Are We Eating the ‘Right’ Seafood?

Over the past 50 years, our global demand for seafood has increased substantially. So why are we consuming more seafood? Which species are in the spotlight? And what do these trends all mean for the future of our blue planet?

We are currently in what some have dubbed “The Blue Acceleration” - a term referring to the exponential expansion of humans into the oceans and blue spaces since the 1970s for industry, energy, resource mining, tourism, and food.¹ When zooming in on fisheries, you may assume the increase in seafood production is due to increased population. But population growth aside, global per capita fish consumption has more than doubled in the past 50 years.³
 

How are we supplying this growing demand?

The short answer is aquaculture. When looking at global trends, capture fisheries, both marine and inland, have been fairly stable in their production since the 1990s, with only a 9% increase between 1990 and 2018. Meanwhile, aquaculture has exploded with a 579% increase in global production between 1990 and 2018 for both marine and inland sources. This increase in aquaculture has been able to support and facilitate increased demand for seafood. However, it should still be emphasised that until 2019 and before disruptions associated with COVID-19 in 2020, capture fisheries production also saw higher volumes of seafood landed in recent years, with the most significant annual catch to date being in 2019.³

Where is seafood demand and consumption growing?

The largest increase in seafood consumption has been coming from Asia, with China dominating production and consumption. But despite the growing demand, it’s worth noting that China’s per capita seafood consumption still remains far lower than that of Europe and many other regions. Sub-Saharan Africa has also seen marked increases in consumption as the expansion of aquaculture has allowed boosted production throughout the region. Seafood consumption is predicted to increase a further 80% globally by 2050, with the highest increases expected in China and India.⁴
 

A fishing boat sails through a floating fish farm in Sanggou Bay, Shandong Province of China. (Yang Zhili/Getty Images)

 

Fish are a rich source of macro- and micronutrients, which can help diversify diets and support good health. However, fish is not merely for subsistence – with wealth increasing in populations in these regions, so does the taste for more ‘luxury’ grade fish at the top of the food chain, such as tuna and salmon.^2,6

On top of this, with a globalised market and increased trade efficiency, it’s more common for consumers to eat fish imported from other regions, and to adopt other fish-eating customs, as seen with the global expansion of sushi and processed seafood products.⁴ However, international fish trading tends to be restricted to urban areas with more facilities to freeze fish, prolonging shelf-life and potentially reducing unnecessary food loss.

Which species of seafood are we eating?

It’s important to note that aquaculture is not purely a means to produce finned fish - scientific literature discussing ‘fish’ or the fisheries sector often refers to all edible aquatic life, including organisms like mussels, prawns and even algae. By weight, shelled molluscs (mussels, clams, oysters, etc.) account for most aquaculture production globally.³ Even within wild capture fisheries, prawns and other crustaceans are a major portion of the total catch.

But looking at finned fish, freshwater carp species are the most commonly farmed, while anchovies are the most common wild-caught species by volume. However, over 600 species are produced in aquaculture, and over 1,800 are caught in the wild.³ 

Discover why "low-trophic aquaculture" can be so sustainable 

How does the future look?

In terms of aquaculture, some research shows that filter feeders, such as molluscs, improve water quality and are beneficial to the region through their cycling of nutrients while also requiring little energy to farm, making them a potentially more sustainable product. On the flip side, mismanagement of mollusc farms can lead to the introduction of toxins and diseases to the mussels and potentially to the humans who consume them. Furthermore, there are also worries that increased filter feeders can impact the natural flow of nutrients, negatively impacting other parts of the local ecosystem.⁴

Moving up the food chain, one of the main points supporting aquaculture is that it removes pressure from wild fish stocks, increasing food security and avoiding incidents such as the infamous Newfoundland cod fishery collapse in the 1960s.⁷ However, there have been studies showing that offshore aquaculture (where the cultivation cages are held within the open ocean) can lead to increased diseases and parasites in wild populations. This is due to the densely farmed populations still inhabiting the same body of water as the wild populations, which allows for the transmission of diseases and parasites.⁸ Furthermore, since salmon are higher up the food web, wild-caught fish - such as sardines - are still needed to comprise a significant portion of the feed used to grow the salmon in aquaculture, contributing to the depleting stocks of those species worldwide.⁹ 
 

Editor's Note - Since the 1970s, due to improving aquaculture feed mixes and reducing waste, we have seen a significant decrease in how many calories of wild fish are needed to produce a calorie of farmed fish. In 1970, the average calorie of farmed fish relied on 1.9 calories of wild fish. But by 2017, the average calorie of farmed fish relied on 0.28 calories of wild fish. (Our World In Data)

Circling back to wild capture fisheries, a significant ecological impact comes from by-catch. By-catch are non-targeted species that get caught in nets and fishing gear while fishing for target species. For example, when fishers go out to trawl for cod, they may also incidentally catch flatfish, haddock or even undersized juvenile cod - with endangered and protected species also at risk of being hauled in the same nets. Smaller target species such as prawns are generally the worst for by-catch, as finer nets are needed to capture them and as a result, there’s less discrimination in what’s caught.¹⁰ While the exact numbers on by-catch are hard to find, estimations indicate around 9.1 million tonnes worth of by-catch occurs annually, or 10.8% of the total catch weight.³

Truly sustainable seafood requires proper management and understanding of each exploited ecosystem and species. But there is still a lot to figure out, as John Shepherd, a professor of Marine Science at the University of Southampton once said:

“Managing fisheries is hard: It’s like managing a forest, in which the trees are invisible and keep moving around”.⁵