Belukia lobsters

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Belukia lobsters

by kobel51 » Thu Feb 20, 2014 5:21 pm
In 1992 outlaw fishing boats began illegally harvesting lobsters from the territorial waters of the country of Belukia. Soon after, the annual tonnage of lobster legally harvested in Belukian waters began declining; in 1996, despite there being no reduction in the level of legal lobster fishing activity, the local catch was 9,000 tons below pre-1992 levels. It is therefore highly likely that the outlaw fishing boats harvested about 9,000 tons of lobster illegally that year.

Which of the following is an assumption on which the argument depends?

(A) The illegal lobster harvesting was not so extensive that the population of catchable lobsters in Belukia's territorial waters had sharply declined by 1996.

(B) The average annual lobster catch, in tons, of an outlaw fishing boat has increased steadily since 1992.

(C) Outlaw fishing boats do not, as a group, harvest more lobsters than do licensed lobster-fishing boats.

(D) The annual legal lobster harvest in Belukia in 1996 was not significantly less than 9,000 tons.

(E) A significant proportion of Belukia's operators of licensed lobster-fishing boats went out of business between 1992 and 1996.

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by Patrick_GMATFix » Thu Feb 20, 2014 5:32 pm
Remember that an assumption must be true for the conclusion to follow from the premises. The full solution below is taken from the GMATFix App; I go through each answer choice in detail.

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by VivianKerr » Thu Feb 20, 2014 6:06 pm
Conclusion: HIGHLY LIKELY boats harvest 9,000 L illegally
Evidence: 1996 - legal L harvest same, 9,000 tons below

Assumption: There wasn't another reason for there to be so much less legal L harvested (lobster illness, etc.)

The author is blaming the small catch in 1996 on illegal harvesting. We really need a piece of information that shows why it's "HIGHLY LIKELY" we're blaming the lobster-thieves.

The Real Question: Does this make it REALLY LIKELY the drop is due to the illegal harvesters?

A) Makes it more likely by saying it wasn't just that there were less lobsters

B) Lots of lobster in the water = where are they going? Higher likelihood of illegal harvest, but doesn't discount other reasons

C)We have no idea of the actual numbers of legal/illegal lobsters - out of scope

D) This is not relevant

E) Even if a high proportion went out of business, the stem says there was no reduction in the level of activity - not relevant

The correct answer must be A. I don't think this is a *great* question, but (A) is the only one that logically follows from the evidence and conclusion.
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by [email protected] » Fri Feb 21, 2014 12:33 am
Hi kobel51,

This CR prompt focuses on a "causal" argument: the idea that one thing causes another. It's a common logic "structure" that you'll see in some CR questions on Test Day. To figure out the assumption behind the prompt, you'll need to understand the logic first.

The Facts:
-1992: outlaw fishing boats began ILLEGALLY harvesting lobsters around Belukia
-Soon after the outlaw harvesting began, annual tonnage of LEGALLY harvested lobsters began declining
-1996: NO REDUCTION in the level of LEGAL lobster harvesting; the legal catch was 9,000 tons BELOW pre-1992 levels

The Conclusion:
-Outlaw fishing harvested about 9,000 tons of illegal lobsters that year.

The Logic:
The causal argument in this prompt is that the outlaw harvesting was the ONLY reason why the LEGAL harvesting was down 9,000 tons AND ALL of those missing 9,000 tons were harvested by the outlaws. To believe this logic, you would have to assume that NOTHING ELSE factored in to the decrease in legally captured lobster.

Answer A tells us that the something else DID NOT decrease the lobster population, thus giving credence to the idea that illegal outlaw fishing boats were the cause of the 9,000 ton decline.

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by GMATGuruNY » Fri Feb 21, 2014 7:49 am
kobel51 wrote:In 1992 outlaw fishing boats began illegally harvesting lobsters from the territorial waters of the country of Belukia. Soon after, the annual tonnage of lobster legally harvested in Belukian waters began declining; in 1996, despite there being no reduction in the level of legal lobster fishing activity, the local catch was 9,000 tons below pre-1992 levels. It is therefore highly likely that the outlaw fishing boats harvested about 9,000 tons of lobster illegally that year.

Which of the following is an assumption on which the argument depends?

(A) The illegal lobster harvesting was not so extensive that the population of catchable lobsters in Belukia's territorial waters had sharply declined by 1996.

(B) The average annual lobster catch, in tons, of an outlaw fishing boat has increased steadily since 1992.

(C) Outlaw fishing boats do not, as a group, harvest more lobsters than do licensed lobster-fishing boats.

(D) The annual legal lobster harvest in Belukia in 1996 was not significantly less than 9,000 tons.

(E) A significant proportion of Belukia's operators of licensed lobster-fishing boats went out of business between 1992 and 1996.
The passage concludes that OUTLAW FISHING IN 1996 was responsible for the DECREASE IN THE LOCAL CATCH IN 1996.
The assumption is WHAT MUST BE TRUE for this conclusion to be valid: that there was NO OTHER REASON for the decrease in the local catch in 1996.

Apply the NEGATION TEST to the answer choices.
The correct assumption is what must be true for the conclusion to be valid.
Thus, when the correct answer choice is negated, the conclusion will be invalidated.

Answer choice A, negated:
The illegal lobster harvesting was so extensive that the population of catchable lobsters in Belukia's territorial waters had sharply declined by 1996.
The negation of A suggests ANOTHER REASON for the decline in the 1996 catch: there were FEWER CATCHABLE LOBSTERS.
Since the negation of A invalidates the conclusion that OUTLAW FISHING IN 1996 caused the decrease in the local catch, A is the necessary assumption: WHAT MUST BE TRUE for the conclusion to be valid.

The correct answer is A.
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by spla626 » Wed Aug 20, 2014 2:34 am
Hi all,

Should we understand that "LOCAL CATCH" means exactly LEGAL CATCH? If so, why?

Thanks in advance