Brad S. Evans

Brad S. Evans
Tassal · Environment and Sustainability

Doctor of Philosophy

About

127
Publications
10,487
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1,347
Citations
Citations since 2016
82 Research Items
574 Citations
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2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100

Publications

Publications (127)
Article
Full-text available
The bacterial disease yersiniosis caused by the bacterium Yersinia ruckeri (non-Hagerman strain) has previously caused significant loss to the Atlantic salmon aquaculture industry in Tasmania (Australia). Despite an ongoing vaccination strategy, the disease can impact commercial freshwater hatcheries and following introduction of smolt to seawater....
Article
Full-text available
Background Despite sexual development being ubiquitous to vertebrates, the molecular mechanisms underpinning this fundamental transition remain largely undocumented in many organisms. We designed a time course experiment that successfully sampled the period when Atlantic salmon commence their trajectory towards sexual maturation. Results Through d...
Article
Full-text available
Genomic information was included for the first time in the prediction of breeding values for Atlantic salmon within the Australian Salmon Enterprises of Tasmania Pty Ltd selective breeding program in 2016. The process to realize genomic selection in the breeding program begun in 2014 with the scheme finalized and fully implemented for the first tim...
Article
The Atlantic salmon (Salmo salar) is a globally important species for its value in fisheries and aquaculture, and as a research model. In order to characterise aspects of sex differentiation at the morphological and mRNA level in this species, the present study examined developmental changes in gonad morphology and gene expression in males and fema...
Article
In Atlantic salmon (Salmo salar) aquaculture, it can be more profitable to produce all-female populations. For this species, all-female populations can be created by crossing normal female broodstock (XX) with masculinised female broodstock (XX, known as neomales). Neo-males are typically produced via the application of an exogenous androgen treatm...
Article
Developing a better understanding of the importance of transfer time/smolt window is critical for farmers of salmonids to maximise growth performance and minimise the poor growth/mortality that can be associated with SW transfer. This study examined physiological and growth responses of juvenile Atlantic salmon (Salmo salar) transferred to seawater...
Preprint
Full-text available
Background: Despite sexual development being ubiquitous to vertebrates, the epigenetic mechanisms controlling this fundamental transition remain largely undocumented in many organisms. Our previous own work showed that despite DNA methylations played a key role upregulating a defined set of genes during the maturation process, methylation alone doe...
Preprint
Full-text available
Despite the importance of sexual maturation as a trait of interest it can be difficult to study, as the timing of onset varies widely in response to both genetics and environmental factors and occurs prior to measurable phenotypic change. To overcome this, we chose to investigate sexual maturation in Atlantic salmon where photoperiod manipulation i...
Preprint
Full-text available
Background: Atlantic salmon farming promotes growth in conditions which mean animals may complete sexual development at weights below harvest size leading to a reduction in productivity. This prompted us to investigate the biological mechanisms that control the timing of sexual maturation. We performed a time course experiment, whereby animals were...
Preprint
Full-text available
Despite sexual development being ubiquitous to vertebrates, the epigenetic mechanisms controlling this fundamental transition remain largely undocumented in many organisms. Through whole-methylome, whole-transcriptome and chromatin landscape sequencing, we discovered global control mechanisms as well as specific regulators of sexual maturation in A...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Article
Control of the parr-smolt transformation (or smoltification) is crucial for the husbandry and successful seawater (SW) transfer of Atlantic salmon (Salmo salar) reared in freshwater (FW) hatcheries. Photoperiod is an important environmental signal that initiates the complex physiological, morphological and behavioural changes that coincide with mar...
Article
Full-text available
The master sex determinant in rainbow trout (Oncorhynchus mykiss), sexually dimorphic on the Y chromosome (sdY), is strongly but not perfectly associated with male phenotype in several other species from the family Salmonidae. Currently, the cause and implications of discordance for sdY-predicted genotypic sex and phenotypic sex in these species is...
Article
Full-text available
The introduction of wild Atlantic salmon into captivity, and their subsequent artificial selection for production traits, has caused phenotypic differences between domesticated fish and their wild counterparts. Identification of regions of the genome underling these changes offers the promise of characterizing the early biological consequences of d...
Article
This study examined morphological, physiological and molecular indicators of smoltification in Atlantic salmon (Salmo salar) juveniles in a flow-through (FT) and recirculating aquaculture system (RAS). Fish were exposed to 24-h light to initiate smoltification, for 5 (FT) and 7 (RAS) weeks prior to transfer from freshwater (FW) to seawater (SW) and...
Conference Paper
Full-text available
Atlantic salmon farming promotes rapid growth in conditions which mean animals may complete sexual development at weights below harvest size. This can lead to productivity losses and has prompted us to investigate the biological mechanisms that control the timing of sexual maturation. We performed a time course experiment, whereby animals were mani...
Conference Paper
Full-text available
Early onset of sexual maturation in Atlantic salmon presents an ongoing challenge for the salmon aquaculture industry due to negative impacts on growth rate and product quality. Consequently, a significant amount of research aims to understand the biological mechanisms driving early salmon maturation. We performed a dedicated animal experiment to e...
Data
The SALTAS breeding program design. Animals are tagged and sampled for DNA testing at around 10 months of age, before the majority of animals are smolted for transfer to sea cages. The two maturation traits were collected 22 months after spawning. Freshwater progeny are maintained as candidates for the subsequent cycles of the breeding program
Data
All significant SNP identified for marine maturation, using both male and female fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided
Data
All significant SNP identified for marine maturation, using only male fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided
Data
All significant SNP identified for marine maturation, using only female fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided
Data
Genotype classes by maturation status for Ssa10 SNP AX-87354755. The distribution of genotype classes are shown separately within males and females in both matured and non-matured animals.
Data
Genotype classes by maturation status for Ssa11 SNP AX-96411005. The distribution of genotype classes are shown separately within males and females in both matured and non-matured animals.
Data
RNA-Seq data used for analysis of tissue specific expression
Data
All significant SNP identified for freshwater maturation, using both male and female fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided
Data
Imputed chromosome Ssa11 SNP surrounding the picalm gene and their association to maturation. The table contains associations to both FMAT and MMAT
Data
Sex specific behaviour at two SNP for both FMAT and MMAT. The table shows the strength of association, effect size and proportion of genetic variance explained in analysis using all animals, males or females alone
Data
Q-Q plots compared between GWAS methods. The expected distribution of p-values is compared to the observed values derived from linear regression (A) and the MLMA-LOCO approach for MMAT (B and C)
Data
All significant SNP identified for freshwater maturation, using only male fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided.
Data
All significant SNP identified for freshwater maturation, using only female fish. The table shows physically co-located genes and their distance from the associated loci (in bp). Gene identifiers, symbol and names are provided
Data
SNP association for maturation traits on chromosome 25. GWAS for FMAT (A) and MMAT (B) are shown spanning the region containing VGLL3 (vertical lines). No association peak was evident for either trait. Minor allele frequency (MAF) for SNP was plotted to search for evidence of a selection sweep for FMAT (C) and MMAT (D). No evidence was seen for dec...
Article
Full-text available
Background A key developmental transformation in the life of all vertebrates is the transition to sexual maturity, whereby individuals are capable of reproducing for the first time. In the farming of Atlantic salmon, early maturation prior to harvest size has serious negative production impacts. Results We report genome wide association studies...
Research
Atlantic salmon is one of the first aquaculture species for which functional genomics is now possible. Development of the underpinning genomic tools and resources has been driven by the Atlantic salmon farming industry and their value as an ecological species of interest. To develop data standards and coordinate relevant data generation and analysi...