Found on the sea floor on both sides of the Atlantic Ocean, the Atlantic wolffish (Anarhichas lupus) is a deep water species that preys on crustaceans, and rarely moves from its rocky habitat. Now listed as a "species of concern" by NOAA due to overfishing, bycatch, and bottom-trawling, its numbers are dwindling in the wild.
But the wolffish holds the potential to become a successful marine aquaculture species - it just needs the right feed and husbandry, according to one Swedish researcher.
"It is a species that is naturally found in confined spaces close to the sea bed, where it forages. It is calm and can withstand stress, and from an animal welfare perspective, my studies indicate that wolffish has great potential for farming. However, it grows slightly slower and needs different feed,” says Dr Ida Hedén from the University of Gothenburg's Department of Biological and Environmental Sciences.
Dr Hedén studied the potential for sustainable aquaculture of wolffish in her doctoral research, looking at the species' physiology with regard to animal welfare, as well as optimal feed ingredients and feeding protocols.
"This involved measuring the stress impact on the fish during handling. I also studied the intestinal function of the wolffish which can help us to understand the types of feed that work best and also the times of day the fish should be fed to ensure optimum growth,” says Hedén.
A former chef as well as a scientific researcher, Hedén says that wolffish has “firm, white flesh that works well on the grill."
However, she notes, in order for large-scale commercial wolffish farming to become possible, challenges remain.
The natural prey of wolffish are crustaceans such as starfish and mussels, indicating that aquaculture feed would need to be high in protein. This, Hedén says, poses a challenge in producing feed which is not reliant on fishmeal from wild-caught fish.
To find a sustainable alternative source of protein, Hedén's research focused on utilizing shrimp and herring byproducts from the fish processing industry, extracting protein from waste water.
She found that feed containing shrimp protein showed "promising results" for wolffish growth, supporting a circular approach in commercial production of the species.
A second challenge, Hedén says, is the slow growth rate of wolffish.
Farmed Atlantic salmon take 1-2 years to grow from larval stage to harvest, but for wolffish, the equivalent growth takes 3-4 years.
“Wolffish breeding programs are needed to develop faster-growing strains of the fish, as was done with salmon," argues Hedén.
"There is absolutely potential to farm wolffish, especially in land-based fish farms. Tanks on land offer good opportunities to control and create a good growing environment for the fish, and reduce the conflict with other coastal interests."
"But someone has to be the first and start a breeding programme. Thinking optimistically, that would give us commercially farmed wolffish in our fish counters in five years’ time,” she adds.