How do we make sure fish stocks have a sustainable future?

While the oceans remain as vast and seemingly inexhaustible as ever, the Food and Agriculture Organization of the United Nations estimated in 2018 that more than one-third of world fish stocks were overfished in 2020, and that this proportion continues to rise as steadily increasing demand places pressure on the almost 60 percent of remaining stocks which are already at their maximum sustainable levels.  

How do we fix this?

Historically the solution has been to increase seafood sustainability. It puts pressure on overfished stocks can be relieved by reducing catch quotas and substituting them for less pressured species. However, this raises prices which, if passed on to consumers, may drive demand for cheaper products without these safeguards. Alternatively, fish farming, or aquaculture, removes pressures on wild stocks completely but not all fish are suited to this approach.

A new approach is emerging ‘cellular aquaculture’. By taking cells from wild fish or seafood, growing and multiplying under conditions similar to those used in laboratory cell culture, and differentiating these cells into muscle fibres and tissues, high quality food products can be produced sustainably.

The advantage of cellular seafood

Similar approaches have been proposed for raising ‘cultured meat’, although interestingly fish possess certain advantages that make them particularly suited to cell culture.

Firstly, the complexity of oceanic and aquatic food chains means that the potential energy and carbon savings are multiplied significantly. Fish and seafood are also more biologically suited to cell culture.

Cellular aquaculture could even improve the safety of fish. Fish is a major source of dietary toxins through bioaccumulation. As big fish eat smaller fish, toxins such as mercury become more concentrated in their flesh as we move up the food chain. This is far worse for ‘bottom feeders’ such as lobsters, crabs and shrimp. By shortening this chain so that cells are directly fed on controlled, toxin-free media, this build-up can be avoided.

Not all plain sailing…

One major challenge will be developing a product that is indistinguishable from, rather than a substitute for, the real thing. Ensuring that fish cells have comparable texture, flavour, mouthfeel and cooking properties to natural fish will require significant optimisation.

Innovators in this field have focused on high-prestige fishes such as sashimi-grade salmon and tuna, which are highly overfished species that can be sold for high prices yet have difficult structures to imitate. Cellular aquaculture may soon be able to replace the large amount of fish consumed as processed products, such as surimi (most often seen in Europe as imitation crab stick) and fishmeal common in animal feed, by taking advantage of the existing processing techniques to achieve the desired texture. However, the main obstacle to cellular aquaculture remains working at scale.

Is cellular aquaculture the answer?

Rather than abandoning seafood altogether, it is vital that we identify ways to exploit this resource sustainably so that the oceans’ bounty can continue to reach those who need it.

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