Tiger sharks are common in the waters surrounding Tenare Island. Usua

Tiger sharks are common in the waters surrounding Tenare Island. Usually tiger sharks feed on smaller sharks, but sometimes they have attacked tourists swimming and surfing at Tenare's beaches. This has hurt Tenare's tourism industry, which is second only to its fishing industry in annual revenues. In order to help the economy, therefore, the mayor of the island has proposed an ongoing program to kill any tiger sharks within a mile of the beaches.

Which of the following, if true, most strongly calls into question the likelihood that implementation of the mayor's proposal will have the desired consequence?

(A) Even if not all the tiger sharks that come close to the beaches are killed, the existence of the program would reassure tourists.
(B) Business owners who depend on tourism are willing to pay most of the cost of implementing the program.
(C) Tourists come to Tenare Island for its beaches, even though the island features a number of other tourist attractions.
(D) The small sharks on which tiger sharks prey feed on fish that are commercially important to the island's fisheries.
(E) Not all tourists who come to Tenare Island enjoy swimming or surfing.

Very tricky,

(D) The small sharks on which tiger sharks prey feed on fish that are commercially important to the island's fisheries.

small shark...feed on fish (small shark eats small fishes)

when tiger sharks will be killed then the number of small sharks will increase then these small sharks will eat the small fishes ,which are commercially important to generate revenue.

Opps i got this wrong. I chose E. I didnt understand D at first, i thought Tiger Sharks are feeding small sharks, with careful reading found out, it is not so!

My take away from HeyGMAT's Explanation - To be careful while choosing options with some,not many, a few sort of wordings. This one is going to my exception list! +1 to you HeyGMAT!

Answer is (D) only.

This is a weaken question. There is a plan - to help the economy, kill tiger sharks within a mile of the beaches.

We have to weaken it i.e. we have to prove that killing the tiger sharks will not help the economy.

The argument tells us the following:
Tiger sharks feed on smaller sharks but sometimes attack tourists.
Tenare's fishing industry provides most revenues and tourism industry is second.

A. Even if not all the tiger sharks that come close to the beaches are killed, the existence of the program would reassure tourists.
This doesn't weaken our plan, it actually strengthens it. Tourists will get reassured and will come back. Economy will be helped.

B. Business owners who depend on tourism are willing to pay most of the cost of implementing the program.
Again, if anything, it strengthens our plan (very slightly though!). The cost of the program will not be paid by the govt and hence the revenues generated will not be lost on implementing the program. So economy will be helped.

C. Tourists come to Tenare Island for its beaches, even though the island features a number of other tourist attractions.
Irrelevant

D.The small sharks on which tiger sharks prey feed on fish that are commercially important to the island\'s fisheries.
If tiger sharks are killed, small sharks will prosper which means the number of fish they feed on will decrease. Since this fish is commercially important, if their availability reduces, the revenues from fishing may reduce. Hence, actually, the economy may not be helped. This weakens our plan.

E. Not all tourists who come to Tenare Island enjoy swimming or surfing.
Irrelevant.

Answer (D)

I struggled with this one because answer D reads as if the "small sharks" are important to the island's fisheries.... because they (along with fish) are being caught by fishermen. Your answer makes sense but only if you don't read that the small sharks are important commercially important to the fisheries.... Did i read something incorrectly?

(D) The small sharks on which tiger sharks prey feed on fish that are commercially important to the island\'s fisheries.

Tiger sharks feed on small sharks which in turn feed on fish that are commercially important to the island.

Option (D) tells you that small sharks feed on the fish that are commercially important to the island. They actually reduce the number of fish that are important. The option does not imply that the small sharks themselves are important to the island.

here's the basic deal:
* economy has 2 main pillars: TOURISM and FISHING
* tiger sharks are hurting TOURISM
* mayor wants to help TOURISM by killing tiger sharks

if you want to weaken this argument, you want to show that killing the tiger sharks will have a deleterious effect on the other pillar of the economy - namely, FISHING. (note how much more obvious this is if you diagram the passage, as i've roughly done above).

choice d is correct, because it shows that, while killing tiger sharks may be good for TOURISM, it will be bad for FISHING (which, the passage asserts, is ultimately a more important industry).

wrong answers:
choice a has the opposite effect: it actually strengthens the mayor's policy, by assuring that there will be a positive effect even if the program is not carried out to the fullest.

choice b is neutral (transferring $ from businesses neither infuses $ into the economy nor removes $ from the economy).

choice c strengthens the policy, because it underscores the idea that the beaches are critical to the economy (and therefore that removal of the tiger sharks is of paramount importance)

choice e is irrelevant, because the non-beach tourists have no bearing on the issue either way.

Tiger sharks are common in the waters surrounding Tenare Island. Usually tiger sharks feed on smaller sharks, but sometimes they have attacked tourists swimming and surfing at Tenare's beaches. This has hurt Tenare's tourism industry, which is second only to its fishing industry in annual revenues. In order to help the economy, therefore, the mayor of the island has proposed an ongoing program to kill any tiger sharks within a mile of the beaches.

Which of the following, if true, most strongly calls into question the likelihood that implementation of the mayor's proposal will have the desired consequence?

(A) Even if not all the tiger sharks that come close to the beaches are killed, the existence of the program would reassure tourists.
This actually say that plan will lead to increased tourist …so in a way this option strengthens the argument

(B) Business owners who depend on tourism are willing to pay most of the cost of implementing the program.
Irrelevant

(C) Tourists come to Tenare Island for its beaches, even though the island features a number of other tourist attractions.
This option only says why it is important to have control on population of tiger sharks. As tourists love the islands beaches, TS are a major threat to the island’s tourists

(D) The small sharks on which tiger sharks prey feed on fish that are commercially important to the island's fisheries.
If TS are killed, the other sharks which TS eats will increase in number (of course a no-brainer).
This option gives us information about what will happen if these other small shark’s number increases.
The option say, this increased number of small sharks prey on fishes which are commercially important. So, the number of fishes will go down and thus will affect the Island’s economy and thus will not let the mayor’s proposal to succeed.
Perfect answer.

(E) Not all tourists who come to Tenare Island enjoy swimming or surfing.
In a way, this option is irrelevant as the argument already says that Tiger shark’s attack has hurt the island’s tourist industry. So knowing how many tourist enjoy the island’s beaches will make no difference to the argument and the mayor’s plan.

For someone struggling with this question, maybe this article can help: https://www.manhattanprep.com/gmat/blog/tackling-a-gmatprep-critical-reasoning-weaken-problem/

Hi experts
I am not able to comprehend the reasoning given for (D) given in various posts. That the number of fish will decrease as small sharks population increases, thereby impacting fishing. There is nowhere in the argument it is mentioned that small sharks feed on fish. Then how can we assume this piece of information?