Q: How did you get into this field?
When I was a kid I loved all animals, I always have, I still do actually and I was really interested in evolution. I had questions like: Why are there 100,000s of species of beetles on the planet. I didn't have a particular group I was interested in, although I kind of thought frogs were cool and I liked worms. Anyway, in college I studied zoology at the University of London and I wanted to stay in London for my Ph.D. So I tried to find a professor who would take me on as his or her student, one who shared my interest in evolution. There was this chap at the British Museum of Natural History who was looking for a student that would study fish, a species of cichlid. They're amazing fish, they live in South America, Central America, Africa, Madagascar and India. He wanted me to study them particularly in Africa. I thought that was great, there were a lot of questions that interested me and it was a chance to go to Africa. So I jumped at the opportunity. And then it turns out that fish are magnificent. They are a great model to study evolution and biodiversity.
Back to Top
Q: What makes a fish a fish?
Fish have rayed fins, and are animals that breathe through gills, not lungs. They have limbs in the form of fins and these fins are spread out like rays. These features will generally nail down what we think of fish.
Back to Top
Q: How many species of fish are there?
Good question. No one knows the answer. It is always a good question if no one knows the answer. At the moment we know about 25,000 species of fish, but that is just the tip of the iceberg. Over 300 new species are discovered each year. We are really only beginning to discover what is out there, under water. There are more fish alive than any other vertebrate group.
Back to Top
Q: How are they related?
Another big question. That is what I spend most of my time doing, trying to figure out how they are related. Not all fish belong to the same family line. For example, lungfish are closer to humans than to fish.
Back to Top
Q: How long have fish as a species been around?
The first true ray finned fishes appeared in the fossil record around 350-400 million years ago. A lot of the coral reef fishes originated as a group probably 40 million years ago.
Back to Top
Q: If all fish were to die tomorrow, what would happen?
That is a really interesting question. The consequences would be terrible. First in many countries, the people would starve. In Southeast Asia and Africa fish is a huge source of protein. So we would suffer, but also whole ecosystems would suffer. Fish play an incredibly important role in balancing ecosystems. The world would be greatly impoverished and the world might not be able to function. Here is just one example. The coral reefs would be covered in algae, and then the coral would die. That could even change the climate of the world. That's another way that the loss of fish could lead to the end of the world as we know it. (see our coral reef article.)
Back to Top
Q: What do fish eat?
Fish eat everything. But certain fish are specialized, to eat a certain thing in nature so they don't have to compete with other fish. Some are omnivores (they eat everything). Some are herbivores (they eat only plants). And some are carnivores (they only eat meat).
Back to Top
Q: How do fish communicate?
In many different ways. Fish live in water which is very different from air. If I wave my hand in the air - you see it but you don't feel it. But you would feel it in water. Every time a fish flicks its tail or fins it sends waves of energy over very large distances. So fish have developed the senses to communicate with these distant waves. It's called distant touch. They use it for navigation, and for sensing their surroundings. Some fish use electric fields also. They can also hear and see just like us.
Back to Top
Q: How do fish poop?
They are just like us. It goes in one end and comes out the other. Here is an interesting fact. Parrot fish eat the algae in the coral. They crunch up the coral into fine white sand and the sand passes straight through them and out the other end. That's how these fish help to form the beautiful sand of coral beaches. Next time you're on a white sand beach, think about that - - you are sitting on fish poop.
Back to Top
Q: How do fish reproduce?
In many different ways, there can be a male and female fish who bring up their offspring together. Other fish change their sex. A male becomes a female or a female becomes a male. Some fish are both sexes, that is called a hermaphrodite. And then the fish fertilizes itself.
Back to Top
Q: What percentage of their eggs survive?
It depends. There are two strategies. Some fish put out 100,000s, even millions, of eggs at a time. Then the eggs and sperm are shed into the ocean, mix, and fertilize and they float off. The parent fish have nothing to do with the offspring. But only a very few survive. Then you can have a case which the female will only have few eggs. The female lays the eggs and the male fertilizes them and then she puts them into her mouth and they stay there till they hatch. She only lets them go when she can't fit them into her mouth anymore. Some fish even give birth to live young.
Back to Top
Q: In what kind of marine habitats do fish live?
Look at it this way. Do you know how much of the world is covered in water? 75%. In fact, the planet should be called Planet Water not Planet Earth, (but that's another story). Now 97.5% of that is ocean, salt water, and more than half of all the species live there. If you look at the number of individuals, it's the oceans that hold the wealth of fish.
The salt water holds 97.5% of all water on the planet and that means that only 2.5% is freshwater. Now over half of that is tied up as ice, 60%; 30% is ground water and about .3% is rivers, lakes and wetlands. But nearly half of all the fishes are fresh water. Only about .01% is fresh water habitat. (like a penny to a hundred dollars)
So, the real diversity is in the fresh water. The fresh water is where it's all happening. By the way - that small amount of freshwater is what humans use for drinking.
Back to Top
Q: Can fish live in harsh conditions?
Fish live in water, from the deepest part of the ocean to the highest mountain streams. So they live in a wide band of about 10 kilometers (6 miles ). There is nothing like that for any land animal. It is quite remarkable and that is why they are such a good group to study evolution.
They have adapted to living in the great depths where there is no light, it is very cold, and the pressure is just incredible. I mean, we would be crushed if we went down there, but they are able to adapt.
Back to Top
Q: How is the pollution affecting the fresh water fish? Salt water fish?
It is a crisis, really. Pollution is the worst around the coasts. Pollution around fresh water is becoming very bad. It is not just the pollution that we are putting in, it is also what we are taking out. Less fresh water means more salt water. One way you can see that is in the increase in cancer and tumors in fish.
Back to Top
Q: What do fish think of humans? What is their initial reaction to a human presence?
Good question. The fish that we haven't exploited are just as interested in us as we are in them. If you go to places where people have not been the animals are not scared of you. I think animals have to learn that people are a threat to them.
Back to Top
Q: Some humans are afraid of sharks. Is there really any reason to be scared?
Not really. In North America you have a better chance of getting killed by a pig or by being struck by lightning. But shark attacks do occur. There are 200-300 species of shark around and only a handful have been charged with attacks. Some sharks will threaten you if you are in its territory, using body language and arching its back. But we are overfishing sharks, so they have more to fear from us.
Back to Top
|
