Polymath World Channel

SHARKS

Dr Kim Holland is Research Professor at the Hawai'i Institute of Marine Biology.  Known as the 'Shark Lab', together with his team Dr Holland runs the sharks and predators research institute of the School of Ocean and Earth Science and Technology at the University of Hawai'i at Manoa, located on Moku o Lo'e (Coconut Island), in Kane'ohe Bay on O'ahu. Holland's work specialises in the organismic and supraorganismic biology of marine organisms. Given the unique settings, they take advantage of this by blending rigorous laboratory work with well-focused field experiments to investigate the behaviour, physiology and ecology of sharks and other marine species. Dr Holland has been doing this since the 1980s and is a pioneer of small boat research and the use of tagging. Innovating this into shark research, he launched the HIMB Shark Research Group and now engages in some of the most groundbreaking tiger shark work on the planet, using acoustic and satellite tracking.

I loved our conversation and you will be gripped by his stories and explanations of this innovative conservational research effort into these magnificent and vital creatures.

Bio: https://www.sharktagger.org/kimhollandbio

Lab: https://himbsharklab.com/

Education: https://www.himb.hawaii.edu/ReefPredator/Team.htm

Tracking Tiger Sharks: https://www.pacioos.hawaii.edu/projects/sharks/

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#PolymathWorldChannel #PursueExtraordinary #Sharks #TigerSharks #MarineBiology #Oceanography #Hawaii #UniversityOfHawaii #Conservation #Ecology #PacificOcean #SharkTagging #SharkConservation #FieldWork #WeatherDependency #DataAnalysis #AnimalTracking #ResearchMethods

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Polymath World (00:01.313)
Hello and welcome to the Polymath World channel and I'm delighted today that we're dipping into marine biology, one of my absolute favourite topics. The thing I always dreamed I would study as a child and we've got one of the best here today. Coming off a magnificent Netflix documentary about the work of Ocean Ramsey and others out in Hawaii, we're going to be talking about sharks a great deal and the life of the oceans and we're joined today by Dr. Kim Holland from the Shark Research Lab at the Hawaii Institute.

for marine biology. Thank you so much for joining me today, Dr. Harland.

Kim Holland (00:34.605)
pleasure.

Polymath World (00:36.011)
Thank you. So, did you always want to get into marine biology? Was it your passion as a child?

Kim Holland (00:42.956)
It was my passion as a late teenager. It was the days of, the early days of David Attenborough and Jacques Cousteau and Hans Haas and so on on the television. And I got enthralled. And my academic ability such as it was as a teenager was...

biology and allied sciences. And so it was a fairly natural progression for me to try and get into marine biology ever since I was in my late teens.

Polymath World (01:21.525)
Did you grow up near the coast?

Kim Holland (01:24.214)
I grew up in Devon, in South West England.

Polymath World (01:27.711)
really? Well, now we have...

Kim Holland (01:29.482)
Actually, I was born and raised in Devon.

Polymath World (01:32.534)
We have to know your journey.

So you end up from Devon all the way out in Hawaii.

Kim Holland (01:38.956)
Well,

Yeah, I came to Hawaii first as an undergraduate, as an international exchange student, with every intention of going back to Well, I had a headmaster at my school who was completely sold on the concept of international education. He came from a college in South Wales called Atlantic College, which was way ahead of its time. And he got a headmaster'ship at my school.

Polymath World (01:48.619)
How did that happen?

Kim Holland (02:10.542)
and he was intent on kicking his charges out as far around the world as he could get them. when I explained to him that want to police or I want to be a marine biologist, I don't know how he knew this to this day, he encouraged me to write to the University of Hawaii and see what happened. So when I was given the choice between going to Hawaii or Newcastle or Bangor, I chose Hawaii.

and with every intention of coming back to the UK. And here it is 50 something years later.

Polymath World (02:45.375)
I imagine it wasn't too hard to want to stay in Hawaii by any way that you can. It's interesting you say that, but... Sorry, go ahead.

Kim Holland (02:51.884)
Well, when I went back, go ahead. No, no, I did come back to England after my bachelor's degree at Hawaii. And I realized that I had a degree in a university that nobody had heard of in a field that nobody was particularly interested in. And fortunately, my trail was still warm back in Hawaii. So I got in touch with one of my professors and said, please help. Can I come back and go to grad school?

And from then on, I tended to look a little further down the road in my life trajectory than a couple of weeks, which had been the way up until that point. And so I was able to come back to Hawaii as a graduate student. And then I went to the mainland to get my PhD, and then a job came back open back here in Hawaii. And I came back and sort of climbed up through the ranks ever since.

Polymath World (03:46.485)
What was your PhD on?

Kim Holland (03:49.314)
My PhD was actually on the sense of taste and smell in channel catfish, which is a freshwater fish, but it was of interest to the research institute where I had my post-doctorate, my pre-doctorate and post-doctoral education, because catfishes are absolutely covered with taste buds of the kind that we have on our tongues, but catfish have them all over their bodies. And the biochemists in my group, or in my institute,

were using catfish as a source of taste buds in the early days of identifying exactly the mechanical mechanism whereby we taste something. So they were using catfish as a study animal, and my PhD was looking at whether or not what the biochemists found in terms of how strong different compounds bind to a taste cell, whether or not that meant anything to the fish. And so I produced a series of...

behavioral assays basically asking the catfish, can you taste this, can you taste this, can you taste this? And if so, how weak, how low can we go before you can taste it? It sounds pretty, it is esoteric, but at the time it seemed to be very important.

Polymath World (05:08.437)
Yeah, I love it. Did you stay in Hawaii to do a postdoc or did you then go straight into marine biology work?

Kim Holland (05:14.862)
So part of story is that while I was in Philadelphia going to the University of Pennsylvania and doing that catfish work, my ex-old professor back in Hawaii had gotten some money to look at whether or not tuna could smell things. And the reason that was of interest was because it was the early days when it was realized how big the

unintentional bycatch of dolphins was in the commercial purse and fisheries of the world. And my professors, old professors concept was let's see if tuna can smell because that way we know dolphins can't smell because they've turned their nose into a blowhole. Let's see if we put odors in the water. Perhaps once the purse center has wrapped its net around both the dolphins and the tuna.

Before things get too serious, let's see if we can draw the tuna out of the dolphins using their sense of smell. So I went back to Hawaii and that's when I started studying tuna in captivity.

we would go and catch them or buy them from the commercial fishermen, keep them in captivity and then see what kinds of things tuna liked to smell. The object of the exercise being eventually to see if we could use that in the open ocean. That part never came to fruition, that was my step into tuna. And that was the next step was to actually use this at the time novel technique called acoustic telemetry whereby you put a pinger on an animal in the water.

and the pinger puts out a signal into the ocean which you can then detect. So I started tracking the movements of tuna, which was novel at the time. And then after a while, there was some occasion when there was a couple of fatal shark attacks in Hawaii, which is unusual. We have a few heart shark attacks, but they're not usually fatal.

Kim Holland (07:15.086)
and these attacks were fatal. Then my students and I realized that we knew absolutely nothing about the typical movement patterns of these sharks. Oh, and by the way, we're tracking tuna. Maybe we can take the same technology we're using for tuna and track sharks and see where they go. And that's how I continued, that's how I started my life in acoustic or in telemetry in general and how I stepped from catfish to tuna to sharks.

Polymath World (07:45.589)
That's phenomenal. I look forward to digging more into acoustic telemetry in a moment. I'm just wondering, was there a moment you remember when you were young? Because this often seems to be the case with marine biologists, where the ocean really captured you and you thought sort of that's where I want to be. And did you do a lot of swimming and surfing and things like that?

Kim Holland (08:05.838)
Yeah, no, it was a part of my boyhood. I'm from central Devon, a little town called Tipperton, but we always used to go up to the north coast of Devon to Croydon and Saunton as kids. That's where we grew up, in the water up there. So it was a very natural transition for me. I was surfing before I went to Hawaii, but I got into it seriously when I got here, obviously.

Polymath World (08:30.485)
And was the situation with the tuna and the research you were doing and the shark attacks, was that the first time you became really switched onto sharks or did that happen before that?

Kim Holland (08:41.326)
No, no, I'm not a shark. I might be now, but I wasn't at the time a shark biologist. was basically a telemetrist even back then, and perhaps I would call myself a tuna biologist. So the move into sharks was very serendipitous, but it was a really good move.

And since then I've sort learned on the job, so to speak, as far as shark biology is concerned. But the common theme is the use of telemetry in understanding the movement patterns of animals.

Polymath World (09:13.813)
Now out in Hawaii obviously it's a surfers paradise. It's a stunningly beautiful place. I think it would be very high on everyone's wish list to visit once. And people go there for all kinds of reasons as well. The ocean, it's one of the most amazing places to experience humpback whales. But I'm aware there's a lot of surfing competitions and things that happen out there.

Now, that's always that there's a dangerous trade-off with sharks when you're surfing. These attacks and these things like that, are they mostly occurring offshore for surfers and things like that?

Kim Holland (09:59.022)
That's a very interesting question and quite a more complex question than you might realize. The first thing to say is that the number of shark attacks are very low. We go from one to four to zero to five to two and so on on an annual basis. And of those, by no means all, a very small percentage are actually fatal. I'm not saying they're not serious, they are serious. So the risk is quite low. Who is most

exposed to the risk, it does seem though, it does, this is not hard and fast, but it does seem that the further you go offshore, the slightly more risk there is to encountering a shark. And that's why it is the surfing population. And then the stand up paddle board guys, the further offshore our recreation takes us, within reason,

the more exposure you seem to have. But again, even that increased exposure is a very low one in Hawaii.

Polymath World (11:04.18)
Now it's very warm water out there, certainly compared to whales and Devon. are the sharks there also to breed and to... are they feeding on the tuna?

Kim Holland (11:20.75)
So the tunas are offshore and most of our incidents and most of our interest, not all of it, is in what we would call coastal sharks. So there are species of sharks such as mako sharks and oceanic white tip sharks that do feed on tuna, but the majority of sharks that humans have interactions with are coastal sharks such as

Tiger sharks, which is a main part of what I study, and bull sharks, which are common in many parts of the world but don't occur in Hawaii. But again, they're a coastal shark. So we do make this somewhat blurred line between coastal and open ocean shark species.

Polymath World (12:11.829)
Yes, when people think of Hawaii, think they probably mainly think of tiger sharks. So they make up the main focus of your own research.

Kim Holland (12:22.574)
correct that and we do quite a lot of work with hammerhead sharks and not because hammerhead sharks are a threat to humans, a very low threat, but just because they've got a fascinating physiology and behavior. But in terms of the human interest so to speak, tiger sharks are the main focus of what we do.

Polymath World (12:47.947)
think your average man and woman on the street when they think of sharks that they're afraid of would probably list great white sharks, tiger sharks and bull sharks. And you've mentioned two of them. But your group and many of the people you've worked with including Ocean Ramsey are part of this new wave of helping people appreciate these sharks in a whole new way. We see people

swimming and free diving with them. I would love to give you the floor here for a moment to just share how essential sharks are for the health of the oceans and why they shouldn't be misunderstood in the way that they are.

Kim Holland (13:33.303)
Okay, well, it's generally, it's accepted, I think, by all biologists that top predators in any ecosystem, whether it be terrestrial or marine or freshwater, top predators play a role in stabilizing the rest of the ecosystem that supports them.

And it's also, I think, quite well accepted these days that as soon as you perturb one part of an ecosystem, you threaten the rest of that ecosystem. It's just a matter of how much damage you do at what level of that ecosystem. And because top predators seem to have perhaps a disproportionately high influence on the rest of their ecosystem, then of course it's disproportionately important to look after them.

And so that's one of the driving principles of conservation. Unfortunately, it's often the top predators that are the ones that are most desirable to catch. Not so much in the shark world, but certainly in the bony fishes. know, tunas and swordfish and salmon are pretty close to the top of their respective food chains. so...

It's a real juggling act as to how you can exploit those resources sustainably. In the case of sharks, their biology is such that they're even more vulnerable to being reduced in their numbers.

The vulnerability is generally ascribed to two factors. One is they're often very slow to mature. It's not like they're a rapidly breeding animal. have to take, depending on the species, several years to come into sexual maturity. And when they do come into sexual maturity, the number of offspring they have is comparatively small. Although...

Kim Holland (15:29.986)
Many sharks have evolved the same strategy as mammals have, and that is to keep their young inside them until they're able to make a go of it. And then they give birth to live young, which is something which...

they share in common with mammals. sharks are vulnerable because they don't grow very fast, they wait a long time to become sectionally mature, and when they have their young, they're quite few. So for all those reasons, they're quite vulnerable to over-exploitation, whether that exploitation is on purpose or in bycatch, by mistake.

Polymath World (16:03.809)
Are people just wrong for thinking that if they're in the water with tiger sharks they are immediately in danger?

Kim Holland (16:14.232)
Yes, that is wrong, but it's probably wrong in the right direction. Which is why I do take issue with a lot of the things that people, tour operators and so on, putting people in the water without cages in the presence of sharks, I think is foolhardy. I think there may have been a time...

when those kinds of exploits may have had an impact on public perception that sharks aren't such a bad thing after all. But to be candid, I think that bridge was crossed decades ago, now least a couple of decades ago. The number of shark documentaries you can find on television is almost endless. So I think the argument of...

taking risks on television in order to sensitize people to how cool sharks are. think that's an old story which doesn't hold a lot of water anymore.

Polymath World (17:20.331)
So tell us about the work that yourself and Dr. Carl Meyer do. Tell us about the Shark Research Lab. What does a week in the life of Kim Holland and his team look like?

Kim Holland (17:32.409)
Well, the first word that comes to mind is unpredictable. We do try and put some structure to what we do, but a lot of our field work, which is the part that's involved with putting transmitters of different kinds on animals, and our collection for bringing animals back into captivity, that is very weather dependent. We need fairly calm water to do that.

And so when we're looking at what's going to happen this week, my colleague Carl Meyer and I are usually, well, what's the weather going to be like this week? And if it looks like it's going to be fairly manageable, then we'll emphasize field work or collection. And if it's going to be unfriendly weather, then it's sitting in front of the computer and analyzing data and doing paperwork and going to meetings.

So it's a typically mixed plate. We're very fortunate in that we've managed to assemble around us a very competent group of young scientists that are working in our group as technicians or...

research fellows and it's always inspiring to me as the old guy to walk into the lab and see everybody laughing and doing science and doing their respective jobs and trying to push our understanding of sharks forward. We've got two, currently we've got two major legs to our activity.

One is the telemetry, which I've described, and we're continuing to push forward the sophistication of the kinds of tags and packages that we can put on animals. And the second leg that we're currently following is having a very objective look at whether or not it's possible to deter sharks from biting things. And our sort of mantra for that work is that...

Kim Holland (19:35.305)
is as important for us to protect sharks from humans as it is to protect humans from sharks. And we are investigating the various off-the-shelf devices that are available for money to buy to see whether or not they actually work or not. And at the same time, we're starting to work developing to test putative shark deterrents of our own or colleagues' design.

There are, as I say, three sub-themes here. One is to protect humans, if it's possible, surfers or divers or whatever. But the others are perhaps in some ways more important, and that is to try and stop sharks being caught in commercial fishing gear, which is the main source of population decline in the open ocean.

And the third leg is trying to stop sharks taking your fish once you've caught your fish. This is a big deal around the world in small-scale commercial and artisanal fisheries is that guys go out, people go out, catch a fish, but before they can get it into the boat, a shark comes and bites it off the hook. It's called, the technical term is depredation. And depredation is a very important,

part of fishing in coastal fisheries. And so our concept is that if we can identify things that are perceived as being nasty by a shark, that nastiness might be engineered in such a way to be useful both to protect humans, to stop sharks from biting your fish, and to stop...

sharks from getting caught in commercial longlines. So we've got these two avenues of research, the tagging and the deterrent research.

Polymath World (21:29.345)
How does one tag a safely and as non-invasively as possible without distressing the animal or putting yourselves at risk?

Kim Holland (21:42.115)
Hmm, very good question. Sharks have this inbuilt natural physiological phenomenon called tonic immobility. And basically this is if you can get the animal on its back upside down, it basically goes to sleep. It's not unique to sharks. You can see it in other things. Chickens will do it, for instance, amongst others. And rabbits, I think, although I've never done it with her.

So we catch the shark and bring it up to the side of the boat. We don't take it out of the water. And when we get it to the side of the boat, we wrestle it over onto its back and put a noose around its tail so it can't...

get loose on its tail and we've got a hook already in the mouth and when it's upside down it goes into tonic immobility which means the shark isn't struggling which protects the shark from injury, protects us from injury and when the shark is in that condition you can do minor surgery such as attaching a tag to it or inserting a tag into its abdomen. If the shark starts to sort of wake up

So to do the the dorsal fin attachment we have to put the shark right side up in order to get at its dorsal fin from leaning. And if it starts to wiggle when it's right set up we just turn it back over on its back until it goes under again and rinsed and repeat until you've got the job done. And then you take the hook out the mouth and take the rope off the tail and give it a push and off they go. It sounds pretty straightforward but there's

Polymath World (23:16.342)
Wow.

Kim Holland (23:20.364)
There's several years of doing it in getting to where we are today.

Polymath World (23:26.593)
Yeah, how long does that process take? Is it sort of a 30 minute or one hour job?

Kim Holland (23:32.941)
Yeah, it's about a 30 minute job. It depends on how tired the shark is before you get to it. So we set fishing gear with baits on it and we let it soak for two or three hours and go back and see what we've caught. set lines with about 10 hooks on it. And if the shark has been struggling for a while before you get back there, then they come up quite quietly. If they've only just been hooked, well, you've got a bit of a...

circus on your hands for a few minutes but then they tire out and you can handle them.

Polymath World (24:08.373)
Wow. Just as an aside, I've heard that if shark numbers were to deplete significantly, you would see other threats to divers such as growing squid populations, you know, that could be aggressive and have a bad bite. Is that...

Kim Holland (24:24.302)
Well, that's the whole part of that whole trophic cascade or imbalance of an ecosystem from removing the top predators. I think there is a...

I don't know how well documented these phenomena, the giant squids and the jellyfishes and so on, are, but there is no doubt that the more you perturb an ecosystem, the more likely you are to see things that you didn't want to happen, including the emergence of less desirable organisms, like giant squid, for instance.

Polymath World (25:06.507)
So tell us more about your research center. noticed you take on PhD students and you have some masters students.

Kim Holland (25:13.88)
Well, we're a department, a research institute within the general structure of the University of Hawaii. And so we function like an academic department does in many ways, and we bring on students. Traditionally, our institute has been focused on graduate education, graduate students, and

more advanced research, although as with many universities around the world, are moving more, well, our institute is moving more and more into undergraduate education and making sure that we have avenues for undergraduates to be exposed to what we're doing.

But yes, the institute itself is not a degree-granting institute, so all of our students are enrolled in academic degree-granting programs, even though they're residents, so to speak, at HIMB, where they actually do their research.

Polymath World (26:15.787)
What a wonderful opportunity. I mean, I would have done anything for that when I was a young boy, certainly.

Kim Holland (26:21.998)
Yeah, I sort of backed into it. I didn't think I realized when I was in the entry level how lucky I was and how I managed to catch myself before I messed it up.

Polymath World (26:39.465)
In terms of structure, are you required to produce a certain amount of research, like a certain number of publications each year?

Kim Holland (26:46.958)
Yes, each institute, each department in the university has its own guidelines. We have that freedom to shape the expectation guidelines according to the kind of institute that you are. I'm sure it's different if you're in the history department or the biochemistry department, but for what we do, our institute has its own publication requirements for different levels of seniority.

Yeah, and again, in our case, what that recognizes is, in our case, what it recognizes is that marine biology often...

involves a lot of fieldwork and fieldwork means, it's blowing like hell next week, I can't do that or something just happened, the boat just broke. So our expectations of publication frequency tend to reflect the fact that fieldwork often requires an inordinate amount of time just to get a very few data points.

Polymath World (27:47.605)
Yes, certainly. Yeah, well acquainted with that myself. Just with Netflix and things like that, does your work often end up being featured in much broader education? You mentioned the David Attenborough's and the Jacques Cousteau's. Have you had the opportunity with your work with Hawaii to see your work showcased in broader education?

Kim Holland (27:52.556)
Okay.

Kim Holland (28:13.23)
Yes, well, yes, is the short answer. again, the vehicle for that has been over the years, our work and myself in particular have appeared on multiple sort of educational documentaries of all stripes. And we do take that quite seriously.

We find that we have to, with sharks it's sort of a double-edged sword. It's very easy to get people's attention because they're so charismatic. But it's also tempting to many producers, I think, to turn it into, you know, number Jaws is up to at this point. Jaws 17 or whatever it is.

So we have to be quite selective in who we say yes to in terms of working with them on documentaries. And in fact, we're getting harder and harder to convince just because we've been burned a couple of times. And also, as I say, we're thinking that the...

educational value of these things is diminishing because there's been so much of it done previously. You have to be very inventive as a television documentary producer to come up with a storyline which doesn't turn into this, you know, blood and guts thing, but which still has enough novelty to warrant doing. And that window, I think, is getting smaller and smaller.

Polymath World (29:47.955)
I can appreciate that. I sort of see you use the word charismatic and I think that's an excellent word for it. I see sharks as almost sort of a universal language. It doesn't matter what age or gender or nationality you are. Everyone can appreciate and be amazed by sharks. It's a universal love. People all over the world can get brought together with that. With the tagging, I was

quite interested, what sort of range do these sharks migrate and the tags sort of work? How far are you covering?

Kim Holland (30:26.53)
Okay, so there are two types of tags basically. Maybe three. One is acoustic transmitters. These are devices that put out a high frequency pulse into the ocean. And that pulse can be coded so you know which tag is which. And the reason you're using sound is because you can't see through water very far, but sound travels very well through water.

So you use sound as the way of saying here I am here I am and by the way, I'm number 75 so the actual range of those tags depends on the size, but you could say a couple of kilometers typically for a shark So you can either follow it around listening to it go beep beep beep Which is the way I got started following tunas around and sharks

Or you can put out a series, a network of listening devices and when that tagged animal passes by one of your receivers, the receivers hears it and registers that to its memory. This is at this time of day, on this day, shark number 75, I heard it and it was here for 10 minutes and then it was gone again. So using those kinds of networks of receivers, you can build up a pattern of movement patterns of these animals.

The other, another kind of tag which dominates what we do now are tags that talk to satellite.

And so every time the shark comes to the surface, we attach the tag to the dorsal fin of the shark. Radio waves don't travel through salt water, so you can't use GPS underwater. You can't use radio in the open ocean. You have to wait for your animal to come to the surface. And when it comes to the surface, the tag is smart enough to say, I'm at the surface. I can transmit and sends a signal. if, coincidentally, not coincidentally, if hopefully there is

Kim Holland (32:26.09)
satellite or more over the top at the time of footprint then that position gets registered with the satellite which relays it down to a base station. And the last pack, last kind

is sort of a hybrid of those and that is you can put different kinds of packages including increasingly small video cameras and you can put those devices on an animal but you rely on that package coming off of the animal at some point, matter of days or sometimes weeks, hours.

comes to the surface, it says, I am, here I am, and you go and pick it up from the ocean again, out of the ocean, and then you can download the video, which otherwise would be too much data to get up to a satellite. So those are the three kinds of acoustic tags and various kinds of satellite link tags. The one that we're using a lot right now.

is a new type of tag which actually collects temperature of the ocean as the animal is swimming up and down during its normal movement patterns. It's collecting the temperature of the water that it's experiencing. And then the next time it comes to the surface, it says, here I am, and by the way, here is a bathy graph of the, here's a temperature depth plot of where I've been. the concept that the tagline is sharks as oceanographers.

So we're asking the sharks to tell us about the ocean that they're swimming in. The next step will be to do the same thing with oxygen and then maybe with chlorophyll.

Polymath World (34:02.657)
Well that's phenomenal data. I mean there's a lot of data I imagine you're getting through that then needs processing and analysis. But that along with the telemetry, the work that you're talking about, it seems like this can help you build a really effective map of shark behavior, shark population and shark migration. It's sort of helping you build an overall picture of everything that's going on.

Kim Holland (34:28.354)
Yes, yes exactly that and one of the things for instance one of our students has just submitted a paper where it seems that the tiger sharks based on acoustic telemetry and having receivers dotted around the Hawaiian islands

It seems that in the breeding season or a pupping season, breeding season, basically fall and winter in Hawaii, a large percentage of adult female sharks go to a particular part of the island chain and then redistribute themselves afterwards. It's what is known as a partial migration. So those are the kinds of insights we're getting into, in this case, the reproductive biology of tiger sharks. We're also...

Another of our students, Mark Royer, who's now a post-doc with us, showed that hammerhead sharks, even though they occur very close to the surface in the daytime, at night time they make these repeated dives down to 800 meters or more, taking maybe 20, 25 minutes to do each dive, and they do it all night long until the sun comes up and then they stop doing it.

Polymath World (35:29.153)
Wow.

Kim Holland (35:38.997)
None of this would have been known were it not for the modern development of these kinds of electronic tags. The other cool thing that Mark showed was that in order to keep their body temperature warm as they dive down into these cold waters, hammerhead sharks close their gills because it's across the gills that most of the heat is gained or lost in a fish. And so in order to stop itself from losing heat,

It's warm at the surface as it dives deep and it stops itself from getting cold, it stops basically breathing. It closes its gills, which also means it can't breathe. So basically, hammerhead sharks hold their breath in order to dive into cold water, probably eat a few squid and then sprint back to the surface and warm up again. So all of these kinds of insights we're getting because of the advancement in the sophistication of telemetry devices.

Polymath World (36:28.086)
Wow.

Polymath World (36:35.253)
That's amazing! And with what you were saying earlier, it sounds like the tiger sharks, some of them have a favorite island. Or seem to have a favorite island.

Kim Holland (36:45.518)
Well, yes, that's one of the things we've been looking at for years is what is the typical home range of a shark. And what we're seeing is what some people would call punctatory displacement. That is, they'll set up shop along a coastline for a while, and then for reasons unknown only to them, say, okay, enough of this, I'm off to somewhere else now. One of the unknown...

One of the things we didn't know before we started doing this is that we've got several instances of large tiger sharks that spend weeks and weeks very close to the shore and then just swim offshore five, 600 kilometers, turn around and come back again. Not only is it amazing that they can navigate that way, which is, think, one of the last frontiers in biology is understanding navigation.

But we would never have known those kind of offshore excursions were happening if we didn't have these technologies.

Polymath World (37:41.921)
Oh, that's amazing. So just a quick question purely for my own interest. Do you get any of the other sharks, the really big ones, whale sharks, basking sharks, do you ever have them as visitors? Obviously it's a volcanic island in the middle of Pacific, nutrient rich. I'm sure you get all sorts.

Kim Holland (38:01.043)
We do, get whale sharks.

We almost ran over one a few weeks ago. Fortunately, we didn't. We do get great whites here, but they're not common. They're uncommon. And the ones that are here seem to be coming from California and Mexico. So we've had colleagues that have put these same acoustic trans-windows I was talking about earlier on. They put them on great white sharks off of the coast of Mexico or off of San Francisco. And a few months later, we picked them up here on our receiver.

in Hawaii. So we do have those large sharks here. We don't have basking sharks. Our equivalent of basking sharks are comparatively temperate cold water animals, which you'll find around the coast of the UK for instance. Our equivalent of basking sharks are whale sharks.

Polymath World (38:50.251)
Yes, yes.

Polymath World (38:55.841)
Amazing. Extraordinary. You know, we had a couple of great white sharks spotted off Cornwall a few years ago that absolutely surprised and shocked the life out of the people that saw them and couldn't believe their eyes. So there's interest in that.

Kim Holland (39:09.07)
Yeah, they're not to be taken like that. Yeah, yeah, they're a serious animal. And one of the few animals, I think, that is not reticent about taking on something quite large. Tiger sharks are actually quite timid most of the time. They're very cautious about what they decide to try and eat. And they take a...

take a while to make up their minds that they're going to do it, whereas white sharks are ambush predators. They just pick a target and accelerate towards it. That's not typically what tiger sharks do.

Polymath World (39:49.959)
I'm enjoying this so much. I could ask you a hundred other questions, but I'm very grateful for your time. But I must ask because my daughter is eight years old and she told me just a few weeks ago she wants to be a marine biologist when she grows up. She loves swimming, but she's become obsessed with the blue planet and documentary shows like that. She wants to be a marine biologist. If you were to give advice to any young people...

Kim Holland (39:53.869)
Ha

Kim Holland (40:12.046)
Sure. Sure.

Polymath World (40:19.585)
you know, eight years old or teenagers like yourself back in the day. What would be your advice for young people who want to get into marine biology as a career?

Kim Holland (40:29.336)
that even though it might be biology and the behavior of animals or the strategies of plants to survive, if you're a biologist, by calling, for goodness sake, force yourself to do the quantitative sciences as well. Get your mathematics under your belt. Get your statistics under your belt. Because there isn't a modern marine biologist that doesn't require

very good level of skill in quantitative sciences. So it's important that in order to be a biologist, you also become at least a competent mathematician and a competent statistician so that when you get to advanced level of education, you can take that background and move into the modern world.

Polymath World (41:21.011)
Excellent, and if people want to know more about your work, where's the best place to find you? Where should they look?

Kim Holland (41:27.038)
Hawaii Institute of Marine Biology, that's University of Hawaii something. If you put in Hawaii Institute of Marine Biology and follow the links, you'll find us.

Polymath World (41:38.273)
Excellent. Thank you so much today, Dr Hollander. It's been a pleasure talking to you and I've loved hearing about your work.

Kim Holland (41:44.473)
Thank very much. enjoyed it too. Thanks a lot. Bye bye.