First post on the forum so be gentle.
TL;DR: The Spanish company Nueva Pescanova is planning to farm octopus and begin selling it on the market in 2023. They intend to sell 3,000 tons of farmed octopus per year, which amounts to several hundred thousand octopuses. This is concerning given that octopuses are highly intelligent animals; there are no released standards for how the octopuses are going to be kept and raised, nor for how they will be slaughtered. There doesn't seem to be much in the way of coordinated action against this yet.
Link to the article: https://www.bbc.com/news/science-environment-59667645
Some of your thinking and estimates here seem reasonable and useful! I just want to pick up on one small subsection that surprised me:
"As in, say a country like Spain outlaws the practice of farming octopus (which in itself may be pretty unlikely), then I think a big multinational company like Nueva Pescanova (the company claiming to start the first commercial octopus farm) perhaps just goes to some other country they work in (and they are present in 20ish). "
Why did this surprise me / why are our intuitions different?
I think there might be some difference in optimism about the value of legislation.
I expect that preventative action is much more tractable than retrospective action to abolish an industry that has already been developed. E.g. see "It is probably easier to abolish a practice through legislation if that practice is not in regular use" here: https://www.sentienceinstitute.org/death-penalty#the-causes-of-legislative-change . So challenging the first example of an unusually negative (and/or unusually unpopular) practice seems especially important. If fighting this specific company encourages a battle that spirals across several countries and results in legislation in several places but fails to stop this specific company farming octopus somewhere then I imagine I would consider that to be a major victory.
Relatedly, I have in my head a model where anti octopus farming legislation in one country makes anti octopus farming legislation in another. E.g. see "Once influential international bodies adopt a value, they may exert pressure on institutions in other parts of the world to adopt the same value" at the same link as above.
Alternatively, maybe it's because you're focusing on helping the octopuses in question in this specific farm. Whereas my concern is not: "(how) can we prevent Nueva Pescanova farming and selling 3,000 tons of farmed octopus per year," but "(how) can we prevent (octopus) farming?"