Original post on my blog: https://ishankhire.blogspot.com/2023/04/overview-of-shrimp-farming-and.html
State of Shrimp Farming
The shrimp farming industry is rapidly growing at a rate of 10% a year. In light of this and new research supporting crustacean sentience, charity entrepreneurship published a report recommending a new charity working in this field. Through its incubation program, the Shrimp Welfare Project was founded.
This post is based on the 80000 after hours podcast with Andres Jimenez Zorrilla, founder of the Shrimp Welfare Project. The post aims to condense the information in the podcast, add new context, and raise several questions regarding shrimp farming.
What does shrimp farming look like?
It’s separated into different stages:
- Sexually active reproductive shrimp are brought to India or Vietnam
- Females undergo “eyestalk ablation” — the crushing of one or two eyes to induce egg laying
- Newly born shrimp spend 30 days growing in small tanks (incubators)
- Shrimp are transported to farms in oxygenated bags - mortality rate during transport can be high
- They’re then moved to “grow-out” ponds which are plastic tanks where they spend the rest of their lives. They spend another 50-120 days there, depending on desired size, and are slaughtered
What are conditions of shrimp farming?
Tanks vary in crowdedness from 5-10 animals per cubic metre in Latin America, to really intensive systems in tiny ponds where there are several hundred animals per cubic metre. In these really crowded conditions, they often get quite sick.
In crowded conditions, they need oxygen, so tanks are aerated. Quality of water also needs to be controlled including pH level, salinity, temperature and concentrations of un-ionised ammonia.
They’re fed with pellets that have fish oil and fish meal, which is produced from what are called “trash fish.” This puts a lot of strain on environmental systems and is also bad for welfare since most of these fish are suitable for human consumption. In fact, the shrimp industry consumes 31% of all fishmeal used in aquaculture and accounts for 16% of global aquafeed production. Around 6 million tons of fish are used to produce fishmeal. Fish caught for fishmeal vary in weight, but if the weight per fish is approximately 100g, the number of fish used to feed shrimp amounts to 1.86 trillion fish! A small percentage of that is from by-catch of other fisheries, or by-products during processing, but most comes from fish caught for the sole purpose of fishmeal. It’s projected that shrimp production will double by 2030, so the demand for fishmeal will likely keep rising.
Given this, it seems plausible that another effective welfare intervention could be replacing fishmeal with alternatives such as soy based-meal, whose quality has increased in recent years.
How many shrimp are there?
Only tonnage is measured, not the individual number. There’re around 4.5-6 million tons of shrimp per year, leading to 300-400 billion shrimp/year which are farmed. And in the wild, Andres Zorrilla claimed estimates go up to 30 trillion shrimp/year. However, 55-60% of shrimp consumed are farmed, because the weight of farmed shrimp is substantially higher. Wait, but that would require wild-caught shrimp to be one hundred times smaller than farmed shrimp, but even considering super colossal shrimp compared to small shrimp, the largest are only 10 times greater than the smallest shrimp. I checked the numbers on this and I think 30 trillion shrimp/year is probably a dramatic overestimate. Considering farmed shrimp are 3-5 times larger than small wild caught shrimp, the number of wild caught shrimp is probably much closer to something like 1-2 trillion at most.
On a side note, for every one pound of shrimp that’s caught, 20 pounds are discarded as bycatch, which is likely horrible both for welfare and the environment.
Are shrimp sentient?
What is sentience?
Sentience is the ability to feel things. One way to understand this is to ask: “Does it feel like something to be this individual?” The precautionary principle states that if there’s a significant chance that an animal is sentient, we don’t need full scientific certainty to use cost-effective measures to improve welfare outcomes.
Scientific Conclusions on Shrimp Sentience
Researchers at LSE published a report recommending that “all cephalopod mollusks and decapod crustaceans be regarded as sentient.” They used 8 indicators to measure this (strongly recommend you read this to understand what they are!). There’s strong evidence that large decapod crustaceans (true crabs) are sentient, but penaeid shrimp have been studied much less, and there is therefore much less confidence of there sentience (this is largely due to information gaps, but is not evidence for the absence of sentience).
Perceptions on Shrimp Sentience
Surprisingly, around 95% of farmers in India agreed they feel pain - likely because farmers see them all the time. They can see when they’re sick, feeding, or doing smart and behaviorally complicated things. Leah Garces shared a similar perception with regards to chicken farmers. I think this goes to show that especially for farmers who work with animals every single day, there can potentially be ways to get them sympathetic to animal welfare and persuade them to increase welfare standards.
For the general public’s reaction, there’s mostly not a big resistance to the idea they feel pain, until you get their diets involved. However, when people were shown that shrimp were included in the UK sentience bill, their opinion changed a lot, and they were willing to pay a premium, at least in principle. I think this is a really interesting example of laws changing public perception and making foreign and strange ideas seem more acceptable. There are of course strong doubts on whether this willingness to pay more will actually play out in the real world, but it has somewhat worked with cageless chickens.
Welfare issues and Solutions
In the slaughtering process, a net is dragged to one corner of the pond, trapping the shrimp so they’re cornered, and scooping them out. They’re put in crates and drained of water to be weighed. When out of the water, they’re asphyxiated and as they’re stacked up, many of them are crushed. They’re supposed to be put in an ice slurry, to slowly reduce their metabolism and kill them. This is also in the incentive of the processor who buys them, since stress during slaughter deteriorates tissue quality. In practice though, often just a bit of ice is put on top for freshness, so many die slow, painful deaths.
Less cruel ways of slaughter
There actually isn’t consensus on whether putting them in an ice slurry is more humane — ice may just slow down bodily functioning, prolonging the death. Electrical stunning seems promising, though there are concerns they’ll just be burned alive instead of stunned unconscious. The way this works is they’re brought out and placed on a conveyor belt on which there are electrodes. To reduce the suffering of scooping them out of water, one suggestion is to just pass a current through the body of water, but there are many safety concerns with that; plus, the water may be so conductive that it just goes around the shrimp.
Pushing stocking densities too high compromises the immune systems of shrimp since they’re really stressed, making them more susceptible to disease and slowing their growth. These infections can also spread from pond to pond, transferred by nets which are sometimes not disinfected, or by birds which pick up shrimp from one pond and may drop them in another. This creates a collective action problem where all farmers are worse off if a single tank has too high of a density. This can create the need for regulation to enforce densities. Low densities may also not reduce the revenue of farmers as bigger lobsters may grow, so they’ll get more money per kilogram, but less animals. Most farmers agree that disease is a big problem for them, meaning they have the incentive to reduce it too.
Because of this, the Shrimp Welfare Project is generally placing itself as a collaborative within the industry, to persuade it from an economic lens to reduce stocking densities by showing that it aligns with its economic incentives. Currently, this is just being done as a proof of concept to show that high welfare shrimp can be made in a profitable way. This is where the Shrimp Welfare Project does most of its work right now.
Other possible ways to improve welfare
- Make conditions better — ensure there’s sufficient dissolved oxygen, low concentrations of un-ionized ammonia, an appropriate pH range, temperature and salinity.
- Scoping of India reveals water quality is higher than expected (with the exception of pH and ammonia) likely due to technicians testing the water on a regular basis and giving feedback to farmers.
- Eyestalk ablation - the process of crushing eyes to release eggs - is very cruel. Brood stock subjected to this practice die from it, or die sooner because of stress on physiology. Welfare improvements here seem quite promising — there are many downsides to the health and longevity of the offspring too, meaning it may be in the incentive of farmers to stop this. Additionally, this is a visceral issue many people can connect with.
- Influence legislation in the US, EU, UK and Japan to raise the welfare bar for imports
- On the consumer side, it might be worth informing people about the conditions so they demand higher wellbeing, but in practice, there’s very little evidence that people pay more for fish welfare.
- Establish a brand that only sells super high welfare shrimp to transition demand — but there’s a very high possibility of harm here
- Plant based shrimp actually seems viable. Shrimp tissue is a lot more uniform than other animals, so it tastes quite similar.
- Humane slaughter technology could be introduced in fishing vessels
- A certification for higher welfare shrimp could be created to incorporate higher welfare modules.
Quality of life
This is very hard to determine as we don’t really know what the preferences of shrimp are. That’s why a lot of Shrimp Welfare Project’s decisions are based on “good bets” that likely don’t cause harm – things that definitely decrease mortality, disease, etc. Being packed together might cause a lot of stress and be very unnatural. In the wild, they generally spawn in one area, go to open water, and then come back to the estuary they spawned from, so they change environments. This may or may not be replicated by moving from different tanks, but there’s a lot of uncertainty.
Charity entrepreneurship determined the lives of farmed shrimp are likely net negative, they might be net positive as well.
Effects on Sustainability
Apart from just improving the lives of shrimp, an increase in welfare standards can also increase sustainability through a few ways:
- Water pollution — poor water quality can contaminate nearby bodies of water, causing large spillover effects like eutrophication.
- Disease — diseases in shrimp affect food safety. The heavy use of antibiotics can also promote the emergence of antibiotic-resistant bacteria
- Ecosystems — Feed for shrimp requires a significant amount of wild fish, putting strain on aquatic biodiversity. Diseases can be spread to surrounding areas as pathogens and parasites may flourish. Wild-caught shrimp are captured using a process called bottom trawling which releases a lot of carbon dioxide. Shrimp farms are also often built on the site of mangrove forests which need to be cut down.
- Livelihoods — indigenous communities rely on the mangrove forests that are cut down. Shrimp processing facilities have involved human trafficking and terrible working conditions. Overfishing can threaten future family businesses and employment opportunities.
The Shrimp Welfare Project is often collaborating with the industry to increase their productivity as well. This may be an issue that leads to lower prices and increases the demand for shrimp, causing more harm than good. Currently, they’re just doing a proof of concept that high welfare shrimp can be produced, but it definitely could be an issue in the future. That’s why it’s probably important for work to be there with consumer awareness and litigation as well.
Open questions and my best guesses:
- How do shrimp welfare standards compare with those of fish? If fish experience greater suffering, and shrimp are a substitute for fish consumption, could shrinking the shrimp industry result in an increase in fish farming? Are they even substitutes?
- My guess is shrimp are more important because there are more shrimp that are farmed and caught in the wild. They also have a lower weight meaning, more have to be killed compared to fish for the same weight. However, according to Rethink Priorities’ Welfare Range Estimates, shrimp are possibly less sentient than Salmon and Carp, which could counteract this effect (though I don’t think it does), depending on how large the difference in sentience actually is.
- A more detailed exploration of how a decrease in consumption in other animals could translate into an increase in others requires far more careful analysis and could probably be the subject of an entirely new post.
- Why has there been comparatively less focus on wild-caught shrimp?
- What has recent progress in shrimp welfare looked like? It’s been about 6 months since the podcast came out.
- If it turned out that shrimp lives were net positive, how would that change the priority/actions taken to improve shrimp welfare?
- How should we weigh uncertainty (about how bad the lives of shrimp are, their sentience, possible actions on the industry) when making decisions about where to prioritize in animal welfare?