Welfare cost and alternatives to pre-sale purging in Chinese carp farming

commitment: 8 hrs/week
flexibility: Open to proposals

mentored by

The project

Carp are the most farmed fish on earth — roughly 15–20 billion individuals a year in China alone — and almost all of it is sold live into the domestic market, so there's no export or certification lever and very little outside attention. Before sale, carp are commonly held for 30–45 days with no feed, at five to six times normal stocking density. The practice has been described in passing but nobody in animal welfare is working on it.

There's a promising crack in it. Removing the muddy off-flavour that drives depuration (geosmin and 2-MIB) appears to take only days, while the multi-week protocols are doing a different job — improving flesh texture and quality. If the long purge is discretionary quality work rather than technical necessity, it becomes far more challengeable — and at least one documented alternative already exists in the literature.

The mentee will produce the first clear-eyed assessment of the practice, to inform whether and how Myrias intervenes. The review will:

Establish, with sources and evidence grades, why the purge is done and how its prevalence and duration vary by region and by tier of the supply chain
Synthesise what it costs the animal — the welfare effects of prolonged fasting combined with crowding
Assess the alternatives on both welfare gain and commercial plausibility

Deliverable: a standalone review plus a short prioritisation memo. No coding or domain expertise required — research synthesis, clear writing and honest evidence-grading matter most.

The mentee's role

The mentee owns the review end-to-end, with weekly guidance from me. Sample tasks:

Pin down the purpose of the purge — off-flavour removal, flesh-quality improvement, gut clearance before transport, or some combination — and how far the stated industry rationale is actually supported.
Establish where the practice happens (farm, wholesaler, distribution centre, retail tank) and for how long, since that determines whether this is a month-long or a two-day problem.
Synthesise the welfare evidence on extended fasting and on high-density holding in carp, flagging clearly where findings are carp-specific and where they're inferred from other species.
Assess documented alternatives — shorter clean-water depuration, low-salinity depuration, feed manipulation, upstream control of off-flavour compounds — for whether they deliver the same commercial outcome.
Write it up as a review plus a memo ranking which alternative is most tractable to push, and what would have to be true for it to work.

Who I'm looking for

Must-haves: strong research and synthesis skills; clear, concise writing; the discipline to source claims and grade evidence honestly rather than overstate; able to work independently between weekly calls.
Nice-to-haves: ability to read Chinese — a real advantage here, as some of the relevant literature and most of the industry practice sits in Chinese-language sources; quantitative literacy for rough scale estimates; familiarity with EA-style cause prioritisation or the ITN framework; existing interest in aquaculture, fish welfare or neglected farmed species.
No coding or formal science background needed. I'd rather have a rigorous generalist than a subject expert who can't be sceptical about their own conclusions.

Questions for applicants

Pick any claim you believe about animal welfare and tell me how strong you think the evidence for it actually is, and why.
Roughly how many hours per week can you commit, and are there weeks in the Aug–Nov window where you'll be unavailable?

Support offered

Shaping direction and scope
Helping structure the review and prioritisation logic
Grading evidence and stress-testing conclusions
Drafting and editing feedback on the written output
If the work is strong — a route into how Myrias evaluates and potentially funds interventions, plus relevant introductions within the animal-welfare and EA funding ecosystem

format: Research & writing · Project scoping
topic: Neglected animal groups · Near-term impact

Carlos Ferrao

Myrias

Carlos is a Programme Director at Myrias, an EA-aligned venture studio targeting the largest and most neglected sources of animal suffering — farmed fish, insects, feeder rodents, and beyond. He recently completed Ambitious Impact's charity incubation programme, where he compared eleven intervention ideas from evidence-heavy research reports and applied cost-effectiveness analysis, theory-of-change design, and ITN prioritisation to decide what's worth building — the same reasoning this project runs on.
Before animal welfare, Carlos spent 20+ years in tech and enablement, including nearly eight years at Google, where he ran large-scale programmes (among them YouTube's first major livestream, to 21M+ viewers) and led global learning and change initiatives at Entain, IHS Towers, and others. He was Director of People & Culture at Animal Think Tank and volunteers as a school speaker and hunt saboteur team leader.
He's most useful to a mentee who wants to learn how a rigorous, evidence-graded prioritisation process actually turns an intuition into a decision — and who'd value a mentor who's managed real programmes end-to-end, not just theorised about them.