Whale Strandings IELTS Reading Answers

Whale Strandings
Why do whales leave the ocean and become stuck on beaches?

When the last stranded whale of a group eventually dies, the story does not end there. A team of researchers begins to investigate, collecting skin samples for instance, recording anything that could help them answer the crucial question: why? Theories abound, some more convincing than others. In recent years, navy sonar has been accused of causing certain whales to strand. It is known that noise pollution from offshore industry, shipping and sonar can impair underwater communication, but can it really drive whales onto our beaches?

In 1998, researchers at the Pelagos Cetacean Research Institute, a Greek non-profit scientific group, linked whale strandings with low- frequency sonar tests being carried out by the North Atlantic Treaty Organisation (NATO). They recorded the stranding of 12 Cuvier’s beaked whales over 38.2 kilometres of coastline. NATO later admitted it had been testing new sonar technology in the same area at the time as the strandings had occurred. ‘Mass’ whale strandings involve four or more animals. Typically they all wash ashore together, but in mass atypical strandings (such as the one in Greece), the whales don’t strand as a group; they are scattered over a larger area.

For humans, hearing a sudden loud noise might prove frightening, but it does not induce mass fatality. For whales, on the other hand, there is a theory on how sonar can kill. The noise can surprise the animal, causing it to swim too quickly to the surface. The result is decompression sickness, a hazard human divers know all too well. If a diver ascends too quickly from a high-pressure underwater environment to a lower-pressure one, gases dissolved in blood and tissue expand and form bubbles. The bubbles block the flow of blood to vital organs, and can ultimately lead to death.Plausible as this seems, it is still a theory and based on our more comprehensive knowledge of land-based animals. For this reason, some scientists are wary. Whale expert Karen Evans is one such scientist. Another is Rosemary Gales, a leading expert on whale strandings. She says sonar technology cannot always be blamed for mass strandings. “It’s a case-by-case situation. Whales have been stranding for a very long time – pre-sonar.” And when 80% of all Australian whale strandings occur around Tasmania, Gales and her team must continue in the search for answers.

When animals beach next to each other at the same time, the most common cause has nothing to do with humans at all. “They’re highly social creatures,” says Gales. “When they mass strand – it’s complete panic and chaos. If one of the group strands and sounds the alarm, others will try to swim to its aid, and become stuck themselves.”

Activities such as sonar testing can hint at when a stranding may occur, but if conservationists are to reduce the number of strandings, or improve rescue operations, they need information on where strandings are likely to occur as well. With this in mind, Ralph James, physicist at the University of Western Australia in Perth, thinks he may have discovered why whales turn up only on some beaches. In 1986 he went to Augusta, Western Australia, where more than 100 false killer whales had beached. “I found out from chatting to the locals that whales had been stranding there for decades. So I asked myself, what is it about this beach?” From this question that James pondered over 20 years ago, grew the university’s Whale Stranding Analysis Project.

Data has since revealed that all mass strandings around Australia occur on gently sloping sandy beaches, some with inclines of less than 0.5%. For whale species that depend on an echolocation system to navigate, this kind of beach spells disaster. Usually, as they swim, they make clicking noises, and the resulting sound waves are reflected in an echo and travel back to them. However, these just fade out on shallow beaches, so the whale doesn’t hear an echo and it crashes onto the shore.

But that is not all. Physics, it appears, can help with the when as well as the where. The ocean is full of bubbles. Larger ones rise quickly to the surface and disappear, whilst smaller ones – called microbubbles – can last for days. It is these that absorb whale ‘clicks! “Rough weather generates more bubbles than usual,” James adds. So, during and after a storm, echolocating whales are essentially swimming blind.

Last year was a bad one for strandings in Australia. Can we predict if this – or any other year – will be any better? Some scientists believe we can. They have found trends which could be used to forecast ‘bad years’ for strandings in the future. In 2005, a survey by Klaus Vanselow and Klaus Ricklefs of sperm whale strandings in the North Sea even found a correlation between these and the sunspot cycle, and suggested that changes in the Earth’s magnetic field might be involved. But others are sceptical. “Their study was interesting … but the analyses they used were flawed on a number of levels,” says Evans. In the same year, she co-authored a study on Australian strandings that uncovered a completely different trend. “We analysed data from 1920 to 2002 … and observed a clear periodicity in the number of whales stranded each year that coincides with a major climatic cycle.” To put it more simply, she says, in the years when strong westerly and southerly winds bring cool water rich in nutrients closer to the Australia coast, there is an increase in the number of fish. The whales follow.

So what causes mass strandings? “It’s probably many different components,” says James. And he is probably right. But the point is we now know what many of those components are.

Questions 14-19

Choose the correct letter, A,B,C or D

14. According to the passage, what is the most common cause of "mass" whale strandings?
A Sudden loud noises that disorient the whales
B The whales' attempt to help a stranded member of their group
C Rapid changes in water pressure and depth
D Magnetic field disturbances caused by solar activity
15. Which factor does the passage suggest can help predict when whale strandings are more likely to occur?
A Changes in ocean currents
B Increase in offshore industry activity
C Elevated levels of microbubbles in the water
D Fluctuations in the whale population
16. How do the physical characteristics of certain beaches contribute to whale strandings, as described in the passage?
A The steep incline makes it difficult for whales to beach themselves
B The rocky terrain prevents whales from being able to strand safely
C The lack of vegetation provides no shelter for the stranded whales
D The gently sloping, sandy nature disrupts the whales' echolocation
17. Why are some scientists skeptical about the link between sonar and whale strandings, according to the passage?
A Sonar technology has been in use for a long time without causing major issues
B Whale strandings have been observed long before the development of sonar
C The evidence connecting sonar to strandings is not conclusive enough
D Whale strandings are a natural phenomenon that cannot be prevented
18. What is the primary theory proposed in the passage for how sonar can lead to whale deaths?
A Sonar disrupts the whales' ability to communicate and navigate
B Sonar causes whales to become disoriented and beach themselves
C Sonar scares whales, causing them to swim too quickly to the surface
D Sonar attracts whales towards the shore, leading to their stranding
19. What does the passage suggest is necessary for conservationists to better understand and reduce whale strandings?
A Analyzing data on past strandings to identify patterns and trends
B Conducting more research on the impact of sonar on marine life
C Improving rescue operations and rehabilitation efforts for stranded whales
D Implementing stricter regulations on offshore industry and shipping activities

Questions 20-23
Look at the following ideas and the list of researchers below. 
Match each idea with the correct researcher A, B, C or D.
Write the correct letter A, B, C or D in the boxes 20-23 on your answer sheet.
NB You may use any letter more than once. 
List of Scientists 
A. Karen Evans
B. Rosemary Gales
C. Ralph James
D. Klaus Vanselow & Klaus Ricklefs

Questions 24-26
Complete the summary below. 
Write NO MORE THAN THREE WORDS from the text for each answer. 
Last year saw many whale strandings in Australia, prompting scientists to explore if future strandings can be predicted. Some researchers, like Klaus Vanselow and Klaus Ricklefs, found a possible link between whale strandings and 24.________________, suggesting magnetic field changes could be involved. However, other scientists, like Karen Evans, criticized their analysis. Evans' own study on Australian strandings from 1920 to 2002 found a different 25. _______________. She linked increased strandings to a 26. _________________ where winds bring nutrient-rich cool water closer to shore, attracting fish, which whales follow, leading to more strandings.