A fishing cooperative tested nets with different mesh sizes in equal-length hauls targeting herring. The table shows the mean number of young and adult fish caught per haul.
| Mesh size / mm | Mean number of young fish caught per haul | Mean number of adult fish caught per haul |
|---|---|---|
| 40 | 80 | 85 |
| 60 | 30 | 60 |
Calculate the percentage decrease in the mean number of young fish caught per haul when the mesh size is increased from 40 mm to 60 mm.
Suggest whether the cooperative should use nets with a mesh size of 60 mm. Justify your answer using the data and your knowledge of sustainable fishing.
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.