Evaluating the feasibility of feeding RAS-produced Atlantic salmon (Salmo salar) during the depuration process: effects on fish weight loss and off-flavor remediation

ABSTRACT

Depuration is a proven pre-harvest procedure that eliminates off-flavor from Atlantic salmon produced in recirculating aquaculture systems. However, applied research indicates that depurating salmon lose weight while fasting, which reduces farmgate revenue. Low-ration feeding was therefore evaluated as a method to mitigate weight loss while depurating 3–4 kg Atlantic salmon. Salmon implanted with passive-integrated-transponders were weighed, exposed to concentrated geosmin (GSM) and 2-methylisoborneol (MIB), and stocked in eight pre-disinfected partial reuse systems. Feed was either offered for 4 days or withheld entirely (n = 4) during a 6-day depuration period. Salmon from both treatments rapidly eliminated GSM and MIB, but slightly lower levels remained in fish that were fed (P < .05). Fed and fasted salmon lost 0.3 and 1.1% of their initial body weight, respectively (P < .05). Under the conditions of this study, feeding Atlantic salmon during depuration minimized weight loss without negatively impacting off-flavor elimination.

KEYWORDS:

• Depuration
• geosmin
• land-based aquaculture
• 2-methylisoborneol
• off-flavor
• recirculating aquaculture systems

Acknowledgments

This research was supported by Research Grant No. IS-5354-21 from BARD, The United States – Israel Binational Agricultural Research and Development Fund. Special thanks are extended to Freshwater Institute staff who supported this project including Curtis Crouse – fish production, Natalie Redman and Megan Murray – water and environmental chemistry analysis, Shanen Cogan and JC Stanley – construction and operations, Kata Sharrer – system drawings and schematics, and USDA-ARS biological science technician Phaedra Page – laboratory technical assistance. Gratitude is also extended to Drs. Jaap van Rijn and Snir Azaria for their collaboration on this project and to Dr Brett Kenney and Mr Sean Estep at West Virginia University for supporting product quality analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data will be made available upon request.

Additional information

Funding

The work was supported by the United States – Israel Binational Agricultural Research and Development Fund [Research Grant No. IS-5354-21].