Hawaiian Monk Seal Pupping Season

Hawaiian Monk Seal Pupping Season

0:00:02.9 John Sheehan: I'm watching this video of a Hawaiian monk seal and her new pup, and you can sort of hear it crying out and scrabbling in the surf, and you can tell the pup is still very young because it's tiny, and its fur is all black, and it's adorable. This is Dive In with NOAA Fisheries, I'm John Sheehan, and today we're celebrating a special time of year in the Hawaiian Islands, pupping season, and it has only just begun.

0:00:27.6 Tracy Mercer: Typically March through August, we tend to think of it as peak pupping season.

0:00:34.1 JS: This is Tracy Mercer, a Hawaiian monk seal research program associate at NOAA's Pacific Islands Fisheries Science Center.

0:00:39.4 Jamie Thomton: Hawaiian monk seals are endemic to Hawaii, they're only found in Hawaii and nowhere else, and they're the only truly tropical seal.

0:00:49.5 JS: And this is Jamie Thomton, KauaʻI Marine Wildlife Stranding Response Island Coordinator at the Pacific Islands Regional Office. Hawaiian monk seals are endangered. In fact, they're a NOAA species in the spotlight, meaning they receive additional attention and resources to stabilize their population and prevent extinction. Today, most monk seals, about 75% of them, reside in the remote northwest Hawaiian islands, and the remaining 25% are in the populated main islands.

0:01:16.5 TM: Their numbers are around 1,600 individuals. The population has actually been on the increase in the last decade or so, so that's really good news.

0:01:28.0 JS: But of course, the population is not out of the woods, and conservation requires a lot of coordinated efforts and vigilance.

0:01:34.4 JT: There are quite a few different threats. So in the northwest Hawaiian islands, it's been things like food limitation, shark predation, getting entrapped in marine debris. And in the main Hawaiian islands, one of the main ones is disease, toxoplasmosis, interactions with fisheries, you know, swallowing fish hooks, getting entangled in gear. Also things like human disturbance, off-leash dogs, things like that.

0:01:58.1 JS: And it is for all these reasons that pupping season can be a harrowing yet joyful time. Jamie Thomton and Tracy Mercer, welcome to Dive In with NOAA Fisheries.

0:02:08.3 TM: Thanks for having us.

0:02:09.3 JT: Yeah, thank you.

0:02:11.5 JS: From what you can tell so far, how is pupping season going? It's off to a good start?

0:02:13.7 TM: It's going great so far. I mean, we're just at the beginning of March, and we've already had three pups born in the main Hawaiian islands. So that's really awesome. We're not aware of any pups yet in the northwestern Hawaiian islands, but we'll learn about that a little bit more once we get our field teams stationed out there this summer.

0:02:30.9 JS: So what does monitoring the pups mean? What are you both doing in preparation for the pups? What does that mean logistically?

0:02:41.6 JT: Logistically, well, part of that is trying to predict how many pups are going to be born and where they're going to be born. Because if you remove humans from the equation, mother monk seals are really good mothers. They take care of the pups. Typically, monk seals like to choose a quiet, remote beach away from people. So when that happens, basically we just monitor and stand back and let the mother take care of the pup. And it's often a sandy beach, a remote beach, someplace with protected, calm waters, say, an inner lagoon. And often, monk seals will choose the beach that they were born on, their natal beach. So the mother will choose that beach to come back, oh, about five, six years later when they're adult age and have their pups there. However, sometimes they choose busy beaches such as Waikiki, and that's happened the last few years.

0:03:24.9 JT: We're not sure why they would choose a busy beach, but when that happens, it's a whole different scenario because we need to make sure the mother and pup are not disturbed 'cause mothers are quite protective of their pups and they can cause harm to swimmers and people in the water. So really, when it comes to preparing for the season, trying to predict where they're going to be, working with partners, and then we sort of stand by. And we do have a way to predict when they're going to pup. I can pass that to Tracy.

0:03:54.3 TM: Yeah. Thanks Jamie. We use kind of our very robust data set to give us a prediction of when a female might pup. Now, we never really do know. You can't just look at a seal and say, "Okay, you're going to give birth." We might have some inklings, but we basically use data we have on when they gave birth the previous year or when they molted. That's when they shed the top layer of skin and fur. So if we have either of those, we can then do a calculation to predict when they might pup in the current year.

0:04:24.1 TM: And it's actually can be pretty spot on. One of the first moms that pupped this year, she pupped just really close to the date we predicted. So it's kind of fun to see how that data feeds into this.

0:04:38.8 JS: Do you try to monitor or verify every pupping event? Is it sort of like, "We got a pup," and it doesn't matter if it's on a busy beach or maybe it's one of your field teams, like, you're on it?

0:04:51.9 TM: Yeah. We definitely want to document and collect information for every pup that's born. We'd like to know who the mother is so we can track that information or data. It really depends on where the animals are born. For instance, here in the main Hawaiian Islands, there's some areas that are very remote and have very little public presence. We don't need to have such a heavy monitoring schedule. We might have people check on them periodically throughout the nursing period to make sure everyone's doing good and there's no concerns. In the remote Northwestern Hawaiian Islands, when there are summer field teams out there, they're doing surveys on a regular basis and documenting what they see, but they're not necessarily standing out there and watching the pups day in and day out. But in places like busy beaches like Waikiki, you pretty much have a human presence there monitoring a perimeter set up, sunrise to sunset.

0:05:42.8 TM: So, that requires a little, I won't say a little, a lot more effort.

0:05:49.7 JT: And what's interesting is that the period that the mom and pup are together is a short period. It's only six to seven weeks, about 40 days, and during that time, the mother seal, she's fasting. She's not leaving the pup. She's not foraging. She's just staying with that pup and converting all of the blubber, the fat that she's accumulated, into milk. And that pup goes from about 35 pounds at birth to close to 200 pounds at weaning, which is, like I said, just about 40 days later. So it's not a long time period that we're managing these beaches.

0:06:21.1 JT: In order to do this during this 40-day period, for each mother-pup pair we work closely with a number of partners. Each island is slightly different, but we work with partners like HawaiʻI Marine Animal Response, or HMAR, as well as the Marine Mammal Center's Ke Kai Ola Hospital, other partners like the State of Hawaii, and it takes hundreds and hundreds of volunteer hours for people to be on the beach to do outreach, to keep an eye on things, and then notify us as biologists if something is not right so we can come and intervene and make sure that each pup survives.

0:06:55.0 JT: With such a small population, there's a huge emphasis on each individual.

0:07:01.9 JS: In the case of a busy beach birth, the red phone rings, and what do you do?

0:07:07.1 JT: On a busy beach, that is a challenge. However, we've become experienced at this. We've had pups born on pretty busy beaches on all of the main Hawaiian islands. The first thing is just to let the mother do the job of protecting the pup. The pup, when it's just a couple days old, is pretty weak.

0:07:23.6 JT: It can't swim very strongly. It can swim, but it needs just space. So basically, we send various teams out and establish a perimeter and keep people at 150 feet. And then we start doing outreach with various partners across the state. So if it's a busy beach that has lots of visitors, we need to talk to hotels, tour operators in the area, and establish basically a 24-hour watch.

0:07:51.7 JS: So you're putting up blockades or maybe ribboned off, cordoned off area, and there's someone there in a tent with binoculars watching the area?

0:08:01.0 JT: That's what it is a lot of times. It depends on how busy the beach is. Sometimes it's a short fence, like a cloth fence. Sometimes it's a rope. Sometimes it's signs. And yes, we'll have a station set up with various volunteers. And that is fairly easy to handle. What's not as easy to handle is once the pup is three, four weeks old, they start to swim a lot more. And then your zone isn't very effective 'cause your zone is up on the beach that's protected. And that's when we need to do more outreach with surfers, swimmers, boaters, things like that, because the mothers can be quite aggressive to protect their pups.

0:08:38.3 JT: However, after the pup weans at that 40-day point, the mother abruptly leaves, and then the pup is on its own. So if it's left on its own in a busy spot, such as Waikiki on Oahu, pups are much like other young animals. They're playful. They're curious. They'll chew on things. They might approach people, approach boats. And then they can become habituated and view people as playmates or things to interact with. So because of that, we often do translocate, is what we call. It's we move a pup from one spot, say a busy beach, to a quieter spot.

0:09:12.5 JT: And that way, the pup can interact with other monk seals, not with people. And interestingly, much of the time, the pup will then imprint on that beach. So if it's a female pup, when she becomes an adult and chooses a spot to have her own pup, she'll choose that beach that she's been moved to or translocated to. So that sort of tries to head off issues five or six years down the road.

0:09:37.3 TM: We take a lot of things into consideration if we're going to intervene and do something like move a pup, a weaned pup, or a pup after it's weaned. And a lot of times, we do take how likely a seal might be habituated to humans. But that really puts a risk to its survival in the wild. There's other risks too out there, areas where people drive on the beach, where a small seal by itself might be missed and could get run over, or there's infrastructure and other things where an animal might become entrapped in, which are cases we've experienced both on Oahu and Kauai, in addition to the human component. So we look at many, many factors before we decide to move a seal, and we're always trying to do things that are in the best interest of the seal and what will be best for its overall survival.

0:10:23.1 JS: Yeah. It sounds there's kind of a threat matrix of all the given circumstances in an area, you have to take all of it into account before you intervene, because intervention is sort of the last... That's a big deal.

0:10:39.0 TM: Correct. You put it perfectly.

0:10:41.0 JS: Jamie, you mentioned pup abandonment. The idea of sort of the mother abruptly leaving and, "You're on your own now, pup." That seems like a pretty intense time for a monk seal pup.

0:10:53.2 JT: Well, females don't abandon pups very often. And right away they establish a bond in the first few hours of birth, and they stick together. So that's usually not an issue as long as disturbance is minimized. However, there's another situation that does come up on occasion, and it's where moms and pups will get switched. And it happens when there's two or three moms on the same beach. So you have three mother seals and three pups all together. And on occasion, the pups will get swapped.

0:11:23.9 JT: So the wrong pup is with the wrong mother, which if they're the same age, that's okay. They should survive. But the problem is when you have a pup that's, say, five weeks old, and another that's only four days old, they switch and the mother has a limited supply of milk. She's got about 40 days worth of milk. So that younger pup is going to end up being weaned at a much younger age, whereas the older pup will end up getting, say, several more weeks and gets very large. So when we see this happen, we intervene and try to reunite the correct mom with the correct pup.

0:11:56.9 JT: And this happened a few years ago here on Kauai. We had three moms and three pups together, and a four-day-old pup was somehow taken by another mother that had a pup that was just about to wean. And we saw that, and that was a situation where the youngest pup was not going to get enough milk and was not going to survive.

0:12:17.7 JS: Jamie actually has video of this interaction. And you can see the mom and pup on shore and the confusion that sets in when another mom kind of swims in and mistakes the pup for her own.

0:12:31.1 JT: So we had to use some stealthy ninja tactics, sneak in and grab one pup away from one mom and the other from the other, and quickly reunite them. And the first time this happened with this one pup, K58, the pup was only four days old. And we got it back with the correct mom, and we thought everything was good. But then, two weeks later, this same pup, K58, was taken by yet another mother with an old pup.

0:12:57.3 JT: So we went down there and saw that this pup, K58, was now with K28, the mother. And she only had a few days left of milk. So we did again the ninja swap, snuck in, took the correct pup, put it by the right mom. This time, however, K58's mom did not accept him. Something was different. She approached the pup, sniffed it aggressively, and then rejected it. It started being aggressive. So we stood by and watched this for about 12 hours, and the mother just seemed really confused that this wasn't her pup, however it was. So then we brought this pup into captivity, K58, and sent it to the Marine Mammal Center's Monk Seal Hospital, Ke Kai Ola, where they were able to hand-raise this pup and then eventually bring it back to Kauai and release it.

0:13:48.8 JT: And it's been about six years since that happened, and this seal, our K58, he's one of the dominant adult males on Kauai, and it's a success story. But he had quite a start to his life.

0:13:58.6 JS: K58, you made it! Let's back up a second. Ninja moves. Like, cover of night, camo, crawling on the beach, subterfuge? Or am I overthinking it?

0:14:12.3 JT: It was more of a bait-and-switch, where the moms view things as threats. So we can send one biologist sort of in the front of the seal, get her attention, while another biologist can sneak in behind, and either use a net, or at the time when it was four days old, you could just scoop it up with your hands and run away with a pup under your arm, and then sneak in with a net with another one and release it nearby. We also use various basic tools, like crowding boards, to separate seals from one area to another. So we're able to use crowding boards to move the mother away, and then quickly grab the seals. We have a very experienced team of biologists here that can handle wild monk seals safely, and we use various tactics.

0:14:55.7 JT: But usually it's get in quick, get out, put things back where they belong. The reason we don't go in with sedation, we get that question quite a bit. "Why don't you just go in and tranquilize?" Well, seals can go into what's called a dive response, where they hold their breath, and they actually can hold their breath until they die. So we find often it's safer for the seal, and quicker just to go in and do what's necessary. Whether that's taking out a hook, whether it's giving antibiotics, or applying flipper tags to pups after they wean, so we can track them the rest of their life.

0:15:27.1 JT: So it looks a little bit like you're wrangling livestock when you're on the beach, but our team is quite skilled and experienced in handling them safely.

0:15:35.4 JS: Let's talk a little bit about some of that data collected. What's happening from the research side, Tracy? So you're observing the pup, at some point you've got to get in there and tag it. What else are you sort of collecting?

0:15:48.5 TM: We do our best to monitor seals throughout their lifetime. And so as soon as we are aware that a female has given birth, we will try to document who's the female, who's the mom. We want to know their identity. And then we'll give that pup an ID so we can track it while it's nursing. We just call it a pup number. We'll have folks monitoring them throughout the nursing period. And then once mom weans, and as Jamie said, that's an abrupt weaning, so mom will just take off.

0:16:20.0 TM: And now you have this little chubby ball of blubber on the beach that really doesn't have a clue what's going on. And we'll wait maybe a day or two just to make sure. And then we'll plan to go in and try to basically flip or tag the pup. So that's where they get these plastic tags that have a letter number engraved on them that's unique. And we will capture the pup and restrain it and put those tags in. And that'll become, we'll use those tag numbers to give it a permanent identification number.

0:16:49.5 TM: And that's actually the number that sticks with it for its lifetime. So it's really cool to be able to track these animals for years and years and years and actually even lineages. We know that we have four and five generations of seals that we can track back to one mom.

0:17:05.8 TM: So it's pretty cool. In recent years, since about 2016, we've also been vaccinating them against something called morbillivirus, which is a phocine or a seal distemper virus. So we've started to vaccinate the pups. When we're tagging them, we'll give them an injection of that vaccine and then follow it up in about three weeks with a booster.

0:17:32.2 JS: So the population has recently been increasing, particularly on the main islands. Do we know why?

0:17:38.4 TM: Oh, we have some ideas. One thing is that, this area, there's a lot less what we see in the Northwestern as food limitation. There's a lot less apex predators here. So there may be more available food for monk seals. What we actually see is seals here in the main islands tend to grow at a faster rate. Anecdotally, they reach sexual maturity earlier. They're pupping. They're giving birth to pups at earlier ages compared to the Northwestern Hawaiian Islands. I think just conditions here are better, which seems counterintuitive because you have a very populated area with lots of people.

0:18:13.0 JS: Besides the people, things are great.

0:18:16.2 TM: Yeah, besides the people, things are pretty good here. But what we don't know is we don't know what maybe the carrying capacity here is in the main Hawaiian Islands. At some point they might cease to increase here because possibly resources might be limited or, we might see more human-related mortalities. It's an exciting thing for the population, but also kind of a delicate balance.

0:18:42.2 JT: Before about the 1990s, there weren't that many monk seals in the main Hawaiian Islands. They hadn't repopulated the previous range that they had been in. And with this new arrival of an old species that used to live here, we've had to foster or promote this culture of coexistence on the beaches. People aren't used to seeing them. Tourists come to Hawaii for beaches and sunsets, and they don't expect to see a large marine mammal resting on that same beach.

0:19:09.7 JT: And so now with more and more pups being born, sometimes on all these busy beaches, promoting this coexistence culture where residents of Hawaii take care of the seals and help us do outreach with the visitors, saying, this is a special, unique animal that's only found in Hawaii, and we need to give them space.

0:19:26.1 JS: Given the last few years and the really encouraging signs of population increase, are you both optimistic, or are you in a, well, wait and see kind of mindset?

0:19:42.9 JT: That's a really good question. It's great to be working on a program with a species that's seeing signs of recovery. However, 2% growth per year, it's promising, but we're still all very cautious and keeping a close eye on the trajectory. The population at 1600 right now, it's only about one-third of historic levels. And in order to consider delisting this species, it needs to be at 3400 for about 20 years. So we're not even halfway to recovery numbers yet. So it's great. We see signs of hope and optimism, but we're not letting our guard down.

0:20:20.9 TM: Jamie said it perfectly, cautiously optimistic. You never know what might happen that might cause things to turn around and see the population go in the opposite direction.

0:20:32.0 JS: Can you talk a little bit more about kind of best practices for visitors and for residents?

0:20:38.7 JT: As with all wildlife, give the wildlife space and respect their space and just let them rest undisturbed. The guidance we give is to stay at 50 feet, that's 50 feet from resting seals on beaches. Mothers and pups, there'll probably be signage, but 150 feet is what we recommend. And if you're in the water swimming and a seal comes up, just don't engage the seal. Don't need to panic, just slowly swim away and the seal will probably just swim on by and continue its day. And if you do see signs posted on the beach, just stay behind the signs as well. Some beaches, there's not that much space, so maybe the signs will be closer to the seals than 50 feet. But as long as you stay behind the signage.

0:21:16.6 JS: Jamie Thomton and Tracy Mercer, thanks so much.

0:21:20.5 TM: Yeah. Thanks for having us. This is really fun.

0:21:23.5 JT: Yeah. Thank you for your interest. And it's been a joy to talk about Hawaiian monk seals.

0:21:30.2 JS: Jamie Thomton is Kauai Marine Wildlife Stranding Response Island Coordinator at NOAA's Pacific Islands Regional Office. And Tracy Mercer is a Hawaiian Monk Seal Research Program Associate at the Pacific Islands Fisheries Science Center. To learn more about best practices when observing monk seals, or to see more adorable monk seal pup videos, check out fisheries.noaa.gov. I'm John Sheehan, and this has been Dive In with NOAA Fisheries.