Depuration System Flushing Rate Affects Geosmin Removal From Market-Size Atlantic Salmon Salmo Salar

Details

• Journal Title:
  Aquaculture Engineering
• Personal Author:
  Davidson, John ; Grimm, Casey ; Summerfelt, Steven ; Fischer, Gregory ; Good, Christopher
• NOAA Program & Office:
  Sea Grant ; OAR (Oceanic and Atmospheric Research)
• Sea Grant Program:
  WISCU (Wisconsin Sea Grant)
• Description:
  Common off-flavor compounds including geosmin (GSM) bioaccumulate in fish cultured in recirculating aquaculture systems (RAS) resulting in unpalatable fillets that are objectional to consumers. Most RAS facilities relocate fish from grow-out tanks to separate depuration systems with increased water flushing to remediate pre-harvest off-flavors, but certain aspects of this procedure have not been optimized including characterization of water exchange rates that effectively diminish off-flavor. To this end, a study was carried out to evaluate the effects of flushing rate and associated depuration system hydraulic retention time (HRT) on GSM removal from Atlantic salmon Salmo salar originally produced in a semi-commercial scale freshwater RAS. Twenty-six fish (5−7 kg each) were stocked into twelve replicate depuration systems operated with system HRTs of 2.4, 4.6, and 11.3-h, respectively (N = 4). Geosmin was assessed at intervals in system water and fish flesh over a 10-day feed withholding period. Waterborne GSM concentration was affected by flushing rate and associated system HRT (P <  0.05). Depuration systems operated with an 11.3-h HRT had greater waterborne GSM levels at 3, 6, and 10 days post-stocking compared to 2.4 and 4.6-h HRT. A similar trend was generally reflected in salmon flesh. Residual GSM levels were successively higher in fillets on Day 6 from depuration systems with increasingly longer HRT. Geosmin levels were greatest in salmon flesh from the 11.3-h HRT treatment on Day 10, but fillet GSM between the 2.4 and 4.6-h HRT was similar. This research indicates that lowest residual GSM is achieved in water and Atlantic salmon flesh in depuration systems with increased flushing and shorter HRT, i.e., 2.4–4.6-h under conditions of this study. Selection of optimal flushing rate to remediate off-flavor from RAS-produced Atlantic salmon may also be dictated by water and energy use metrics and site-specific water availability among other factors.
• Keywords:
  Aquaculture Atlantic Salmon Atlantic Salmon
• Source:
  Aquaculture Engineering 90: 102104, 2020
• DOI:
  https://doi.org/10.1016/j.aquaeng.2020.102104
• Sea Grant Document Number:
  WISCU-R-20-005
• Document Type:
  Journal Article
• Funding:
  Grant no. NA18OAR4170097 ; Grant no. NA18OAR4170336
• Rights Information:
  CC BY
• Compliance:
  Library
• Main Document Checksum:
  urn:sha256:2c69bc601b1d7e05fe8e1d1c38b3d655f8f15f78927a285f3ca09b211504801b
• Download URL:
  https://repository.library.noaa.gov/view/noaa/37515/noaa_37515_DS1.pdf
• File Type:
  [PDF - 1.46 MB ]