CREATING ARTIFICIAL REEFS
In the coastal waters of the US, a nation’s leftovers have been discarded. Derelict ships, concrete blocks, scrapped cars, army tanks, tyres filled with concrete and redundant planes litter the sea floor. However, this is not waste disposal, but part of a coordinated, state-run programme. To recently arrived fish, plants and other sea organisms, these artificial reefs are an ideal home, offering food and shelter.
Sea-dumping incites widespread condemnation. Little surprise when oceans are seen as 'convenient' dumping grounds for the rubbish we have created but would rather forget. However, scientific evidence suggests that if we dump the right things, sea life can actually be enhanced. And more recently, purpose-built structures of steel or concrete have been employed - some the size of small apartment blocks -principally to increase fish harvests.
The choice of design and materials for an artificial reef depends on where it is going to be placed. In areas of strong currents, for example, a solid concrete structure will be more appropriate than ballasted tyres. It also depends on what species are to be attracted. It is pointless creating high-rise structures for fish that prefer flat or low-relief habitat. But the most important consideration is the purpose of the reef.
In the US, where there is a national reef plan using cleaned up rigs and tanks, artificial reefs have mainly been used to attract fish for recreational fishing or sport-driving. But there are many other ways in which they can be used to manage the marine habitat. For as well as protecting existing habitat, providing purpose-built accommodation for commercial species (such as lobsters and octupi) and acting as sea defences, they can be an effective way of improving fish harvests.
Japan, for example, has created vast areas of artificial habitat - rather than isolated reefs - to increase its fish stocks. In fact, the cultural and historical importance of seafood in Japan is reflected by the fact that it is a world leader in reef technology; what’s more, those who construct and deploy reefs have sole rights to the harvest.
In Europe, artificial reefs have been mainly employed to protect habitat. Particularly so in the Mediterranean where reefs have been sunk as physical obstacles to stop illegal trawling, which is destroying sea grass beds and the marine life that depends on them. If you want to protect areas of the seabed, you need something that will stop trawlers dead in their tracks,' says Dr Antony Jensen of the Southampton Oceanography Centre.
Italy boasts considerable artificial reef activity. It deployed its first scientifically planned reef using concrete cubes assembled in pyramid forms in 1974 to enhance fisheries and stop trawling. And Spain has built nearly 50 reefs in its waters, mainly to discourage trawling and enhance the productivity of fisheries. Meanwhile, Britain established its first quarried rock artificial reef in 1984 off the Scottish coast, to assess its potential for attracting commercial species.
But while the scientific study of these structures is a little fewer a quarter of a century old, artificial reefs made out of readily available materials such as bamboo and coconuts have been used by fishermen for centuries. And the benefits have been enormous. By placing reefs dose to home, fishermen can save time and fuel. But unless they are carefully managed, these areas can become overfished. In the Philippines, for example, where artificial reef programmes have been instigated in response to declining fish populations, catches are often allowed to exceed the maximum potential new production of the artificial reef because there is no proper management control.
There is no doubt that artificial reefs have lots to offer. And while purpose-built structures are effective, the real challenge now is to develop environmentally safe ways of using recycled waste to increase marine diversity. This will require more scientific research. For example, the lactates from one of the most commonly used reef materials, tyres, could potentially be harmful to the creatures and plants that they are supposed to attract. Yet few extensive studies have been undertaken into the long term effects of disposing of tyres at sea. And at the moment there is little consensus about what is environmentally acceptable to dump at sea, especially when it comes to oil and gas rigs. Clearly, the challenge is to develop environmentally acceptable ways of disposing of our rubbish while enhancing marine Safe too. What we must never be allowed to do is have an excuse for dumping anything we like at sea.
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Question Focus: Detail question - factors affecting construction
Correct Answer: B
Why this is correct: This is correct because the writer clearly says the design and materials depend on where the reef is placed. Strong currents need different structures, so location directly affects construction.
Passage Reference: The choice of design and materials for an artificial reef depends on where it is going to be placed. In areas of strong currents, for example, a solid concrete structure will be more appropriate than ballasted tyres.
Paraphrasing: Passage: 'depends on where it is going to be placed' = Option: 'the intended location of the reef'
Tips: Look for sentences that explain cause and effect. Words like 'depends on' are strong signals.
Key Vocabulary:
- currents = moving water
- appropriate = suitable
Question Focus: Detail question - checking which factors are mentioned
Correct Answer: A
Passage Reference: In the US, where there is a national reef plan using cleaned up rigs and tanks, artificial reefs have mainly been used to attract fish for recreational fishing or sport-driving. But there are many other ways in which they can be used to manage the marine habitat. For as well as protecting existing habitat, providing purpose-built accommodation for commercial species (such as lobsters and octupi) and acting as sea defences, they can be an effective way of improving fish harvests.
Why this is correct: This option is not mentioned as a factor in deciding how to construct an artificial reef. The passage talks about fishing activity as a result or use of reefs, not something that affects their design or construction. This is a Context shift trap.
Tips: Check whether the option answers the exact question. Here, the question is about construction decisions, not outcomes.
Key Vocabulary:
- harvests = catches of fish
Question Focus: Detail question - checking which factors are mentioned
Correct Answer: C
Passage Reference: The choice of design and materials for an artificial reef depends on where it is going to be placed. In areas of strong currents, for example, a solid concrete structure will be more appropriate than ballasted tyres. It also depends on what species are to be attracted. It is pointless creating high-rise structures for fish that prefer flat or low-relief habitat. But the most important consideration is the purpose of the reef.
Why this is correct: The passage never mentions existing reef structures as something planners consider when building a new reef. This idea sounds logical, but it is not stated in the text, which makes it a Not Given trap.
Tips: Do not choose an option just because it sounds sensible in real life. Only choose what is clearly stated.
Question Focus: Detail question - factors affecting construction
Correct Answer: D
Passage Reference: It also depends on what species are to be attracted. It is pointless creating high-rise structures for fish that prefer flat or low-relief habitat.
Why this is correct: This is correct because the writer explains that reef design depends on which species are being attracted. Different fish need different types of structures.
Paraphrasing: Passage: 'what species are to be attracted' = Option: 'the type of marine life being targeted'
Tips: When you see examples, like fish preferring flat habitats, use them as proof for the option.
Key Vocabulary:
- species = type of animal
- habitat = natural home
Question Focus: Detail question - main consideration in construction
Correct Answer: E
Passage Reference: But the most important consideration is the purpose of the reef.
Why this is correct: This is clearly correct because the writer directly says that the most important consideration is the purpose of the reef. This tells us function strongly affects how it is built.
Paraphrasing: Passage: 'the purpose of the reef' = Option: 'the function of the reef'
Tips: Strong language like most important often points directly to a correct answer.
Key Vocabulary:
- purpose = function
- consideration = factor to think about
Question Focus: Detail question - distinguishing examples from factors
Correct Answer: F
Passage Reference: Japan, for example, has created vast areas of artificial habitat - rather than isolated reefs - to increase its fish stocks. In fact, the cultural and historical importance of seafood in Japan is reflected by the fact that it is a world leader in reef technology; what's more, those who construct and deploy reefs have sole rights to the harvest.
Why this is correct: The passage mentions cultural importance only when describing Japan as an example, not as a factor used to decide reef construction. This is a Wrong section trap.
Tips: Be careful with country examples. Ask yourself: is this an example, or an answer to the question?
Key Vocabulary:
- cultural = related to traditions and history
General Tips:
- For multiple-answer questions, check every option carefully. There can be more than one correct answer.
- Detail questions follow passage order, so the answers are usually close together in the text.
- Look for phrases like 'depends on' or 'the most important' - they often signal key factors.
- Do not use real-world logic. IELTS only tests what is written in the passage.
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