Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

DEVELOPING TOOLS AND STRATEGIES FOR PREVENTION OF ATYPICAL FURUNCULOSIS IN SABLEFISH Anoplopoma fimbria

Kenneth  D Cain*, Joseph Dietrich, Veronica Myrsell ,  Wendy Olson, and Jie Ma

 NOAA – Fisheries,  Northwest Fisheries Science Center

Manchester Research Station

7305 Beach Dr. East

Port Orchard, WA 98366

ken.cain@noaa.gov



 Sablefish  (black cod)  represent  a  promising  and high-value species for marine aquaculture in the US .  Research efforts to  optimize  culture strategies and methods have been ongoing for more than 2 decades and t his species  is  commercially  produced  using land-based RAS in combination with net-pen grow out in Canada . To set the stage for expanded production of farmed sablefish in the US, NOAA  Fisheries  has  prioritized research projects and partnerships  to address remaining challenges. One  such  challenge  that affects production of this species is the disease furunculosis. This appears to be  the  primary disease threat for sablefish and is caused by an atypical strain(s) of Aeromonas salmonicida, a gram negative bacterium . Although antibiotic treatments exist and can reduce mortality once an outbreak occurs ,  disease p revention  through vaccination would be more desirable and has been identified as a high-priority need within the industry . Project s  that are ongoing focus on vaccination methods and strategies that  have the potential to  prevent furunculosis or minimize  its  impact during an outbreak. These  vaccine projects will be discussed and include an oral vaccination study that  assesses  the potential for utilizing a simple killed A. salmonic ida  vaccine delivered orally via alginate/gelatin micro-particles  to young fish as a way to minimize handling stress associated with injection vaccination. Another project  that is underway  is aimed at developing  attenuated  atypical  A. salmonicida  strains  that  could be administered via immersion during early juvenile stages. T o create  attenuated vaccine candidates,  a  known virulent  strain of  atypical A. salmonicida (T30) was passaged in culture  on TSA  media containing increasing concentrations of the antibiotics rifampicin and novobiocin.  In addition, three putatively virulent atypical strains of A. salmonicida (recently isolated from infected sablefish showing clinical signs of furunculosis) were passed in a similar manner . The  resistant  isolates  are being tested for attenuation against their respective ‘parent’ strain s with the  aim  of determining if attenuated strains that are not pathogenic to sablefish were produced . If fully attenuated strains are confirmed, these strains would be considered  potential vaccine candidates  and their ability to elicit a protective immune response will be further assessed.