The Atlantic bluefin tuna, Thunnus thynnus, is a highly migratory predator of significant commercial value.
The fork length (the length from the snout to the fork of the tail) of bluefin tuna varies between individuals.
The table below shows data on the fork length of bluefin tuna caught in a designated zone of the Mediterranean Sea during an ecological survey.
| Fork length, yyy (cm) | Frequency |
|---|---|
| 100≤y<140100 \le y < 140100≤y<140 | 18 |
| 140≤y<180140 \le y < 180140≤y<180 | 62 |
| 180≤y<220180 \le y < 220180≤y<220 | 124 |
| 220≤y<260220 \le y < 260220≤y<260 | 158 |
| 260≤y<300260 \le y < 300260≤y<300 | 96 |
| 300≤y<380300 \le y < 380300≤y<380 | 40 |
Explain how to construct a suitable histogram to represent these data, specifying the required scales, labels, and the heights and widths of the bars.
Variation in organisms can be caused by genetic and environmental factors. Explain why the data shown in the table indicates that at least some of the variation in fork length of the bluefin tuna is caused by environmental factors.
It is vital that commercial fishing of pelagic species is managed sustainably to prevent population collapses.
Fish farming (aquaculture) of tuna is extremely challenging, so other conservation strategies are required.
List three other strategies that national or international authorities could implement to improve the sustainability of commercial marine fishing.
Suggest why international agreements are particularly crucial for achieving sustainable marine fishing.
