(engine humming) - [Jes Burns] Catching one of the Pacific Northwest's top predators takes time, a little luck.

- [Alex] All right, coming down!

- [Jes] And big chunks of meat.

- [Alex] Let's get some stuff in the water.

- [Jess] We're in.

- All right, good luck down there.

(water splashes) - [Jess] So we're gonna leave these two buoys sitting for about 30 minutes, and then we'll go check them.

- [Jes] These scientists from Oregon State University's Big Fish Lab are studying broadnose sevengill sharks, one of about 15 shark species native to Oregon and Washington.

- Understanding sevengills is understanding the entire ecosystem.

They are apex predators, and so understanding them is like understanding how all the other animals in the ecosystem are existing.

- [Jes] Yet, very little is known about sevengills or any of the other shark species here in Willapa Bay.

- [Jess] We just know that they're here.

Period.

- [Alex] Period.

- [Jess] Period.

- [Alex] We know they're here, we know they're eating stuff.

- [Jess] We know they're here, we know they're eating stuff.

(engine humming) - This one looks sharky to me.

- [Jes] And what they're eating today is the bait.

- Got it?

- Yep.

So, we have a sevengill.

We have two sevengills.

Woo!

They're so chill right now.

Oh my gosh, she's huge!

- [Jes] Two on one line.

It shows just how plentiful the sharks are in Willapa Bay.

- [Jess] Sharks in general are really hard to find.

There's typically not very many of them.

- She's a chonk.

- [Jess] But here in Willapa Bay we find a ton of sharks, just an absolute bonkers amount of sharks.

This is what haunts me at night.

Why are there so many sharks here?

(crank clicking) I would say the biggest ones are around 300 pounds.

I would put her, this one, around that weight.

Shark coming down.

- [Alex] Shove it back just a little, there you go.

- [Jess] Thanks, lady.

- [Jes] They take good care of the shark once she's onboard.

A wand pushes water over the gills so she can breathe, and the cloth keeps her calm.

- [Jess] Sevengills are very, very unique.

They're, like, one of two species in the world that have seven gill slits.

And it's thought that they have seven gill slits because they're such an ancient species.

So these are actually one of, if not the, oldest shark species alive.

- [Jes] Similar sharks have been swimming in our oceans for more than 200 million years.

The crew tags, measures, and draws blood all in a span of five to ten minutes.

With female sevengills like this one, they have another kind of opportunity.

- Are you recording?

- I'm recording.

- One of our specialties in the Big Fish Lab is learning more about shark moms.

We are trying to advance our understanding of shark reproductive ecology.

So basically what shark moms do, where they go, how often they give birth.

- [Jes] Traditionally, trying to figure these things out involved killing and dissecting female sharks.

But here, ultrasound is the tool of choice.

- [Alex] So the ultrasound works exactly the same as it works for humans.

We literally even use gel.

- [Jess] There's some circles on there.

- [Alex] A lot of the females we capture generally, in Oregon and Washington, tend to have eggs or are already pregnant.

[Alex] Unfertilized eggs, so she's not pregnant, but she seems to be ready to become pregnant at some point.

- [Jess] Ready, shark coming down!

(water sloshes) Thanks, lady.

- [Jes] These sevengill sharks come to Willapa Bay every March.

Over the past few summers, the crew has tagged more than 300 here.

They've learned the sharks can cover a lot of ground in the off-season.

- [Jess] We had one shark that was tagged here in Willapa Bay that swam all the way down to San Diego and was caught by a fisherman.

And then, we had another tag that was put on a sevengill and ended up swimming up to Alaska.

- [Taylor] All right, Huckster, jump on buddy.

- [Jes] The next day, lead scientist Taylor Chapple and his son Huck join the crew, hoping to get some more sevengills on the boat.

(engine humming) - It's your workout.

Understanding what sharks are doing helps us understand how to keep the system together.

So, if we wanna be able to fish to catch salmon, to catch crab, we need to understand how the predators are playing in those systems, and that's what the work that we do with sharks is really helping to tell us.

- [Jes] Their fishing starts off decidedly slower.

- [Taylor] Not looking good for the home team.

- [Jes] They get a feeding frenzy, but not the kind they were hoping for.

But then, on another line, another visitor.

A Pacific spiny dogfish, another species of shark native to the Pacific Northwest.

And, eventually, they get a hookup.

(Huck claps) - [Taylor] All right, watch the spines.

- [Jes] Spiny dogfish are named that for a reason.

- [Taylor] Yeah, they've got a venom in them.

So if they get stabbed, it doesn't feel good.

- [Jes] The Pacific Northwest has its own distinct population of these sharks.

- [Alex] That's what I'm really interested in, because that population of Pacific spiny dogfish appears to be falling and we're trying to figure out why.

- [Jes] Despite their small size, dogfish are among the longest-lived sharks, about the same lifespan as a human.

And another ultrasound reveals this female is old enough to have eggs.

- [Alex] I'm gonna do one more pass, and then we'll be done with this.

What I do know is that they do reach maturity, for females, particularly, at about 30 years old, which suggests to me that that animal's probably older than I am.

So you see how there is, like, little white and brown layers in here?

Those can be used to age the dogfish, kind of like, you know, rings in a tree.

- [Jes] Catching Pacific spiny dogfish is expected here in Willapa Bay.

It's like a shark super highway.

- [Taylor] We find sevengills, we find tope sharks, smooth-hounds, we find dogfish.

There's a number of species of rays that we'll find in here as well.

And so it really is an incredibly diverse ecosystem, I'd almost say to the extent that we don't actually know all of what's in here yet.

- [Jes] When it comes to the sevengills, that question of, "Why here?"

still haunts Jess.

- They're actually much more social than we think they are.

And so it's possible that they could be coming up here for some sort of sevengill hangout, in addition to, you know, a buffet of food that they've got available.

- [Jes] Willapa is an incredibly productive bay.

There's shark food everywhere.

And what the sevengills are eating is one mystery Jess and the team have been able to solve.

(water sloshing) - Up.

(crank clicking) - Up.

- [Jes] And they've learned this by looking inside the sharks.

Or more accurately, bringing what's inside into the light.

- [Jess] All right, you're on head.

- [Taylor] I'm on head.

You're on stomach.

- [Jess] It's called a nonlethal lavage.

It doesn't harm the shark, but it does take their lunch.

- [Jes] On the boat, they call it "puking the shark."

- [Jess] All right, going in.

- [Jes] Almost immediately, Jess gets a whiff of something familiar.

- I think there's definitely seal.

I can smell the seal.

- [Jess] It's just like a weird side effect of this job that I've developed.

(laughs) A weird skill that I have, that many people don't, is that I can predict what's inside the shark based on the shark's breath.

You got your chunks.

- I can't see you.

- Hold on.

So, these are the stomach contents that we just collected from a broadnose sevengill shark, and it looks like we have a bunch of harbor seal.

And we can tell it's a harbor seal from the fur, so we know it's a mammal, and the spotting pattern that we have on the fur.

So, that's pretty distinct for harbor seal.

We also see a flipper of a harbor seal, as well as what appears to be a nail.

- [Jes] Willapa Bay is full of salmon and sturgeon, yet nearly two thirds of what they've found in the stomachs of sevengills here has been seal.

And this has big implications for the local food chain.

- [Jess] Harbor seals and other marine mammals, like sea lions, eat a lot of salmon, and so it's potential that the sevengills eating the harbor seal could be really good for the salmon in a sense that they're keeping marine mammal populations down and allowing salmon populations to rebound.

Okay, are we ready?

We're gonna release the shark.

I meet a lot of people who have no idea that there are sharks in these waters.

And it's not a bad thing to have sharks here, in fact, it's a really good thing.

You know, if you want to have a healthy ecosystem, you need to have sharks in the area.

- [Jes] And the sheer number of sharks that call these waters home show just how pristine Willapa Bay is.

- And as they go out into the broader Pacific Northwest, we hope that we can help understand how these sharks are interacting with fisheries to maintain those healthy ecosystems.

That's why this research is really important to me, because it's filling in these gaps that I don't think we even knew that we had.

And I think it's just really valuable to remember sharks when we're thinking about healthy oceans.