Experimental Platform for Aquaculture Production

The principal aim is to support and improve offshore Atlantic salmon aquaculture through a translational experimental approach that addressed critical knowledge gaps in salmon production biology by working closely with industry partners including the Tasmanian selective breeding program.

Translation will consider the impact of genetic and key environmental variables, most relevant to current and future offshore sites, on salmon performance.

There are two major challenges:

1. Quantifying the impact of genetic and key environmental variables on salmon performance in current and future offshore sites
2. Addressing a knowledge gap around the translation of experimental data into commercial outcomes.

Successful outcomes will come from understanding how to relate differences in salmon performance to underlying mechanisms and across experimental and commercial systems. A second aim is to build capability and support career development to meet industry needs

We congratulate Harriet R. Goodrich (IMAS/UTAS) on her recently published research into digestive tract function in Atlantic Salmon.

While the physiological effects of environmental stressors have been widely studied, the involvement of the gastrointestinal system to growth outcomes remains poorly understood. Harriet’s research investigates the association between gut phenotype and growth performance in 83 Tasmanian Atlantic salmon following 86 days of experimentally induced summer conditions and a 38-day recovery period.

We congratulate Max Canepa on his recently published research into size with respect to the effects of suboptimum summer conditions on Atlantic salmon production.

This paper is a key piece of the Experimental Platform for Aquaculture Production (EPAP) project. It captures the core of our first two major experiments and provides solid evidence on how suboptimum summer conditions affect salmon performance, especially in relation to fish size. Small seawater salmon (~420 g) showed strong resilience, feed intake increased by 42% during recovery compared to before the summer challenge, and efficient growth (feed conversion ratio) improved by 8.6%.

In contrast, large seawater salmon (~2600 g) experienced a 56% drop in feed intake under suboptimum summer conditions and recovered less well, 18.5% below acclimation levels. Overall efficient growth (feed conversion ratio) improved by 28% during recovery, but interesting many individuals (39%) still lost weight. We used Machine Learning analyses to reveal that around 30% of the large salmon had poor growth trajectories, this was less than 9% in small salmon. These findings are directly relevant to Tasmanian Atlantic salmon farming, offering practical insights into size-based resilience and helping us build predictive tools and mitigation strategies. It is a strong foundation for the next phase of our research with industry.

The final phase of EPAP involves an extensive experiment to investigate differences in feed efficiency among groups of salmon, now underway at IMAS-Taroona. The project team is exploring relationships between feed efficiency among four family phenotypes; families are classified as having high or low growth rates and high or low fillet fat.

The research started in May using approximately 1000 Atlantic salmon with an initial average weight of 150 grams. After 6 months some of these families have achieved an average weight of approximately 1.6 kg, with some individuals have attained 2.4 kg. It is exciting that our preliminary results show a strong correlation between the combination of the above-mentioned phenotypes (traits) and feed efficiency.

EPAP will help understand the underlying molecular mechanisms of feed efficiency and growth by using OMICS to identify potential biomarkers for application beyond EPAP. Results are informing the Tasmanian Atlantic salmon industry selective breeding programs, to allow choices about improving feed efficiency that potentially support more sustainable offshore aquaculture.

The Project Team has developed a final and extensive experiment for the project. The exciting experiment will use the EAF for almost 12 months and grow early seawater salmon (post-smolts) up to market size. The major aim is to investigate differences in feed efficiency among of groups of salmon, and to then to explore the strength of relationships with measurable differences in fundamental nutritional physiology as measured by OMICS and other potential biomarkers. These can then be applied to understand salmon in other situations such as offshore locations.

Additional and valuable information will be added through continued collaboration with the industry Selective Breeding Program and using families characterised by having high or low growth rates and having high or low fillet fat. It will be fascinating to relate feed efficiency to these phenotypes, including the opportunity to consider feed efficiency in terms of wet growth but also the efficiency of retaining protein and fat (energy) and to investigate where and how much fat is deposited. The salmon are currently at the SALTAS Wayatinah hatchery and will be transported to IMAS Taroona to start the experiment in April 2024.

Professor Chris Carter, Program Leader of the Seafood and Marine Products program, led a successful Blue Economy CRC workshop on Atlantic salmon skeletal structures in relation to offshore aquaculture in August with participants from Huon Aquaculture, Tassal, Petuna & Skretting in attendance.

The workshop provided expert information about salmon skeletons and current R&D activities to industry and research attendees with opportunities for industry to engage in identifying opportunities for future Atlantic salmon R&D.

“The workshop was very rewarding for all who attended, it was great to see such strong support from our industry participants from Atlantic salmon aquaculture and to be part of the enthusiastic and lively discussions happening in the room. We were particularly pleased to welcome two of the world’s foremost scientists Prof Eckhard Witten and Prof Ann Huysseune from Ghent University working on fish skeletons and look forward to planning a second workshop for wider BECRC participation.” said Chris Carter.

The workshop also provided an opportunity for our PhD students to present their research to industry with the team heading into preparations for an upcoming webinar on fish skeletons in relation to aquaculture. Stay tuned for details!

The Experimental Platform for Aquaculture Production project achieved an important milestone in March by reaching the end of the first phase of a large experiment being conducted in experimental tanks and at sea in salmon pens.

The project aims to better understand genetic and environmental influences on salmon performance and how to link experimental and commercial data. The main focus is on climate change impacts by tracking salmon through sub-optimum summer conditions and an autumn recovery.

IMAS researchers, alongside the Atlantic salmon selective breeding program (SBP), Tassal, Huon Aquaculture and Skretting, took a range of measurements from a cohort of nearly 160 families held at the EAF at the Experimental Aquaculture Facility (IMAS Taroona). A week later, sampling was repeated from the same families held in a salmon pen.

In the second phase, starting in April, the same cohort of salmon, now at a much larger size, will follow exposure to the same summer to autumn conditions.

In addition to informing selective breeding values for different families the project aims to use proteomics and metabolomics to explore fundamental aspects salmon performance by identifying which physiological / biochemical systems operate across different environments to better understand how to translate experimental information to commercial outcomes.

Project Lead Professor Chris Carter was keen to acknowledge the excellent contributions from Dr Gianluca Amoroso (Deputy Project Leader) and Lewis Rands (Saltas) for their excellent ongoing contributions to the project successes including on-the-ground management and hard work during sampling.