Analyze and interpret quantitative data

El Niño and a coastal fishery

Units 4 and 5
10 points
About 23 minutes

You can use a calculator on this question, just like on exam day.

You read values and trends from a data table or described graph, explain what the data show about an environmental problem, and propose and justify a solution. On the exam: Question 2 of 3 in the 70-minute free-response section (Section II is 40% of the exam score).

The question and its sources

Off the coast of Peru, cold, nutrient-rich water normally rises to the surface and supports one of the world's largest fisheries, for a small fish called the anchoveta. Table 1 shows sea surface temperature anomalies (the difference from the long-term average) for the eastern equatorial Pacific and the anchoveta catch over eight years.

Table 1: Sea surface temperature anomaly and anchoveta catch

Year	Sea surface temperature anomaly (°C)	Anchoveta catch (million metric tons)
1	−0.6	6.8
2	+0.2	5.9
3	+2.1	1.7
4	+0.4	4.1
5	−1.0	7.3
6	+0.1	5.6
7	+1.8	2.0
8	−0.3	6.2

Source: Hypothetical data

Suggested time: 23 minutes

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Part (a)

1 point

Identify the year with the lowest anchoveta catch.

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Part (b)

1 point

Identify the climate phenomenon most likely occurring in Year 3.

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Part (c)

1 point

Describe the relationship between the sea surface temperature anomaly and the anchoveta catch shown in Table 1.

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Part (d)

1 point

Explain why the anchoveta population declines when the surface water off Peru is warmer than average.

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Part (e)

1 point

Year 5 had the most negative temperature anomaly. Describe the trade winds in the equatorial Pacific during that year compared with an average year.

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Part (f)

1 point

Describe one effect El Niño can have on weather in a region far from Peru.

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Part (g)

1 point

Explain how the tragedy of the commons applies to the anchoveta fishery.

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Part (h)

1 point

Anchoveta are eaten by seabirds, sea lions and larger fish. Describe one effect a collapse of the anchoveta population could have on the ecosystem.

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Part (i)

1 point

Propose one realistic fishery-management solution that could help prevent the anchoveta population from collapsing.

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Part (j)

1 point

Use the data in Table 1 to justify the solution you proposed in part (i).

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