man on a boat at sea pulling his net into a bucket

Salmon research worth its salt

Deakin has signed a new research agreement with Australia’s largest Atlantic salmon producer, Tassal Operations, to improve the welfare and survival of thousands of salmon that are transferred from freshwater hatcheries every year to sea cages.

The Tasmanian-based company is committed to improving the welfare and survival of salmon during the sensitive transferral from fresh to sea cages at the “smolting” stage of the salmon lifecycle.

Having pioneered salmon farming in Australia in 1986, Tassal now produces over 20,000 tonnes of salmon each year and is one of Tasmania’s largest employers.

Its new contract with Deakin builds on two previous research projects that have been undertaken with Deakin’s scientists Dr Luis Afonso and Dr Paul Jones, from the School of Life and Environmental Sciences at the Warrnambool campus.

Dr Afonso explained that in the natural life cycle of salmon, the first 10 to 12 months are spent in freshwater, with the young adults heading to sea at smolting time. During this period in freshwater, fish will undergo, at their own pace, physiological, behavioural and morphological changes (smoltification) that will enable them to survive in sea water.

Under cultured conditions, fish don’t have a choice, and thousands of fish are transferred to sea cages at the same time. If the fish are not ready to be transferred, their growth, resistance to disease and, ultimately survival, are jeopardized.

“Under culture conditions, successful sea water entrance depends on the farmer’s ability to properly determine whether most of the fish have completed the changes and are ready to be transferred,” Dr Afonso said.

“We can’t transfer salmon individually, but we can optimise the time of transferral by more closely aligning salmon development and monitoring the readiness of individuals.”

In the new project, Dr Afonso and his Deakin team will develop baseline information about hormonal and biochemical indicators (to determine smolt readiness, and evaluate Tassal’s hatchery husbandry practices, in order to optimise factors such as light exposure (photoperiod) and temperature, to improve smolt timing.

“There has been no baseline physiological information about these factors in Australia, so we need to build up the profile of different hatcheries, and achieve a validated method,” he said.

Tassal staff are also working with Deakin Fisheries and Aquaculture and Marine Biology students, in teaching and learning activities related to “Aquatic animal health and reproduction.”

Deakin students are also doing work placement at Tassal farms.

“It is rewarding to partner with a visionary company that understands and values the importance of education. Tassal has so much to offer in terms of providing students with contextualised learning and exposure to real world challenges,” noted Dr Afonso.

“The collaboration is giving students the chance to understand the value of applying research to real world questions. I hope that it will inspire, empower and build employability skills, based on high quality research.”

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