FACTORALY - E4 FISH

Episode Date: September 21, 2023

One of our favourite fellow podcasts is not about fish, even though it's named after them. This differs in one particular aspect in that it's all about fish. Hosted on Acast. See acast.com/privacy for more information.

Hello, hello, hello! Hello everybody, welcome, welcome and welcome. To all, no, seven. Oh, do you know what, I'm beginning to lose count actually we've got listeners coming out of our ears this is factorally indeed it is and he's simon wells and he is bruce fielding and we are going to talk to you about facts so bruce and I very much enjoy facts. We like useless information. We like researching things. We're that annoying chap in the pub who puts his hand in the air and goes, ah, did you know? Yes. We also like the sounds of our own voices, but that's not really surprising.

It's not surprising that we are both voiceover artists and we spend a vast proportion of our time sitting in a small space talking to ourselves um in padded spaces padded spaces surrounded by expensive microphones and uh and tech yes and so on so every week we take a different subject we've had all sorts of interesting subjects in the past but today today we're going to be talking about fish. Well, that is a very, very different kettle of fish, isn't it? Why is it called a kettle of fish? Why a kettle? I don't know.

Why is it called a kettle of fish? I don't know. It's called a kettle of fish. So this is a copper kitchen receptacle that you lay a whole fish in. You put water in the bottom uh the water boils it steams the fish so it's a fish kettle it's a kettle of fish i've seen those i've never used one i've never used one either but we are going to have to get to the culinary bit of fish at some point yes it's quite a big factor of the whole topic isn't it so let's start with let's start with them when they're still alive so fish um

the the definition of the word fish is it's quite vague but it's a creature that lives in water and breathes through gills and uses fins and a tail for swimming so that could apply to quite a lot of creatures and um the the etymology of the word fish comes from the latin word piscis which gives us the star sign pisces it gives us the french word poisson even indirectly it gives us the word porpoise and piscatarians piscatarians um and it gives us fish which obviously sounds nothing like it but we are english and we change and we morph and we end up i guess unless it starts with PH. Now, fish is a bit of a sticky topic

in some circles. Some would claim that there is no such thing as a fish. I've heard this. Which apart from being the title of a podcast, which both of us enjoy listening to. Definitely. It is a scientific debate that goes on

that this term fish is just so, so broad. And all of the creatures that we used to just call a type of fish have been classified, reclassified, given very, very technical scientific names until there's such a point now where there's no real need scientifically for the word fish. I mean, when the word fish applies to creatures so diverse as a starfish, a jellyfish, a crayfish, a shellfish. Excuse me, can I just stop you there? You may. A jellyfish isn a crayfish, a shellfish. Excuse me, can I just stop you there? You may. A jellyfish isn't a fish.

Well, precisely. Actually, neither is a starfish. No. And neither is a crayfish. No, exactly. That's the point. The word fish, going back to about the 14th century, the word fish was a generic word for pretty much any animal that lived in the sea.

But a seahorse is a fish, even though it's not a horse. Hang on a second, Bruce. What are you saying? There are horses that are fish, but there's jelly that isn't. Great. Yep, fine. So you can see why scientists don't really like using the word, because it's a bit vague and it's a bit broad and it's not specific enough which has led to some scientists saying there is no creature that you can point

at and say that is a fish and nothing else therefore fish don't exist but if they did exist there would be a lot of them yes do you know how many how many fish in the sea? I know there are always plenty more. But I think there are about 30,000 varieties of fish or something. That's a lot, isn't it? It's an awful lot of fish. And of that 30,000 different types of fish around the world, do you know how many different species we have around the UK coasts? I have no idea. Just 300.

So where are the other 29 700 living elsewhere um this this this planet has quite a lot of water on it so um there is an awful lot of space for those fish if indeed they are fish to live well technically i guess they live in the in a bigger environment than the environment that we live in. Because not only are they sort of just the surface area, they also go down quite a long way as well. Absolutely, yes. They've got a lot more, I was going to say they've got a lot more ground to cover, but that's completely the point. They don't. They have a lot more water to cover than we have ground to cover. They do.

They do. And you see them in vast numbers in some places and then none at all in others. Yeah, absolutely. And they're so diverse in terms of their size, shape, colour, physiology, everything. Some of those deep sea fish look really weird. They do, don't they? Yes. There are species of fish that have become blind over the generations because they live in such dark places that they've

evolved to not need their eyes. But generally, I think fish have really good senses, don't they? They can hear really well. They can see really well and smell really well. Yes. Yes. That old thing about a shark being able to smell one drop of blood in 100 gallons or whatever it is of water.

Yes. It's quite impressive. Very. And sharks, of course, come under the... They're fish! They are fish. Whales are not, because whales are mammals. Which is defined as? Something different.

I think it has to give birth to live young and then suckle. That seems reasonable. Yes. So whales are not fish. But the whale shark is a fish. Yeah, I know.

It's a headache. And the whale shark is in fact the biggest fish hey in uh in the world um whale sharks have been known on occasion to grow up to 18 meters in length from tip of the nose to the tip of the tail that's that's quite big if i saw one of those coming i would worry so that's the the largest fish um the whale shark by contrast the world's smallest fish is really difficult to pronounce. So we're going to try. I'm going to try anyway it's called the pedocypress progenetica. Wow. You can correct me if I'm wrong. Okay. So we've done the big fish, the little fish. What we should really do now… Something about cardboard boxes.

Yeah, absolutely. And this little fish, this P. docypris progenetica, is roughly 10 millimeters in length. So less than half an inch. It's about a fingernail. And these are found off the coast of Sumatra and the UK. I didn't realise this. Did you know fish don't have eyelids? Ah, so they can never blink.

Sorry, most fish don't have eyelids. Sharks, for some reason, do. But the vast majority of fish don't have eyelids. So they never enter a staring competition. Never enter a staring competition with a fish. And this is because eyelids in land-living creatures such as ourselves, eyelids are there to moisten the eyes. And what with living in water, fish's eyes are moist the whole time and therefore they don't need eyelids. That never occurred to me.

That never occurred to me either. there you go that's amazing so no eyelids no eyelids um and lay eggs they lay eggs yes they um they breathe through gills do you know much about gills i don't so gills are um they are sort of a fibrous strand like organ they sort of look a bit like the strings of a harp and they they sit just under the the flank the side of the the fish and the fish takes a large mouthful of oxygen rich water it passes over the gills and the gills have blood running through them and by some form of osmosis the oxygen from the water seeps into the bloodstream circulates around the fish and then the water that's just had the oxygen removed from it is passed out through a small hole behind the gills back into the

water. Well and that can be seawater or freshwater I guess yeah I guess so yeah there are different species of fish that prefer to live in one or t'other but the principle is the same I don't know how the saltiness or lack thereof affects that process no I wouldn't I can't look it up either but maybe you get saltier air

maybe you do get saltier air if anyone knows the answer to that yes in the comments it's what the comments are for we we love learning as much as we love boring the pants off everyone we know with this trivia so um if you know something we don't know please tell us there are fish that can you know like talking like a fish out of water there are actually fish that can survive for short periods out of water. There's a fish called a mudskipper that can actually walk on its fins from place to place, like from one body of water to another body of water on land.

Really? And it kind of like, it holds water in itself. It's almost like wearing an astronaut suit full of air. It kind of wears an astronaut suit full of water and it just holds this water in and re-oxygenates while walking across land. Mudskippers. Brilliant. Weird things. Huh, interesting. And then there's the flying variety of fish.

Yes. Which don't fly. No. But they swim very, very fast up and out of the water. Their fins look vaguely wing-like. They do sort of glide a bit. They glide a bit, but not much. And then plop back down into the water again.

Yes. But they look lovely when you're on a boat and you see a whole shoal of flying fish coming past you. Shoals are interesting, actually. I was just going to say, you've just said the word shoal. Is there a difference between a shoal and a school? Ooh. Because fish gather in both.

Is it just a mispronunciation? I think it's probably just British people. You know how we sort of like anglicise words? We do that. It's probably officially a shoal. Yes. Officially. Somebody in English said.

Officially. that probably it's probably officially a shoal yes and officially somebody officially somebody english i can't i can't be bothered to pronounce show let's call it a school school sounds a bit like school i know the word school that works yeah so but they're they're defensive generally aren't they shoals they are yes so the the point of a shoal is that um they're defensive generally, aren't they, shoals? They are, yes. So the point of a shoal is that they exist for the greater good. What's the word for it? Sort of herd immunity. If a predator is going after a single fish, it will win. If a predator goes after a shoal of several hundred fish, it might only capture a couple of them, and the majority is kept safe so it's a form

of protection in groups safety in numbers um and the way that the the shoal of fish move around it sort of confuses the predator into thinking that it's one entity rather than yes hundreds so you see a dirty great thing coming at you yeah I think I'm not going to tangle with this. Absolutely, yeah. And if you sort of see footage of a shoal of fish suddenly moving, changing direction, the way they reflect light, that's one of the purposes of a fish having scales.

So the scales of a fish help to protect it, a little bit like armour. They help to make it more aquadynamic they help to make it more uh aqua dynamic is that the watery equivalent of dynamic yes yes helps them swim faster and they can really go for it actually tuna i think goes about 70 70 70k so about 45 miles an hour yeah's quick, isn't it? That's very quick. Gosh. But the scale thing is interesting because people have found uses for scales. If you ever see somebody in lipstick, the likelihood is that they are wearing fish scales. Right. Because they use a lot of fish scales in lipstick to make them to make it shiny

do they huh but we use we do use bits of fish for all sorts of interesting things my my favorite thing which i discovered only recently is that because fish live in a in generally in cold places i mean that the sea is cold and the deeper you go the colder it gets yeah and generally it's below sort of freezing yeah and because it's salt water it doesn't freeze at that freezing point it's sure freezes lower than freezing point but the fish have to defend their blood from freezing you don't want to you don't want your blood to freeze so fish fish have actually developed an ice-structuring protein, which stops their blood from freezing. Interesting. And Unilever have actually decided that it's a really good idea to take a clone of this protein and use it in the manufacture of ice cream.

Because if you use it in ice cream, ice cream doesn't then melt at quite such high. It actually melts at a lower temperature because it's using this protein. So if you've got your Magnum or your Cornetto or something, the reason why it doesn't just melt and go all over your fingers immediately is because it's got this protein in it that keeps it icy and cold for longer. Well, I never knew that. There's lots of other things we don't know. I mean, fish are weird because we know quite a lot about fish,

generally from catching them and eating them. But there are certain things that we don't know that human beings have spent a lot of money on finding out where eels come from. And eels are so fascinating. Eels, especially European eels. European eels are wild. I could do a whole episode on eels. They are so good.

For years and years, since the Greeks, since Aristotle and Pliny and that lot, eels have been fascinating people. Because they don't appear to have any reproductive organs. And yet there's always eels. Oh, okay. So how does that happen? Magic. And where always eels. Oh, okay. So how does that happen? Magic. And where do eels breed? It was believed that they were magic or that the way that eels bred was that they scraped against rocks and bits of eel would turn into fresh eels.

Okay. There was all sorts of beliefs about eels and they had magic powers and you could wear a coat of eel skin and that would protect you from the dark forces. And there's all this wild stuff about eels. And it was only kind of reasonably recently that people started to go, well, actually, where do eels come from? And it was the mission in life of a guy who was Danish. I mean, the Danes eat a lot of eels. Right. And this Danish guy was so passionate about it. who was Danish. I mean, the Danes eat a lot of eels. Right, okay. And this Danish guy was so passionate about it,

he spent every penny he had trying to find where eels went to breed. Oh. And then he got married to his boss's daughter. Right. And given that he worked at the Carlsberg Brewery, his boss had quite a lot of money. And so did the boss's daughter.

So he spent millions. But whenever you have a bottle of Carlsberg, think of an eel. Because that's where a lot of the money went, was to find the source of the eels. And where he managed to attract them to was the Sargasso Sea in the Atlantic. This is a sea within a sea and the sargasso sea is about the size of germany france and the uk combined it's huge and so mapping it to try and find out the exact spot where eels went to breed was practically impossible and eels also have a weird life because they change from being these little sort

of like centimeter long things to your this is european eels right um to then they become um an invisible fish they're sort of like these trans translucent fish oh really and then they go from translucent fish into sort of like a yellow eel and that's when they're sort of growing up and then they eat everything they can until they get to the point where it's time to go and spawn again and then they turn into these silver things which then go back to the sargasso sea and they haven't at this point got any reproductive organs but on the swim back from europe to the sargasso sea they grow organs that's when they grow all the bits that you need

to reproduce incredible they spend however much of their life it is genderless and it's only on their way back to reproduce that they suddenly start growing the reproductive organs to do the job yes and this is why they were so popular amongst ancient Greeks and people in medieval times. It's because they were seen as pure. They were seen as something which was not led by their sexual desires. They had no sexual desires because they had no sex. Yes, yes, sure. And whenever I think of eels, I always sort of think of the fens, you know, around sort of Cambridgeshire going into East Anglia.

Yes. And the mysticism and the eeriness that sort of is represented by that place. So I suppose that sort of goes hand in hand with that landscape, doesn't it? It does. And they are amazing. I mean, they are huge. They used to be food that, you know, that was everywhere. And it was very cheap.

They're now one of the most expensive foods you can buy. Really? Which has meant that there is a massive trade in illegal eel smuggling. Illegal eel. Illegal eel. That's a good tongue twister for the day, isn't it? So this illegal trade in European eels is worth about £2.5 billion a year. No.

Yes. And people smuggle them in from Europe into Japan in suitcases, in crates, in whatever they can find. It's so valuable to have eels. They're one of the most valuable things you can smuggle after drugs. And yet, I think of eels as being a very common food sort of the preserve of east londoners for generations you know they were but now they're getting deal pies and things well one of the things that's happening is because the smugglers are culling the young eels and not letting them get back to the sargasso sea to breed um they're becoming more and more rare although interesting they're now that

they know about this smuggling trade they're they're cracking down on it so that the eel population is rising again but it was shrinking quite significantly because of this eel smuggling wow do you know um do you know what a young eel is called i do but tell me it's called an elva isn't that lovely that's a nice word elva elva's great uh the latin name for an eel is anguilla anguilla right eels are also i mean they're very long lived they can live up like up to 80 years well um they can live you know obviously they get eaten and what have you all There's all sorts of shenanigans. They can switch from being freshwater to seawater. Okay. They come as little as like five millimeters long and as long as three meters.

Oh, my goodness. So a decent-sized moray eel is nine foot long and weighs about the same as me. And I'm not small. That's impressive, isn't it i know they're just it's just a massive there's something like 800 species of eel crikey i mean we talked about you know how many species of fish there are of those species 800 of them are eels who'd have thought i did yeah i'd sort of i picture an eel and i picture a moray or a conga i guess yes and that's about it big well they all work in terms of the way that they hunt they all hunt the same way which is they basically hide

and then leap out at fish and crustaceans and stuff yes and and well i i've had a moray leap out at me that's quite frightening when you're scuba diving but nasty yeah you want to stay away from the mores oh with with my with my fear of snakes, I think eels are a little bit too close to snakes for my liking. Yes. The way they swim is quite... They swim in the same way that snakes move, which is they undulate, which creates a wave in the water, which propels them forward. But an eel can go as fast backwards as it can forwards because it just has to undulate the other way. Does it the other way? Yes.

Yeah. Oh, that's great. I have to say that researching eels has been very, very enlightening. I'm now fascinated by eels. I think you've made more out of the eel section of this than the whole of the rest of the fish section. You've suddenly come to life whilst talking about eels no one has ever found a european eel egg in the wild ever really yeah i mean that you can farm them you can take the sure you can take the eels out of the sea and put them into a into a farm

yeah and you can have farm deals and that's fine yeah but no one's ever found a wild egg no wow god slippery little things well you you say that they were cheap food but actually in medieval times you could use eels to pay your taxes they were they were so valuable really so dry deals were used to pay taxes there was a case in a in medieval britain in a village had to pay the the guy who owned the village that the earl yes um i think it was 75 000 eels was an that was an annual rent for the village wow that's i mean that's that's quite a large tank of eels, isn't it? Well, they were tried. So I guess you can spend the year catching them and drying them or whatever and then give them to the lord of the manor as your rent fee.

I'm purely hypothesizing right now, but having mentioned the fens of Cambridgeshire, I wonder if there's a connection between the word eel and the city of Ely. Do you suppose Ely is named after the fact that there are lots of eels nearby? Could do. I don't know. Let's say it is. If anyone can confirm or deny that, please drop it in the comments. That's what the comments are for.

Yes, and we'll probably find that there's a lot of people who are into eels who comment hugely on the fact that I'm wrong about most of this stuff. Which we welcome. Yes. We're not experts. We're just two chaps having a natter like you would down the pub, getting it wrong. About fish.

About fish. Exactly. Which we knew very little about until we started to do some research. We knew a lot more. Apart from the fact they were delicious. Yes. We could talk about dangerous fish. Oh, go on then. In fact the eel um is also poisonous it can take you it'll send you into anaphylactic shock if you eat raw eel oh um because it has a

toxin in it which is um the toxin is um eliminated by cooking Okay. So a cooked eel, not a problem. Raw eel. So it's there to put predators off. Yes, exactly. Biting into it. Yeah, so that's not a nice thing to eat. But there are also things like lionfish, which are hugely poisonous, and stonefish, which are even more poisonous,

that live more in the warmer waters of the Caribbean and Indian Ocean. And jellyfish, which aren't fish. That's true. Have you ever been stung by jellyfish? I haven't, but I've heard it's not comfortable. So we don't know very much about fish at all, but there are some fish that we know quite a lot about, generally because we eat them. And one of those is salmon.

Right, OK. And there's lots of different types of salmon there's chum and pink and chinook and sockeye and and coho but but they all have this thing where they return to where they were born yes to to spawn again yes um we we both live fairly close to the river river thames in different of it, but quite close to the River Thames. And in my neck of the woods, there are a series of what they call salmon leaps installed, which are sort of, I guess they're kind of like staircases with water running over them that help the salmon to go around locks and weirs and things

in their journey back upstream to where they come from in order to breed. So we've moved on from the live ones to the dead ones, which we consume. As a nice little transition, I started looking at how much fish do we consume, where does our fish come from, all that sort of stuff without getting too political or anything. The majority of the fish that we catch around British shores is sold off to elsewhere, mostly to the EU, and the majority of fish that we eat in the UK comes from elsewhere, largely Sweden, Denmark, and Germany. I don't know why that is, but it's an interesting thing.

Yes, I think that the Norwegians have actually been quite clever about the use of their fish, because their fish generally don't have parasites. And in fact, there was a very clever, I think he was Norwegian, salesman who went to Japan and tasted some of their sushi. And went, oh, this is nice. And they said, oh, that's the hardest. We never really have salmon sushi because there's so many parasites in salmon

that it's impossible to make it into really good sushi. the norwegian guy said norwegian salmon doesn't have parasites really and the japanese went this is very interesting and from that conversation something like 20 of all norwegian salmon is shipped to japan wow and we now it's now quite common to salmon in sushi, whereas a few years ago it actually wasn't. So, yes, eating fish. In the UK, we have over 10,000 fish and chip shops. We spend £1.2 billion a year at fish and chip shops we spend 1.2 billion pounds a year at fish and chip shops

and we consume a rough a rough number of 167 million meals of fish and chips per year in this country i think that sounds reasonable yeah so that's me what about you? My local chippy here in Shepparton has a sign outside it saying Fish Friday, which I didn't used to think anything of. It's a nice bit of alliteration. You can have fish any day of the week, obviously. But the more I've thought about it, the more I realized Fish Friday is actually a thing, that people frequently eat fish on a Friday. And I hadn't really realized this. I just thought it was a marketing ploy by the fish and chip shop. But I started looking into it, and it turns out

it is a Christian thing, because in a Christian faith, Jesus was killed on Good Friday. And out of a mark of respect, early Christians decided not to eat meat of warm-blooded animals on a Friday, which left them rather conveniently open to cold-blooded animals. So they started eating fish on a Friday. And this has just carried on. It's sort of become a tradition, particularly in the Catholic world. When Henry VIII had his little bit of a tradition particularly in the catholic world when henry the eighth had

his little bit of a tiff with the roman catholic church um he decided to completely abolish that you know this this is a popish dish to eat fish on a friday we're going to scrap that all together so he stopped fish fasting by a matter of law and it wasn't until his son edward took over that fish fridays came back into place. And they've been there ever since. Aha. Now, another area of fish that I had a little bit of a look into was pet fish. Aha, yes, the tank.

The tank, the fish tank or the fish bowl. So we as a nation appear to be quite keen on keeping fish. I've never owned one. I've never seen the attraction of it. But apparently this country, 4 million UK households own a pet fish. Is that probably goldfish that they won at the fair or something? Well, quite possibly. But it also includes tropical fish, which are a really serious thing these days.

Buying the equipment, the tank, the filtration systems, the correct food, identifying which fish is right for your environment, and so on and so on. It's quite a big industry. And we spend, apparently, as a nation, we spend £400 million to £500 million a year on pet fish ownership. Goodness me. Something I found out about goldfish is that their size is dependent on their environment ah so if you have one in a fish bowl it's never going to grow out it's never going to outgrow the fish bowl precisely if you release a goldfish it will grow um and quite a few goldfish have been

released you know as you say the goldfish has been purchased at the fair or given as a birthday present the novelty is worn off the fish has been ceremonially released by flushing it down the toilet um and they're not always dead you know no precisely when they're floating yeah because they have a float bladder and if they get an infected float bladder that they float. But they're not actually dead. So sometimes you'll see a fish that's kind of got an infection. Right.

And you're going, oh, poor thing. Flush it down the toilet. Give it a Viking funeral. And then it suddenly recovers. And wherever it gets to, it's going to recover or die. Right. Because those infections, those flat bladder infections can be. Well, apparently the ones that don't die of the bladder infections, the ones that are released and let out into the wild, they seem to do quite well. When they're not confined by the goldfish bowl, they can reach up to two feet long.

In the sewers? Sewers, which eventually lead out to rivers. Rivers, wow. They can be quite dangerous in the wild because they eat a lot of things and they can ruin the biodiversity of the local area. Goodness me. So don't release your goldfish, Bruce. Or if you do release it, release it into the ground

rather than into the water. Yes. And on the subject of goldfish, we all know the wonderful fact that goldfish only have a memory of three seconds and is that true uh no it's not it's not at all um again maybe whilst they're swimming around in their bowl looking a little bit gormless um perhaps it's it's sort of understandable but um an american student as part of her second year university studies um did an experiment with her pet goldfish and she created a little maze um to put in the the fish tank and she encouraged by way of putting food here and there she encouraged her goldfish

to swim through the maze in a particular way and um doing this over a period of time she she found that this goldfish had a memory of up to a month because after a month it was still going the same route through the maze even after she'd taken away the treats um so that whole thing of the three second memory is is not necessarily true unless she just had a very intelligent goldfish so this thing about goldfish not having a good memory is that that true? Well, no, it's not actually because there was a student who went, hang on, we've been here before.

I think that's a brilliant place to stop fishing. I think it is. I think it's high time we stopped carping on about all of this stuff. Oh dear. Are we in the right place though? Oh, nice. Well, there we go then. So thank you to all of this stuff oh dear um are we in the right place though oh nice well there we go then so thank you to all of our listeners and don't forget to do the usual bits and pieces which are

simon uh clicking liking subscribing commenting telling other people uh you can even visit our website at www.factorally.com where you can find all of our previous episodes ready for you to listen to at your leisure. Marvellous. So thank you very much for listening. See you all next time. Bye-bye now. Bye-bye.