Update: Andrés Jiménez Zorrilla (CEO of SWP)  has provided some additional information in the comments. In particular:

1. SWP is looking to raise over $1m for this effort, to deploy additional stunners and add a dedicated staff member 
2. SWP's goal with this project is for it to severe as a catalyst to industry-wide adoption
3. While SWP's estimate of animals impacted includes only 50-75% at each producer, the pilot would likely be extended to cover 100% if successful

Summary

• The Shrimp Welfare Project (SWP) has a novel opportunity to spend up to $115,500 to purchase and install electric stunners at multiple shrimp farms
• The stunners would be used to stun shrimp prior to slaughter, likely rendering them unconscious and thereby preventing suffering that is currently experienced when shrimp asphyxiate or freeze without effective analgesics 
• Based on formal agreements SWP has signed with multiple producers, raising $115,500 would enable the stunning (rather than rather than conventional slaughtering) of 1.7 billion shrimp over the next three years, for a ratio of nearly 15000 shrimp/dollar 
• I performed a preliminary cost-effectiveness analysis of this initiative, looking at direct impacts only (i.e. not considering the potential for this project to catalyze industry-wide change). I reached the following three tentative conclusions:
  • The expected cost-effectiveness distribution for electric shrimp stunning likely overlaps that of corporate hen welfare campaigns
  • The cost-effectiveness of electric shrimp stunning is more likely to be lower than that of corporate hen welfare campaigns than it is to be higher
  • Shrimp stunning is a very heavy-tailed intervention. The mean cost-effectiveness of stunning is significantly influenced by a few extreme cases, which mostly represent instances in which the undiluted experience model of welfare turns out to be correct
• Given these results, electric shrimp stunning might be worth supporting as a somewhat speculative bet in the animal welfare space. Considerations that might drive donor decisions on this project include risk tolerance, credence in the undiluted experience model of welfare, and views about the likelihood of this project accelerating more widespread adoption of humane shrimp slaughter practices.

Description of the Opportunity

The following information is quoted from the project description written by Marcus Abramovitch on the Manifund donation platform, based on information provided by Andrés Jiménez Zorrilla (CEO of SWP) : 

Project summary

Shrimp Welfare Project is an organization of people who believe that shrimps are capable of suffering and deserve our moral consideration [1]. We aim to cost-effectively reduce the suffering of billions of shrimps and envision a world where shrimps don't suffer needlessly.

• Programme: our current most impactful intervention is to place electrical stunners with producers ($60k/stunner): We have signed agreements with 2 producers willing and able to use electrical stunning technology as part of their slaughter process which will materially reduce the acute suffering at the last few minutes / hours of shrimps lives. Collectively, these 2 agreements will impact more than half a billion animals per year at a rate of more than 4,000 shrimps/dollar/annum. Please take a look at our blog post on the first agreement here. 
• We are in advanced negotiations with 2 more producers which would take the number of animals to more than 1 billion shrimps per annum.
• See our back-of-the-envelope calculation for the number of shrimps and cost-effectiveness analysis here

Project goals

• Simplified end-game of this programme: the interim goal of placing these stunners with selected producers in different contexts/systems is to remove some perceived obstacles to the industry and show major retailers and other shrimp buyers that electrical stunning is something they can demand from their supply chain 
• The ultimate goal is for electrical stunning to be:
  • widely adopted by medium to large shrimp producers in their slaughter process (pushed by their buyers), 
  • included by certifiers in their standards, and eventually
  • considered (eventually) to be an obvious requirement by legislators when drafting policy (e.g. EU review of decapod welfare in 2028-2030)

How will this funding be used?

• Room for more funding: Our 2023 general budget is fully funded so any additional money would go to this programme. We believe we can place 3 stunners during 2023 which would mean a potential to use an additional $180k at an extremely cost-effective rate of >2,000 animals helped per dollar per year.
• During 2024, we estimate we could place up to 12 stunners ($60x12 = $720k)

How could this project be actively harmful?

• London School of Economics report [2] - Only had “medium confidence” that electrical stunning renders decapods unconscious (although “no confidence” for ice slurry which is the current slaughter method).
• The “Weineck” study [3] - The only published academic study on the electrical stunning of shrimps only stunned a single shrimp at a time
• Tesco/Hilton case study [4] - ~2% of shrimps continued to demonstrate heart and gill bailer activity after electrical stunning
• University of Stirling study [5] - To address these uncertainties, Open Philanthropy is funding a study to optimize electrical stunning parameters for shrimps

What other funding is this person or project getting?

• Open Philanthropy and the EA Animal Welfare Fund are funding our operations roughly at 60/40, respectively. 
• We are attempting to fundraise for the stunner programme independently from our two main funders as we have been advised by them that we should diversify our funding pool

Cost-Effectiveness Analysis 

The goal for my cost-effectiveness analysis (CEA) was to compare this opportunity against corporate cage-free campaigns for hens, since corporate campaigns have historically received the largest share of animal welfare-directed EA-linked donations. 

The metric of interest in this analysis was welfare-range-weighted hours of disabling-equivalent pain averted per dollar spent. For shrimp, this metric was computed by multiplying welfare range (fraction of humans’), hours of suffering during slaughter, pain intensity weight (relative to disabling pain) during slaughter, probability of electric stunning eliminating pain, and shrimp stunned per dollar. For chickens, this metric was computed by multiplying welfare range (fraction of humans’) and hours of disabling-equivalent pain averted per dollar spent on corporate campaigns. The sources for each of these components are discussed in the following paragraphs, and all code is available on GitHub. 

To weight pain in each species by shrimp and chickens’ likely differing capacities for welfare, I used the welfare range distributions for chickens and shrimp from the Rethink Priorities Moral Weight Project (MWP). The MWP makes several significant assumptions in arriving at its results, including utilitarianism, hedonism, valence symmetry, and unitarianism. Its results for chicken and shrimp are shown in Table 1 and Figure 1. An important characteristic of these results is that there is an extreme tail in shrimp’s moral weight distribution, potentially leading to them having up to 10x the capacity for welfare as a human. This tail is driven by MWP’s inclusion of the “undiluted experiences” model of welfare as one element of the mixture model. In the undiluted experiences model, pain is made worse by an animal’s lack of cognitive capacity to contextualize their experiences, thus tending to produce moral weights that have an inverse correlation with neurological complexity. 

Table 1. RP Moral Weight Project Results for Chickens’ and Shrimp’s Welfare Ranges (Fraction of Humans’ Welfare Range) 

To categorize the different types of pain experienced by a given animal, I used the pain standards established by the Welfare Footprint Project (WFP). My medium-confidence guess is that when suffocating or freezing, shrimp are mostly experiencing discomfort that would meet WFP’s “disabling pain” standard:

Disabling Pain: Pain at this level takes priority over most bids for behavioral execution and prevents all forms of enjoyment or positive welfare. Pain is continuously distressing. Individuals affected by harms in this category often change their activity levels drastically (the degree of disruption in the ability of an organism to function optimally should not be confused with the overt expression of pain behaviors, which is less likely in prey species). Inattention and unresponsiveness to milder forms of pain or other ongoing stimuli and surroundings is likely to be observed. Relief often requires higher drug dosages or more powerful drugs. The term Disabling refers to the disability caused by ‘pain’, not to any structural disability.

I think it is likely that some dying shrimp meet WFP’s “excruciating pain” standard, particularly those that are crushed under other shrimp or under ice. However, this level is so extreme that I expect it does not make up the bulk of suffering experienced during slaughter. It is also possible that a fraction of shrimp are successfully rendered unconscious quickly under current methods by coming into contact with ice, reducing the average level of pain to WFP’s “hurtful pain” level. To weight pain at these different levels, I followed the same approach as the recent Rethink Priorities report “Cost-Effectiveness of Historical Farmed Animal Welfare Ballot Initiatives,” authored by Laura Duffy, which weights an hour of hurtful pain as equivalent to 0.15 hours of disabling pain and an hour of excruciating pain as equivalent to 5 hours of disabling pain. Because I think the average pain level is most likely slightly above the “disabling’ level, with significant uncertainty, I estimated the average pain intensity weight for shrimp during slaughter as a gamma distribution with ɑ = 1.5 and β  = 1 (clipped at a range of 0.15 to 5). This distribution gives an average pain intensity weight of 1.5x the disabling pain level, and is shown in Figure 2.
 

The duration of suffering during slaughter is currently an area of significant uncertainty for me. Based on SWP’s “minutes / hours” statement, I estimated the distribution of suffering during slaughter as a lognormal distribution with a mean of 20 minutes and a 97.5th percentile estimate of 3 hours. This distribution is shown in Figure 3. 

Ideally, stunning would remove 100% of the pain associated with slaughter. However, as indicated in SWP’s summary, there is some disagreement among experts as to the effectiveness of electric stunning in rendering shrimp unconscious. My educated guess, based on the conflicting scientific evidence and the LSE report’s “medium confidence” estimate of electric stunning’s effectiveness, is that electric stunning has about a 2 in 3 chance of rendering shrimp unconscious, for a probability of 0.667.

The number of shrimp stunned per dollar was estimated based on SWP’s “back-of-the-envelope calculation” included in the Manifund description. This information is provided in Table 2. I translated SWP’s calculations into a probability distribution by assuming that the number of shrimp helped per dollar was normally distributed with mean equal to SWP’s estimate (14796) and standard deviation equal to the average difference between the number of shrimp helped per dollar at each producer and the total average (7708). The lower end of this range might represent SWP encountering unexpected challenges that prevent the stunners being fully successfully utilized, while the upper end of this range might represent the stunners being successfully used (and having counterfactual impact) for more than the three years baselined in SWP’s analysis. This distribution is shown in Figure 4.
 

Table 2. Estimate of Shrimp Helped Per Dollar (from SWP Project Description)

	SIGNED		TOTAL
Metric	Mer Seafood	Seajoy - Cooke
Total production p.a. (MT)	2,300	12,500	14,800
Total production p.a. (g)	2,300,000,000	12,500,000,000	14,800,000,000
Number of grams per shrimp (1)	14	14	14
Total production p.a. (MT)	164,285,714	892,857,143	1,057,142,857
% Committed to be stunned (2)	75%	50%	54%
Total number of shrimps stunned p.a.	123,214,286	446,428,571	569,642,857
Number of years brought forward (3)	3	3	3
Number of shrimps helped	369,642,857	1,339,285,714	1,708,928,571
Cost-effectiveness
Cost (€)	50,000	55,000	105,000
FX US/EUR	1.10	1.10	1.10
Cost ($)	55,000.0	60,500.0	115,500.0
Shrimps helped / $ / annum	2,240	7,379	4,932
Shrimps helped / $	6,721	22,137	14,796

Notes:
1. Assumption of size approximately 70 shrimps / kg
2. As per signed commitment
3. Assumes we counterfactually bring forward adoption by such many years

My estimate of hours of disabling pain averted per dollar spent on corporate chicken welfare campaigns comes from Duffy (2023). The report estimates that corporate welfare campaigns have averted 1.7 years of disabling-equivalent pain per dollar spent, with a 95% confidence interval from 0.23 to 5.0.^[1] I approximated this result as a gamma distribution with ɑ = 1.7 and β = 1, multiplied by (24*365) to convert to hours per dollar. This distribution is shown in Figure 5. 

Using these inputs, I computed distributions for welfare-range-weighted hours of disabling- equivalent pain averted per dollar spent on shrimp stunners and on corporate welfare campaigns for chickens. These results are shown in Figure 6. I also repeated the calculation with the welfare capacity range of shrimp capped at 0.1x that of humans, with results shown in Figure 7. Summary statistics are provided in Table 3. 

Table 3. Results Summary Statistics

Discussion

A theme throughout this analysis is the high degree of uncertainty in estimating the cost-effectiveness of humane shrimp slaughter. Many key parameters are based on subjective guesses, and there is a large amount that remains unknown. There are reasons to think that the cost-effectiveness estimates provided here for both SWP and corporate hen welfare campaigns could be higher than the true values; some values in the SWP analysis are based on data provided by the organization itself and the data on corporate campaign effectiveness is backward-looking. And one could reasonably argue against certain assumptions underlying the RP Moral Weights Project’s results, or against the implicit assumption within this analysis that harms across many neurologically simpler shrimp can, in aggregate, outweigh harms to fewer, more neurologically complex chickens. 

With all that said, I do think this analysis provides some useful information. It indicates that:

1. The expected cost-effectiveness distribution for electric shrimp stunning likely has overlap with that of corporate hen welfare campaigns
2. The cost-effectiveness of electric shrimp stunning is more likely to be lower than that of corporate hen welfare campaigns than it is to be higher
3. Shrimp stunning is a very heavy-tailed intervention. The mean cost-effectiveness of stunning is significantly influenced by a few extreme cases, which mostly represent instances in which the undiluted experience model of welfare turns out to be correct

Based on this information, it seems reasonable to conclude that this project should not be dismissed out of hand. While these results are suggestive that shrimp stunning is a less cost-effective intervention than corporate hen welfare campaigns, they cannot clearly establish which is better —an important result given that corporate campaigns are the “gold standard” EA animal welfare intervention. 

In light of item three, one might reasonably argue that this intervention constitutes something of a Pascal’s mugging, in that a large share of the impact is driven by a small number of relatively unlikely extreme cases. Most but not all the impact is driven by these cases—capping shrimp’s welfare range at 0.1x that of a human drops the mean cost effectiveness by about a factor of 5. This is still much greater than the 5th-percentile estimate of corporate hen welfare campaigns’ cost-effectiveness, but is low enough as to appear relatively uncompetitive with corporate campaigns in expectation. Potential donors should think carefully about their risk tolerance, credence in the undiluted experience model of welfare, and willingness to make hits-based bets when considering this initiative. 

One last item to mention is the future potential of shrimp stunning. While this CEA has focused on the more quantifiable short-term impacts of SWP’s proposed intervention, it is possible that piloting stunners today could substantially improve the likelihood of long-run mass adoption. To me, this seems like one of the strongest arguments in favor of this project. Corporate hen welfare campaigns may not remain cost-effective forever (as fewer hens remain in conventional systems), and aquaculture is a rapidly growing industry worldwide. I think it makes sense to include some more speculative bets in the EA animal welfare portfolio, and shrimp stunning appears to be a possibly cost-competitive bet to make. In tandem with continued investment in fundamental welfare biology research, moderate-scale investments in shrimp stunning could enable learning by doing as part of the long-run development of effective interventions to improve conditions in aquaculture.  

Thank you to Aaron Bergman for providing comments on a draft version of this post. 

1. ^{^}

    This calculation is based on the pain data for caged and cage-free systems from WFP, using a weighting scheme to convert annoying, hurtful, and excruciating pain to equivalent times spent in disabling pain.