Postgraduate Funding - Population Biology And Dynamics Of Yellowfin Whiting
Funder
Fisheries Research and Development Corporation
Funding Amount
$75,000.00
Summary
The South Australian Marine Scalefish Fishery (MSF) is the most complex fishery in South Australia and is currently undergoing transition through structural reform, development of new harvest strategies and review of the Management Plan. Changes in the dynamics of the fleet have resulted in redirection of effort from primary species such as garfish, snapper and King George whiting towards secondary species including yellowfin whiting.
Yellowfin whiting Sillago schomburgkii is the second ....The South Australian Marine Scalefish Fishery (MSF) is the most complex fishery in South Australia and is currently undergoing transition through structural reform, development of new harvest strategies and review of the Management Plan. Changes in the dynamics of the fleet have resulted in redirection of effort from primary species such as garfish, snapper and King George whiting towards secondary species including yellowfin whiting.
Yellowfin whiting Sillago schomburgkii is the second most valuable Sillaginid after King George whiting and one of the most valuable secondary species in the MSF fishery with most catches from Northern Spencer Gulf, and smaller catches from the West Coast, Southern Spencer Gulf, and Gulf St Vincent. There are also significant recreational catches (31.5% of State catch in 2013/14).
There is a need for improved understanding of the life-history of yellowfin whiting with quantitative estimates of population dynamics including reproduction, growth performance and stock structure. Oceanographic separation of Spencer Gulf and Gulf St Vincent suggests that yellowfin whiting may constitute separate stocks in these regions while possible population sub-structuring occurring at smaller scales has implications for fishery management. There is potential to compare results of the proposed study with previous work to investigate whether decadal changes in the demography and population dynamics of yellowfin whiting have occurred in the South Australian Gulfs, as well as potential factors driving any change.
This project proposal aims to (i) build the capacity for scientific investigation of finfish species in South Australia by providing an opportunity for a science graduate to develop skills in fishery science, (ii) improve the understanding of life-history and population dynamics of yellowfin whiting, and (iii) improve understanding of the stock structure of yellowfin whiting. This project will have linkages to another FRDC funded project (2017/023), “ESD risk assessment for under-utilised species to facilitate structural reform of South Australia’s commercial Marine Scalefish Fishery”.
Objectives: 1. Define the stock structure of yellowfin whiting in South Australia and the relationship to Western Australian stocks using genomic approaches. 2. Define finer scale population structure of yellowfin whiting in the South Australian gulfs using otolith chemistry. 3. Examine spatial and temporal trends in catch among yellowfin whiting and other species in the marine scalefish fishery and how representation among different life-history strategy groups has changed. 4. Investigate size and age structures of yellowfin whiting in the two gulfs of SA and how these have changed over a 22 year period. 5. Increase fisheries science capacity in South Australia through training of the next generation of researchers. Read moreRead less
Assessment Of The Utility Of Genomics For Sydney Rock Oyster Breeding
Funder
Fisheries Research and Development Corporation
Funding Amount
$620,000.00
Summary
Genomics is routinely used across many livestock and plant breeding industries. It is now practical, within certain considerations, to consider applying genomic selection to aquaculture breeding programs due to significant cost reductions in the last decade. Its use in aquaculture breeding programs is increasing and genomics has already been researched for oyster breeding by USC (Vu et al. 2021a; Vu et al. 2021b).
Genomic selection has the potential to reduce the cost of estimating bre ....Genomics is routinely used across many livestock and plant breeding industries. It is now practical, within certain considerations, to consider applying genomic selection to aquaculture breeding programs due to significant cost reductions in the last decade. Its use in aquaculture breeding programs is increasing and genomics has already been researched for oyster breeding by USC (Vu et al. 2021a; Vu et al. 2021b).
Genomic selection has the potential to reduce the cost of estimating breeding values, which presently is a costly and challenging exercise with SROs and also may potentially increase genetic progress and selection accuracy for the SRO BP. The research proposed in this application will evaluate if it is possible to increase genetic progress for the productivity traits of QX disease resistance and growth as well as the product quality trait of meat condition. Increased QX survival and growth are particularly important traits for the SRO industry at this current time due to Port Stephens, the second largest SRO producing estuary in NSW, reeling from the impact of QX disease outbreaks. Climate change resilience is a new trait being investigated for incorporation into the breeding program for industry to respond to this threat. We would also like to assess whether genomics can provide a pathway to increase selection for resilience.
This project has been developed in line with the Oysters Australia Strategic Plan 2020 and the FRDC R&D Plan 2020-2025. The outcomes from this project will assess the feasibility of increasing selection accuracy for traits that improve productivity (growth and meat condition) as well as reduce impacts caused by QX disease and climate change through breeding for resilience. The outcomes will assess the possibility to improve genetic selections for multiple traits such that oysters can be selected on their ability to adapt to new climate conditions, survive QX disease whilst having faster growth and better meat condition. Additionally, this project will build new knowledge skills and networks through a NSW DPI, The University of the Sunshine Coast and The University of New South Wales alliance as well as create post-doctoral study opportunities. These meet the goals in Program 1, 2 and 3 outlined in the 2020-2025 Oysters Australia Strategic Plan.
With respect to the FRDC R&D Plan 2020-2025, this project will build capacity and create knowledge through developing skills and networks between NSW DPI, The University of the Sunshine Coast and The University of NSW to breed oysters that offer oyster businesses greater profitability, reduced risk and that can adapt to changing environments.
This project will explore alternative methods to what is presently used for SRO breeding to assess feasibility of genomic selection and what might be required today to move towards genomic selection in the future. This project will start compiling a reference library for SROs that can be used in the future and promote innovation in SRO breeding to integrate the technology developed from this project. Moreover, costs associated with genomic selection are reducing which increases the value proposition for incorporation into the future. The ultimate success and transfer of outcomes from this project to end user beneficiaries will be through incorporation of these new technologies into the SRO breeding program. Objectives: 1. Collect tissue samples using non-lethal methods and tagging to identify oysters 2. Sequence the whole genomes of selected individuals at high read depth, which will serve as the genotype resource for the project 3. Identify the associations between genotypes and phenotypes and compile a list of genetic markers and the genes associated with QX survival, whole weight and meat condition to then use modelling (for genomic predictions) to give individuals breeding values Read moreRead less
Optimising plant populations for ecological restoration and resilience. When choosing individual plants for restoration populations, there is potentially a trade-off between maximising genetic diversity (‘adaptability’) and selection for desirable properties (‘adaptation’). This project aims to develop pioneering methods to quantify this trade-off, and facilitate the design of optimised populations, with a focus on two Australian rainforest trees that are being impacted by myrtle rust infection: ....Optimising plant populations for ecological restoration and resilience. When choosing individual plants for restoration populations, there is potentially a trade-off between maximising genetic diversity (‘adaptability’) and selection for desirable properties (‘adaptation’). This project aims to develop pioneering methods to quantify this trade-off, and facilitate the design of optimised populations, with a focus on two Australian rainforest trees that are being impacted by myrtle rust infection: Rhodamnia argentea and Rhodamnia rubescens. By studying the genetic variation in each species, and how this relates to myrtle rust resistance and climate, this project aims to design populations that are genetically diverse, maximally resistant to myrtle rust, and adapted to future climate.Read moreRead less
Genome evolution & adaptation of the multinuclear wheat stripe rust fungus. Animals and plants package their genomes into a single nucleus within each cell. In contrast, millions of fungal species accommodate multiple nuclei containing individual haploid genomes. It is currently unknown what the evolutionary implications are for this unusual genome division into multiple nuclei. Here we explore the evolutionary consequences of genome division into multiple nuclei for the first time by applying c ....Genome evolution & adaptation of the multinuclear wheat stripe rust fungus. Animals and plants package their genomes into a single nucleus within each cell. In contrast, millions of fungal species accommodate multiple nuclei containing individual haploid genomes. It is currently unknown what the evolutionary implications are for this unusual genome division into multiple nuclei. Here we explore the evolutionary consequences of genome division into multiple nuclei for the first time by applying cutting edge genome biology tools and algorithms. The economically significant study system is the devastating wheat stripe rust fungus. This pathogen costs Australian farmers over $100 million a year. New understanding is expected to lead to better disease management, reduced fungicide applications, and increased yields.Read moreRead less
Diagnostic Detection Of Aquatic Pathogens Using Real-time Next Generation Sequencing
Funder
Fisheries Research and Development Corporation
Funding Amount
$216,000.00
Summary
Current diagnostic programs generally rely on highly -specific assays for pathogen detection. While these techniques are invaluable, they are one dimensional and do not provide detailed information critical to a disease investigation. These gaps include the inability to detect unknown pathogens and potential variants of know pathogens and provide no additional genomic or transcriptomic data. Moreover, samples must be shipped to trained personnel in a laboratory, further delaying the time to diag ....Current diagnostic programs generally rely on highly -specific assays for pathogen detection. While these techniques are invaluable, they are one dimensional and do not provide detailed information critical to a disease investigation. These gaps include the inability to detect unknown pathogens and potential variants of know pathogens and provide no additional genomic or transcriptomic data. Moreover, samples must be shipped to trained personnel in a laboratory, further delaying the time to diagnosis. The MinION, on the other hand, can theoretically detect any pathogen and can potentially be deployed to the field. Moreover, the MinION can rapidly generate full-length genomes, allowing for epidemiological tracking of viral or bacterial strains in near real-time. Such rapid data, which cannot be obtained as quickly using existing methods, are vital if the intention is to intervene in an outbreak and reduce impacts on the productivity and profitability of aquaculture facilities. For example, a rapid, early diagnosis may allow mitigating actions to be taken on-farm, such as the diversion of intake water, movement restrictions of stock and the isolation of infected ponds. These qualities make the MinION an attractive complimentary platform to fill several gaps in the data obtained during disease outbreak investigations, or routine diagnostics, and potentially for use in the field. However, results from the misuse or lack of understanding of the technology could also have adverse regulatory implications for aquaculture industries. For example, without appropriate guidelines, an inexperienced diagnostician may misinterpret a distant DNA match in a pathogen database as a significant result, this may create unwanted attention to industry and potential stock destruction or changes to disease status that are unjustified. Thus, it is critical that the MinION is evaluated at the Australian Animal Health Laboratory, and guidelines and procedures are developed for accurate diagnostic evaluations. The activities detailed in this application will establish the feasibility of using the MinION for diagnostic applications, and ensure that the data is reliably generated and interpreted appropriately.
Objectives: 1. Evaluate if MinION data meets or exceeds the data obtained using established laboratory-based NGS platforms. Objectives (1) and (2) align with Methods section (1).The first objective of this project is to demonstrate if the MinION can obtain quality genome assemblies of known pathogens, such as WSSV, AHPND, OsHV-1 and HaHV that have been created using existing NGS technology. Moreover, determine if the MinION is capable of producing a diagnostic result more rapidly and with greater confidence than traditional techniques. STOP/GO POINT: If MinION data does not produce reliable genome assemblies, no improvement in genome quality, or is significantly more laborious to set-up/run or analyse than existing NGS technologies, do not proceed with objective 2. 2. Evaluate the performance of the MinION using existing diagnostic extraction techniques and produce robust methods and protocols for sample preparation, sequencing and data analysis. This objective will optimise MinION protocols for sample pre-processing, optimal sequencing conditions, and data post-processing. We will then evaluate the MinION data produced from a range of aquatic organisms against data produced using traditional techniques from the same samples. STOP/GO POINT: If after these optimisations, the MinION cannot detect pathogens as reliably as traditional techniques, do not proceed with objective 3. 3. Compare the applicability of MinION to standard molecular assays for identification of pathogens in diagnostic samples. Objective (3) is aligned with Methods section (2).In this objective, diagnostic samples will be tested using existing diagnostics tools (qPCR, cPCR) and MinION sequencing. Analysis between the methods will be detailed, including time to result, pathogen identity and genomic information. This objective will not only provide an insight into real-time sequencing for diagnostics, but in addition the feasibility of MinION technology for field application in the future. Read moreRead less
Aquatic Animal Health And Biosecurity Subprogram: Comparative Pathogenicity Of Exotic Acute Hepatopancreatic Necrosis Disease (AHPND) And The Presumptive Bacterial Hepatopancreatitis Detected In Farmed Penaeus Monodon In Queensland
Funder
Fisheries Research and Development Corporation
Funding Amount
$131,106.00
Summary
Australian prawn production, forecast at 24 kilotonnes in 2014/15, is valued at >$310 million. The prawn fishery is an important natural resource that supports a substantial export industry. Prawn aquaculture in northern Australia accounts for approximately 20% of the total volume of Australian production. The new, emerging disease syndrome, characterised by hepatopancreatitis and mortalities in farmed P monodon, was first reported in north Queensland in early 2015. The disease was again detecte ....Australian prawn production, forecast at 24 kilotonnes in 2014/15, is valued at >$310 million. The prawn fishery is an important natural resource that supports a substantial export industry. Prawn aquaculture in northern Australia accounts for approximately 20% of the total volume of Australian production. The new, emerging disease syndrome, characterised by hepatopancreatitis and mortalities in farmed P monodon, was first reported in north Queensland in early 2015. The disease was again detected in late 2015 and emerged in central Queensland in early 2016. The disease in two prawn farming regions in Queensland is ongoing. While there are similarities with the emerging disease in central and north Queensland with exotic AHPND, the following important information is still unknown:
1) what is the variability (if any) in host bacterial strains associated with the AHPND toxin genes in diseased prawns in Queensland, particularly between the two different regions currently affected?
2) what is the pathogenicity of Australian bacterial isolates containing the AHPND toxin genes to P. monodon and P merguiensis how does this compare to disease caused by exotic AHPND isolates?
3) the preliminary WGS analysis needs to be repeated/confirmed using a more stringent and advanced platform.
This project will characterise the causative agent(s) and hepatopancreatitis disease in Australian farmed P. monodon. This information is critical for the prawn industry, policy-makers and regulators in order to respond to the disease. The Project aligns with Key Research Area 6.2.1 of the FRDC AAHS R&D Plan “Knowledge about new and emerging infectious diseases”.
Objectives: 1. Compare the pathogenicity of exotic AHPND and the presumptive bacterial hepatopancreatitis in Penaeus monodon and P. merguensis. 2. Compare the pathology caused by exotic AHPND and the presumptive bacterial hepatopancreatitis in Penaeus monodon and P. merguensis. 3. Determine the whole genome sequence of the Vibrio harveyi strain from farmed Penaeus monodon and P. merguensis presumptive bacterial hepatopancreatitis. 4. Optimise, evaluate through inter-laboratory testing and then implement improved diagnostic tests for the Pir toxin gene. Read moreRead less
Discovery Early Career Researcher Award - Grant ID: DE240100573
Funder
Australian Research Council
Funding Amount
$450,877.00
Summary
Genomics of extinction and isolation on Australian island arks. This project aims to measure the genetic health of key populations of threatened Australian mammals. With the highest rate of extinction in the world and over 30% of surviving species under immediate threat, Australian mammals require urgent focus to secure their future. This project focuses on island populations, which are increasingly used as sources to rewild mainland Australia. Using cutting-edge genomic tools, this project plan ....Genomics of extinction and isolation on Australian island arks. This project aims to measure the genetic health of key populations of threatened Australian mammals. With the highest rate of extinction in the world and over 30% of surviving species under immediate threat, Australian mammals require urgent focus to secure their future. This project focuses on island populations, which are increasingly used as sources to rewild mainland Australia. Using cutting-edge genomic tools, this project plans to determine the extent and nature of genetic variation, including harmful mutations, on islands and in declining mainland populations. The anticipated outcome is to understand how genetic factors contribute to extinction, to improve conservation strategies for threatened species.Read moreRead less
Snapper Science Program: Theme 1 - Biology And Ecology
Funder
Fisheries Research and Development Corporation
Funding Amount
$1,982,523.00
Summary
A comprehensive understanding of the general biology and ecology of any fishery species is fundamental to determine its response to exploitation and inform appropriate fishery management. Despite the significant body of research into the biology of Snapper, there remain considerable knowledge gaps regarding the underlying factors that drive interannual variation in juvenile recruitment and the demographic processes that maintain populations. Furthermore, there is uncertainty in how these process ....A comprehensive understanding of the general biology and ecology of any fishery species is fundamental to determine its response to exploitation and inform appropriate fishery management. Despite the significant body of research into the biology of Snapper, there remain considerable knowledge gaps regarding the underlying factors that drive interannual variation in juvenile recruitment and the demographic processes that maintain populations. Furthermore, there is uncertainty in how these processes will be influenced by changing environmental conditions associated with climate change. As such, understanding drivers of recruitment variability was identified as one of the highest research priorities for Snapper at the most recent National Workshop (FRDC Project No. 2019-085; Cartwright et al. 2021). Given the strong relationship between episodic recruitment and fishery production described above for the SG/WCS and GSVS, this recommendation was also strongly endorsed by fishery researchers, managers, and industry stakeholders in SA (Drew et al. 2022).
This research proposal has been developed to address four research priorities: • To understand the biological and environmental factors that affect recruitment of Snapper in SA and evaluate the potential influence of climate change. • Provide a contemporary understanding of stock structure for Snapper on the west coast of Eyre Peninsula to inform the appropriate spatial scale for fishery management. • Develop a contemporary series of biological parameters for each stock of Snapper in SA to be used as inputs in the stock assessment model. • Evaluate changes in the physical environment that may affect Snapper recruitment.
Consequently, Research Theme 1 – Biology and Ecology involves four projects: 1.1 Investigating recruitment variability and evaluating the potential effects of climate change for Snapper in South Australia 1.2 Contemporary demographic processes and stock structure for Snapper on the west coast of Eyre Peninsula 1.3 Review of biological parameters for Snapper in South Australia 1.4 Benthic habitat survey for Gulf St Vincent.
1.1 Investigating recruitment variability and evaluating the potential effects of climate change for Snapper in South Australia The population dynamics and fishery productivity for Snapper in SA are fundamentally driven by highly variable interannual recruitment, i.e., the number of age 0+ juveniles that enter the population each year (Fowler et al. 2017, Fowler and Jennings 2003). As such, a relative index of annual age 0+ juvenile abundance would be a powerful, fishery-independent tool to predict future trends in fishable biomass. To address this need, a recent project was undertaken to identify the most appropriate sampling methodology for age 0+ Snapper in SA’s gulfs and to develop a pre-recruit index (FRDC Project No. 2019-046). The first component of the present study involves the continuation of annual surveys for age 0+ Snapper for each stock to monitor trends in juvenile recruitment. The surveys will be repeated annually at the recognised nursery areas for each stock, i.e., northern Spencer Gulf (NSG) for the SG/WCS and northern Gulf St Vincent (NGSV) for the GSVS (Fowler et al. 2017). In addition, age 1+ juvenile Snapper will be sampled from annual fishery-independent surveys for the Spencer Gulf and Gulf St Vincent prawn fisheries, which will provide further information to determine relative year class strength.
The second component of the study involves investigating the relationships between environmental parameters and recruitment. The datasets for juvenile abundance will be considered with annual population age structures to develop a time series of recruitment for the two stocks (i.e., late 1960s to 2020s). Long-term time series of environmental parameters (e.g., temperature, salinity, productivity, wind stress) will be developed and compared to the time series of recruitment for each stock. In conjunction with the pre-recruit index, understanding the environmental influences that drive recruitment variability would provide even greater predictive capability to forecast trends in recruitment and fishable biomass, particularly under changing environmental conditions associated with climate change.
The third component of the study will investigate the potential effects of environmental change for Snapper in SA. Using the environmental datasets previously developed, a high-resolution oceanographic model for SA will be hindcast to determine the intensity of local environmental change and identify potential climate ‘hot spots’. The model will then be forecast with different climate change scenarios to predict changes in ocean conditions over the next 5, 10, and 50 years. Based on the physiological tolerance ranges for Snapper spawning and larval development, these predictions will be used to evaluate potential shifts in the availability of suitable environmental conditions for Snapper in SA. Such responses will be considered in terms of potential implications for future trends in recruitment and fishable biomass.
1.2 Contemporary demographic processes and stock structure for Snapper on the west coast of Eyre Peninsula There are three recognised stocks of Snapper in SA waters: the SG/WCS, the GSVS, and the Western Victoria Stock (WVS) (Fowler 2016, Fowler et al. 2017). The population of Snapper on the West Coast of Eyre Peninsula (WC) is a regional component of the SG/WCS. It is hypothesised that in most years, the WC population is replenished by local demographic processes that maintain the population at a relatively low level. However, episodically in years of exceptionally strong recruitment in northern Spencer Gulf (i.e., 1991, 1997, and 1999), the WC population is replenished through the density dependent emigration of fish of a few years of age that disperse from northern Spencer Gulf, through southern Spencer Gulf and to the WC. These fish then remain on the WC for the remainder of their lives.
As a consequence of the prolonged period of poor recruitment in northern Spencer Gulf since 1999 and the subsequent depletion of the population in Spencer Gulf, it is unlikely that this density dependent movement from Spencer Gulf to the WC has occurred to a major extent for a number of years or will occur until the Spencer Gulf population has recovered. Furthermore, age structures for the WC developed in 2020 and 2021 showed that only a very small number of fish from the strong 1997- and 1999-year classes in northern Spencer Gulf remained in the population, and there were several other year classes in the age structures for the WC that were not present in northern Spencer Gulf (Drew et al. 2022). Consequently, there is a need to understand the relative contributions of local population processes and emigration from northern Spencer Gulf to the WC population. This is particularly important following the regionalisation of the fishery through the Marine Scalefish Fishery (MSF) Reform (Smart et al. 2022).
This study will investigate the contemporary demographic processes that maintain the population of Snapper on the WC through the regional comparison of population age structures, elemental chemistry of otoliths, and population genomics. The findings will provide insight into the relative contributions of local recruitment and emigration to the WC population, that will be compared to the existing conceptual model of stock structure for Snapper in SA (Fowler 2016, Fowler et al. 2017). The proposed study will build on several previous projects that have investigated the stock structure of Snapper in SA (i.e., FRDC Project No. 2002-001, FRDC Project No. 2012-020, ARC Linkage Project No. LP180100756).
1.3 Review of biological parameters for Snapper in South Australia The biology of Snapper in SA has been studied over the past 40 years, with particular focus on northern Spencer Gulf (e.g., Jones 1981, 1987, McGlennon 2003). Since 2000, a weekly market sampling program has been undertaken by SARDI researchers that has provided biological data for Snapper caught by commercial fishers across SA. The sampling program has been augmented with periodic trips to regional areas, research cruises, and targeted research projects. Since the closure of the SG/WCS and GSVS in November 2019, biological samples from the two stocks have been accessed through a targeted sampling program which involved contracting commercial fishers. The data collected through these projects and programs is maintained in a MS Access database which currently contains biological information (i.e., capture date, location, length, weight, sex, reproductive stage, and age) for >27,000 Snapper and length information for >75,000 individuals.
This study will investigate potential changes in the biological characteristics of Snapper throughout SA over the past 40 years in response to temporal changes in environmental conditions and stock abundance. This will involve spatial and temporal comparisons of length, age, growth rate, and length at maturity for Snapper from each region of SA. The study will also consider various approaches to estimate natural mortality. A key output of the study is a summary of contemporary biological parameters for each stock of Snapper in SA that will be incorporated into the stock assessment model (‘SnapEst’).
1.4 Benthic habitat survey for Gulf St Vincent Snapper utilise a diversity of different benthic habitats throughout its life history, ranging from soft sediments that are favoured by recently settled juveniles to high relief structures that act as aggregation sites for spawning adults. As a result of the significant interannual variation in recruitment observed for Snapper in SA and the subsequent development of a pre-recruit index, there is particular interest in the spatial distribution and relative abundance of benthic habitats that act as nursery areas for age 0+ juvenile Snapper. In order for the pre-recruit index to provide reliable estimates of annual recruitment, it is essential that the key areas which support 0+ Snapper are sampled consistently each year.
In the recent project to develop a pre-recruit index (i.e., FRDC 2019-046), sampling for 0+ juvenile Snapper was targeted at the hypothesised nursery areas for each stock, i.e., northern Spencer Gulf (NSG) for the SG/WCS and northern Gulf St Vincent (NGSV) for the GSVS (Fowler et al. 2017). For NSG, the sampling design was informed by the results of annual surveys in the region from 2000 to 2010, which identified a strong relationship between the spatial distribution and abundance of 0+ Snapper and localised areas of soft, silty benthic substrate (Fowler and Jennings 2003, Fowler et al. 2010). There were no previous surveys for 0+ Snapper in NGSV, and therefore sampling locations were determined by the presence of suitable benthic substrate from existing habitat studies (Shepherd and Sprigg 1976, Tanner 2002). However, from 2021 to 2023, the catches of age 0+ Snapper in NGSV were very low in each annual survey and it cannot be determined if this reflected poor juvenile recruitment in these years, or if key nursery areas were not adequately sampled.
The aim of this study is to quantify the spatial distribution and relative abundance of benthic habitats in GSV, with particular emphasis on localised areas of soft substrate that may support age 0+ juvenile Snapper. The study will use towed underwater video and particle size analysis of sediment samples to quantify habitat types at ~150 sites throughout GSV following the methods recently applied in Spencer Gulf (FRDC 2020-002; Grammer et al. in prep.). The spatial distribution and relative abundance of benthic habitat types identified in this study will be compared to previous surveys in 1964-69 (Shepherd and Sprigg 1976) and 2000-01 (FRDC Project No. 1998-208; Tanner 2002) to assess changes in benthic habitats in GSV over the past 50 years, and how such changes may relate to trends in recruitment and stock abundance for Snapper over this time.
Objectives: 1. Quantify the abundance of age 0+ Snapper in northern Spencer Gulf and Gulf St Vincent to provide relative estimates of recruitment for 2024, 2025, and 2026. Examine the otoliths of these fish to improve the understanding of early life history processes. 2. Evaluate the relationships between environmental parameters and recruitment variability for Snapper in South Australia and evaluate the potential effects of environmental change on spawning and recruitment. 3. Determine the contemporary demographic processes that maintain Snapper populations on the west coast of Eyre Peninsula, i.e., local recruitment vs. emigration from adjacent regional populations, and to use this information to assess stock structure. 4. Assess possible changes in key biological parameters of Snapper for each stock in South Australia in response to temporal changes in environmental conditions and stock abundance. 5. Quantify the spatial distribution and relative abundance of benthic habitats utilised by juvenile Snapper in Gulf St Vincent and assess potential changes over the past 50 years. Read moreRead less
Diatom lipids to reveal sea-ice history in remote Antarctic regions. This project aims to understand seasonal Antarctic sea-ice extent using molecular, geochemical, elemental and genomic characteristics of specific marine phytoplankton (diatoms). Little is known of the seasonal sea-ice variation and the position of the summer sea-ice extent a million years before satellite records, but this information is critical to determining air-sea gas exchange and ecosystem food web regulation. This projec ....Diatom lipids to reveal sea-ice history in remote Antarctic regions. This project aims to understand seasonal Antarctic sea-ice extent using molecular, geochemical, elemental and genomic characteristics of specific marine phytoplankton (diatoms). Little is known of the seasonal sea-ice variation and the position of the summer sea-ice extent a million years before satellite records, but this information is critical to determining air-sea gas exchange and ecosystem food web regulation. This project will unite geochemical and biological approaches to provide the data to improve past Antarctic ecosystem and climate models where sea-ice data is missing. Studying diatom biomarkers in deep sea cores from Australia’s Southern Ocean will redefine knowledge of Antarctic climate and provide data necessary to improve global ecosystem and climate models.Read moreRead less