When I was in college I was interested in the stock market, in particular people betting against each other in the stock market. In order to write a paper on the topic, I checked out a book on Differential game theory.

It turns out differential game theory does not have a lot to do with the stock market or moving graph lines, but it does pertain to chasing games. This is where I came across the interesting fact that WWII planes were in some cases faster than modern jets. Modern fighters optimize for manueverability instead of speed, because turning radius is what really matters when it comes to dog fights. Look at how the wing surface area and aspect ratio are so different in the planes from these 2 eras:

Having had this thought seeded in my brain, over the past few years I have noticed a similar thing in a few marine species. Specifically Orca whales are one that comes to mind as having these huge dorsal and pectoral fins.

credit: Exploring Nature

Swordfish and Great Whites also come to mind as chasing-predators.

Compare this with some common prey fish and it is notable how much smaller and less pushed forward the dorsal and pectoral fins are:

Minnow
Sardine
Shad
Mullet

Its hard to compare fish one-to-one on fins because there is so much variation in what fins they even have, and it can be hard to tell how much their own body should be counted towards the “wing” effect that their fins have.

I’ve also seen one page comparing a blue-shark’s pectoral fins to the wings of a 737. Blue sharks are open-water species, and large pectoral fins help them cruise high in the water column efficiently. I can’t find this source now, but this one and others emphasize that the pectoral fins are long.

I asked GPT about it: Link to Conversation Here. It pointed me to a few cool resources such as fishbase which states that the aspect ratio of the caudal fin is related to activity level.

It also said some other stuff. I’m tired of writing so if you care about this then just read the original conversation.

The point is I believe you could have a stat for each fish that is just called “findex” which predicts it’s predatory-ness or maneuverability. This probably exists already, but I don’t know about it because I also got tired of researching before figuring out much.

I’m thinking of something like the stats on the back of a baseball card. It would be cool if there was a website called “fish cards” or something. From what I can tell, this is not currently tracked on fishbase. My chat about this “card” thing with GPT