I think the kind of diet you outline also makes sense on asymmetric consequentialist views, including negative utilitarianism. See Brian Tomasik’s writing. That being said, the net positive lives are for pretty large animals (cows), so you have very little impact on them either way, and the main effects are likely on wild animals, and then you’d want to judge their lives and the effects on them.
Population effects on wild-caught fish (including for fishmeal, fed mostly to farmed fish and shrimp) and other animals in their ecosystems together can be messy, but wild-caught fish supply may be so inelastic (regionally and in the aggregate) that the main (short-term) effect of eating wild-caught fish on animals would be to increase fish farming. In case wild-caught fish supply is sufficiently elastic (regionally, even if aggregate supply is inelastic due to negative elasticities from overfishing and positive elasticities from underfishing cancelling out when aggregated), then eating farmed fish (fed fishmeal) could have very large effects on wild animals with very uncertain sign.
I think the kind of diet you outline also makes sense on asymmetric consequentialist views, including negative utilitarianism. See Brian Tomasik’s writing. That being said, the net positive lives are for pretty large animals (cows), so you have very little impact on them either way, and the main effects are likely on wild animals, and then you’d want to judge their lives and the effects on them.
Population effects on wild-caught fish (including for fishmeal, fed mostly to farmed fish and shrimp) and other animals in their ecosystems together can be messy, but wild-caught fish supply may be so inelastic (regionally and in the aggregate) that the main (short-term) effect of eating wild-caught fish on animals would be to increase fish farming. In case wild-caught fish supply is sufficiently elastic (regionally, even if aggregate supply is inelastic due to negative elasticities from overfishing and positive elasticities from underfishing cancelling out when aggregated), then eating farmed fish (fed fishmeal) could have very large effects on wild animals with very uncertain sign.