Summary

• Bivalve aquaculture increases population health, increases food security, improves developing country welfare, benefits the environment, mitigates climate change, and improves animal welfare.

• There is enough availability of suitable coastline to support at least an order of magnitude more production.

• Bivalves are significantly more expensive than meat, and the demand curve can absorb large increases in supply.

• There do not appear to be any intractable problems preventing significant expansion.

• Increasing production can be financially risky, which is why we have less bivalve production than is optimal. 

Bivalve aquaculture means marine farming of scallops, oysters, clams, mussels, and similar. We will be focusing on these four because they are the largest production share of edible bivalves. In contrast to intensive fish aquaculture, bivalve aquaculture is an extensive form of aquaculture; bivalves feed on algae that occur naturally in the ecosystem and no additives such as vitamins and antibiotics are added.

It has multiple benefits, the main ones being developing country welfare, food security, climate change and environmental benefits, and animal welfare. These will be described fully in their respective sections.

Bivalve aquaculture is one of the most promising interventions but not the top one along each of these dimensions. For example, Allfed approaches it from a food security perspective, finding that it is worth further research based on this alone. Tren Griffin is interested in it for its positive impact on climate change.This positioning means that it falls between the cracks and is not prioritized. Indeed, a search for the term “bivalve aquaculture” on the Effective Altruism forum did not return any relevant hits apart from my draft post on this topic.

We should prioritize this cause area because its combined benefits mean that it is an intervention with very high impact.

This is an initial look into this cause area; approximately 35 hours was spent on research and on “shallow” introductory discussions with people interested in this idea.

Note: The preliminary idea for this submission was previously posted here. This post contains additional research and supersedes the previous post.

Bivalves are the most preferred protein source

Epistemic confidence for this category: high

People mostly love the taste of scallops, oysters, clams, and mussels. In some areas of the world, such as most of East and Southeast Asia, they are considered to be highly prestigious luxury foods. They are also desired in South America and many parts of Europe. Bivalves are less popular in North America, and so we would expect North Americans to underestimate the desirability of bivalves as a food.

Here is a brief overview of how these bivalves are seen:

• Scallops are universally loved: “Even people that don’t naturally enjoy seafood eat scallops. Because of the rich taste, it is a best seller.”

• Oysters are polarizing. A significant proportion of people hate oysters, while many others love them. This is fine for bivalve aquaculture potential because the oyster-haters don’t matter – current production levels of 6 million tonnes per year (in 2018) represents less than 0.2% of total food production of 4 billion tonnes (2020), and increasing production even by an order of magnitude wouldn’t dent the demand curve.

• Clams are popular, and especially popular in Asian cuisine: “Clams are delicious, and what they taste like will depend on the time of year.” Even people in the United States are familiar and accepting of clams, such as in New England clam chowder. Their relatively neutral taste makes them versatile.

• Mussels are slightly less popular because of their inferior texture, but are still considered yummy: “What Do Mussels Taste Like: Yummy or Yucky? They are super healthy yet yummy at the same time.”

In most parts of the world, seafood is more highly valued than meat like beef, chicken, or pork. When available, seafood readily substitutes for meat, and the main obstacle is that seafood is more expensive. For example, here is a typical Chinese wedding banquet menu that has three options. We compare the cheapest one with the most expensive one.

To make it easier to compare, we cancel out identical items and ignore the non-meat or seafood ones, and categorize them as “meat”, “seafood”, or “bivalve”.

The cheap option includes pork and chicken. The expensive one contains seafood and bivalves. This implies that most people like the taste of bivalves more than meat, as shown by their willingness to pay extra for it. If we were to substantially increase bivalve production, it would mostly substitute for a lot of other protein sources, mainly beef, pork, and chicken – we do not need to worry about a demand deficit or a lack of substitution effect.

How big is the opportunity?

Epistemic confidence for this category: high

The global production of marine bivalves for human consumption is more than 15 million tonnes per year (average period 2010–2015), which is about 14% of the total marine production in the world. For a ballpark comparison, total food production was 4 billion tonnes in 2010. Most of the marine bivalve production (89%) comes from aquaculture, with a total economic value of 20.6 billion US$ per year, and only 11% comes from the wild fishery. Asia, especially China, is by far the largest producer of marine bivalves, accounting for 85% of the world production and responsible for the production growth.

Here is a breakdown of production by type of bivalve, and by continent, as a time series:

Bivalves are more expensive than farmed animals at the moment. For example, retail prices at my local supermarket for fresh food are:

Scallops$49/kg (Australian dollars)Beef$28/kgPork$18/kgChicken$13/kg

We observe a large price gap between scallops and other meat. Combined with the small current bivalve percentage of total food production, this implies that a large increase in the supply of scallops would meet ample latent demand at a good market-clearing price. This intuitively makes sense, since bivalves are the most preferred protein source as shown in the previous section.

Seasonality is another potential concern. If bivalves are only available for a few months of the year, then demand would be harder to match to supply.

Oysters are usually seasonal but can be farmed to be year-round: “Perhaps the best reason to only buy oysters during the fall, winter, and spring—the "r" months—is related to the creature's reproductive cycle […] a new genetic procedure being used by some commercial oyster farms renders farm-raised oysters sterile, so they don't spawn at all. These prime oysters are available for year-round enjoyment.”

Clams and mussels share the same seasonality as oysters, but are less sensitive: “Clams and mussels do lose quality in months without R, but not as noticeably as oysters.” Scallops also have similar seasonality, but I wasn’t yet able to find supporting evidence.

All bivalves can be cost-effectively snap frozen for transport and for future use, with a small loss in quality. This reduces the seasonality effect significantly.

Lots of room to scale

Epistemic confidence for this category: high

“Across the world there is an estimated 1.5 million sq km (579,000 sq miles) of coastline suitable for growing bivalve shellfish. According to Willer, developing just 1% of this could produce enough bivalves to fulfil the protein requirements of more than one billion people.”

The July 2020 article in Nature by Willer maps out tropical regions that are suitable for bivalve aquaculture. These regions contain a majority of the world’s population: