Sablefish, Anoplopoma fimbria, are a high-value species that is farmed to a limited extent in the US and Canada. NOAA’s Northwest Fisheries Science Center has been working to optimize culture methods and develop tools and strategies to minimize disease-related impacts. Early work with sablefish addressed all life stages and methods for spawning, egg incubation, larval weaning, and grow-out to market size. Current efforts are focused on optimizing such methods and refining technologies to enhance growth, survival, and reproductive efficiency of broodstock. Specific research efforts linked to improved growth and enhanced survival will be highlighted in this talk. Since sablefish exhibit sexually dimorphic growth, the production of monosex all-female stocks to capitalize on their faster growth has been a high priority. Several studies found that sex differentiation of XX-genotype fish could be redirected towards testicular development instead of ovarian development using dietary 17-alpha methyltestosterone (MT) treatment. This was utilized to produce neomale (i.e., XX-genotype male) F1 broodstock that could be bred with normal female broodstock. The offspring from neomale x female crosses are therefore 100% female. This method is now used routinely, and semi-commercial scale trials have demonstrated the importance of all-female monosex breeding technology to the economics of sablefish aquaculture.
Another bottleneck for this species involves the disease furunculosis, which is caused by an atypical strain of the bacterium Aeromonas salmonicida. Although antibiotic treatments can be administered following an outbreak, their effectiveness is limited, and disease prevention through vaccination is desirable. This has been identified as a high-priority need for sablefish aquaculture and the NWFSC has initiated several vaccination projects to explore new vaccine development (e.g. attenuated bacterins), practical delivery strategies (i.e. oral and immersion administration), and assess adjuvant effects when using more traditional vaccine formulations. Progress on the selection of attenuated vaccine candidates will be discussed along with results from the adjuvant study, which showed that protection could be achieved by combining immersion vaccination with an injection booster. This resulted in high antibody titers in the adjuvant groups and strong long-term protection in all vaccinated groups. Production level vaccination using the same approach appears successful as no furunculosis-related mortality has occurred in fish reared to market size in both net-pen and land-based tank systems. Although efforts to eliminate the need for injection delivery are continuing, the above protocol currently represents the most practical disease prevention strategy for furunculosis in sablefish. These advances in culture technologies emphasize the potential for continued expansion of commercial sablefish aquaculture.