This is the quote:
> Tesco and Sainsbury’s published shrimp welfare commitments, citing collaboration with SWP (among others), and signed 9 further memoranda of understanding with producers, in total committing to stunning a further ~1.6B shrimps per annum.
It is a secondary source. It does not present firsthand information. It describes commitments made by Tesco, Sainsbury's, and others.
Setting this aside, the point I made is simple. This article argues for a radical change in morality; folks generally view a human life as worth much much more than 32 shrimp lives.
A well-written radical argument should understand how it differs from mainstream thought and focus on the premise(s) that underlies this difference. As I am unimpressed with the premises, I find the article unconvincing.