Passage Summary: In a specific coastal area, a type of plankton has decreased, and three types of fish that eat that plankton are dying off. Curiously, nothing else in the local environment seems to be having any trouble.

Reasoning: A 10 percent drop in P-plankton coincides with high death rates in three specific fish species that eat them, while the rest of the ecosystem remains unaffected.

Analysis: The mystery here is why a relatively small 10% drop in a food source is causing 'extraordinarily high' death rates in these specific fish while leaving the rest of the ecosystem untouched. We need a piece of information that explains why these fish are so uniquely sensitive to this specific change. Look for an answer that provides a mechanism for this high mortality, perhaps suggesting the plankton drop is a symptom of a larger problem or that these fish rely on that 10% more than it seems. The fact that no other species are affected suggests the cause is highly specific to the relationship between these fish and the plankton.