Recent publications in Science and Engineering

College of Science and Engineering Recent publications in Science and Engineering

Younes Cárdenas, Nicolás, Joyce, Karen E., and Maier, Stefan W. (2017) Monitoring mangrove forests: are we taking full advantage of technology? International Journal of Applied Earth Observation and Geoinformation, 63. pp. 1-14.
Mangrove forests grow in the estuaries of 124 tropical countries around the world. Because in-situ monitoring of mangroves is difficult and time-consuming, remote sensing technologies are commonly used to monitor these ecosystems. Landsat satellites have provided regular and systematic images of mangrove ecosystems for over 30 years, yet researchers often cite budget and infrastructure constraints to justify the underuse this resource. Since 2001, over 50 studies have used Landsat or ASTER imagery for mangrove monitoring, and most focus on the spatial extent of mangroves, rarely using more than five images. Even after the Landsat archive was made free for public use, few studies used more than five images, despite the clear advantages of using more images (e.g. lower signal-to-noise ratios). The main argument of this paper is that, with freely available imagery and high performance computing facilities around the world, it is up to researchers to acquire the necessary programming skills to use these resources. Programming skills allow researchers to automate repetitive and time-consuming tasks, such as image acquisition and processing, consequently reducing up to 60% of the time dedicated to these activities. These skills also help scientists to review and re-use algorithms, hence making mangrove research more agile. This paper contributes to the debate on why scientists need to learn to program, not only to challenge prevailing approaches to mangrove research, but also to expand the temporal and spatial extents that are commonly used for mangrove research.

Antunes, Elsa, Jacob, Mohan V., Brodie, Graham, and Schneider, Philip A. (2017) Silver removal from aqueous solution by biochar produced from biosolids via microwave pyrolysis. Journal of Environmental Management, 203 (Part 1). pp. 264-272.
The contamination of water with silver has increased due to the widespread applications of products with silver employed as antimicrobial agent. Adsorption is a cost-effective method for silver removal from aqueous solution. In this study biochar, produced from the microwave assisted pyrolysis of biosolids, was used for silver removal from an aqueous solution. The adsorption kinetics, isotherms and thermodynamics were investigated to better understand the silver removal process by biochar. X-ray diffraction results demonstrated that silver removal was a combination two consecutive mechanisms, reduction and physical adsorption. The Langmuir model fitted the experimental data well, showing that silver removal was predominantly a surface mechanism. The thermodynamic investigation demonstrated that silver removal by biochar was an exothermic process. The final nanocomposite Ag-biochar (biochar plus silver) was used for methylene blue adsorption and photodegradation. This study showed the potential of using biochar produced from biosolids for silver removal as a promising solution to mitigate water pollution and an environmentally sustainable approach for biosolids management and re-use.

Parackal, K.I., Ginger, J.D., and Henderson, D.J. (2017) Correlation of peak wind loads at batten-truss connections. In: Proceedings of the 24th Australasian Conference on the Mechanics and Structures and Materials, pp. 1899-1904. From: ACMSM24: 24th Australasian Conference on the Mechanics of Structures and Materials, 6-10 December 2016, Perth, WA, Australia.
Wind loads on roofs fluctuate significantly, both across their surfaces and in time. A 1/50 scale wind tunnel study was conducted to determine the correlations of these load fluctuations on batten to truss connections. This study found that load histories between neighbouring connections are correlated and are sensitive to wind direction. Critical wind directions that cause the highest uplift loads are not necessarily those that experience the highest correlations amongst neighbouring connections. Additionally, for different wind directions loads at connections to the left, right or diagonally across from the critical connections are more correlated, suggesting that the path that a progressive failure takes is dependent on wind direction and the location on the roof where it initiates.

Jaditager, Mohamed, and Sivakugan, Nagaratnam (2017) Influence of fly ash-based geopolymer binder on the sedimentation behaviour of dredged mud. Journal of Waterway, Port, Coastal, and Ocean Engineering, 143 (5). pp. 1-9.
This laboratory study investigated the sedimentation behavior of a fly ash–based geopolymer-stabilized dredged-mud slurry extracted from the Port of Townsville, Queensland, Australia. Settling-column tests were conducted to study the sedimentation behavior of 400%-water-content dredged mud of untreated and geopolymer-stabilized slurries at 6, 12, and 18% content by weight. Dredged-mud slurry interface height movements with elapsed time were recorded, and their settling patterns were observed. Mineralogical and microstructural characteristics of dried, untreated, and geopolymer-stabilized dredged-mud sediments were determined using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) analysis. The study found that a fly ash–based geopolymer gel coating the dredged-mud particles in the slurry led to a flocculated settling behavior, and the geopolymer stabilization reduced the overall dredged-mud slurry sedimentation duration. XRD and SEM/EDS analysis showed that the geopolymer stabilization altered the microstructure of stabilized dredged-mud sediment and reduced its desiccation shrinkage cracks.

Rowen, David J., Templeman, Michelle A., and Kingsford, Michael J. (2017) Herbicide effects on the growth and photosynthetic efficiency of Cassiopea maremetens. Chemosphere, 182. pp. 143-148.
Herbicides from agricultural run-off have been measured in coastal systems of the Great Barrier Reef over many years. Non-target herbicide exposure, especially photosystem II herbicides has the potential to affect seagrasses and other marine species. The symbiotic benthic jellyfish Cassiopea maremetens is present in tropical/sub-tropical estuarine and marine environments. Jellyfish were exposed to agricultural formulations of diuron or hexazinone to determine their sensitivity and potential for recovery to pulsed herbicide exposure. Jellyfish growth, symbiont photosynthetic activity and zooxanthellae density were analysed for herbicide-induced changes for 7 days followed by a 7 day recovery period. Both the jellyfish and endosymbiont were more sensitive to diuron than hexazinone. The 7-day EC50 for jellyfish growth was 0.35 µg.L-1 for Diuron and 17.5 µg.L-1 for Hexazinone respectively. Diuron exposure caused a significant decrease in(p<0.05) in jellyfish growth at all concentrations and at levels0.1 µg.L-1, a level that is below the regional Great Barrier Reef guideline valuesvalue. Jellyfish recovery was rapid with growth rates similar to control animals following removal from herbicide exposure. Both diuron and hexazinone caused significant decreases in photosynthetic efficiency (effective quantum yield) in all treatment concentrations (0.1 µg.L-1 and above) and this effect continued in the post-exposure period. As this species is frequently found in near-shore environments, they may be particularly vulnerable to herbicide run-off.

Roth, Christian, Addison, Jane, Anthony, Ken, Dale, Allan, Eberhard, Rachel, Hobday, Alistair, Horner, Nerida, Jarvis, Diane, Kroon, Frederieke, Stone-Jovicich, Samantha, and Walshe, Terry (2017) Reef 2050 Plan Review Options: Final report submitted to the Department of the Environment and Energy. Report. CSIRO, Australia.
[Extract] In preparation for the 2018 midterm review of Reef 2050 Plan, the Reef 2050 Plan Joint Implementation Team commissioned an expert consortium from CSIRO, the Australian Institute of Marine Sciences, James Cook University and Eberhard Consulting to provide advice on review options. This report provides a summary of the analysis undertaken to underpin the recommendations on scope and process of the midterm review, as well as providing recommendations on additional steps for the Joint Team to consider in preparation for the 2020 review. This report is supplemented by a separate Appendix Report that provides a more detailed account of the analysis undertaken.

Satheeskumar, Navaratnam, Henderson, David James, Ginger, John David, and Wang, Chi-Hsiang (2017) Three-dimensional finite-element modeling and validation of a timber-framed house to wind loading. Journal of Structural Engineering, 143 (9). pp. 1-11.
This paper presents a three-dimensional (3D) finite-element model (FEM) of part of a contemporary timber-framed house for assessing the load sharing and contribution of lining elements to load sharing. Assembled with intercomponent connections (i.e., batten-to-cladding connections, batten-to-truss connections, and roof-to-wall connections), the model consists of structural frame elements (e.g., trusses, battens, metal roof cladding, top plates, bottom plates, and wall studs) and lining elements (e.g., ceiling, wall lining, and ceiling cornice). The model analyses agree favorably with results from full-scale structural tests. The FEM shows that adding lining elements decreases the vertical reaction of the roof-to-wall connection by approximately 25%. This validated model provides confidence for assessing the structural response of a range of typical house geometries and materials including the effects of construction defects to wind loads.

AL-Jumaili, Ahmed, Alancherry, Surjith, Bazaka, Katia, and Jacob, Mohan V. (2017) Review on the antimicrobial properties of carbon nanostructures. Materials, 10 (9). pp. 1066-1052.
Swift developments in nanotechnology have prominently encouraged innovative discoveries across many fields. Carbon-based nanomaterials have emerged as promising platforms for a broad range of applications due to their unique mechanical, electronic, and biological properties. Carbon nanostructures (CNSs) such as fullerene, carbon nanotubes (CNTs), graphene and diamond like carbon (DLC) have been demonstrated to have potent broad-spectrum antibacterial activities toward pathogens. In order to ensure the safe and effective integration of these structures as antibacterial agents into biomaterials, the specific mechanisms that govern the antibacterial activity of CNSs need to be understood, yet it is challenging to decouple individual and synergistic contributions of physical, chemical and electrical effects of CNSs on cells. In this article, recent progress in this area is reviewed, with a focus on the interaction between different families of carbon nanostructures and microorganisms to evaluate their bactericidal performance.

AL-Jumaili, Ahmed, Bazaka, Kateryna, and Jacob, Mohan V. (2017) Retention of antibacterial activity in geranium plasma polymer thin films. Nanomaterials, 7 (9). pp. 1-22.
Bacterial colonisation of biomedical devices demands novel antibacterial coatings. Plasma-enabled treatment is an established technique for selective modification of phyiso-chemical characteristics of the surface and deposition of polymer thin films. We investigated the retention of inherent antibacterial activity in geranium based plasma polymer thin films. Attachment and biofilm formation by Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was significantly reduced on the surfaces of samples fabricated at 10 W RF power compared to that of control or films fabricated at higher input power. This was attributed to lower contact angle and retention of original chemical functionality in the polymer films fabricated under low input power conditions. The topography of all surfaces was uniform and smooth, with surface roughness of 0.18 and 0.69 nm for films fabricated at 10 W and 100 W, respectively. Hardness and elastic modules of films increased with input power. Independent of input power, films were optically transparent within the visible wavelength range, with the main absorption at ~290 nm and optical band gap of ~3.6 eV. These results suggest that geranium extracts-derived polymers may potentially be used as antibacterial coatings for contact lenses.

Carter, A.B., Davies, C.R., Emslie, M.J., Mapstone, B.D., Russ, G.R., Tobin, A.J., and Williams, A.J. (2017) Reproductive benefits of no-take marine reserves vary with region for an exploited coral reef fish. Scientific Reports, 7. pp. 1-12.
No-take marine reserves (NTMRs) are expected to benefit fisheries via the net export of eggs and larvae (recruitment subsidy) from reserves to adjacent fished areas. Quantifying egg production is the first step in evaluating recruitment subsidy potential. We calculated annual egg production per unit area (EPUA) from 2004 to 2013 for the commercially important common coral trout, Plectropomus leopardus, on fished and NTMR reefs throughout the Great Barrier Reef (GBR), Australia. Geographic region, NTMR status, fish size, and population density were all found to affect EPUA. The interactions among these factors were such that, EPUA on NTMR reefs compared to reefs open to fishing was 21% greater in the southern GBR, 152% greater in the central GBR, but 56% less in the northern GBR. The results show that while NTMRs can potentially provide a substantial recruitment subsidy (central GBR reefs), they may provide a far smaller subsidy (southern GBR), or serve as recruitment sinks (northern GBR) for the same species in nearby locations where demographic rates differ. This study highlights the importance of considering spatial variation in EPUA when assessing locations of NTMRs if recruitment subsidy is expected from them.

Gangur, Alexander, Smout, Michael, Liddell, Michael, Seymour, Jamie, Wilson, David, and Northfield, Tobin (2017) Changes in predator exposure, but not diet induce phenotypic plasticity in scorpion venom. Proceedings of the Royal Society of London Series B, Biological Sciences. (In Press)
Animals embedded between trophic levels must simultaneously balance pressures to deter predators and acquire resources. Venomous animals may use venom toxins to mediate both pressures, and thus changes in this balance may alter the composition of venoms. Basic theory suggests that greater exposure to a predator should induce a larger proportion of defensive venom components relative to offensive venom components, while increases in arms races with prey will elicit the reverse. Alternatively, reducing the need for venom expenditure for food acquisition, for example due to an increase in scavenging, may reduce the production of offensive venom components. Here, we investigated changes in scorpion venom composition using a mesocosm experiment where we manipulated scorpions’ exposure to a surrogate vertebrate predator and live and dead prey. After six weeks, scorpions exposed to surrogate predators exhibited significantly different venom chemistry compared to naïve scorpions. This change included a relative increase in some compounds toxic to vertebrate cells, and a relative decrease in some compounds effective against their invertebrate prey. Our findings provide, to our knowledge, the first evidence for adaptive plasticity in venom composition. These changes in venom composition may increase the stability of food webs involving venomous animals.

Bower, Deborah S., Lips, Karen R., Schwarzkopf, Lin, Georges, Arthur, and Clulow, Simon (2017) Amphibians on the brink. Science, 357 (6350). pp. 454-455.
[Extract] Over the past three decades, the emergence of a globalized pandemic lineage of chytrid fungus (Batrachochytrium dendrobatidis) has caused declines of amphibian species in Central America, Europe, Australia, and North America (see the figure). By 2004, where documented, 43.2% of amphibian species globally experienced some level of population decrease, and the amphibian chytrid fungus was identified as a major contributing factor for hundreds of species (1). The recent discovery of a related but functionally distinct chytrid fungus, Batrachochytrium salamandrivorans, that has begun exterminating salamanders in Europe (2) fulfills predictions that further infectious fungal pathogens will continue to emerge (3). The threat of chytrids and similar fungal pathogens to areas where they have not yet emerged—for example, in New Guinea—is of critical conservation concern.

Mohandass, Dharmalingam, Campbell, Mason J., Hughes, Alice C., Mammides, Christos, and Davidar, Priya (2017) The effect of altitude, patch size and disturbance on species richness and density of lianas in montane forest patches. Acta Oecologica, 83. pp. 1-14.
The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700–2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.

Benham, Claudia F. (2017) Aligning public participation with local environmental knowledge in complex marine social-ecological systems. Marine Policy, 82. pp. 16-24.
The incorporation of local and traditional knowledges into environmental governance regimes is increasingly recognised as a critical component of effective and equitable conservation efforts. However, there remain significant barriers to integration of community-based knowledge within mainstream environmental governance. This paper explores community-based knowledge in the context of Environmental Impact Assessment (EIA), a widely-used governance tool designed to predict and manage the impacts of development. Drawing on a social survey and interviews, the paper documents local community knowledge of environmental changes associated with dredging and the construction of Liquefied Natural Gas (LNG) plants in a large industrial harbour located in the Great Barrier Reef World Heritage Area, and compares this knowledge with public consultation opportunities offered throughout the project lifecycle, including during assessment and after project approval. The findings highlight a misalignment between community knowledge of environmental change, which is acquired largely after impacts become apparent, and the public participation opportunities afforded through EIA, which generally occur before construction or dredging is undertaken.

Heindler, Franz M., Alajmi, Fahad, Huerlimann, Roger, Zeng, Chaoshu, Newman, Stephen J., Vamvounis, George, and van Herwerden, Lynne (2017) Toxic effects of polyethylene terephthalate microparticles and Di(2-ethylhexyl)phthalate on the calanoid copepod, Parvocalanus crassirostris. Ecotoxicology and Environmental Safety, 141. pp. 298-305.
Large amounts of plastic end up in the oceans every year where they fragment into microplastics over time. During this process, microplastics and their associated plasticizers become available for ingestion by different organisms. This study assessed the effects of microplastics (Polyethylene terephthalate; PET) and one plasticizer (Di(2-ethylhexyl)phthalate; DEHP) on mortality, productivity, population sizes and gene expression of the calanoid copepod Parvocalanus crassirostris. Copepods were exposed to DEHP for 48 h to assess toxicity. Adults were very healthy following chemical exposure (up to 5120 µg L−1), whereas nauplii were severely affected at very low concentrations (48 h LC50value of 1.04 ng L−1). Adults exposed to sub-lethal concentrations of DEHP (0.1–0.3 µg L−1) or microplastics (10,000–80,000 particles mL−1) exhibited substantial reductions in egg production. Populations were exposed to either microplastics or DEHP for 6 days with 18 days of recovery or for 24 days. Populations exposed to microplastics for 24 days significantly depleted in population size (60±4.1%, p<0.001) relative to controls, whilst populations exposed for only 6 days (with 18 days of recovery) experienced less severe depletions (75±6.0% of control, p<0.05). Populations exposed to DEHP, however, exhibited no recovery and both treatments (6 and 24 days) yielded the same average population size at the termination of the experiment (59±4.9% and 59±3.4% compared to control; p<0.001). These results suggest that DEHP may induce reproductive disorders that can be inherited by subsequent generations. Histone 3 (H3) was significantly (p<0.05) upregulated in both plastic and DEHP treatments after 6 days of exposure, but not after 18 days of recovery. Hsp70-like expression showed to be unresponsive to either DEHP or microplastic exposure. Clearly, microplastics and plasticizers pose a serious threat to zooplankton and potentially to higher trophic levels.

Maxwell, Stephen J., Dekkers, Aart M., Berchauer, David P., and Congdon, Bradley C. (2017) A new Domiporta species (GASTROPODA, MITRIDAE) from tropical Queensland. The Festivus, 49 (3). pp. 199-205.
A new species of Mitridae, Domiporta valdacantamessae, is described from Dingo Beach, Queensland, Australia. The shell shows similarities with other Queensland Domiporta species: D. carnicolor Reeve, 1844, D. filiaris Linnaeus, 1771, D. gloriola Lamarck, 1811, D. granatina Cernohorsky, 1970 and D. praestantissima Röding 1798, however the new species can be differentiated based on the clathrate micro-sculpture. At present this species is only known from Queensland, Australia.

Zamborain-Mason, Jessica, Russ, Garry R., Abesamis, Rene A., Bucol, Abner A., and Connolly, Sean R. (2017) Network theory and metapopulation persistence: incorporating node self-connections. Ecology Letters, 20 (7). pp. 815-831.
Network analysis is gaining increasing importance in conservation planning. However, which network metrics are the best predictors of metapopulation persistence is still unresolved. Here, we identify a critical limitation of graph theory-derived network metrics that have been proposed for this purpose: their omission of node self-connections. We resolve this by presenting modifications of existing network metrics, and developing entirely new metrics, that account for node self-connections. Then, we illustrate the performance of these new and modified metrics with an age-structured metapopulation model for a real-world marine reserve network case study, and we evaluate the robustness of our findings by systematically varying particular features of that network. Our new and modified metrics predict metapopulation persistence much better than existing metrics do, even when self-connections are weak. Existing metrics become good predictors of persistence only when self-connections are entirely absent, an unrealistic scenario in the overwhelming majority of metapopulation applications. Our study provides a set of novel tools that can substantially enhance the extent to which network metrics can be employed to understand, and manage for, metapopulation persistence.

Kiup, Emma (2017) Maximizing nutrient utilisation and soil fertility in smallholder coffee and food garden systems in Papua New Guinea by managing nutrient stocks and movement. Masters (Research) thesis, James Cook University.
Smallholder farming systems in Papua New Guinea (PNG) are intensifying and becoming increasingly reliant on cash cropping. In the Highlands of PNG, coffee is the main cash crop and sweet potato the predominant subsistence crop. Due to the seasonality of coffee and low prices, farmers are increasingly growing vegetables and fruits for sale. This diversification in the cropping system has implications for nutrient dynamics and soil fertility. The aim of this study was to identify and quantify the movement of nutrient in food garden systems and interpret the effects of these nutrient movements on soil fertility. The study was conducted on six farms in Bena in the Eastern Highlands of PNG. At each farm, soil samples were collected from three food gardens. The aim of the soil sampling was to collect samples from areas with and without application of coffee pulp, fire ash, mulch or fertilizer. Harvested crop samples were also collected, washed and separated into consumable and non-consumable parts (e.g. skin), weighed, oven dried, ground and analysed for nutrient content. The two main pathways of nutrient flow quantified in this study were the output in harvested crop and input in inorganic fertilizers. Soil fertility was generally adequate, except for extractable P and exchangeable K. Many individual gardens also had low soil N concentrations. The application of nutrient sources such as coffee pulp, kitchen peelings and ash was limited, but the areas that had physical evidence of such applications generally had higher soil K concentrations. Crops grown for market had the highest nutrient concentrations because of the addition of fertilizers. Crops like broccoli and sweet potato had high nutrient concentrations but the amount exported per square meter was lower than cauliflower and cassava due to lower planting density and plant biomass. Market demand also affects the net export of nutrients, as greater market demand for certain vegetables like broccoli and sweet potato will result in greater nutrient export. The amounts of N and K exported in harvested crops exceeded the amounts imported in inorganic fertilizers, resulting in a negative balance of those nutrients. The P balance was positive, which may result in its accumulation. However, the extractable P concentration in soil was low so the accumulated P may still not be fully available to crops. The low input farming system currently practiced by smallholder farmers will continue to deplete the soil nutrients and the soil may become deficient in N, P and K. The process of crop harvesting and preparation results in the production of residues or wastes that might be better managed to retain nutrients. However, this option may be perceived as inconvenient and not practiced because the value of the nutrients in the waste is not appreciated. Therefore, adoption of these nutrient retention methods will require education about the value of nutrients in waste products versus the value of convenience.

Zenger, K.R., Khatkar, M.S., Jerry, D.R., and Raadsma, H.W. (2017) The next wave in selective breeding: implementing genomic selection in aquaculture. In: Proceedings of the Conference of the Association for the Advancement of Animal Breeding and Genetics. From: 22nd AAABG Conference 2017, 2-5 July 2017, Townsville, QLD, Australia. (In Press)
Advanced animal breeding in aquaculture has reached a tipping point where the commercial implementation of genomic selection to improve productivity and disease resistance is becoming reality. However, the success of practical implementation of genomic selection depends on the specific aquaculture species, production system and available phenotyping and genetic resources. Using the experience learned from commercial programs for pearl oysters and marine shrimp, we highlight current benefits and options in cost-effective high-throughput genotyping and phenotyping technologies for genomic selection applications relevant to aquaculture species, followed by discussion of some of the lessons learnt when dealing with its practical implementation, including what is needed to build adequate genotype resources for non-model species; confounded breeding objective verse trait measurements; complex traits and unknown interactions; multi-family breeding schemes; multi-stage selection schemes, and transition to a genomic selection breeding program incorporating minimisation of inbreeding.

Khatkar, M.S., Zenger, K.R., Jones, D.B., Prochaska, Jeff, van der Steen, H.A.M., Jerry, D.R., and Raadsma, H.W. (2017) Quantitative genomic analyses in the pacific whiteleg shrimp litopenaeus vannamei. In: Proceedings of the Conference of the Association for the Advancement of Animal Breeding and Genetics (22). From: 22nd AAABG Conference 2017, 2-5 July 2017, Townsville, QLD, Australia. (In Press)
Traditional genetic improvement programs for Pacific white-leg shrimp (Litopenaeus vannamei) rely on family selection to improve growth and disease resistance traits. DNA technologies can help in simplifying breeding schemes and increasing genetic gains particularly for complex or difficult to measure traits. Here we present the results of genome-wide association and whole genomic prediction analyses using average family allele frequencies and the family mean of a growth trait in a genetic resource population consisting 1,934 animals and 690 families of L. vannamei genotyped with 8,967 genome-wide SNPs. After correcting for FDR, no significant SNPs were detected for growth. The accuracy of DGV in mirror prediction is much higher (0.65-0.69) as compared to forward prediction. A SNP that may be closely linked to the sex locus was identified with the female being the heterogametic sex.

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