Tuna: A Favorite Fish Faces Dangerous Depletion One of the biggest, fastest and warmest fish in the sea is also one of the most sought after, and one of the most threatened. Can bluefin tuna stocks around the world be saved? Experts explain the history of the tuna, and discuss tracking methods that might help preserve the fish.
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Tuna: A Favorite Fish Faces Dangerous Depletion

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Tuna: A Favorite Fish Faces Dangerous Depletion

Tuna: A Favorite Fish Faces Dangerous Depletion

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This is Talk of the Nation: Science Friday. I'm Ira Flatow and for the rest of the hour we're going to be talking tuna. But not Charlie the tuna, not the kind you'll find in the can or in your tuna sandwich. We're going to be talking about the giant bluefin tuna.

Marine scientists marvel at the bluefin's extraordinary qualities, it's a half ton fish that can swim at highway speeds, and the bluefins can warm their bodies to 80 degrees in frigid waters. But sushi lovers prize the bluefin for it soft buttery flesh. And this delicacy does not come cheap.

Now if you want to get into the bluefin tuna business, a single bluefin can command over a hundred thousand dollars, that's a hundred grand for just one fish on the market. And so for fishermen it's like winning the lottery each time they catch one fish.

But experts say we may be eating the bluefin into extinction. Is there a way to have our fish and eat it too? Well, joining me now to talk about the bluefin ten - tuna, and it's journey from the open ocean to the sushi bar is Richard Ellis, author of over a dozen books on the ocean and it's inhabitants, and this new book is called "Tuna: A Love Story."

He's here with us in our New York studios. Welcome to the program, Richard.

Mr. RICHARD ELLIS (Author, "Tuna: A Love Story"): Thank you, Ira.

FLATOW: It's a hard title to have a love story with a tuna.

Mr. ELLIS: It turns out that - excuse me - it turns out that everybody loves tuna for one reason or another.

FLATOW: I love it.

Mr. ELLIS: I love it. I love it. I have eaten tuna fish sandwiches and tuna salads.

FLATOW: Right.

Mr. ELLIS: I've eaten bluefin tuna as a matter of fact, but that comes later in the story. But I love it most, because it is such an accomplished creature. It is beautiful. It's strong. It's fast. It's smart. It has modifications that exceed those of any other fish in the ocean, and I actually am also a painter...


Mr. ELLIS: And so what I do is I paint the things I admire. Other people shoot them, some people fish for them. I paint them. And so I've paint - I actually painted the jacket illustration for this book.

FLATOW: Beautiful.

Mr. ELLIS: And I just think it is marvelous looking, so from one perspective anyway, I love the bluefin tuna, but everybody else does too...

FLATOW: Mm-hm.

Mr. ELLIS: Especially the Japanese who eat the fat-belly meat of the bluefin tuna to such a degree, that the fish itself is bordering on extinction.

FLATOW: Is that what we call Turo? That...

Mr. ELLIS: It's called Turo or Magaro(ph)

FLATOW: Mm-hm.

Mr. ELLIS: It is only a certain part of the fatty, belly meat of a bluefin tune. And as you said before, bluefin tuna can weigh a half ton or more. So when you recognize that what they're eating is a very small proportion of the entire fish, it's conceivable that most of this fish is being wasted.

FLATOW: Huh. They throw out the rest of the fish?

Mr. ELLIS: They don't throw it out, but isn't the high level tuna that commands these bizarre prices.

FLATOW: Wow, wow. Tell us a little bit about this fish. You say the fish can heat up its body to 80 degrees in 40-degree water.

Mr. ELLIS: Well, most fish as everybody knows, are cold-blooded vertebrates.

FLATOW: Right..

Mr. ELLIS: That means that their body temperature is the same as the environment in which they live. A codfish, say living in - off the Grand Banks in 40 degree water, has a body temperature of 40 degrees.

A butterfly fish living in the Caribbean next to a coral reef with a water temperature of 75 degrees, will have a body temperature of 75 degrees. A bluefin tuna, on the other hand, living in say 40-degree water, can raise its body temperature to 80 degrees.


Mr. ELLIS: It has a complex series of counter current exchangers in its circulatory system that warm up its muscles. Just think of an athlete warming up, but a tuna, a bluefin tuna is always warmed-up.

FLATOW: Mm-hm.

Mr. ELLIS: And so it is more competent than the fish it's chasing, it can swim faster than most things in the ocean. Tuna have been clocked at 55 miles an hour...

FLATOW: Gee whiz.

Mr. ELLIS: They can catch anything that swims.

FLATOW: Right.

Mr. ELLIS: Except, perhaps, a sailfish, which can swim 68 miles an hour. But that's all spines and pointy bits, and you wouldn't want to eat those anyway.

FLATOW: Right. So here's this creature that has all these marvelous modifications. Fins can be made flush with this body.


Mr. ELLIS: They tuck in to slits, its eyes are flushed with its body.

FLATOW: It's the perfect - not aerodynamically...

Mr. ELLIS: Hydrodynamical.

FLATOW: Hydry - hydrodynamic fish.

Mr. ELLIS: At MIT, they decided to try and figure out whether or not they could power boats by some means other than the circulating propeller. And since the tuna - this hydrodynamic marvel - wags its tail to move, they built a robo-tuna, they built a fish that wag its tail. And they thought, well, maybe we can apply this to ships, maybe this is the best way to go.

FLATOW: Right.

Mr. ELLIS: It turns out that they fail to replicate the speed or the hydrodynamic capabilities of the tuna, and they gave up. The tuna is better at what it does than MIT could possibly create.

FLATOW: Wow. 1-800-989-8255. Talking tuna with Richard Ellis, author of "Tuna: A Love Story." Let's talk about the life cycle of a tuna.

Mr. ELLIS: Tuna - first of all, female tuna lay anywhere from a million to three million eggs. They need to be a certain age and a certain size before they spawn, and that too comes later in the story. A tuna when it's born is about the size of a grain of rice. It increases in size assuming it gets to its full size...

FLATOW: Mm-hm.

Mr. ELLIS: It increases in size a billion times. ,It goes through obvious growth stages...

FLATOW: Mm-hm..

Mr. ELLIS: There are smaller ones, until they get to be large ones, they feed on various things in the ocean. And for the most part, when a tuna is the size of a grain of rice or the size of say, your little finger, most things feed on them.


Mr. ELLIS: So laying a million eggs doesn't mean you're going to get a million tuna.

FLATOW: Right. Right.

Mr. ELLIS: It means that some very small percentage will survive.

FLATOW: Yeah. I've seen wild kingdom, I know how that works.

Mr. ELLIS: The little ones become part of the plankton.

FLATOW: Yeah. Right.

Mr. ELLIS: And everything eats little tiny things in the ocean.

FLATOW: Mm-hm.

Mr. ELLIS: They eventually get to be a full size, which can - in the bluefin tuna - can be anywhere from a thousand to 1,500 pounds.

FLATOW: And when we catch them out at sea, how were they caught? They were in this size range.

Mr. ELLIS: Well, they're caught in many, many different ways. Off New England, they are harpooned like...

FLATOW: Really?

Mr. ELLIS: Yeah.

FLATOW: That big you use a harpoon on it.

Mr. ELLIS: Well, because it's illegal to catch them any other way off New England.

FLATOW: I see, I see..

Mr. ELLIS: In other parts of the world like the Mediterranean and Australia, they catch them in huge purse things. And they draw these purseins closed, and they catch thousands and thousands of fish at a time. But off New England, they - it looks kind of like a miniature whaling vessel.

FLATOW: Right. Right.

Mr. ELLIS: It has a big pulpit in the front. And a man is standing there with a harpoon. They spot a tuna and they drive after it, and the guy throws the harpoon.


Mr. ELLIS: And they pull in one fish at a time.

FLATOW: And in the Mediterranean, how do they get them back here, when you purse...

Mr. ELLIS: Well, first we have to catch them in the Mediterranean...


Mr. ELLIS: And this is probably the major problem with tuna. First of all, the Mediterranean is the breeding ground for the Atlantic bluefin tuna. Second of all, for several thousand years people have been fishing for bluefin in the Mediterranean. Early on they fished for them in what was called the Metanza, where they had a series of ever-decreasing nets, where the fish would be guided into the final net, where they'd then be hauled up and stabbed. Of stabbed or hacked to death.

This is virtually extinct now, this method of fishing been replaced by big purseins, where they spot them from the air, they spot huge schools from the air. They surround them in the pursein, they purse the net closed, they tow this whole net full of fish, there can be thousands of fish. They tow this whole net full of fish to a floating pin, they put the tuna in this pen, they feed them for six to eight...

FLATOW: How long a distance are they to them?

Mr. ELLIS: Well, in the Mediterranean, they could tow them five or 10 miles.

FLATOW: Uh-huh.

Mr. ELLIS: Because they know where to fish for them.

FLATOW: Right. Right. Right.

Mr. ELLIS: I mean, because they see them from the air, or they're spotted from the air. Then they put them in these pens and they fatten them up, they feed them fish.

Tuna don't eat fish food that you could buy in your pet store and sprinkle in the pen. So you have to have fish for the tuna, so in another words we're catching fish to feed the fish. And of course...

FLATOW: It's like a tuna ranch. They're ranching tuna.

Mr. ELLIS: It is. It's a feed lot of - mentality, in fact. And they fatten them up, and then they kill them, and then they ship them all to Japan. Every single country in or on the Mediterranean, Spain, France, Italy, Greece, Croatia, Morocco, Tunisia, Algeria, Libya - they're all doing this. And because they're all doing it and because the controls of this fishery are lax, there is something called ICCAT, the International Convention for the Conservation of Atlantic Tunas, and it puts out quotas and the Libyan fishermen and the Spanish fishermen and the French say thank you very much and they go right on fishing for tuna because the market in Japan is so intense.

FLATOW: 1-800-989-8255. Allan(ph) in Murrells Inlet, South Carolina. Hi, welcome to Science Friday.

ALLAN (Caller): Thank you. I had a question for the author about that very issue about other countries cheating on the international limits for blue fin tuna and what can be done to curb Japan's apparently insatiable appetite for this?

Mr. ELLIS: Well, those are two different questions. The cheating problem is almost impossible to stop. The World Wildlife Fund has recently called for a cessation of all tuna fishing in the Mediterranean. Even with that, even having called for that doesn't make it happen. And so there's still fishing because, now, this gets us to the second part of your question, because the Japanese market still exists. And the Japanese have what actually amounts to nothing but a fad. I mean, they don't need this. It's not particularly nourishing. They think it's particularly delicious, and so they want as many blue fin tuna as they can get.

In Tokyo, at the Tsukiji Fish Market, every single day, they bring in thousands and thousands of tuna and I've been there and I've photographed the fish market and as you look at this, it's not only tuna in this fish market, it's everything that ever swam in the ocean and as you look at it, you think to yourself, they must have vacuumed up the whole ocean. There can't be anything left and yet the next day, you go back and just like it was that day before, with thousands of tuna lined up in rows and these are the famous tuna auctions where one tuna was once auctioned off for 173,000 dollars.

FLATOW: Just for the little part of that tuna.

Mr. ELLIS: No, the whole fish. It was a 440-pound fish. And it was bought.

FLATOW: But they were looking for that fatty part of the fish.

Mr. ELLIS: Well, what they do at these auctions is they walk around and there's a piece of skin peeled back and they feel the meat with their fingers to see what the fat content is, they smell it and since they're going to eat it raw, they taste it. And this fish, the 173,000-dollar fish, was so perfect from the standpoint of the buyer that he was willing, and this is an auction, so somebody bid 100,000 dollars, somebody bid 100 and a quarter. They're Japanese, so they're not really bidding in dollars. But the fact is that it ended up being sold for 173,000 dollars because this man believed that when it was cut up into bite size pieces as it were, people would spend 100 dollars a piece for one these pieces. So the fish that was sold for 173,000 dollars probably ended up being a half-a-million-dollar fish by the time it got to the table.

FLATOW: It's a 5,000-dollar bite to taste that fish. Let's go to Judy in Portland, Oregon. Hi, Judy.

JUDY (Caller): Hi there. How are you?


JUDY: Hey, I've been to that market. I was telling the gal when I called in. It is amazing to see the amount of fish that there is out there. That people - I mean, it's amazing to think that people have got to have the blue fin because I was born and raised in Japan, blond hair, blue-eyed but you know, and so I've eaten Japanese food my entire life and I rarely eat the toro or the magro because of the fact that there's clams to eat, etc. And on rare occasions, I do. The sushi guy that I go to, who's you know, from Japan, he'll go ahead, I've got in some bodhi which is also fatty belly or the toro, you ought to try some, it's really outstanding and it's this pale, pale pink. It almost looks like you're eating a piece of beef. And it is very buttery. I mean, granted, it is really really good.

But you know when there are other things out there that I think are just as good. I mean, the stuff that's like a halibut or the different clams like the Gooey Duck Clam, the midu(ph) guy and different clams, Akagai and all these different of clams that maybe Americans aren't necessarily aware of that they should try. And of course, there's always (unintelligible) and my kids are like in their 30s now, and they know about the gaijing roll, gaijing means foreigner in Japanese. And the gaijing roll is like the Philadelphia roll where you get the cream cheese and the...

FLATOW: All right, Judy, we get the point. Thanks for calling. Have a good weekend.

JUDY: Bye.

FLATOW: 1-800-989-8255. Talking with Richard Ellis, author of "Tuna: A Love Story," on Talk of the Nation Science Friday from NPR News. And lots to talk about. Why can't we just farm the fish? Why can't we make a pen if they're being taken to a pen, why can't we make big fish farms?

Mr. ELLIS: We can. Well, it's been done. It's been done. The Japanese tried to do it for obvious reasons and they succeeded in raising a handful, literally, a handful of fish to market size. The European fishery is so intense that it isn't really necessary for the Japanese to do this. On the other hand, in Australia, in South Australia, there is a company called Clean Seas which is a fish farming organization. They have successfully raised yellow fin and another fish, I can't remember the name but they raise them in large tanks and they - this year in fact, in the calendar year of '08, they succeeded for the first time anywhere in getting blue fin tuna to breed in captivity.

While I was in South Australia, I went to research this book. I went to South Australia last year and at that point, I saw the facility, I saw this giant tank that they built which they can control the temperature and the light level to fool the fish into thinking they're in Indonesian waters and at the right time of year, because Tuna breed only once a year, at the right time of year, the tuna were supposed to say, oh good, let's have some babies now, dear. But in fact, they failed last year and so I finished writing the book last year, except that this year, in March, they succeeded. And what they've done is they've fooled the tuna. In other words, the tuna spawned. They've got these little tiny fry and they're trying to raise them.

Now, it'll be years before these tuna can be raised to market-size so it's impossible to say that this experiment has succeeded but there's no reason why it shouldn't, because these people know what they're doing and they know how to raise these fish. And so therefore, it is possible that this event in South Australia, which occurred in March of '08 will change the equation completely. It might not change it for the better but it will change it completely, because there will be something that can compete with the European fishery and it's conceivable. These people didn't go into it to save the tuna. They went into it to make money, but if you can create a whole lot of saleable tuna without having to go fish for them and shoot them in the head and whatever else you have to do, then you change the balance completely and it's possible.

FLATOW: They've shown that you can do it. They probably have a trade secret, I imagine.

Mr. ELLIS: When I went there. They were very careful to tell me no photographs. I couldn't even photograph the place from outside. I don't know why that they thought maybe I was going to sell their technology to the Japanese or the Koreans but in fact, I saw it. I saw all these pumps. I had no idea what they did. I saw this huge tank and we fed the fish in this huge tank and they are giant fishes. They are 700-800 pound fish that they, in fact, have raised from wild fish that they caught in the ocean.

FLATOW: We're talking with Richard Ellis, author of 'Tuna: A Love Story.' We're going to have a take a short break. We'll come back and talk. I'll ask more with Richard and also talk about an attempt to track the tuna around the oceans and maybe find a way to save them from extinction that way. With our taste for sushi it's getting worse out there. Stay with us. We'll be right back after this break. I'm Ira Flatow. This is Talk of the Nation Science Friday from NPR News.

(Soundbite of music)

FLATOW: You're listening to Talk of the Nation Science Friday. I'm Ira Flatow. We're talking about bluefin tuna. This is the fish, I think, most people have seen in the either a sushi or a sashimi in their local sushi bar. I'm talking with Richard Ellis, author of "Tuna: A Love Story." And our next guest has seen these massive tuna out at sea and she's tagged hundreds of them with small computers to track their movements around the world and hopefully, that research could help us in blue fin conservation efforts. And Barbara Block is the professor in Marine Sciences at Stanford University's Hopkins Marine Station in Pacific Grove, California. She's on the phone today from a conference where there are a hundred of scientists gathered to talk about tracking methods of all creatures - penguins, whales, elephant seals and of course, blue fin tuna. Welcome back to the program, Dr. Block.

Dr. BARBARA BLOCK (Professor, Marine Sciences): Hello. Glad to be here.

FLATOW: How is tagging going help up conserve tuna?

Dr. BLOCK: Well, our team has actually put over 2,000 tags in tunas in several oceans and the tags help us find out where tunas go when they're beneath the sea. So, for all of mankind or for all of time, we haven't been able to actually track tunas beneath the sea very well.

FLATOW: We don't know where they come and go?

Dr. BLOCK: Well, we did until recently and so what we've been doing is we have two types of archival or data or log or tags that are similar to taking, if you will, an IBM laptop, throwing it inside your local tuna and then letting them go again. So these tunas have been carrying around these tags and they're actually running a 17th century algorithm on 21st century tag. They're measuring sunrise and sunset and from sunrise and sunset, we can actually figure out the longitude and latitude of where the tuna is while they're beneath the sea.

FLATOW: How do you tag a tuna?

Dr. BLOCK: Well, what we do is we go out to places like the coast of North Carolina, down there at Morehead City. We're about to go up to Canada, and we work with fishers that are the best at finding out where the tunas are. But tuna, actually is caught on hook and line with a hook that's a special type of hook called a circle hook. We can pull a tuna as large as 1100-1200 pounds even into a boat, de-hook the tuna, put a hose in the mouth to keep the oxygen flowing over its gill and then we quickly either put an external tag on, that's called the pop up satellite archival tag, or we do a quick surgery with a local anesthetic where we were able to stick an archival tag, this little IBM-like computer, inside the tuna. I should say it's more like an iPhone in terms of its memory, and then the tag has external sensors, that sense the marine environment around the tuna. We let it go and then we tag the outside of the tuna with a simple spaghetti tag that says "if you find me," it's colored green, "we'll give you a big reward to get the tag back."

FLATOW: Richard Ellis, have you ever seen a tagged tuna?

Mr. ELLIS: Sure. First of all, let me say hello to Barbara. I think what she has done and is doing is one of the most important biological experiments being done because it is giving us knowledge that we never had before, that we never could have before, and the ability to tag and follow tuna, and understand where they go. We also, this also clocks their depth. We know that tuna now can dive to 3,000 feet, at the same time with monitoring their body temperature. So I think what she's doing is great.

Dr. BLOCK: I think it's great. You're there and I'm glad you're on the show and thanks for welcoming me. It turns out they can dive to deeper than that depth - (unintelligible) is actually they've hit our limits of 2,000 meters or 6,000 feet and it's a remarkable story. And I've been at a conference this week. Of all the biologgers in the globe, we had 20 nations, about 90 species being discussed, and gadgets were being put on a whole lot of animals and were opening up the mystery of our undersea world with these same electronics that allow us to talk to satellites on our telephones, we're actually able to get lots of information.

FLATOW: Does the tuna have to surface so that it hits the satellite?

Dr. BLOCK: Well, on the tunas, we're using two types of tags. So one tag is a recorder, or a data-logger. And it's actually just taking data, archiving it...

FLATOW: I see...

Dr. BLOCK: And we don't get it back until a fisherman catches that same tuna a second time.

FLATOW: Does he get a bounty for catching that tuna?

Dr. BLOCK: They get a reward for catching the tuna and returning the tag. So we have lots of tags coming back to us in the Atlantic, probably at this point 30 nations have returned 20 percent of the tags we put in the ocean of the Archival type, in the Pacific a whopping 50 percent of the tunas we tag have had their archival tags returned by about three nations.

FLATOW: And what did you give - what, 500 dollars, something like?

Dr. BLOCK: We give them back 500 dollars in the Pacific and actually a thousand dollars in Atlantic because they are rarer to find. The second type of tag we uses is as pop-up satellite tag, and it combines the brains, if you will, the controller of the archival tag that - it's put out on the outside of the fish. And on a given day, it could be your birthday, we program it to come up and what happens is a stainless steel pin, corrodes, through electrolysis. The tag floats to the surface with syntactic foam, comes up to the surface and then transmit its data to an earth-orbiting satellite.


Dr. BLOCK: Just like having your tuna phone home.

(Soundbite of laughter)

FLATOW: And you learn - I can't believe 6,000 feet, a diving - I mean that, how does it - you know - they ask - it begs all those same questions we wonder about seals and other animals that can dive so deeply and not be affected by the bends and things like that.

Dr. BLOCK: Right. Well fish are breathing with gills so they're not taking a packet of air inside them such as in their lungs. In the story of the tunas, what's remarkable is they go down a...

FLATOW: Pressure.

FLATOW: They spend time in waters as cool as ice water. And they actually come back to the surface quite fast.

FLATOW: They don't get squosen(ph) down there by all that water pressure?

Dr. BLOCK. No. Actually, they're sort of incompressible because they too are sort of a fluid, and without having lungs it isn't as much of a problem.


Dr. BLOCK: So some of the big picture questions for blue fin is that their warm body, as Richard said, they get to be as warm as about 85 to 88 degrees inside. They actually have hearts that are exposed to the cold water, so the real conundrum of tuna biology, if you will, when we're trying to figure out how they work is that their hearts are actually delivering blood to a warm body, and the warm body screams for more oxygen and more energy. And the heart actually can function over a much wider temperature range than our mammal heart.

FLATOW: Let's go to Jonah in Queen's, New York. Hi, Jonah.

JONAH (Caller): Hi. Thanks for having me. Two-part question. How did tuna originally get to have the appeal that it does? And is it they're only expensive now because it's rare?

FLATOW: Hmm. When did sushi first start? Has it been in the Japanese diet forever?

Mr. ELLIS: Well, you would think so. But in fact, it's a relatively recent innovation. Because up until the Second World War there were no such things as home freezers or even much in the way of refrigerators in Japan. It was only after the war when refrigerators and freezers were introduced that the Japanese could freeze fish. Prior to that they smoke fish or they pickled it, or they dried it. But the introduction of the refrigerators in the 1960s enabled them to freeze it and therefore store it for time and then introduce sushi. So sushi - this whole thing that you tend to believe the Japanese have been eating forever only began around the 1960s. And just think of this for a moment.

Now we can say that we're sushi and sashimi on the air here and everybody says, oh, yeah, I'd love that, my favorite Japanese restaurant is. But 40 years ago, even 30 years ago, most Americans - for most Americans the idea of eating a piece of raw fish was nigh on to disgusting, nobody wanted to eat raw fish. The Japanese started it, they exported the technology, they exported the menus. And all of a sudden it's become this enormously popular, enormously expensive thing.

FLATOW: And Barbara, what other kinds of research do you want to learn? I mean, you learned how deep this tuna can dive, what other things do you hope to learn from tagging this fish?

Dr. BLOCK: Well, yeah, here at Stanford and with the Monterey Bay Aquarium we have sort of two programs. One is that we actually keep tunas. I heard the discussion about clean seas where I have visited this year too. We actually have a land-based facility that's been operational since 1994, and we actually are learning about the tunas as Olympians in our land-based facility. They are one of the greatest athletes in the world. And from the tagging studies, what we've learned is a single tuna, no bigger than 30 pounds, can actually swim across the Pacific and back three times in the mission on its tag. Most of us would go into the cold water of Monterey Bay and not get very far, but the tunas in their warm bodied sort of missile shape are able to actually power themselves efficiently across the ocean. And we're learning where are their corridors, where are their forging grounds that might be equivalent to the watering holes of the African planes where are the Savannah's that they're feeding on. And for all of these areas that are sort of out of sight not in mind when they're - we're talking about the ocean. The tags are sort of giving us that view.

FLATOW: It's so bad you can't train a tuna. Because then you could put it in, you know, with one of these aquariums where they - they can't train a tuna.

Mr. ELLIS: Well, you can...

FLATOW: Why would you eat something that's, you know, doing all kinds of flips and swirls and things like that...

Mr. ELLIS: Oh, people do that all the time. And there are people who watch horses and cows and things jumping around. But, one of the interesting things is while you don't necessarily train them very well, at the Monterey Bay Aquarium there's what's called the outer bay tank which is this giant tank, this million-gallon tank. It's bigger actually than the tank at Clean Seas where they're breeding them. At the Monterey Bay Aquarium they have blue fin and yellow fin tunas swimming around. And for me, at any rate, you asked me earlier why I loved the tuna. I can stand in front of that tank for hours at a time - that's in fact the tank where they're now, today - have the fourth young great white shark. And it draws great crowds to look at, you know, this mini jaws. But most of the fish in the tank are blue fin and yellow fin tuna. And it is breathtaking, for some of us anyway, to watch them in that tank. And I've stood there for hours and watch them. And you can see them circling relatively slowly, tuna have to keep moving. You've heard about sharks...

FLATOW: Yeah, yeah.

Mr. ELLIS: But that doesn't always works for sharks but it certainly always works for tuna. If you trap a tuna in a net and it can't keep swimming, it will drown. But I will watch them - and Barbara has a much better opportunity when she's not at sea because she's a lot closer to the Monterey Bay Aquarium than I am - although I'm going to be there in October. The fact is that I watch them and I watch them circling and suddenly, bang, a fish that used to be there isn't there anymore because for reasons known only to this tuna, it accelerates instantaneously, and you think, wait a minute, this can't be happening. I was just looking at that fish, it's not here anymore. Because they are so powerful and so fast - I love the description of them being Olympic athletes because they are better at what they do than any other fish.

FLATOW: Barbara, are you as passionate about doing it as Richard is?

Dr. BLOCK: Well, I'm sure. I think that we'd be in the same ball park so - Stanford and Monterey Bay Aquarium working together has brought this view of blue fin as well as the white shark that we can see today at the Monterey Bay Aquarium, and there's life at the open sea. And now millions of people can come by and see the beauty of the color, the form, and the gorgeous way that they swim because we have this open-sea tank that we've helped with the science and the aquarium with their tremendous knowledge of animal husbandry together - put together.

FLATOW: Talking about tuna this hour on Talk of the Nation: Science Friday from NPR News. I am Ira Flatow talking with Richard Ellis, author of "Tuna: A Love Story" and also with Barbara Block. I will see if we can get a phone call or two in here. Let's go to Amy in Chandler, Arizona.

AMY (Caller): Hi. Thank you for taking my call. I have two quick questions. I was curious as far as the farm-raised tuna. If they're as good to eat because my experience with salmon, all the farm-raised salmon from, I guess, the Atlantic aren't near as good. I am originally from Alaska. And from what I've heard, that they actually pump red food dye coloring in the farm-raised because they don't eat the natural crustaceans that actually turn them, you know, same as the flamingos that's how they get their color. And the other quick question is as far as their body temperature, are they actually warm-blooded or can get up to 85-88 degrees because of the pure fact of being able to swim very fast.

FLATOW: We are running out of time so ... Richard, do you have any answers about the food and how they taste?

Mr. ELLIS: Well, the first question I need to answer, is that they haven't succeeded in raising farm-raised tuna yet so we don't know how they're going to taste. I can't answer how they do taste or how are they going to taste. As far as the second question is concerned, they are essentially warm-blooded fishes. They're not mammal, they're fishes, and this doesn't - the fact as they breathe with gills, they breathe water after all. That doesn't make them mammals. They are able, by the way, to raise and lower their temperature at will. They're not always swimming at 88 degrees. If it's not necessary they can lower their body temperature, which is itself a miracle and something to marvel at.

FLATOW: So, Barbara, what would you like to know about the tuna that you don't know yet?

Dr. BLOCK: That's a tough question. What would I like to know? We don't know enough about when and where they spawn. And critical to protecting the remaining blue fin tuna in the Atlantic Ocean is really pinpointing the whole story of when a giant blue fin tuna literally has sex. So we're really interested in knowing where is the spawning occurring? When is it occurring? And how then we can actually protect this spawning (unintelligible) so that blue fin tomorrow are here on Earth.

FLATOW: Richard, what would you like to know?

Mr. ELLIS: I would like to know that the blue fin tuna is safe. I would like to know that this marvelous creature is not the subject of an insane Japanese fad to eat them out of existence. I would like there to be a device, whether it is a conservation device or a scientific device, some way of assuring that my grandchildren will be able to see blue-fin tuna. I don't care whether they eat them or not, but see them.

FLATOW: Is this the same tuna that we pedestrians eat in the sushi shop? What like - a different kind of tuna, I want to make that clear to our listeners.

Mr. ELLIS: No. What you eat in the sushi shop, even if it's reddish in color, is yellow fin or big-eye tuna. Blue-fin tuna, by in large, makes its way almost entirely to Japan.

FLATOW: That fatty-type of fish that we don't see very often. Well, good luck to you, Richard.

Mr. ELLIS: Thank you.

FLATOW: Thank you very much for joining us. Richard Ellis, author of Tuna: A Love Story." And to you too, Barbara Block. Thank you for taking time to be with us.

Dr. BLOCK: Thank you.

FLATOW: She is Charles and Elizabeth Prothro - a Prothro professor in Marine Sciences at Stanford University's Hopkins Marines Station in Pacific Grove, California. That's about all the time we have for this week. To Greg Smith, composed our theme music. We had help today from NPR librarian Kee Malesky. Surf over to our website at sciencefriday.com. We've got those new videos up this week. A great one about the butterflies whose eyes shine in the dark, though you want to see that one. Also you can send us email there or send us regular mail, Science Friday 4W 43rd St. Rm 306, New York, New York, 10036. And also we're blogging and podcasting there. You can download all our video and audio podcasts. Have a great week. We'll see you next week. I am Ira Flatow in New York.

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