The Origin Of Recruits To The East Coast Yellowfin Tuna Fishery And The Delineation Of The Structure Of Yellowfin Stocks In The Western Pacific
Funder
Fisheries Research and Development Corporation
Funding Amount
$549,631.19
Summary
Objectives: 1. To develop the use of microsatellites for the genetic analysis of yellowfin tuna 2. To determine the genetic relationships of yellowfin tuna form the Coral Sea To those from the east coat of Australia and to those from other Western Pacific fisheries 3. To develop techniques for estimation of oxygen 18/16 isotopic ratios in otoliths using SIMS microprobe 4. Using analysis of otolith chemistry and isotopic ratios examine the hypothesis that all recruits to th ....Objectives: 1. To develop the use of microsatellites for the genetic analysis of yellowfin tuna 2. To determine the genetic relationships of yellowfin tuna form the Coral Sea To those from the east coat of Australia and to those from other Western Pacific fisheries 3. To develop techniques for estimation of oxygen 18/16 isotopic ratios in otoliths using SIMS microprobe 4. Using analysis of otolith chemistry and isotopic ratios examine the hypothesis that all recruits to the ECTUNA fishery are derived from spawning grounds in the Coral Sea 5. In the event of rejection of the null hypothesis that there is a single panmictic WP stock, use otolith chemical data collected from yellowfin collected throughout WP to estimate the proportion of immigrant recruits and determine their most likely origin Read moreRead less
Development Of An Artificial Neural Network For Automated Age Estimation
Funder
Fisheries Research and Development Corporation
Funding Amount
$132,072.00
Summary
Current age determination methods, even when aided by image analysis software still depend on interpretation by an experienced "reader". The process of ageing is also laborious, time consuming and hence, relatively expensive. For production ageing, where there is an ongoing requirement for age estimates, there is a problem of consistency of interpretation. At present, when readers change, there is a substantial training and verification period needed to ensure that the new reader is interpretin ....Current age determination methods, even when aided by image analysis software still depend on interpretation by an experienced "reader". The process of ageing is also laborious, time consuming and hence, relatively expensive. For production ageing, where there is an ongoing requirement for age estimates, there is a problem of consistency of interpretation. At present, when readers change, there is a substantial training and verification period needed to ensure that the new reader is interpreting otolith structure in a consistent and correct manner. Automatic ageing would have the primary advantage of being a far more objective method than is possible with even the best training, reducing discrepancies both between readers and organisations. This factor will increase the precision of estimates and therefore provide greater confidence for the stock assessment process. Benefits associated with the development of this technique also include the reduced sample processing time which would increase the number of samples able to be processed and hence, reduce the cost.
The pilot project which has been completed has demonstrated the potential for artificial neural networks to objectively and consistently classify samples of some species. With refinements of the system, it should be applicable to any species for which production ageing is required. Objectives: 1. Compare the effect of different forms of data input on the performance of an ANN model for automatic ageing. 2. Compare the effect of different forms of ANN models on their performance. 3. Develop a protocol for the application of an ANN model to the process of automatic ageing. Read moreRead less
Age Determination And Growth Of Tiger Flathead [Platycephalus Richardsoni]
Funder
Fisheries Research and Development Corporation
Summary
Objectives: 1. Resolve uncertainty & develop a valid technique for age determination in tiger flatheads. Re-analyse existing samples of otoliths; obtain growth, total mortality & exploitation rate parameters from existing sample data for 1981-85 for eastern Bass Strait
Coastal Stocks Of Fish: From Which Estuaries Are Most Adults Derived?
Funder
Fisheries Research and Development Corporation
Funding Amount
$142,684.00
Summary
The origins of many stocks of fish are unknown. As juveniles, many fish are found in estuarine regions. After a period in these habitats they may leave estuaries for coastal reefs and shelf waters. Degradation of habitats within estuaries (from pollution, land reclamation, marinas etc) and death of fish as by-catch in commercial and recreational fishing may affect abundances of adults on coastal reefs. The contribution of each estuary to total stock size in coastal waters is unknown. It is ....The origins of many stocks of fish are unknown. As juveniles, many fish are found in estuarine regions. After a period in these habitats they may leave estuaries for coastal reefs and shelf waters. Degradation of habitats within estuaries (from pollution, land reclamation, marinas etc) and death of fish as by-catch in commercial and recreational fishing may affect abundances of adults on coastal reefs. The contribution of each estuary to total stock size in coastal waters is unknown. It is difficult to determine which estuary adult fish may have come from using conventional tagging methods, because of the small size of fish in estuaries. Alternative methods for determining the origins of adult fish are needed.
Molecular genetics provides one possibility, but these methods are in their infancy. An alternative method may utilise chemical elements in bones to show origins of fish. Chemical analyses have proven useful in distinguishing between periods of freshwater and marine residence within individual fish (e.g. Kalish 1990) and have also been used to distinguish stocks or sub-populations within marine species (e.g. Edmonds et al. 1989, 1991, 1992, 1995). Recently, we (Gillanders and Kingsford 1996) have used chemical analyses of ear bones to distinguish recruits that settled to seagrass from those that settled to reef habitats. We then analysed the centre region of adult ear bones to determine the origin (estuary or reef) of adult fish showing that this approach is possible.
Many studies have documented important estuarine "nursery" areas in terms of numbers of fish, but if few fishes from these areas reach coastal reefs, such habitats may be relatively unimportant to sustaining populations of adults. The research will focus on snapper (Pagrus auratus) because it is the most important species (in terms of production) that has individuals leaving estuaries for coastal reefs or shelf waters (Bell and Worthington 1993). Objectives: 1. To solve a pressing problem for the fishery by determining what proportion of the commercial catch is from different estuaries. 2. To use methods being developed on juvenile fish to establish a chemical "fingerprint" for each estuary so that in future years the proportion of adults from each estuary can be determined. Read moreRead less
Investigation Of The Potential For Automatic Ageing Using Image Analysis: A Pilot Study
Funder
Fisheries Research and Development Corporation
Funding Amount
$43,294.00
Summary
Objectives: 1. Develop new methods for semi-automatic/automatic ageing of sectioned otoliths using image analysis software. 2. To validate automatic ageing using known age samples from species with clear otoliths. 3. To evaluate the potential of artificial neural networks for the process of objective age determination of fish.
Immunodiagnosis Of Virulent Strains Of Aeromonas Hydrophilia Associated With Epizootic Ulcerative Syndrome (EUS) Using A Monoclonal Antibody.
Funder
Fisheries Research and Development Corporation
Funding Amount
$41,520.00
Summary
Objectives: 1. Produce monoclonal antibodies for management of problems in Aust fisheries & aquaculture & to apply techniques to: 2. (a) detection, monitoring & control of virulent strains of Aeromonas hydrophilia associated with epizootic ulcerative syndrome & 3. (b) rapid identification of eggs
Developing Techniques To Estimate The Age Of Bigeye Tuna And Broadbill Swordfish Off Eastern Australia: A Pilot Project
Funder
Fisheries Research and Development Corporation
Funding Amount
$26,793.90
Summary
The BET and BBL swordfish fishery is expanding rapidly off the east coast of Australia and is now a significant fishery. The warning 'trigger', set by AFMA, of 800t of BBL caught this year has been exceeded. There is now an urgent need to gain an understanding of the stock structure of this fishery. There are now grave concerns, both within the Pacific and the Indian Ocean, on the possibility of over exploitation of these species.
Very little is known scientifically on these species (W ....The BET and BBL swordfish fishery is expanding rapidly off the east coast of Australia and is now a significant fishery. The warning 'trigger', set by AFMA, of 800t of BBL caught this year has been exceeded. There is now an urgent need to gain an understanding of the stock structure of this fishery. There are now grave concerns, both within the Pacific and the Indian Ocean, on the possibility of over exploitation of these species.
Very little is known scientifically on these species (Whitelaw and Unnithan. 1997). Critically there is no verifiable information on the size at maturity and age-structure of populations of BET and BBL in the western Pacific.
Stock assessments require knowledge of size at maturity, size at age, growth rate and estimates of the variability in these parameters within the stock.
For management plans to be devised and implemented it is necessary to expand our biological knowledge. A first step in a structured stock assessment of a fishery is to determine whether ages of individuals can be estimated from their bony parts (otoliths and spines). There is a need to develop verifiable age estimation techniques for stock assessment studies.
Refs; Whitelaw, A.W. and Unnithan, V.K. 1997. Synopsis of the distribution, biology and fisheries of the bigeye tuna, with a bibliography. CSIRO Marine Laboratories Report 228. 62pp. Objectives: 1. To collect hard parts (otoliths and spines) from broadbill swordfish and otoliths from bigeye tuna (much of this has been completed). 2. Assess a range of standard age estimation techniques using otoliths, vertebrate and spines of BET and BBL. This will be carried out in collaboration with SPC and NMFS. 3. Compare age estimates derived using these techniques with those of the SPC and NMFS using other techniques. 4. Using marked (strontium chloride) BET otoliths from previous SPC/CSIRO tagging studies, as well as tag release/recapture growth data from other tagging programs, attempt to validate our age estimation methods and techniques. 5. Make recommendations to Eastern Tuna MAC on the feasibility of an extended ageing project to provide biological information to stock assessment studies. Read moreRead less
Stock Structure Of Northern And Western Australian Spanish Mackerel
Funder
Fisheries Research and Development Corporation
Funding Amount
$349,436.69
Summary
The proposed work is fundamental for assessment and sustainable, optimal harvest of Australia’s Spanish mackerel resources. This goal requires accurate information on which management decisions can be based. This project therefore seeks to describe the stock structure of a national shared resource, with a view to the development of complementary management approaches.
The NT, WA, Qld, Torres Strait and NSW have separate management regimes for the mackerel fisheries in their waters. ....The proposed work is fundamental for assessment and sustainable, optimal harvest of Australia’s Spanish mackerel resources. This goal requires accurate information on which management decisions can be based. This project therefore seeks to describe the stock structure of a national shared resource, with a view to the development of complementary management approaches.
The NT, WA, Qld, Torres Strait and NSW have separate management regimes for the mackerel fisheries in their waters. However, our lack of information on stock structure means that the appropriate scale of management units is just not known. It is unlikely that it will coincide with current administrative boundaries. Basic questions such as whether management actions in one state will impinge on the fisheries of others cannot yet be answered. With such uncertainty, for example, would declines in one area reflect interception during migration, or over-fishing of spawners in another area? Different responses to such questions may require fundamentally different management approaches. Hence the Northern Australia Fisheries Management meeting of May 1997 recognized that stock definition was required for effective assessment and management of this species.
Most fishery assessments assume a randomly mixed unit stock; an alternative is to explicitly include spatial dynamics. Possibly with the exception of the east coast, there is no real basis for defining Spanish mackerel unit stocks. In none of the Australian fisheries are spatial relationships sufficiently understood to be addressed in assessments. The proposed research is requisite for basic stock assessment, and the first step in developing spatially structured models and management.
Spanish mackerel are also taken across our northern boundaries, in Indonesia, Papua New Guinea, and Pacific Island states. The proposed research is the basic work necessary to develop the methodology and information base for future research into these shared stocks, and for future studies into fine-scale spatial dynamics.
Recently available information suggests the Spanish mackerel fishery is growing rapidly in both commercial and recreational sectors. This underlines the need for this work as a basis for rational management. Commercial catches in WA and NT have increased substantially in recent years, and prices continue to rise. A recent recreational survey in NT revealed that recreational Spanish mackerel catches are of similar order to commercial catches. The species is a favoured target in the rapidly-growing and lucrative fishing tour sector.
The need for good for stock assessment is thus growing. Each state has responded with FRDC- or internally-funded programs. The results of this project could substantially change the directions of these projects, by establishing whether the assessment and management should be on a joint basis across states, or whether they should be on a more regional basis. Objectives: 1. Establish the degree of stock structure in the northern Australian Scomberomorus commerson stock, over a wide geographic range; 2. Having demonstrated structural differences within the northern stock on the large scale, describe finer scale spatial structure; and, 3. Provide advice to the fishery administrations on the appropriate geographic scale of assessment and management actions. 4. To include the analysis of otolith and genetic material collected from Kupang (Indonesia). 5. To collect and analyse parasite samples from Spanish Mackerel. Read moreRead less
Use Of The Bomb Radiocarbon Chronometer To Validate Fish Age
Funder
Fisheries Research and Development Corporation
Funding Amount
$254,208.17
Summary
Objectives: 1. Validate ages of SBT(Thunnus maccoyii), redfish(Centroberyx affinis), blue grenadier(Macruronus novaezelandiae), and school shark(Galeorhinus australis) 2. Determine the suitability of the radio carbon chronometer for age validation of oreo species 3. Determine other species suitable for age validation via the bomb radiocarbon chronometer
Determination Of The Migration Patterns Of Juvenile Southern Bluefin Tuna And Jackass Morwong
Funder
Fisheries Research and Development Corporation
Summary
Objectives: 1. Determine whether or not all juvenile southern bluefin tuna migrate down coast of WA, hence whether Aust fishery based on all or part of each cohort. 2. Validate ageing techniques for adults. 3. Are bays & estuaries in southern Tasmania the sole nursery grounds of jackass morwong?