FRDC 2016-068 Vulnerability of the endangered Maugean skate population to degraded environmental conditions in Macquarie Harbour- presentation to the 6th international conference of fish telemetry 23
An abstract accepted to present the work from FRDC 2016-068 at the International fish telemetry conference later this year. Given that the final year of the project happened right in the middle of the pandemic, we have not yet had an opportunity to present the work in any international forum. Since then we have new information that has clearly shown that the Maugean skate is in a critical state and requires immediate conservation action. As such, the interest in the species is very high at the moment, and the results from this project are even more relevant now. So we think this is a great opportunity to help communicate this novel and very important work.
This would allow us to communicate our findings to a broad technical audience, increasing the outreach and impact of the project. The work that will be presented will have important benefits for the conservation of the species and inform management of industry and other users of Macquarie Harbour.
Pushing the envelope: Facilitating commercial performance in a changing climate
Understanding and mapping the Tasmanian public perception to Atlantic Salmon farming
Storm Bay Observing System: Assessing the Performance of Aquaculture Development
Sex reversal and sex differentiation in Atlantic salmon (Salmo salar)
Based on the National Fishing and Aquaculture RDE strategy 2016, our project relates to Strategic Goal 3: Benefits and value from fisheries and aquaculture resources (productivity and profitability) are maximised, and aquaculture production increased.
Priority area: Develop new technologies and systems to improve the efficiency of production methods.
This project is needed because the Australian Atlantic Salmon Industry is lacking basic and applied knowledge that could lead to the development of a reliable, non-steroidal method to produce all-female populations of Atlantic salmon. One of the drivers of this project is the fact that eliminating males from the production cycle (grow-out period), will reduce the effects of precocious sexual maturation, including reduced growth, reduced flesh quality, and susceptibility to diseases. As a consequence of eliminating males from the production cycle is a concomitant increase in overall productivity (biomass produced) and profitability
We will use genetic and morphological techniques to improve our understanding of sex differentiation in Atlantic salmon. This knowledge is needed to inform the exact period that sex reversal treatments with exogenous substances are more effective to produce neo-males. This exact timing can then be used in the trial of next generation non-steroidal substances, ensuring that they have the greatest chance of success. This will be the first time that detailed gene expression and morphological information will be collected throughout the entire period of sexual differentiation.
Final report
1. Based on histology and morphology, sex differentiation in Atlantic Salmon seems to occur by 79 dph.
2. Based on gene expression, three male specific genes are upregulated prior to morphological sex differentiation, whereas in females only one gene is differentially upregulated prior to morphological sex differentiation.
3. Immersion treatment with MDHT and MDHT+DMSO led to masculinization of genetic females to rates between 81 and 87%.
4. Immersion in MDHT led to the upregulation of male specific genes, which occurred 15 days after (dph) the date observed in normal males (34-66 dph) in the sex differentiation study.