Northern fur seals spend more than half their lives at sea. But every summer, they congregate on the rocky, charcoal-colored beaches of Alaska’s Pribilof Islands to mate and give birth to tiny, black-furred pups.
Researchers take advantage of the seals’ short time on land to learn more about them and try to understand why their populations have been declining since the mid-1970s. Part of this research involves attaching GPS trackers to the seals’ bodies so satellites can monitor their movements from afar.
But it’s not easy walking into a fur seal breeding colony full of aggressive, 500-pound males – not to mention getting close enough to attach a satellite tag. In this episode, Noel Pelland and Jeremy Sterling, researchers at NOAA’s Alaska Fisheries Science Center in Seattle, describe what it’s like to work with these beautiful yet unpredictable creatures.
Listen to Jeremy recount his experience crawling into a fur seal rookery full of cuddly pups with razor-sharp teeth and hear Noel describe what the satellite tags tell us about fur seal migrations. Find out how modern science is confirming what native Alaskans have known for centuries about seal migrations and learn what it’s like to watch male fur seals battle for territory with nothing more than a plywood box for protection.
Read more about tagging seals in the Pribilofs in this blog series from NOAA and learn more about how winds influence seal pup migration in this press release from AGU. And watch this video from NOAA to learn more about fur seals and their migrations.
This episode was produced by Lauren Lipuma and mixed by Kayla Surrey.
All photos taken under marine mammal permit numbers 14327-01 and 782-1708-00.
Shane Hanlon: Hi, Nanci.
Nanci Bompey: Hello, Shane.
Shane Hanlon: So… Do you wanna play a game?
Nanci Bompey: Yeah, I mean, so long as it’s a fun game.
Shane Hanlon: Well, okay. It’s more of a test.
Nanci Bompey: Ugh.
Shane Hanlon: So, maybe…(laughs)
Nanci Bompey: Not really a game. It’s a test.
Shane Hanlon: Okay, so how do you feel about seals?
Nanci Bompey: Oh, I love seals.
Shane Hanlon: Okay, perfect. How do you feel about sea lions?
Nanci Bompey: I like sea lions.
Shane Hanlon: Do you know the difference?
Nanci Bompey: They bark.
Shane Hanlon: Who’s they?
Nanci Bompey: The sea lions. Don’t they bark? Do seals bark, too?
Shane Hanlon: Well, okay. This is what we’re gonna do. Seals or sea lions, which ones have ear flaps?
Nanci Bompey: Ear flaps. I’m gonna go with seals.
Shane Hanlon: Which ones have really strong like front flippers?
Nanci Bompey: I’m gonna go with sea lions. Sea lions have whiskers. What?
Shane Hanlon: Whiskers? They do have whiskers. I don’t know where that one came from. Which ones can easily walk on land?
Nanci Bompey: Oh, sea lions.
Shane Hanlon: I have to note Lauren’s in the room giving Nanci hints. So, it’s actually a trick question because that depends on the species.
Nanci Bompey: Ah!
Shane Hanlon: Yeah, so, actually, a lot of seals and sea lions that most people might be familiar with, like I work at the zoo, part-time, and the sea lions can do some things and the seals can do some things, but there are some seals that are more closely related to sea lions than actual seals. Isn’t that really cool?
Nanci Bompey: That is really cool. They make a noise like (makes noises)(laughs)
Shane Hanlon: And we’re back to barking. Well, okay, I think it’s really cool.
Nanci Bompey: No, it is.
Shane Hanlon: Welcome to the American Geophysical Union’s podcast about the scientists and the methods behind the science. These are the stories you won’t read in the manuscript or hear in a lecture. I’m Shane Hanlon.
Nanci Bompey: And I’m Nanci Bompey.
Shane Hanlon: And this is Third Pod from the Sun.
Shane Hanlon: Alright, today we’re gonna talk with Lauren, who has a story for us. Hi, Lauren.
Lauren Lipuma: Hey, guys.
Nanci Bompey: Hi, Lauren.
Lauren Lipuma: Hi.
Shane Hanlon: So, What do you got for us?
Lauren Lipuma: Back in February at the Ocean Sciences Meeting in Portland, I met these two scientists who study seals.
Noel Pelland: I’m Noel Pelland and I’m a physical oceanographer and postdoc at the Alaska Fisheries Science Center in Seattle.
Jeremy Sterling: And I am Jeremy Sterling and I am a fishery biologist with the Alaska Fisheries Science Center, studying fur seals and sea lions in Alaska.
Shane Hanlon: Alright Lauren, so what are Noel and Jeremy doing?
Lauren Lipuma: Well, what they do is they actually track northern fur seals off the coast of Alaska.
Nanci Bompey: Cool! Why?
Lauren Lipuma: (Laughs) Good question, Nanci. Northern fur seals are actually top predators, which I did now know, so they are really important ecologically, but historically they were really important to the fur trade. When Europeans came to Alaska and the Aleutian Islands in the 17th and 18th centuries they started hunting seals for their really warm fur, it’s a really lucrative trade. So that’s why we’ve been studying them for a long lime and we know a lot about them as a species.
Nanci Bompey: That makes sense. So what do they actually do to study them?
Lauren Lipuma: So, what they do is: Jeremy goes up to Alaska and the Aleutian Islands and the small group of islands called the Pribilof Islands and they put trackers, like little satellite tags, on the fur seals’ bodies.
Shane Hanlon: So this is like a Garmin for seals? Or GPS or Google Maps, whatever, whatever the reference is, just not Apple Maps.
Lauren Lipuma: No, not Apple Maps, ’cause Apple Maps is the worst. (Laughs) Yeah, it’s like GPS for seals, basically. And I also, I feel, I should say that the seals are not hurt in this process at all.
Nanci Bompey: That’s good.
Lauren Lipuma: But it can actually be pretty dangerous because they go up there when the seals are breeding and these males are giant, they are about five hundred pounds and you really don’t wanna mess with a five hundred pound fur seal when he is trying to get it on.
Nanci Bompey: No, you don’t!
Shane Hanlon: I’m just like picturing like a rodeo with seals.
Lauren Lipuma: Yeah, it’s pretty much what it’s like.
Shane Hanlon: (Laughs)
Jeremy Sterling: During that period the males are very aggressive and defending their territories for the … to be able to breed with the females. (Fur seal making noise) And so but to get access to them we have to have some protection, you can’t just walk in there and do the work. We’ll go up and what we actually have to get in to protective box, it’s essentially a four-walled plywood box maybe three-eighths-inch plywood, it has a door in the front and it’s used to protect us from the adult males that are aggressively protecting their territories where the females are, but we wanna catch the females and put a tag on them.
Jeremy Sterling: Think of the Flintstones, imagine you are the Flinstones, it’s yabba dabba doo and they get up and they run, it’s kinda the same thing with this box, we pick… we have handrails on the side, we pick the box up and you have three people trying to walk in synchrony over rocks and logs and getting kinda pushed around by males (Fur seal making sound) and to catch, to catch the females.
Lauren Lipuma: You are in this little box, this wooden plywood box and only three-eighths-inch plywood is separating you from these giant five-hundred-pound male fur seals. Is it scary? Like, what’s it like for you to do that?
Jeremy Sterling: I think it’s scary only when you have a male that’s not behaving as you can… as you perceive it will behave, sometimes you make the wrong decision, and you decide to kind of mess with the wrong guy and typically what will happen is they just won’t budge and they’ll start to push the box back and then that’s when everybody… you know… you don’t turn the box around, everybody just stops, turns around and then runs the box back out of their territories (Fur seal making noise)
Lauren Lipuma: So what was it like the first time you had to do this?
Jeremy Sterling: That’s a funny question, actually (chuckles). So the first time I ever did this I volunteered, I was a volunteer. I was working with Dan Costa at the University of California, Santa Cruz, I was a student at the university at that time doing my undergraduate work, and he had a graduate student Mike Goebel, who’d spent many years working up in the Pribilofs on northern fur seals.
The first time that I went up there I got into the box and that scared me. That was… the… that was a part of his project, the early part of the season, all three of us jumped into this box and I said, “What, we are really gonna get in this thing?” And then as we went into the rookery itself, I just could not believe that we were in and amongst, so close, you just look over the side and there is… there is all the animals. And sometimes other males that aren’t in the rookeries themselves are very opportunistic, and so when we had moved the box, this is my first time in the box, moved into that colony, those males see something different going on, that they are wading in the water, and one of them just bolted through to try to establish a territory, cause there was some… something else going on… it was distracting the other males that came in, and decided to set up shop with is back right on next to the box because he didn’t have to worry about getting hit by anybody behind him.
Literally, I kid you not, fur is flying into the box and then my eyes were probably, I don’t know how big, and then Mike just casually turned around said: “Okay, let’s get out of here.” It’s you know.. Cause it was a little it too busy going on and I pulled that box all the way down the hill (laughs). I was.. I was scared.
Shane Hanlon: This reminds me of being in hunting blinds when I was younger.
Nanci Bompey: So I actually have a pretty funny story about hunting blinds. Yeah, never been in one, I grew up in a total complete suburbs, never went hunting but I used to live in North Carolina, I worked for the newspaper, and one day there was a plane crash, we had to go up to… look at the plane that was crashed on the side of this mountain. And these guys are taking me up in their, you know, off-road vehicle and I’m like, “What’s that? A tree house?” (all laughing) And they were like. “No…” (laughing) Girl from New York!
Lauren Lipuma: I probably would have said the same thing, I don’t know what a hunting blind looks like, I’ve never been hunting.
Nanci Bompey: Yeah.
Shane Hanlon: I think a tree house is probably much more fun for the animals than a hunting blind. (laughing, agreeing)
Lauren Lipuma: I mean, isn’t it basically just a tree house though, that you hunt from?
Shane Hanlon: Um, it could be on the ground too…
Lauren Lipuma: Oh, okay.
Shane Hanlon: But yeah, kind of.
Lauren Lipuma: But if it was on a tree, it’s basically just a tree house.
Shane Hanlon: Yeah, exactly.
Lauren Lipuma: Alright, that’s cool.
Shane Hanlon: Deadly tree house.
Lauren Lipuma: Yeah, but see, the thing here, Shane, the difference is that in a hunting blind you are far away from the animals you’re hunting. Here they are getting right up close and personal with these giant five-hundred-pound fur seals.
Shane Hanlon: That doesn’t sound exciting at all..
Lauren Lipuma: No, it’s pretty terrifying, but the good thing is, is that after breeding season is over, you know, all the males kind of chill out a little bit and then what the researchers have to do is, they crawl into these rookeries, which is just where the male…I mean, sorry, the females have their pups, once they go in there they have to tag the females and the pups that are… just been born. So it’s a little bit safer for them.
Jeremy Sterling: Later in the season you crawl in to these rookeries, you lay down, you sneak in, you have an animal that you’re choosing to … that’s part of the study if it’s either a pup or a juvenile or an adult… adult female. And you have a big net and you’re dragging that along the ground and you sneak in and you can get really close to them, the distance of us which is about two feet and you can, you know, if you’re really lucky and the wind doesn’t change and they don’t really…they can see you sometimes, but if they don’t smell you, you’re okay.
You don’t have a lot of contrast, so you’re kind of in green gear and you’re trying to blend in with the environment, cause you using, you know, beach logs as areas to hide behind and sneak around and get to the animals that you want to. Then you catch them with the net, a big net, and you get them inside the net and there’s… when you go in there’s typically two people, the other person has just a pole and the pole is used to slide in through the net so you can pick the animal up and walk it of the rookery.
And then you take it to an area… a safe area where we can work, there is a restraint board that we put the animal in and then we can take whatever samples we need to take or put whatever technology or satellite tag on the animal and then just release them and let them go.
Noel Pelland: Jeremy told me, as he showed me, I’ve never been to tag northern fur seals before, but he shown me these really nice, sunny videos of them at San Miguel Island which is the southernmost northern fur seal rookery in the United States, which looks like a beach party. And so these pups are around and then there is really cute, incredibly intricate featured pups that that you just wanna pet. (pups making noise) But as we’re watching the video Jeremy’s saying, you know: “They look cute, Noel, but they’ll rip your finger out if you give them a change.” (everybody laughs)
Jeremy Sterling: We call them… the nickname is the Little Chainsaws. (everybody laughs) So…
Lauren Lipuma: Has one ever tried to bite your finger off? (laughs)
Jeremy Sterling: Yes. I’ve lost lots of flesh to little pup… to pups, during this. Particularly in the fall because at that time there… particularly with females… their canines have started… they’ve already come in and they can be fairly aggressive at that time of year. Typically, the bigger they are the less likely they’re gonna fight, they are not as feisty cause they’re just so full, you know they’re just…
Lauren Lipuma: (laughs) They are like fat n happy.
Jeremy Sterling: We call them Butter Balls, you know.
Shane Hanlon: So with Butter Balls, I’ll never look at turkeys the same way again.
Nanci Bompey: I don’t care, I don’t really like turkey.
Shane Hanlon: You don’t like turkey?
Lauren Lipuma: How can you not like turkey? What do you do on Thanksgiving?
Nanci Bompey: I don’t really like poultry. I’ll eat a little piece, but that’s it…
Shane Hanlon: Just to… just to say you did?
Nanci Bompey: Yeah.
Lauren Lipuma: I feel bad for you.
Shane Hanlon: Okay. Alright, so… So back to seals, this… this is a… with a pup this is fun, this is adorable, but why are they actually doing what they’re doing? The scientists?
Lauren Lipuma: Well, seal populations have actually been declining for a while for, you know, ever since around mid-20th century and scientists aren’t really sure why, so that’s why they go to these rookeries and place the tags on them so they can track them when they go into the ocean and they spend almost a year at sea on this long migration, that’s where they are foraging for food and they are resting and you know just kinda hanging out on the water, so that’s why they wanna know where they go and they’re especially interested in where the pups go.
Noel Pelland: Both moms and pups and adult males are all doing this cycle and they are doing it in slightly different ways, but it’s a really long amount of time spent at sea in a lot of different ecosystems and big shifts in weather, climate, eddies, from year to year could conceivably really impact a lot of individual northern fur seals in their ability to eat, how much food they can gather. A big thing about the pups is that they… they’re four months old, they’ve never migrated before and they don’t get any help from their mom and dad on how to migrate. There’s maybe some speculation that they’re also starting this migration with a ton of other experienced animals who are just in the water around them.
We also know as they are starting out they’ve never foraged before either, so they go in the water and they have a certain amount of fat on their bodies and before they have exhausted all that fat, they have to learn how to forage or else they’ll starve.
Lauren Lipuma: Right.
Noel Pelland: So it’s a very perilous and critical time for them, it’s also the weather’s really bad, water’s getting colder with every day that goes by, so a lot of things have to go right for them to be able to make it.
Adult marine mammals, year to year they survive at a pretty good rate, you know, generally for your adults, ninety per cent or more, if they are thirteen, they’re gonna make it to fourteen. But for pups, it’s more like, you know, it might be fifty pe cent, it might be twenty percent, it might be less and it might change from year to year.
If we can figure out what is causing those year to year changes, it might give us some insight into what is causing these … these bigger, long term changes in the population which we don’t know if those are because of pup survival or not, but we wanna find out.
Shane Hanlon: I’m just picturing the sad Sarah McLachlan commercial but with seal… her holding seal pups instead of puppies.
Nanci Bompey: Oh yeah, that would’ve cause all like the public access, or whatever it is…
Lauren Lipuma: Oh my God…It gets me every time, it’s like emotional suicide…
Nanci Bompey: I know! I don’t even like dogs so much, as you know, but…
Lauren Lipuma: But…
Nanci Bompey: Even then I’m like, “Oh my God!”
Lauren Lipuma: Nothing tugs at my heart strings like that commercial.
Shane Hanlon: So what’s actually causing the pups to die?
Lauren Lipuma: Well, that … they’re not really sure… I could just be bad weather, cause imagine being a tiny little seal pup and you’re in the ocean that’s really cold and the wind’s blowing and there’s a storm and all that, it’s terrible!
But so that’s what kinda Noel’s looking at. He’s looking at whether those directions that the winds are blowing are affecting where they go and maybe that’s affecting where they can find food and whether they survive or not. So for a couple years they’ve been looking at that, the tags that they place on these seal pups. Some years they saw that the pups ended up further to the east, kinda like closer to the coast of, you know, Western North America. Or some years they end up further south. And what they found is that the directions that winds were blowing actually matched where the pups went.
Nanci Bompey: Huh!
Noel Pelland: We’ve found that the pups on average moved downwind and to the right. When a wind, a steady wind blows across the surface of the ocean, it exerts a drag on the ocean. (Sound of waves, wind blowing)
It’s kind of like you putting your hand on a sheet of paper and moving it along a table, but because of the rotation of the Earth, the currents that are forced by that, that drag, forced by that hand pushing it along, they aren’t straight down the wind in the Northern Hemisphere, they’re downwind and are a bit to the right as well.
So when we saw that it was kind of the first, one of our first interesting clues that, “Okay, we’re seeing real physical signals here, in these pups.” So from there we … we then kept looking at it in more detail and then we found well, as the wind gets stronger, the pups tend to move, they move in more concentrated way, downwind.
Lauren Lipuma: Is that good or bad? Or do you know yet?
Noel Pelland: So that’s kinda the million-dollar question behind our research. And the way that we have to go about that, short answer, no, we … we.. or short answer: we don’t know. It’s what I mean to say. And the reason or the way that we need to find that out is we need to have some knowledge of the year-to-year survival of pups and then we have to be able to compare that to the year-to-year changes in the wind and what that means for pups.
Lauren Lipuma: So, Shane, you probably know a lot about Alaska, cause you’ve been there, right?
Shane Hanlon: I’ve been… I’ve only been once, but I love Alaska, I…
Nanci Bompey: I’ve been to Alaska too!
Lauren Lipuma: You have? You guys have both been to Alaska? I’ve never been to Alaska.
Nanci Bompey: Sweet.
Shane Hanlon: it’s great, you should go.
Lauren Lipuma: I wanna go, I’ve never been. But I actually kinda learned a lot about the history of Alaska from talking to these guys. Something interesting that came out of their work is they wanted to see… so they saw that seals kinda travel with the wind, right? They wanted to see if anyone else had ever documented this, so at their lab they have this huge archive of old papers and memos and things about fur seals, you know, from the past couple centuries because they were so important, you know, to the fur trade.
And so nestled within all these papers they found this discussions about that same thing: whether the weather was affecting where the pups were go.
Shane Hanlon: From how long ago?
Lauren Lipuma: Like a couple hundred… maybe a about a hundred or so years, like in the 1800s.
Shane Hanlon: Oh wow.
Nanci Bompey: That’s so interesting that people have been looking at this like… since back then.
Lauren Lipuma: Yeah, back when colonists first got to Alaska and they talked to the native Alaskans about it. So there was… so basically Jeremy was looking through all these papers and he would find one paper that cited another paper and cited another paper and blah-blah-blah all the way like to 1890s. So what happened was is that the US bought Alaska in 1867, probably with money they got from the seal fur trade…
Shane Hanlon: Probably.
Lauren Lipuma: Yeah. So they owned all of Alaska, they own islands where the fur seals breed in the summer time and so….but all the other fur traders from the European countries, from Great Britain and Russia and Japan, so they couldn’t hunt them on the islands anymore, cause now it was US territory. But, so they decided they were gonna go and hunt them in the open ocean cause they didn’t wanna stop. So when they did this, started going out on to the open sea, what happens is they would kill … a lot of times kill the adult females, they might have been pregnant or might have been nursing pups back on land ..
Nanci Bompey: Ooooh, so and they never came back to the land for the pups…
Lauren Lipuma: Nooo, the pups would die, it’s so terrible right? Your mom just dies at sea and you never see her again…
Shane Hanlon: Ooh, jeez…
Lauren Lipuma: I know, it’s terrible!
Shane Hanlon: Oh, we’re back to Sarah McLachlan.
Lauren Lipuma: Yeah we are! Oh my God. So that was a big problem. So if the population is just totally tanked, you know, no one knew what was going on.
Noel Pelland: It had a very, very dramatic effect on the population which was declining rather rapidly and there were lots of people on the islands that were witnessing that. What the US response to that was, “Well, we are gonna seize your sealing vessel if you are hunting fur seals pelagically.” Well that was illegal back then to do that, cause there was no maritime rule saying that we actually own that resource outside out of the island itself, it was the high seas. And so what ended up happening is the US and Great Britain were in… there was a court case, a tribunal, that occurred in France, and so the reason that all this information was gathered from or the testimony or the affidavits were taken from the Aleuts and the Aleutians at that time was to present this information on the US side to the court to make the case that the US owned the species no matter where it was in the ocean essentially.
Shane Hanlon: So how does one get testimony from the Aleuts?
Lauren Lipuma: Good question, Shane.
Shane Hanlon: Thank you.
Lauren Lipuma: So at the time the secretary of the Treasury sent this guy Captain Hooper and he was a US Revenue Marine, which was the predecessor to the coast guard. They sent Hooper to the Aleutian Islands to interview the Aleuts and get their testimony and find out what exactly they knew about fur seals and their migration. Because they had been hunting for seals for thousands of years. So his job was to go and get their testimony to present it as evidence for this first court case. He interviewed tons of Aleut hunters about what they knew about fur seals and they told him a lot.
Noel Pelland: At that time, they sent him to the Southern Bering Sea and the Gulf of Alaska with instructions from the Secretary of the Treasury to, among other things, collect affidavits from the locals there regarding the behaviors of the northern fur seals, they were really focused on which passes on the Aleutian Island chains that they went through.
Jeremy Sterling: He’d spend a lot of time up in Alaska and a lot of the different communities so he is very familiar with it, so it wasn’t anything new.
Previously he was involved in actually seizing British vessels, or he was outfitting camps or he was involved in searching for explorers that were up in the Arctic, where they didn’t return.
I think what’s interesting about him is that his testimony or the way that he writes about his experience is that he’s very respectful of the various communities that he’s gotten into, the people that he was working with, he had… translators that were Aleuts and that seems to come through.
Lauren Lipuma: Did they have any records of what Noel’s found about the winds influencing where the pups end up? Or did they have any knowledge of that?
Jeremy Sterling: They knew that the winds influenced the direction that they go, if it was really stormy or a lot of big waves they wouldn’t see the animals and presumably, what they hypothesized was that they were spending a lot of time under water going deeper in the water.
Noel Pelland: But there is a general statement that the pups go through certain passes and the reasons that they go through those passes are because the prevailing winds blow in this direction. The Aleuts are consistent in saying that the seals travel with the prevailing winds, they will travel with the fair wind.
Jeremy Sterling: They also talked a lot about the different passes and the currents and which passes had really strong currents and which ones were… didn’t have nearly as strong currents and the pups tended to utilize the passes with the … where the currents weren’t nearly as strong and if you go and look at any physical observations, current or recent history observations, there are observations of the passes are exactly what has been quantified and what we see today.
Noel Pelland: It’s remarkable in looking at the old data and what Hooper collected, the real agreement that we do see between the life cycle as it was understood then and the way we understand it now.
Nanci Bompey: Oh! So what happened with the court case?
Lauren Lipuma: Well – shocker- the US lost the case because…
Shane Hanlon: Bom-bom
Lauren Lipuma: The court found, no you cannot prevent people from hunting seals on the high seas cause it’s not your territory.
Nanci Bompey: Yeah.
Lauren Lipuma: But, the case actually led to this treaty being signed by all these, you know, international powers that outlawed … eventually outlawed open-water seal hunting and so the population did eventually rebound, which was good for the little seal pups.
Nanci Bompey: Oh that’s good news!
Shane Hanlon: Yeah…
Nanci Bompey: In the end.
Shane Hanlon: I just feel good about this, like this is… this is the story I needed right now.
Nanci Bompey: Even after being sad now you feel good.
Shane Hanlon: Yeah, yeah, so now we’ve come full circle from like cute adorable to seals dying to now … no longer be able to hunt them.
Nanci Bompey: Yeah, yeah, so cute.
Shane Hanlon: Alright folks, that all from Third Pod from the Sun.
Nanci Bompey: Thanks so much to Lauren for bringing us yet another wonderful story and Noel and Jeremy of course for sharing their work with us.
Shane Hanlon: And the podcast is also produced with kelp from Josh Speiser, Oliva Ambrogio and Liza Lester. And thanks to Kayla Surrey for producing this episode.
Nanci Bompey: We’d love to hear your thoughts on the podcast. Please rate and review us on iTunes and listen to us where you get your favorite podcasts and of course, Third Pod from The Sun dot com.
Shane Hanlon: Thanks all and we’ll see you next time.