Parland's alligator population has been declining in recent years, primarily because of hunting. Alligators prey heavily on a species of...
GMAT Critical Reasoning : (CR) Questions
Parland's alligator population has been declining in recent years, primarily because of hunting. Alligators prey heavily on a species of freshwater fish that is highly valued as food by Parlanders, who had hoped that the decline in the alligator population would lead to an increase in the numbers of these fish available for human consumption. Yet the population of this fish species has also declined, even though the annual number caught for human consumption has not increased.
Which of the following, if true, most helps to explain the decline in the population of the fish species?
Passage Analysis:
| Text from Passage | Analysis |
| Parland's alligator population has been declining in recent years, primarily because of hunting. |
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| Alligators prey heavily on a species of freshwater fish that is highly valued as food by Parlanders, who had hoped that the decline in the alligator population would lead to an increase in the numbers of these fish available for human consumption. |
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| Yet the population of this fish species has also declined, even though the annual number caught for human consumption has not increased. |
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Argument Flow:
The passage sets up a puzzle by first explaining the situation (alligator decline due to hunting), then describing logical human expectations (fewer alligators should mean more fish), and finally revealing the contradictory reality (fish are also declining despite stable human fishing). This creates a mystery that needs solving.
Main Conclusion:
There's no explicit conclusion here - this is a puzzle presentation. The passage shows that fish populations declined unexpectedly even though their main predator (alligators) also declined and human fishing didn't increase.
Logical Structure:
This isn't a traditional argument with premises supporting a conclusion. Instead, it's a 'mystery setup' that presents contradictory evidence: we'd expect fish populations to rise when their predators decline, but they're falling instead. The question asks us to explain this contradiction.
Prethinking:
Question type:
Paradox - We need to explain why something unexpected happened. The puzzle here is: fewer alligators should mean more fish (since alligators eat fish), but instead fish populations are also declining even though humans aren't catching more fish.
Precision of Claims
The key claims involve population changes over time: alligator population declining due to hunting, fish population also declining despite fewer predators, and human fishing levels remaining constant.
Strategy
For paradox questions, we need to find explanations that resolve the apparent contradiction. We're looking for factors that could cause fish populations to decline even when their main predator (alligators) is also declining. We need to accept all the given facts and find a missing piece that makes the puzzle make sense.
This tells us that fishers can now access previously dangerous areas due to fewer alligators. However, the passage explicitly states that 'the annual number caught for human consumption has not increased.' If fishers could access new areas safely, we'd expect increased catches, but that's not happening. This doesn't explain why fish populations are declining - it actually suggests they should be stable or increasing since fishing pressure hasn't risen.
This suggests increased commercial fishing capacity with more boats. But again, this contradicts the passage's clear statement that annual catches for human consumption haven't increased. If there were more fishing boats, we'd expect either more fish caught or the same catch with less effort per boat. This doesn't resolve our paradox about declining fish populations.
This is our answer! It creates a perfect ecological explanation. If alligators eat both the valued fish AND the main predator of those fish, then fewer alligators means less control over the fish that prey on the valued species. So even though there's less direct alligator predation on the valued fish, there's increased predation from other fish species whose populations are no longer kept in check by alligators. This explains why fish populations decline despite fewer alligators.
This explains why people hunt alligators (for valuable skins rather than to protect fish), but it doesn't help explain why fish populations are declining. The motivation behind alligator hunting doesn't affect the ecological relationships we're trying to understand. Whether hunters target alligators for skins or fish protection, the result is still fewer alligators, which should theoretically benefit fish populations.
This discusses alligator populations in neighboring countries, but our focus is on Parland's fish population decline. What happens to alligators in other countries doesn't directly explain why fish populations in Parland are declining. Even if this created some cross-border ecological effect, it doesn't address the core paradox we're trying to resolve.