A further example of endangered species is the shark. Around 40 million sharks are killed each year. That's quite a lot. Consequently the number of sharks is decreasing. So let's take a closer look at the causes of this.
Firstly, in recent decades sharks have become important. This is largely due to the growing popularity in some parts of the world for the consumption of shark - it has become a very valuable food source.
OK, so maybe you're thinking ‘Well, lots of other fish like cod, salmon or tuna are caught for human consumption and they aren't disappearing at the same rate as sharks.’ Well, that's true. But the difference here is sharks are not able to repopulate or reproduce themselves quickly like the other types of fish that are commonly fished as a food source. Why? Because sharks are slow breeders. Sharks mature slowly and it takes them years to reach the age for egg production and then they produce only a few eggs so that means just a few new sharks. Humans have a nine month pregnancy or gestation period whereas some shark species are thought to have extremely long gestation periods, as long as three years. This makes them much more vulnerable and in danger of dying out than many other fish species.