Sharks What do you know about sharks (familiar triangular dorsal fin cuts the surface; more than 300 types; similar species have existed for 400 million years; most are large, though some families are relatively small; no gas bladder, so they have to swim continuously; young hatch inside mother and emerge alive)? Are they all killers (many, such as basking sharks, feed on plankton; the great white shark in this picture could eat humans; about 25 people a year are attacked by sharks and far fewer die than in other marine accidents)? How do they attack (they can sense movement and detect blood in the water, for example from an injured fish speared by a diver; usually attack from underneath; may even kill each other)?

Fishing industry Which countries fish for food (90 per cent of fishing is in seawater, only 10 per cent freshwater, so especially islands, like Britain, and coastal countries; Mediterranean and northern European countries; Japan, North and South America, Africa; virtually all the world, apart from desert areas, when you include fresh water)? What techniques are used (dredging the bottom, often for crustaceans; using nets, either a single boat or a pir working in a circle; sonar and radar have made it more scientific; rod and line is very inefficient by comparison)? How can you “over-fish” when the oceans are so huge (more than 5 million people work in fishing worldwide; some people catch small fish, so they never reach adult size and do not breed; nets can kill other aquatic life, such as seals)?

Predators Are predators, such as sharks, evil creatures (no more than us, for we kill animals and fish to stay alive)? What is the opposite of “predator” (“prey”, but remember that most species can be both: birds eat worms and insects, but in turn are hunted by cats and birds of prey; we kill fish, but a shark could kill us)?

Writing Write a poem lamenting the ignominious death of this magnificent shark.

Should we protect certain species?

For “Survival of the fittest” is a cruel reality, but humans should intervene to prevent extinction. Diversity is important and predators have a right to exist, like other creatures. Once a species has gone it cannot be brought back. Only humans have the insight and the means to take the necessary action.

Against It is hypocritical to advocate protection of sharks when both we and they are killers. What will be will be. Intervention upsets the balance of nature. If earlier species had been artificially protected, or culled, we might never have evolved. When a shark dies, other fish thrive.

Ted Wragg is professor of education at the University of Exeter