A Mako Shark's Last Meal

[ music and rushing water ] [ music ] I am Antonella Preti. I'm a shark biologist and I analyze the diet of sharks. I've been working on stomach analysis for more than 15 years, and I think I dissected more than 2,000 stomachs. So this is actually though, the very biggest one I have ever dissected. [ record scratching ] Narrator: Now wait a second, is this a shark? [ tape rewinding ] Nope, all this came from inside the shark's stomach. [ music ] Antonella Preti: This is the stomach of a large female mako shark. This is possibly the largest mako shark that was ever caught. Narrator: A quick run-down: this is the shortfin mako shark that was legally caught by recreational fishermen on June 3rd off the coast south of Los Angeles. This shark was over 12 feet long, over 1,300 pounds, and possibly a world record. The fishermen donated the shark's organs to science . . . which brings us back to its stomach. Antonella Preti: Oh wow. There's ah . . . it looks like a, oh wow. It's a little heavy though, I need some help. Yea, what is it? Whoa! Suzy Kohin: Looks like a sea lion maybe? Antonella Preti: Yea, it looks like it's the head of a sea lion. Audience: Incredible! Antonella Preti: You can see the teeth. It almost looks like a dog. [ music ] Narrator: A typical adult California sea lion weighs about 200 pounds, so this is a big meal, and typical for a large mako shark. But makos are known to eat just about anything including fish, squid, other sharks, and even sea birds. As for this sea lion, the mako got all of it. Antonella Preti: Oh wow, this is the foreflipper, and it looks like there's bites, so it looks like there's a teeth mark there. We can see more teeth marks here. And you can notice mako sharks, they have these very pointy teeth on the contrary of white sharks where they're more like triangular, serrated teeth, so you really see, like, punctures. Let's see what else we find in here. So it was a huge stomach. You can see the lining of the stomach, it's like a blanket pretty much. Suzy Kohin: And you have to look carefully to here cause there's otoliths . . . Antonella Preti: Yea, we'll have to analyze it all in detail. So these are the large parts of the prey items that we find. Then we also go through all the particulate, that's what you find in there. And there's a lot of gastric juices and you can find all kinds of things in here. [ music ] So there's more bones, oh look, they belonging to the sea lion. And we will have to go through all this liquid. Everything will need to be washed and super-analyzed because there could be remains of other prey items, so there's a lot that could be hiding in any single portion. So it will take me hours now to go through every single portion of this sea lion. So far I don't really any trace of teleosts or squid so looks like this was the main meal. Many people ask me, "why would I want to know what's inside the stomach of a shark?" And that's a good question. Studying the diet of sharks, and fish in general, really gives you an understanding of the way the food chain works. And it's very important for our understanding of the ecology and the biology of these sharks and also it gives a chance, hopefully in the future, to build a stronger ecosystem management, because to manage a fishery, if we don't understand how every species is inter-relating, and who eat's who, it's not really possible to do a proper management of fisheries.