were transplanted from Hardwicke Bay to Stansbury at the centre of the die-off in an attempt to recolonize the area. This was done with the help of commercial abalone divers. In the following October, a subsample indicated the transplants were uninfected and were growing well. However, by March 1998, many of the abalone had recently died and the remainder were heavily infected.
In July 1989, 195 greenlip from Tipara Reef were tagged and transplanted to the same site. A subsample the following March indicated that there was good growth, very little infection, and no sign of recent deaths. The epizootic had evidently passed and these abalone were successfully recolonising the area. However, a follow-up sample a year later - in April, 1992 - indicated that many of the animals had become infected though there was no sign of recent deaths.
The die-back area is near the northern limit for greenlip abalone in the Gulf of St Vincent. Laboratory experiments showed that abalone infected with Perkinsus died more frequently than uninfected abalone and that stress such as high temperature may predispose the abalone to disease. The time of the original die-back corresponded to warm winters on the Yorke Peninsula.
Laboratory and field observations suggest that the parasite is common in greenlip in late summer. During winter abalone are able to contain and eliminate the infection. We conclude that the parasite is widespread around the Yorke Peninsula in hosts other than greenlip, and that greenlip near the upper limit of their temperature range are likely to contract fatal infections.
The effects of environmental factors on microbial growth in prepared seafood products and prediction of shelf life and safety
Final report
This project commenced in July 1987, with the cooperation of various sections of the fishing industry, including oyster growers and processors, salmonid farmers, and producers of value added products.
For each of the products investigated, the basic research method has been to determine the microbial status of the product in conjunction with sensory evaluation. In this way a knowledge of the microbial ecology of each product under different storage conditions is built up and related to the functional characteristics (appearance, odour, taste, etc.) that cause rejection of the product by the consumer.
Most fresh seafood products in chill storage deteriorate rapidly as a result of the growth of gram negative psychrotropic bacteria mainly Pseudomonas and Alteromonas (now Shewanella). These organisms produce putrid spoilage compounds such as sulphides, ammonia and some amines. Manipulation of the storage conditions (e.g. gaseous atmosphere) or formulation of the product (pH, water activity) may lead to replacement of the gram negative microbiota with gram positive bacteria. The latter organisms tend to grow less rapidly at chill temperatures and produce less obvious spoilage changes leading to a longer shelf life.
Consultancy to investigate FIRTA pearl oyster research
Final report
There has been recent revitalization of the West Australian pearl culture industry to a stage where annual production is now worth about $40 million. Mortalities of pearl shell transported to the culture farms and concerns regarding the state of pearl oyster stocks stimulated a series of research projects which have been funded largely from the Fishing Industry Research Trust Account.
This year, funds were sought for two projects, in hatchery and nursery culture and on developing on-growing techniques and disease prevention husbandry.
Rapporteur/editor for the Indo-Pacific Commission Symposium on the Exploitation and Management of Marine Fishery Resources in South-east Asia, Darwin, Australia, 16-19 February 1987
A biological study of east coast tunas and billfishes with particular emphasis on yellowfin tuna (Thunnus albacares)
Final report
The East Coast Tunas and Billfishes Research Program was funded by the Fishing Industry Research Trust Account (FIRTA F86/127) from July 1986 to June 1988.
The objectives of the program were to identify the stock(s) exploited by the east coast tuna and billfish fisheries, examine the structure of those stocks and collect background fisheries and biological information on the species. Particular emphasis was placed on research into the biology of yellowfin tuna, Thunnus albacares, a species of considerable economic importance to commercial longline fishers.