BEST IELTS Academic Reading Test 431

BEST IELTS Academic Reading Test 431

IELTS Academic Reading Test

Blue Sharks

A. The blue shark inhabits a great diversity of areas around the world. It dwells in temperate, tropical and subtropical waters up to 350 meters deep and is found near all coasts except those of Antarctica. It concentrates mainly in latitudes between 20 degrees and 50 degrees north and likes waters with temperatures of between 7 degrees and 16 degrees centigrade, although it can tolerate warmer temperatures slightly above 21 degrees Celsius. It likes approaching shores, where divers and boats see it often. The blue shark inhabits the shallower zones near the coasts and the continental shelves, but if it dwells in tropical waters, then it tends to be found in deeper waters.

B. The blue shark is a carnivorous predator that feeds on about 24 species of cephalopods and 16 species of fish. Its diet includes octopus, squid, mackerel, tunas, lobsters, crabs, small sharks and occasionally seabirds. They usually seek to catch small prey, but if they find large mammal carrion, it will become part of their food. The blue shark surrounds its prey before attacking it. When needed, it joins with other sharks of the same species and cooperates to attack larger prey and facilitate its capture.

IELTS Academic Reading Test

Its swimming speed and its triangular teeth help the shark to tear the skin and flesh of the most complicated of animals. Because it is rather easily excited by the presence of almost anything perceived as prey, the blue shark has made some attacks on people, establishing notoriety amongst divers. As in other shark species, there are rows of teeth present, each row being in a progressively different stage of development. As the front teeth fall out or break, new ones replace them from the next row.

C. Many sharks are solitary, but blue sharks live in small groups called schools. Some of these groups consist only of females and others consist only of males. Within each group, there is a certain order, with the largest member often being the leader of the group. They travel in these groups for protection and they also often hunt in groups.

IELTS Academic Reading Test

D. Blue Sharks are highly migratory with complex movement patterns and spatial structure related to reproduction and the distribution of prey. There tends to be a seasonal shift in population abundance to higher latitudes associated with oceanic convergence or boundary zones, as these are areas of higher productivity.

Tagging studies of blue sharks have demonstrated extensive movements in the Atlantic with numerous trans-Atlantic migrations, which are accomplished by utilising current systems. The blue shark is a slow-swimming animal that increases its speed when stimulated by external factors, such as the presence of animals on which it can feed. If this happens, it then becomes one of the fastest fish.

IELTS Academic Reading Test

E. The blue shark reaches reproductive maturity at around 5 or 6 years old, after which it can reproduce through viviparity. The blue shark migrates northward to deliver their offspring and, after mating, both mother and father separate and do not join again, since this species is polygamous. Reproduction has been reported as seasonal in most areas, with the young often born in spring or summer, although the periods of ovulation and parturition may be extended.

After a gestation period lasting between 9 and 12 months, the female gives birth to a large number of offspring. An unusual case was a mother that had 130 pups, but the average amount ranges between 25 and 50. The newborns soon separate from their mother who does not provide any parental care.

IELTS Academic Reading Test

F. The most significant challenge faced by the blue shark is that of fishing, as millions of individual animals are caught every year, mainly as bycatch in long-line and trawl fisheries. The fins are used for consumption and the skin for leather and leather products. The oil produced in the liver for buoyancy is also in high demand. After death, the meat is rapidly contaminated by secreted ammonia and so is not widely valued. Landed carcasses can be processed for fishmeal, but loopholes in EC legislation mean that many are still discarded at sea.

Fisheries catch data assessments suggest a 60 per cent decline of blue shark populations in the northwest Atlantic, and declines have been observed elsewhere in this range. Better monitoring of these fisheries is needed to determine Atlantic trends, as there are real concerns about the impacts of the removal of so many animals from the ecosystem. The blue shark is also the target of sports fishing in the United States, Australia and some parts of Europe, though sharks are usually released unharmed after capture.

IELTS Academic Reading Test

As a consequence of all this, the blue shark is ‘Near Threatened’, according to the Red List of the International Union for the Conservation of Nature. Blue sharks also have a few predators, including larger sharks such as the mako and the great white. They are also eaten by sea lions and seals, which eat just their stomach and liver.

G. International obligations that regulate the fishing of sharks include the United Nations, the International Plan of Action for Sharks, and the U.S. Sustainable Fisheries Act. Although some countries have banned finning, there are no binding international treaties for the management of sharks, including the regulation or outlawing of finning.

The blue shark is listed on Annex I of the 1982 Convention on the Law of the Sea, which stresses the need for international cooperation in the conservation, management and utilisation of living aquatic resources, especially of migratory species. This does not, however, enforce any regulations. Fortunately, the blue shark is a prolific species and its distribution offers a reasonable buffer against total removal from the ecosystem.

IELTS Academic Reading Test

The text on the previous pages has 7 paragraphs A – G. Choose the correct heading for each paragraph from the list of headings below. Write the correct number (i – x) in boxes 1 – 7 on your answer sheet.

i. Threats

ii. Social Habits

iii. Environments

iv. Disease

v. Nutrition

vi. Pollution

vii. Young

viii. Conservation

ix. Mutations

x. Movement

IELTS Academic Reading Test

1. Paragraph A

2. Paragraph B

3. Paragraph C

4. Paragraph D

5. Paragraph E

6. Paragraph F

7. Paragraph G

IELTS Academic Reading Test

Write NO MORE THAN TWO WORDS from the text for each answer.

8. Blue sharks usually are found in _______________ when inhabiting warmer seas.

9. The _______________ of blue sharks is because of their history of attacks on humans.

10. Although it helps with obtaining food, it is to ensure _______________ that blue sharks are often found in numbers.

IELTS Academic Reading Test

Write NO MORE THAN TWO WORDS from the text for each answer.

11. What do blue sharks exploit to complete their journeys across the Atlantic Ocean?

12. What part of a blue shark’s own biology spoils its flesh and makes it unsuitable for consumption?

13. What feature of blue sharks helps protect it from the threat of extinction?

IELTS Academic Reading Test

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IELTS Academic Reading Test

1. iii

2. v

3. ii

4. x

5. vii

6. i

7. viii

8. DEEPER WATERS

9. NOTORIETY

10. PROTECTION

11. CURRENT SYSTEMS

12. (SECRETED) AMMONIA

13. (ITS) DISTRIBUTION

IELTS Academic Reading Test

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