Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Fishing-aquaculture substitution and aquafeeds, published by MichaelStJules on June 3, 2024 on The Effective Altruism Forum.
Key takeaways
Various fishing-related interventions and aquafeed-related interventions (e.g. supporting fishmeal substitutes) can have important effects on animal agriculture, and there are potentially important tradeoffs to consider. I graph the relationships between various foods and feeds, and provide background on them. Focusing on the impacts on farmed animals, the most important takeaways are probably the following:
1. Increasing the catch of wild aquatic animals for feed, increasing the utilization of aquatic animal byproducts for feed, increasing/improving non-animal fishmeal substitutes or pushing for lower fishmeal requirements (promoting herbivorous species, R&D to reduce fishmeal inclusion rates) per farmed aquatic animal
1. is likely to increase aquaculture (Costello et al., 2020, Section 4, Figure S2 and Tables S13-S16; Kobayashi et al., 2015, Table 3 / World Bank, 2013, Table E.2; Bairagi et al., 2015, Table 1 / Bairagi, 2015), including shrimp aquaculture in particular, as they are major fishmeal-consuming species.
2. is likely to decrease insect farming, by reducing the need for or the relative appeal of insects as a fishmeal substitute.
3. has unclear effects on the use of live brine shrimp nauplii and other live feed for crustacean larvae, and fish larvae, fry and fingerlings. I have not investigated this, but it's worth flagging the possibilities of complementation and substitution.
4. Conversely, decreasing the catch of wild aquatic animals for feed is likely to decrease aquaculture and increase insect farming, but has unclear effects on brine shrimp nauplii and other live feed.
2. Decreasing the catch of wild aquatic animals for food (direct human consumption) has unclear impacts on farmed (and bred) animals.
1. By substitution, it would probably increase aquaculture (and other animal agriculture) overall by weight, but this may not say much about numbers or welfare impacts, given shifts between farmed species.
2. It could increase (by substitution) or decrease (by reducing the availability of fishmeal from fish/crustacean byproducts) shrimp farming and the farming of other animal-consuming species. This could also then respectively increase or decrease insect, feed fish and/or brine shrimp nauplii production for feed.
3. It would also reduce fishmeal from byproducts, which could increase insect farming.
4. The effects on fish stocking depend on how the reduction is achieved. If achieved through an increase in overfishing, fish stocking could increase. If achieved through a reduction in fishing pressure where fishing pressures are already low, fish stocking could decrease. This would have an effect on brine shrimp nauplii production in the same direction as that on fish stocking, assuming brine shrimp nauplii are fed to fish raised for stocking.
Note that demand shifts for wild-caught animals can have the opposite sign effects on their catch due to overfishing (St. Jules, 2024a). The above considers the actual quantities supplied directly, not the effects of demand shifts.
All of this also ignores the effects of shifts in food production on wild animals, both aquatic and terrestrial, which could be good or bad and more important in the near term (Tomasik, 2008-2019a, Tomasik, 2008-2019b, Tomasik, 2015-2017, St. Jules, 2024b).
Acknowledgements
Thanks to Brian Tomasik, Ren Ryba and Tori for their feedback on an earlier draft, and Saulius Šimčikas for his supervision on an earlier unpublished project. All errors are my own.
Relationships between products
Fishing, aquaculture and other animal agriculture and breeding interact in multiple ways, as depicted in the figure below:
1. Fishing competes with animal agriculture and ani...

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