Page 28 - World of Animals - Book of Sharks & Ocean Predators

Sharks & Ocean Predators
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Basking shark

This huge shark is equipped with an extremely wide
jaw and large gill slits, but is no threat to humans
Basking sharks are truly incredible creatures that use more than
1,500 gill rakers to strain plankton from roughly 1.5 million litres
(330,000 gallons) of water per hour. They are the second largest

fish species, growing to 10 metres (33 feet) in length. An adult
basking shark’s liver can weigh around one tonne (157 stone),
making up a quarter of its total body weight. It can live to the
grand old age of 100 in the wild. These sharks have unfortunately

been hunted in large numbers for their fins, liver, flesh and skin.

They are also vulnerable to attack from killer whales and tiger
sharks, as an adult basking shark can provide a hugely nutritious
meal for either of these two predators. However, a decline
in basking shark numbers is mainly down to human hunting.
Their cartilage is still used today in Chinese medicine and as an
aphrodisiac in Japan.

Dusky shark

Threatened by humans and eaten by other
sharks, the dusky shark’s population has
dramatically dwindled
Found in tropical and temperate waters, the dusky shark
can reach lengths of 4.27 metres (14 feet) and a weight
of 180 kilograms (400 pounds). Each year dusky sharks
embark on a voyage known to exceed 3,700 kilometres
(2,000 miles), as they swim towards the Poles in the
summer before returning to Equatorial waters for the
winter months. An unusual fact about the dusky
shark is that it takes 20 years for it to reach
sexual maturity, something that has
made the recovery of their struggling
population almost impossible, as it
has one of the lowest reproductive
potentials of any shark in existence.
Their population has dropped to
between 15 and 20 per cent of the

figure from 1970, due to the continued

shark fin soup trade and because they often
die after being accidentally caught by fi sherman.
Scientists believe it could take up to 400 years for their
population to recover.

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