Early light regime impact on maturation

The effect of circannual rhythm, photoperiod and environment during freshwater production upon maturation trajectories of Atlantic salmon

Degree type


Closing date

27 March 2023



Citizenship requirement


About the research project

The seasonality of reproduction in temperate fishes is thought to be ultimately controlled by a circannual rhythm (i.e., endogenously driven cyclic change in physiology with free-running periodicity of ~1 year). Seasonal changes in photoperiod and other environmental cues act as a zeitgeber, entraining the circannual rhythm so that sexual maturation coincides with environmental conditions conducive to offspring survival.

The Tasmanian Atlantic salmon industry utilises various artificial photoperiod conditions to promote growth and smoltification (preparation for transfer from freshwater to seawater) during the freshwater phase of production. The precise hatchery photoperiod regime used depends on the intended calendar timing of seawater transfer, however each regime is similar in that they involve prolonged periods of constant long day length and abrupt directional changes in day length over relatively short succession.

It is not well understood how the different smolt-production strategies used affect: 1) the circannual rhythm controlling reproduction; and 2) the incidence of sexual maturation during the seawater phase of production. Inhibition of sexual maturation in commercial harvest fish is important as development reduces flesh quality and final harvest weight.

This project aims to investigate the effects of various smolt-production strategies and their associated photoperiod regimes on reproductive development in farmed Atlantic salmon using various techniques including blood and tissue markers to quantify maturation hormones, histological features, and gene expression.

This PhD project is prestigious and in honour of Dr Harry King who was a widely respected aquaculture biologist and left an indelible mark on the Atlantic salmon industry as a research scientist and farm manager. A fully funded scholarship by the "Dr Harry King Memorial Scholarship" will provide the opportunity to begin a career in salmon reproduction and continue Harry’s work to build fundamental knowledge on environmental impacts upon salmonid reproductive physiology and to apply impactful solutions to aquaculture production. The successful applicant will be embedded in an emerging salmon maturation team of academic and industry leaders inclusive of IMAS, CSIRO, Tassal, Huon Aquaculture and BioMar.

Primary Supervisor

Meet Dr Gianluca Amoroso


Applicants will be considered for a Research Training Program (RTP) scholarship or Tasmania Graduate Research Scholarship (TGRS) which, if successful, provides:

  • a living allowance stipend of $31,500 per annum (2023 rate, indexed annually) for 3.5 years
  • a relocation allowance of up to $2,000
  • a tuition fees offset covering the cost of tuition fees for up to four years (domestic applicants only)

If successful, international applicants will receive a University of Tasmania Fees Offset for up to four years.

If successful, applicants will also receive a top-up scholarship of $2,500 per annum for 3.5 years. This scholarship is funded from the Dr Harry King Memorial Scholarship, which is a scholarship program for the benefit of outstanding students undertaking PhD studies in scientific research in the field of sustainable aquaculture (including salmon production) at the University of Tasmania.

As part of the application process you may indicate if you do not wish to be considered for scholarship funding.


Applicants should review the Higher Degree by Research minimum entry requirements.

Additional eligibility criteria specific to this project/scholarship:

  • Applicants must be able to undertake the project on-campus

Selection Criteria

The project is competitively assessed and awarded.  Selection is based on academic merit and suitability to the project as determined by the College.

Additional essential selection criteria specific to this project:

  • Molecular biology proficiency at Honours/Masters level
  • Experimental design and statistical analysis
  • High-level written communication and ability to publish research
  • Handling and sampling experimental animals
  • Willing to travel and work in remote locations and commercial environments

Additional desirable selection criteria specific to this project:

  • Bioinformatic analysis

Application process

There is a three-step application process:

  1. Select your project, and check you meet the eligibility and selection criteria;
  2. Contact the Primary Supervisor, Dr Gianluca Amoroso to discuss your suitability and the project's requirements; and
  3. Submit an application by the closing date listed above.
    • Copy and paste the title of the project from this advertisement into your application. If you don’t correctly do this your application may be rejected.
    • As part of your application, you will be required to submit a covering letter, a CV including 2 x referees and your project research proposal.

Following the application closing date applications will be assessed within the College. Applicants should expect to receive notification of the outcome by email by the advertised outcome date.

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