Fig. 7.1 shows the results of a study of the number of fish caught in a coastal area over four years. The area had been heavily overfished, and to allow the...
Question 1 Report
Fig. 7.1 shows the results of a study of the number of fish caught in a coastal area over four years. The area had been heavily overfished, and to allow the fish population to recover, a limit was placed on the number of fish that could be caught, starting in year 2. Scientists recorded the mass of fish caught by the fishing fleet each year, in thousands of tonnes. The results of the study are shown in the table and can be used to describe the effect of the fishing limit on the fish population.
| Year | Mass of fish caught / thousands of tonnes |
|---|---|
| 1 | 85 |
| 2 | 40 |
| 3 | 52 |
| 4 | 70 |
(a) Using the data, describe how the mass of fish caught changed from year 1 to year 4. [2]
(b) Explain why placing a limit on the number of fish caught allows the fish population to recover. [3]
(c) State two other methods that can be used to conserve fish stocks. [2]
Answer Details
This question tests reading catch data and explaining how a catch limit lets an overfished population recover.
(a) From year 1 to year 4 the mass caught fell sharply from year 1 to year 2 (85 to 40 thousand tonnes) [1], then rose again from year 2 to year 4 (40 up to 70) [1]. The initial fall reflects the limit imposed in year 2, and the later rise shows the stock recovering.
(b) A catch limit lets the population recover because fewer fish are removed / caught [1]; so more fish survive to reach breeding age and reproduce [1]; and the population can increase back towards its original size [1].
(c) Any two other conservation methods (1 each): control net mesh size so young fish can escape; set a minimum catchable size; create protected areas or closed seasons; or impose fishing quotas [2].
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