Lobsters

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by ssgmatter » Thu May 20, 2010 9:37 am
DanaJ wrote:OK I am going to try it again...

Why should you be confused? So you have the argument:
- illegal fishermen started operating in 1992
- legal fishermen were still putting in the same amount of effort in their attempt to catch lobsters, but their overall catch diminished by 9000 tons in 1996 as compared to 1992
- so we need to conclude that the 9000 tons went to the illegal fishermen

But what if there was something else that triggered the decline in the legal fishermen's catch? Option A provides a hint: the catch might have been smaller because the total population of lobsters had declined because of overfishing. If the illegal fishermen had gone too far with fishing in one year, this might have affected the lobster population for years to come, because there were fewer of them mate and produce new lobsters.

Negate B and see if the argument falls apart: The average annual lobster catch, in tons, of an outlaw fishing boat has decreased steadily since 1992. Does this mean that the illegal fishermen could not have been responsible for the 9000 ton decrease? No.

D does not matter, since the amount of decrease/increase in catch or its previous levels are issues not discussed in the argument. The argument is simply trying to establish the source of the decrease.
Thankyou Dana for all your efforts in making me understand this toughie.

Yes A is the assumption here because if the poaching reach a very high level then the legal catch would almost diminish as the year progress because no lobster would be there to mate....so it has to be assumed that poaching was not so extensive....hence A it is

As far as D is concerned , i understand that the arg is concerned with the source of the decrease which is poaching here...

Hwever not very confident on B.....i m little confused with the negation that you have applied for B...please elaborate a bit more on B...however my interpretation of B is that if poaching has steadily increased from 92 then by now all the lobsters should be gone...none were left for mating...so i think this could possibly be one of the assumptions here....Does it make sense?.....Please share your thoughts...

Thankyou!
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by DanaJ » Thu May 20, 2010 10:09 am
I cannot give you more than the initial example for B... If the initial poaching level was 2 tons, then if you have an increase of 2 tons per year, in 1996 you'll have 10 tons. However, compare this to 9000 and it's not really important. The question here is that you do not know quantities.

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by kevincanspain » Thu May 20, 2010 10:11 am
The argument reasons that if legal fisherman caught 9000 fewer tons than before, we know that 9000 tons were caught illegally. This assumes that the same number of fish are caught each year. But what if A is true? A gives us a good reason to doubt this assumption.


Similarly,

Last year, our apple pickers picked 5000 kg of apples. After the harvest, we laid off the man who used to keep most of the kids out of the apple orchard, kids who would steal ripe apples right off the trees to sell them to street vendors. If this year, our apple pickers have picked 4000 kg of apples, can we conclude that kids have stolen 1000 kg of apples off our trees this year?
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by Prashant Ranjan » Sat Aug 18, 2012 11:57 pm
DanaJ has made an excellent attempt to simplify the argument and arrive at the correct answer. I think this is an excellent question to learn the intricacies of CR, pertaining to the real world thinking.

I would attempt to further deconstruct the argument, at the risk of being redundant though, and try to arrive at the correct answer choice.

The arguments says:
- illegal fishing started since 1992
- Legal fishermen were putting the same amount of effort in their attempt to catch the lobsters, but their overall catch diminished by 9000 tons in 1996 as in 1992.

The conclusion made was that this fishing of 9000 tons of lobsters, is done by illegal fishermen.
So basically it states that current lobsters caught by legal fishermen + 9000 = pre-1992 level.

What do we mean by the above statement.
It means that the amount of lobsters caught by illegal fishermen each year since 1992 to 1995 (including) was replenished at the end of that year, so that the total amount remained the same (equal to pre-1992 level). That's why we can still say that in 1996, 9000 + current level = original level of pre-1992 years.

But this is not the only possible assumption. What if the illegal fishermen caught such a huge amount of lobsters in years from 1992 to 1995 (including) that the level never got replenished to the pre-1992 level before the starting of 1996 (DanaJ has already stated this in her earlier post. Kudos to her!!)

In that case, we cannot say that exactly 9000 tonnes was caught by illegal fishing. It may be the case that only few tonnes was caught, but that additive to the extensive illegal fishing done from 1992 to 1995 + current level of legal fishing done in 1996 = pre-1992 levels.

This will become more clear if you attach numerical figures to the case.
Imagine that the pre-1992 level of lobsters was 12,000.
As per the argument:
- in 1996, 9000 lobsters were fished out illegally. So for legal fishing only 3000 were left ( that's why(D) thus can't be 100% true.
All is good till here --> Conclusion.
But what if from 1992 to 1995, 6,000 lobsters were fished out (cumulatively), and in these years 1000 got replenished. So we 12,000 - 6000 + 1000 = 4000 left. Out of these 4,000, 3000 were fished by legal fishing and 1000 by illegal fishing in 1996. So total amount still remains 12,000.

Note that the above figures were only hypothetical and not the actual figures. SO there are a lot of combinations that can be construed, to support (A).

(D) On negation of this choice, the amount may be significantly lower than 9000 tonnes, that was caught by legal fishing. We don't know from the passage that what amount was caught by legal fishermen. Even if the amount of lobsters was significantly ower than 9000 tonnes, it still doesn't shatter the conclusion.

Thanks
Prashant

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by hjafferi » Thu Aug 23, 2012 1:05 am
IMO A

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by amanmish88 » Tue Oct 01, 2013 12:18 pm
Hi DanaJ,

When I started doing this question under the time constraint of two mins, the first thought that came to me after reading the first option was that this one is an inference and not the assumption.So I moved on the the other options.

When i read the (C), i did the following :-
1) Applied the negation rule :- option C states that ,as a whole bunch, the outlaw fishing boats did not catch more lobsters than the legal boats did. Lets negate it - the outlaw boats did catch more number of lobster than did the legal boats.So the outlaw boats caught more than those 9000 lobsters. This statement does harm the argument because the argument says that the legal boats caught 9000 less lobsters. Hope you got where i am heading. If one side increases, the other side should go down.

2) Tried to put the option (C) between premise and the conclusion :- This was how i constructed the statements:
"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.Since outlaw fishing boats did not, as a group, harvest more lobsters than did licensed lobster-fishing boats,the outlaw fishing boats harvested about 9,000 tons of lobster illegally that year."

Can you please tell me what mistake i am making?

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by kinji@BTG » Sun May 18, 2014 9:43 am
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.
If this is negated, the argument falls apart - Hence A) If it has declined the argument that the gap of annual catch between 1992 and 1996 can be attributed to illegal catch.

B. The average annual lobster catch, in tons, of an outlaw fishing boat has increased steadily since 1992. -Out of scope as we are talking about the 1996 illegal catching of lobsters.

C. Outlaw fishing boats do not, as a group, harvest more lobsters than do licensed lobster-fishing boats. - We are not comparing the legal and illegal catch

D. The annual legal lobster harvest in Belukia in 1996 was not significantly less than 9,000 tons. - Lets say it is 4k tons. The argument doesn't break or support the argument.

E. A significant proportion of Belukia's operators of licensed lobster-fishing boats went out of business between 1992 and 1996. - it doesn't affect the argument as per the premise - "despite there being no reduction in the level of legal lobster fishing activity"

I will pick A)

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by kinji@BTG » Sun May 18, 2014 9:46 am
amanmish88 wrote:Hi DanaJ,

When I started doing this question under the time constraint of two mins, the first thought that came to me after reading the first option was that this one is an inference and not the assumption.So I moved on the the other options.

When i read the (C), i did the following :-
1) Applied the negation rule :- option C states that ,as a whole bunch, the outlaw fishing boats did not catch more lobsters than the legal boats did. Lets negate it - the outlaw boats did catch more number of lobster than did the legal boats.So the outlaw boats caught more than those 9000 lobsters. This statement does harm the argument because the argument says that the legal boats caught 9000 less lobsters. Hope you got where i am heading. If one side increases, the other side should go down.

2) Tried to put the option (C) between premise and the conclusion :- This was how i constructed the statements:
"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.Since outlaw fishing boats did not, as a group, harvest more lobsters than did licensed lobster-fishing boats,the outlaw fishing boats harvested about 9,000 tons of lobster illegally that year."

Can you please tell me what mistake i am making?
Option C. Outlaw fishing boats do not, as a group, harvest more lobsters than do licensed lobster-fishing boats.

Lets negate it : Outlaw fishing boats , as a group, harvest more lobsters than do licensed lobster-fishing boats.
Lets say outlaw group harvested 4K and legal catching was 3k. Does it support the argument though it satisfies the negated option.

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reply

by rashedais » Wed Oct 31, 2018 6:34 pm
ssgmatter 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.

Clueless!Any thoughts
How does the negation of (A) destroy the argument? @GMATGuruNY

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question

by rashedais » Fri Nov 02, 2018 8:22 pm
ssgmatter 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.

Clueless!Any thoughts
How to use negation technique here. Please help @GmatGuruNY