Q17 - Traditional hatcheries raise fish in featureless envir

[Laura Damone]

Question Type:
Necessary Assumption

Stimulus Breakdown:
Conclusion: fish raised in the experimental hatcheries are more likely to survive after release. Premises: the experimental hatcheries expose fish to more visual stimulation and varied routines as compared to traditional hatcheries. When released, fish from experimental hatcheries are bolder in exploring new environments and trying new foods.

Answer Anticipation:
There's a big gap here between being bolder and being more likely to survive. We can predict either a bridge assumption that links the two concepts (fish that are bolder are more likely to survive) or a defender assumption that defends against an objection to this link up (going into new environments and eating new foods doesn't make fish more likely to die).

Correct answer:
C

Answer choice analysis:
(A) This is a classic trap answer for Necessary Assumption questions. The economic feasibility of a course of action is almost never necessary to assume. Consider the negation of this one: it's not economically feasible. Who cares? That just means the experimental hatcheries aren't a model for the future of commercial hatcheries.

(B) Does this have to be true in order to conclude that there's something else effecting their survival rate too (the hatchery they're from)? Nope. Eliminate.

(C) Does this one have to be true? Hard to say, maybe, so negate to be sure. What if no fish from traditional hatcheries ever die because of their foraging timidness. Well, if that's true, then how can we conclude that the fish from experimental hatcheries have a survival advantage just because they're bolder? We can't, so this negation ruins the argument, making it the correct answer.

(D) The degree of this one is troubling: "need to eat" and "many different types" make this an unlikely candidate. To see why, negate: one hatchery-raised fish can survive eating only a few types of food. Does that blow up our argument? Nope. Remember, when negating a conditional statement, just raise the possibility of a non-conforming case. If that non-conforming case doesn't ruin the argument, the answer is wrong.

(E) Another conditional, so negate with a non-conforming case! If one fish in the wild lives in a visually boring environment, does that ruin our argument? No way.

Takeaway/Pattern:
There are a lot of ways a necessary assumption can be phrased, so don't freak out if you make a solid prediction but don’t see it among the answer choices. Work wrong to right, keeping an eye out for classic traps and degree issues (A, D, and E), and stay focused on the exact task of the question. Ask yourself "does this really need to be true of the argument to work?" If the answer is no, eliminate (B). If you're not sure, negate.

#officialexplanation

[Wenjin]

Would D be a better answer if it addresses “ new food” instead of “different types of food”?

[ohthatpatrick]

Agreed. They don't need to have a diet of many foods at once, but the implication is they may need to be willing to try a food source that wasn't previously one they had used.

"need" is still too strong. This is just supposed to aid in their survival, not be necessary to it.

If it said
"hatchery-raised fish have a better chance of surviving if they try more new types of food"
it seems legit

[ZhengL938]

Would answer choice (B) be a better one if it said "The quality of the envoronments into which hatchery-raised fish are released does not have significant effect on the fish's survival rate "?

Thanks!

[StratosM31]

Would answer choice (B) be a better one if it said "The quality of the envoronments into which hatchery-raised fish are released does not have significant effect on the fish's survival rate "?

Thanks!

I don't think so.

We have no information regarding what kind of environments the wild fish are released to and whether there is a difference among their quality. Therefore, we can't make any statement regarding whether it is a necessary assumption or not.

Assuming it does have a significant effect: so what? It could be the case that all fish, from both traditional and experimental hatcheries, are released to the same environment, or to environments with exactly the same quality. In that case (which we are allowed to assume, since there is no information given about it), the assumption would not be necessary.

To be honest, I chose exactly this option (B) when I took this PT b/c I didn't know what timid means (English is not my first language)