Great question, thank you! :)
Did you mean to ask it as part of the AMA?
If so, could you please repost it as a comment there? It’s easier for coordination.

The world gets more seafood from aquaculture than wild catch. I believe this data insight from OWID may suggest increasing aquaculture is better than increasing wild catch, whereas I think the harm (per mass of fish consumed) is larger for aquaculture:

There are two ways to produce seafood: catch fish in the wild or farm your own. Seafood farming is often called “aquaculture”. Aquaculture is dominated by the farming of fish, but also includes other organisms, such as crustaceans and aquatic plants.

Aquaculture has grown rapidly over the last few decades. In fact, as the chart shows, it has overtaken wild catch since 2013.

This has relieved some pressure on wild fish stocks: if this increased demand for fish had been satisfied by wild catch, then many more would be severely overexploited [emphasis mine]. 

I sent a message to OWID expressing my concerns.

While I wholeheartedly agree that it's individuals that matter first and foremost, I also think we shouldn't give in to the temptation to directly advocate against the conservation of species. Unless I'm negative utilitarian, I would think the best outcome would be if they could live happily ever after.^[1] Politics disincentivises nuance, but we shouldn't forget about it entirely.

If direct advocacy for interventionism is too controversial, an attitude of compassionate conservation could perhaps be a more palatable alternative:

Compassionate conservationists argue that the conservation movement uses the preservation of species, populations and ecosystems as a measure of success, without explicit concern given to the welfare and intrinsic value of individual animals. They argue instead, that compassion for all sentient beings should be what guides conservation actions^[5] and claim that the killing of animals in the name of conservation goals is unnecessary, as these same objectives can be achieved without killing.^[6]

1. ^{^}

   My axiology is primarily about wishes and liking. And given that a large number of humans seem to wish some aspects of nature conserved, I think it would be selfish of me to dismiss their wishes entirely.

   (I also just aesthetically prefer that we don't kill off our Earthly siblings, but I'm just one person, so I try not to let this affect my moral conclusions.)