The views expressed here are my own, not those of my employers or people who provided feedback.
Summary
- I Fermi estimate the past cost-effectiveness of Shrimp Welfare Project’s (SWP’s) Humane Slaughter Initiative (HSI) is 639 DALY/$, which is:
- 412 and 173 times my estimate for the (marginal) cost-effectiveness of broiler welfare and cage-free corporate campaigns, such as the one supported by The Humane League (THL).
- 64.3 k times my estimate for the cost-effectiveness of GiveWell’s top charities.
- I calculate helping shrimps slaughtered via air asphyxiation is 21.0 times as cost-effective as helping those slaughtered via ice slurry.
- Consequently, holding the number of shrimps helped per $ constant, it is much better to target producers slaughtering shrimps via air asphyxiation.
- I believe SWP’s work on removing sludge from shrimp ponds might be even more cost-effective than HSI, but it is not clear.
Cost-effectiveness of HSI
The calculations are in this Sheet.
I estimate the past cost-effectiveness of HSI is 639 DALY/$, multiplying:
- 15 k shrimps helped per $, which I got from the product between:
- 0.0426 DALYs averted per shrimp helped, which I determined from the product between:
- An equivalent additional time of a practically maximally happy life per shrimp helped of 0.931 years, which I obtained assuming:
- All of the shrimps helped transition to electrical stunning, 95 % from air asphyxiation, and 5 % (= 1 - 0.95) from ice slurry. These fractions are informed by Aaron’s comment at the end of this section, here and here.
- For ice slurry, Rethink Priorities’ (RP’s) estimates for the time in the 4 categories of pain defined by the Welfare Footprint Project (WFP). 0 h in annoying pain, 3.02*10^-4 h in hurtful pain, 0.0239 h in disabling pain, and 0.00604 h in excruciating pain. Feel free to check RP’s related post.
- For air asphyxiation: time in disabling pain equal to the maximum time during which shrimp can remain alive of 30 min, although Aaron noted he and his colleagues have seen some alive for 6 h; time in excruciating pain as a fraction of that in disabling pain equal to that of ice slurry (0.126 h); time in hurtful pain as a fraction of that in disabling pain equal to that of ice slurry (0.00633 h); and time in annoying pain as a fraction of that in hurtful pain equal to that of ice slurry (0 h).
- For electrical stunning: time in disabling pain equal to 1.39*10^-4 h (= 0.5/60^2), as Aaron mentioned shrimps are electrically stunned within 1 s, which I interpreted as a uniform distribution ranging from 0 to 1 s, whose mean is 0.5 s (= (0 + 1)/2); time in excruciating pain as a fraction of that in disabling pain equal to that of ice slurry (3.51*10^-5 h); time in hurtful pain as a fraction of that in disabling pain equal to that of ice slurry (1.76*10^-6 h); and time in annoying pain as a fraction of that in hurtful pain equal to that of ice slurry (0 h).
- Annoying pain is 10 % as intense as a practically maximally happy life.
- Hurtful pain is as intense as a practically maximally happy life.
- Disabling pain is 10 times as intense as a practically maximally happy life.
- Excruciating pain is 100 k times as intense as a practically maximally happy life.
- RP’s median welfare range of shrimps of 0.031.
- An equivalent additional time of a practically maximally happy life per shrimp helped of 0.931 years, which I obtained assuming:
My assumptions for the pain intensities are guesses for my personal time trade-offs, and imply each of the following individually neutralise 1 day of a practically maximally happy life:
- 10 days (= 1/0.1) of annoying pain.
- 1 day of hurtful pain.
- 2.40 h (= 24/10) of disabling pain.
- 0.864 s (= 24*60^2/(100*10^3)) of excruciating pain.
My estimate for the past cost-effectiveness of HSI is:
- 278 and 173 times my estimates for the cost-effectiveness of broiler welfare and cage-free campaigns of 1.55 and 3.69 DALY/$.
- 64.3 k times my estimate for the cost-effectiveness of GiveWell’s top charities of 0.00994 DALY/$.
In addition, I estimate the past cost-effectiveness of HSI linked to helping shrimps slaughtered via:
- Ice slurry is 31.9 DALY/$, or:
- 20.6 and 8.64 times the cost-effectiveness of broiler welfare and cage-free campaigns.
- 3.21 k times the cost-effectiveness of GiveWell’s top charities.
- Air asphyxiation is 671 DALY/$, or:
- 433 and 182 times the cost-effectiveness of broiler welfare and cage-free campaigns.
- 67.5 k times the cost-effectiveness of GiveWell’s top charities.
- 21.0 times (= 671/31.9) that linked to helping shrimps slaughtered via ice slurry.
Consequently, holding the number of shrimps helped per $ constant, it is much better to target producers slaughtering shrimps via air asphyxiation. I assumed the same number of shrimps helped per $ for both methods, so the higher cost-effectiveness of helping shrimps slaughtered via air asphyxiation comes from the respective reduction in the disease burden per shrimp being 21.0 times as large. Given this large difference, I asked Aaron whether he had any estimates/guesses for the fraction of shrimps HSI helps which were being slaughtered via each of the 2 methods. Here is Aaron’s reply:
“This is tricky because the answer is kind of both...
Most of the producers we work with are already implementing some kind of ice slurry, as they typically sell to the European market, and ice slurry improves the quality (for example sometimes sodium metabisulfite is added to the slurry mix, which prevents discolouration).
However, for ice slurry to function as a slaughter method, the shrimp has to be submerged for long enough (which we currently understand to be over 30 seconds), and typically instead the crates of shrimps are “dipped” into ice slurry for a few seconds, so in reality once removed they die of asphyxiation/crushing.
Though it’s important to note that practices can vary significantly by country and production systems (and producer).”
I am currently planning to direct my next annual donations to SWP.
Cost-effectiveness of sludge removal
SWP also works on removing sludge from shrimp ponds, which:
- Improves water quality via reducing un-ionised ammonia and hydrogen sulphide.
- Reduces stocking densities via making the ponds deeper, and SWP asking farmers to commit to lower densities as a precondition for the sludge removal.
Aaron noted he thinks most of the benefits come from the 1st point:
“I also want to add that although we do ask farmers to lower their densities - densities in India are already pretty low anyway (at least in the remote villages we’re working in), so I don’t think most of the benefits are realised here, I do think it’s mostly water quality improvements (and primarily hydrogen sulphide and un-ionised ammonia).”
I believe SWP’s work on removing sludge from shrimp ponds might be even more cost-effective than HSI, but it is not clear. I calculate high stocking density and un-ionised ammonia account for 5.33 and 7.67 times as much suffering as ice slurry slaughter. Nonetheless, Aaron caveated that:
“Our current shrimps helped / $ / year on this is ~500 [i.e. 1/3 (= 500/(1.5*10^3)) of HSI’s] (though the India team keeps on optimising the process and bringing costs down, so this number is improving month after month - I’m hopeful this will eventually equal HSI).
Also worth noting that the scale here is much lower than that of HSI, each pond we work with typically stocks ~100,000 shrimps, meaning we're impacting in the range of 10s of millions of shrimps each year. Whereas with HSI, each producer we work with commits to stunning a minimum of 100 million shrimps. So even if cost-effectiveness here exceeded that of HSI, the number of shrimps helped will almost certainly be much higher with HSI.
It’s also tough to know here how to convert from per $/year to just per $, as sludge slowly re-accumulates, so the impact year after year is reduced (and the program hasn't been running for long enough for us to assess if farmers continue to remove sludge after our initial intervention).”
Acknowledgements
Thanks to Michael Johnston for nudging me to Fermi estimate the cost-effectiveness of shrimp welfare interventions. Thanks to Aaron Boddy for feedback on some of the inputs. Thanks to Aaron and Michael for feedback on the draft.
Thanks so much Vasco for your work on this! As with MHR in the past, we really appreciate folks doing in-depth analyses like this, and are very appreciative of the interest in our work :)
In the spirit of this week’s Forum theme, I wanted to provide some more context regarding SWP’s room for more funding.
Our overheads (i.e. salaries, travel/conferences) and program costs for the India sludge removal work, are currently covered by grants until the end of 2026. Meaning that any additional funds are put towards HSI. (For context, our secured grants do also cover the cost of some stunners, but HSI as a program is still able to absorb more funding).
Each stunner costs us $55k and we ask the producers we work with to commit to stunning a minimum of 120 million shrimps per annum. This results in a cost-effectiveness of ~2,000+ shrimps helped / $ / year (i.e. our marginal impact of additional dollars is higher than our historical cost-effectiveness).
We’re having our annual team retreat (which we call “Shrimposium”) next week, during which we hope to map out how we can deploy stunners in such a way as to catalyse a tipping point so that pre-slaughter stunning becomes the industry standard.
We’ve had some good indications recently that HSI does contribute to “locking-in” industry adoption, with Tesco and Sainsbury’s recently publishing welfare policies, building on similar wins in the past (such as M&S and Albert Heijn).
This has always been the Theory of Change for the HSI project. Although we’re very excited by how cost-effective it is in its own right, ultimately we want to catalyse industry-wide adoption - deploying stunners to the early adopters in order to build towards a tipping point that achieves critical mass. In other words, over the next few years we want to take the HSI program from Growth to Scale.
I would be surprised if post-Shrimposium our targets regarding HSI required less funding than our current projections. In other words, though I don’t currently have an exact sense of our room for more funding, I’m confident SWP is in a position to absorb significantly more funding to support our HSI work.
If anyone wants to reach out to me directly, you can contact me at aaron@shrimpwelfareproject.org. You can also donate to SWP through our website, or book a meeting with me via this link.
Thanks. I will update the analysis using 95 % (= (0.9 + 1)/2), which results in the same expected cost-effectiveness as using a uniform distribution ranging from 90 % to 100 %.