Aquaculture could be more sustainable if byproducts from industrial feed production were used instead of processing wild-caught species into aquaculture feed, according to studies at the University of Gothenburg in Sweden.
One of the most important challenges in aquaculture is access to fish meal, the announcement said, noting that current demand outweighs supply due to the rapid expansion of the aquaculture industry.
A new thesis at the University of Gothenburg has studied farming of two species: Atlantic wolffish and European lobster.
“These two species are popular among consumers and have a high market value in Sweden. The goal of the studies was to contribute to a knowledge base for the farming biology of these species with the welfare of the animals, a circular economy model and minimal environmental impact in mind, in accordance with the U.N.’s 2030 Agenda,” said thesis author James Hinchcliffe, a doctoral student in the university's department of biological and environmental sciences.
According to the announcement, studies from the thesis show that it is possible to produce high-value feed protein from unused byproducts. For example, the meat left on the bones after fish fillets have been removed is not used today.
“With a new process, we can use fish meat to give fish meal a higher protein content. By using feed containing byproducts from the seafood industry to a greater extent in general, use of wild-caught [aquaculture feed], like anchovies, can be reduced,” Hinchcliffe said.
Through laboratory experiments, Hinchcliffe and his fellow researchers also developed a species-specific feed to meet the need for suitable nutrients for lobster larvae.
“One of the greatest challenges of farming lobster is improving survival in the larval stages. That’s why we’ve developed a knowledge base about the most beneficial feed composition for the early life stages,” he said.
Lobster larvae grow and survive best when they can eat related species, which is why a lot of cannibalism is seen in today’s lobster farming industry, according to Hinchcliffe.
The studies investigated around 10 different kinds of feed with local ingredients.
“We found that a diet with a percentage of shrimp, which came from local byproducts from the industry, was the best source and most promising candidate for sustainable lobster feed,” Hinchcliffe said.
The studies also investigated the nutritional needs of Atlantic wolffish, the university said.
“The share of protein needed in the feed for optimum growth turned out to be relatively high — at least half the content of the feed,” Hinchcliffe reported.
Collectively, the studies show that Atlantic wolffish seem to be a good species to farm, the university said. The fish are relatively easy to manage and resistant to stress.
“My hope is that the results of the studies will contribute information and can be used for environmentally sustainable aquaculture and production of nutritious food in Sweden,” Hinchcliffe said.
Hinchcliffe's dissertation, "A Circular Economy Approach for Sustainable Feed in Swedish Aquaculture," was supervised by Elisabeth Jönsson Bergman in the university's department of biological and environmental sciences.