Our World in Data has a sprawling and data-dense article on everything to do with fish, fisheries, and aquaculture. It’s well worth digging into if you have five or six hours, but I could stare at the pictures alone for an hour if I actually had that kind of time.

Here were a few highlights for me:

• Some species are really in trouble, sharks in particular, but on balance the overfishing situation has improved significantly over the past decade or two. When looked at by weight, about 80% of fishing is sustainable, and when looked at by individual fisheries (which vary in size), about 2/3 is sustainable. Tuna, in particular, is pretty well managed these days.
• They dug into a particular paper which the media summarized as “the oceans will be empty by 2048”, explain why that didn’t even make sense as a summary of what the authors intended at the time, and then explain why this conclusion no longer holds with better data on fish stocks as opposed to just fish catch.
• Fish catch has largely stabilized over the past few decades while aquaculture has boomed. Aquaculture has become much more efficient – some wild fish are still used to feed animals, but this has declined and animal feed has become more plant-based. Also, environmentally-motivated not-quite-total vegetarians should feel pretty good about eating farmed mussels, clams, and oysters.
• The most damaging forms of fishing, such as bottom trawling, have declined, although they are still in wide use in developing countries.

Fish are the classic example often used to teach stocks and flows – they illustrate how time lags and feedback loops can lead to counterintuitive results if you are just eyeballing the trend in one particular flow, rather than gaining an understanding of the underlying system structure and how that explains its behavior. This is one reason why the simplistic science communication we have had during the Covid crisis has been ineffective, in my view. Unfortunately, data (sometimes called “facts”, but that assumes we can accurately measure the state of the world, which we never can with 100% uncertainty) doesn’t just transform itself into good policy and good decisions. The media seems to create this expectation in people, and then I think they are disappointed and confused when the story seems to change and evolve from day to day. At some point, they conclude that a made-up opinion is as likely to be accurate as the garbled message coming from the scientists/or and policymakers. And then of course, some cynical people exploit this disillusionment for their own cynical purposes.