Band 8.5 model answer: problem and solution

A band 8.5 model answer to a real IELTS Writing Task 2 question, with the paragraph plan that fits it. Aim for 250 to 290 words in 40 minutes.

The question

In many countries, wild fish populations are declining due to overfishing, and fish farming (aquaculture) is increasingly used to meet demand. What problems does this trend cause, and what solutions can be suggested?

Your 4-paragraph plan

Introduction (40-50 words). Paraphrase the issue and preview that you will cover causes and solutions.
Body paragraph 1 (80-100 words). The main cause or problem, with a specific example of its effect.
Body paragraph 2 (80-100 words). One or two realistic solutions, saying who should act (government, schools, individuals).
Conclusion (40-50 words). Summarise the problem and your strongest solution.

The trap in this question type

Vague solutions like 'raise awareness' score poorly. Name who acts and what exactly they do, then say what changes as a result.

Band 8.5 model answer

335 words, the length a strong candidate produces in the 40 minutes Task 2 allows (the minimum is 250). Written for this exact question in the official format. Read it once for ideas, then write your own before comparing.

Aquaculture has expanded rapidly enough that farmed fish, from Norwegian salmon pens to Vietnamese catfish ponds in the Mekong Delta, now account for a large and growing share of the fish humans eat, overtaking wild catch for direct consumption within the past decade. While this shift eases pressure on wild stocks, the way farming is currently practised creates problems of its own, and the two sides of this issue deserve equally serious treatment. The central problems are environmental rather than purely economic. Densely stocked pens release concentrated waste, uneaten feed and antibiotics into surrounding waters, and sea lice outbreaks on Scottish salmon farms have occasionally forced producers to cull entire stocks. Escaped farmed salmon can also interbreed with wild Atlantic salmon, ironically harming the same wild populations aquaculture is meant to protect. Compounding this, many farmed carnivorous species are fed fishmeal made from wild-caught anchovies and sardines off Peru's coast, meaning aquaculture can quietly deplete other wild fisheries rather than replacing fishing altogether. One solution lies in containment and waste management. Governments can mandate closed-containment systems, which Norway has begun piloting, so that waste, chemicals and escaped fish no longer pass freely into open water. Stricter permitting tied to water-quality monitoring would give regulators the power to shut down farms that repeatedly breach discharge limits, rather than relying on voluntary compliance. A second, equally important solution addresses feed sourcing and consumer pressure. Shifting feed formulas toward algae-based protein, already produced commercially by the company Calysta, would loosen the industry's dependence on wild-caught feed fish. Certification schemes such as the Aquaculture Stewardship Council also let consumers reward farms meeting stricter environmental standards, creating market incentives for reform that regulation alone cannot achieve. In conclusion, aquaculture is not an automatic remedy for overfishing, since its pollution and feed demands can generate new ecological damage of comparable scale. Only by combining tighter containment rules with cleaner feed sources and credible certification can fish farming become a genuinely sustainable substitute for the wild fisheries it was designed to relieve.

Why this answer earns band 8.5

The concession that escaped salmon 'interbreed with wild Atlantic salmon' shows Task Response through honest handling of a complication rather than a one-sided argument.
Giving containment and feed/certification separate paragraphs balances the two halves of the prompt, a Coherence and Cohesion choice that stops the solutions section from being thinner than the problems section.
The phrase 'ironically harming the same wild populations aquaculture is meant to protect' uses an adverbial comment plus an embedded relative clause, showing Grammatical Range through a complex single-sentence structure.
'quietly deplete' and 'loosen the industry's dependence on' are collocations with a slightly figurative edge, illustrating Lexical Resource beyond flat, literal verbs like 'reduce' or 'use'.
The cohesive device 'compounding this' links the two problem paragraphs' ideas causally, an example of Coherence and Cohesion doing work that a simple 'also' would not.

The plan, reusable on any question of this type

Introduce the shift toward aquaculture and state that both its problems and its solutions deserve equal attention (~73 words)
Explain the environmental problems: pollution, disease and dependence on wild-caught feed fish (~90 words)
Present the first solution: closed-containment systems and stricter discharge regulation (~58 words)
Present the second solution: alternative feed sources and consumer-facing certification schemes (~60 words)
Conclude that only combined technical and regulatory change makes aquaculture genuinely sustainable (~54 words)

Phrases worth learning

compounding this	to add a second, related problem within the same paragraph on any problem-solution essay
ironically harming the same X it was meant to protect	to highlight an unintended negative consequence of a well-intentioned policy or technology
rather than relying on voluntary compliance	to argue that enforceable rules are stronger than optional or self-regulated measures
creating market incentives for reform that regulation alone cannot achieve	to justify a consumer-driven or economic solution alongside a legal one
is not an automatic remedy for	to introduce a balanced conclusion that avoids overstating a single solution's power

Questions about this answer

What band is this model answer?

It is written to band 8.5, and the notes under it quote the answer's own words to show why.

How long should my answer to this question be?

Write at least 250 words and aim for 250 to 290 in the 40 minutes Task 2 allows. This model answer is 335 words.

What is the most common mistake on a problem and solution question?