sablefish (Anoplopoma margin) It is found in the deep waters of the North Pacific basin, from Japan to Baja California. Also known as black cod, it is similar to but not related to cod. Commercial sablefish fisheries use longlines, deep-water trawls, and bottom traps (pots).
North American sablefish stocks and landings have declined steadily and dramatically over the past three decades, but demand for and consumer recognition of sablefish is steadily increasing globally, thanks to its use by celebrity chefs and high-end sushi restaurants. Japan has long been the main market for sablefish, but it has been caught elsewhere as an alternative to Chilean seabass, which has also seen supplies dwindle in recent years.
Early attempts at aquaculture
In the 1960s, researchers at the Canada Pacific Biological Station successfully raised wild-caught sablefish, but it soon became clear that sustainable farming, as with many aquatic species, required a reliable supply of fingerlings that They are raised in hatcheries. Canadian researchers eventually found methods for captive hatching and fry rearing, and by the late 1990s fingerlings became available from several sources in British Columbia. Following the first commercial harvest of farmed sablefish in 2002, a gold rush mentality led to significant interest and investment in sablefish farming, concentrated along the west coast of Vancouver Island.
A number of unresolved constraints in the production cycle, particularly difficulties relating to the availability of broodstock, larval survival and extended larval period, have led to a general decline in what was initially seen as a promising new sector. The most successful consolidation of operations occurred in the late 2000s and early 2000s. Although some industry observers have ruled out sablefish aquaculture, this diagnosis seems premature.
How did you sleep?
The hatchery stage has historically been a major obstacle to commercialization, but some sablefish hatcheries have been successful. Experience is required in broodstock maintenance and hatching, larval feeding and rearing, biosecurity, temperature control and environmental lighting.
Broodstock are collected from open water during late summer and fall, often using longlines, and are held to maturity before spawning the following winter and spring. Since mature fish are usually found in deep water habitats, broodstock are maintained at cool temperatures with low light. Female reproductive development is assessed using ultrasound, and hormone implants are used to encourage final maturation. Fecundity can reach 250,000 eggs or more, a factor that may help reduce individual fingerling costs as the industry advances. Light treatment has been used to speed up or delay egg laying, and this will also be important in commercial operations, allowing fingerlings to be available to farmers throughout the year. Nursery at 5-6s C takes 12 to 14 days, and another 30 days are required for the yolk sac to be absorbed.
Breeding to marketable sizes of 1.8 to 3.6 kg has been successful with sablefish grown in both RAS facilities and net pens.
© NOAA
Once the fry are ready to feed, they are transferred to tanks containing the algal paste and fertilized rotifers, and the water temperature is raised to 10s C or slightly higher. One function of algae is to provide background coloration, so that larvae can see their prey more easily, and over the past few years, algae have been successfully replaced with clay suspensions that serve the same purpose at a much lower cost. Light levels are initially low, but gradually increase (as does temperature) as the larvae grow. During this time, the fry are switched from a rotifer-based diet to a rotifer-based diet Artemia He was eventually weaned on processed diets. Larval survival typically ranges from 10 percent to 40 percent. Research indicates that the rearing temperature is 15s C leads to better growth and survival than 12s A, but although higher temperatures can accelerate growth further, they lead to a lower survival rate.
Size grading at this time is important, in order to minimize losses due to cannibalism during the incubation stage. Fingerlings typically reach 75 grams about 200 days after spawning. The breeding process has been successful to market sizes ranging from 1.8 to 3.6 kg in both net pens and RAS facilities, with harvest reaching approximately two years. A range of feed conversion rates for sablefish farming has been reported for both production strategies, from 1.1 to 1.6, but a more typical value may emerge as the industry becomes more standardized. Sablefish take commercially available salmon feed well, but some producers make their own feed.
© Golden Eagle Sablefish
Research updates
As with any new type of aquaculture, a significant investment of time and money has been required to develop production methods, with contributions from researchers and the private industry.
Ruby et al. (2021) presented results suggesting that selective breeding can significantly improve sablefish hatchery survival. From an original brood group of 12 females and 6 males, they found that after 12 months of culture, 90% of the remaining offspring were produced by only five females and 93% were sired by only three males. Other studies suggest that optimal larval temperature may also be influenced by genetic influences.
Like many other bony fishes, sablefish have an XX (female)/XY (male) sex determination system. Because female sablefish show better growth, scientists have used the technique of masculinizing female sablefish at a very young age (through hormone treatment) to produce “tumors,” which are genetically female but phenotypically male. When crossed with natural females, these fish can produce hormone-free offspring. Overall growth increases of 10 to 12 percent are typical when breeding female sablefish. Sex reversal techniques are not complicated, and once experience is gained, producing new tumors does not represent a significant cost on a per-fish basis, due to the high fecundity of the species.
A number of nutritional studies have been conducted on sablefish over the past decade. Nilan et al. (2024) found that the inclusion of microalgae Schizophrenia In fish-free diets levels of polyunsaturated fatty acids (PUFA) can increase without a significant decrease in growth or health indicators. Johnson et al. (2020) found that taurine supplementation in plant feed improved growth, feed efficiency and protein retention in juvenile sablefish. And Niklasson et al.reported that sablefish growth was higher when hot soybeans and soy protein concentrate were used as plant protein sources, with the former resulting in significant cost savings.
When I asked Dr. Ken Cain, of NOAA Fisheries, for his views on current and future sablefish research, he noted: “Two key areas or research that we are addressing or need to address are disease prevention (the development of non-invasive vaccines) New patterning of boils for sablefish) and achieving consistent captive spawning of wild caught birds and/or F1 broodstock. Other important areas include simplifying larval production and reducing the cost of live feeding prior to weaning on commercial diets. Production of all females has been successful; It has been shown to lead to faster growth compared to mixed-sex populations.We are currently comparing growth in terrestrial production (flow-through and RAS) with net sablefish production and hope to explore other markets (such as the live market) that can be targeted and expanded.
Resistance to commercial fishermen
Commercial fisheries have expressed concerns about sablefish aquaculture for a number of years – primarily focusing on potential impacts on supply and demand prices. One concern is that as farming methods improve and become easier to adopt, producers will base their operations in low-cost countries. Mexico and South Korea may develop sablefish aquaculture, and China is already pursuing research on sablefish production and disease management.
Wild harvesters in the United States and Canada have emphasized the potential negative environmental impacts of sablefish aquaculture in order to generate public support. But recently, wild fisheries have faced greater problems related to environmental issues. In 2021, the US National Marine Fisheries Service (NMFS) issued an incidental permit to take humpback whales into the West Coast sablefish fishery. The Center for Biological Diversity (CBD) later filed a lawsuit against the agency, citing failure to adhere to provisions of the Marine Mammal Protection Act. In March of 2023, a federal court in California ordered NMFS to develop a plan to reduce the potential for humpback whales to become entangled in vertical lines attached to pots commonly used by commercial fishermen targeting sablefish.
In January of this year, the CBD filed a second suit against NMFS, on the grounds of failure to protect sea turtles and their critical habitat against negative impacts, including entanglement, from the sablefish fishery off the central coast of California. “These areas have already been designated as critical habitat for sea turtles, and should not be a death trap,” a CBD attorney stated, adding, “Leatherbacks are on the verge of extinction, and we cannot allow them to go extinct.” “They were killed by commercial fishing gear.” Sablefish farming may become an important case study in the relative environmental benefits of aquaculture compared to commercial fisheries.
Pioneers of commercial aquaculture
Only a few producers have had success with sablefish, including Marine Aqua (of Troutlodge, Inc) in Washington and Hawaii; Hub City Fisheries in Nanaimo, BC and Totem Sea Farm in Jervis Inlet, BC.
Perhaps the most innovative is Golden Eagle Sablefish, which markets its product as Gindara Sablefish. Golden Eagle uses RAS facilities (originally developed for coho salmon production) for hatchery operations and transports advanced fingerlings to marine pens for grow-out. In 2020, Jindara became the first Canadian marine fish farm to receive a “Top Choice” designation for the Seafood Watch Program. Its clients can be found in Japan, the United States, Canada, Europe and many other countries.
I spoke with Terry Brooks, president of Golden Eagle Sablefish, about the business and the fish they raise. He stated that progress in maintaining captive broodstock and improving conditions during fry rearing were the two most important achievements in terms of business success. According to Brooks, the ability to deliver high-quality products on a regular basis was also key to economic survival. He pointed out that the farm “has been achieving weekly sales since 2007, and many customers in Japan and the United States have been with us since day one.” “The main advantages of this fish in the market are the inherent high value, with superior shelf life and quality,” he added.
When asked if there was one thing he would change about the sablefish, Brooks' answer was “growth rate.” Golden Eagle already uses all-female production stocks, and is currently working with the University of Victoria to advance the use of molecular genetic methods for sex markers and ancestry determination. The farm has also worked with several global feed companies over the years, providing valuable insights to all parties involved and providing the hatchery with access to “the best larval feed in the world,” he said.
When I asked Brooks to sum up his experience with the sablefish, he replied: “It was an interesting trip.” We hope the journey continues well into the future.
