'Calling yourself a vegetarian when you eat fish is verging on demented'

If I have to hear another pescatarian calling themselves a vegetarian, I'll scream.

Last time I looked, fish were part of the animal kingdom. Calling yourself a vegetarian because the animals you choose to eat live in water, is verging on demented.

There are many cases where our thinking around food is plain bonkers. Of course it is: we're human. Quite often, I delight in the madness of these prejudices, but there are instances where I'm not ready to laugh them off.

In this particular case - the seafood that doesn't count as meat - there are two reasons.

The first is that the moral high-ground cloak worn smugly by some - not all of course - who don't eat animals with eyelashes, is infuriating.

It's infuriating because of the second and more important reason: that it's precisely this sort of thinking that keeps us making worse food decisions than we otherwise might have.

The only way we'll ever make better decisions about what and how we eat - whether we're talking health, ethics or environment - is to understand that it's not about the ingredient, it's about the process.

Don't compare fish to beef, don't compare tofu to cheese. Compare well-raised and/or harvested, sustainable seafood with badly raised/harvested seafood (as some pescatarians of course do), and do the same with beef, cheese and beans.

Creating a division based on species rather than farming and harvesting methods gets you nowhere closer to eating healthily, ethically or more in tune with the environment.

Sea animals are so varied that lumping them together just because they live in water is a whole madness on its own.

Some pescatarians say they choose fish because you should only eat things you could kill yourself and still be okay with eating. Hmm, I can see how this works with trout, but I wonder about hunting down and butchering a massive, thrashing, blood-spewing 10-year-old tuna, and then settling down for sashimi.

Process, that's what it's about.

Octopus, we know from numerous studies, have a complex and large central nervous system (they're a bit like dogs apparently) but nobody seems bothered that their deaths are often lingering, and usually unmonitored.

And then there's my favourite bugbear, the issue of by-catch: for certain seafood (definitely most prawns), this means that in a very real way, a large unseen part of the meal is not even fish. It's often marine birds, tortoises, dolphins, seals and so on. It's the how, not the what, that counts most.

And process-wise, modern fishing is arguably far more wasteful than any other harvesting on the planet.

How to know what's better or worse? Make sure to have the information from SASSI at your fingertips. Go to wwfsassi.co.za and download the app that helps you make greener seafood choices.

• This article was originally published in The Times.