Scientists monitored a herring stock during one fishing season. The table shows their estimates.
| Measurement | Mass in tonnes |
|---|---|
| Herring stock at the start of the season | 624 000 |
| Herring caught during the season | 96 000 |
| Increase in the stock from breeding | 24 000 |
Assume there were no other changes to the mass of the stock during the season.
Calculate the overall percentage decrease in the mass of the herring stock during the season.
Give your answer to 3 significant figures.
Scientists predict that breeding will continue to increase the stock by 24 000 tonnes each season. The fishing industry plans to catch 120 000 tonnes of herring each season.
Explain why this plan is unlikely to be sustainable.
87 exam-style questions on AQA GCSE Biology 7.5 Food production, covering 7.5.1 Factors affecting food security, 7.5.2 Farming techniques, 7.5.3 Sustainable fisheries, and 7.5.4 Role of biotechnology. Each one has a worked solution and a mark scheme showing where the marks go.