Cod are fish that live in the sea. Fishing boats from many different countries catch cod in the same area of sea.
The Table shows the mass of adult cod in this area of sea in different years.
Table
| Year | Mass of adult cod in thousands of tonnes |
|---|---|
| 1970 | 270 |
| 1980 | 160 |
| 1990 | 80 |
| 2000 | 40 |
| 2006 | 35 |
| 2010 | 55 |
| 2015 | 110 |
In 2006, the countries agreed to fishing quotas. A quota limits the mass of cod that each country's boats can catch each year.
Describe the trend in the mass of adult cod between 1970 and 2006.
Explain how the fishing quotas helped the mass of adult cod to increase after 2006.
Explain why it can be difficult to get different countries to agree to fishing quotas.
Suggest one reason why it is difficult to check that fishing boats keep to their quotas.
109 exam-style questions on OCR GCSE Biology 6.1 Monitoring and maintaining the environment, covering 6.1.1 Field investigation of distribution and abundance, 6.1.2 Human interactions and biodiversity, 6.1.3 Maintaining biodiversity, and 6.1.4 Environmental change and distribution of organisms. Each one has a worked solution and a mark scheme showing where the marks go.