Passage Summary: A new power plant started putting its wastewater into a river, and right after that, people started catching fewer bass fish in the area below the plant.

Reasoning: A power plant began discharging wastewater into a river, which was followed by a decline in the number of bass caught by anglers downstream.

Analysis: The stimulus presents a correlation between the plant's operation and a decline in fishing success, and we need to find an explanation for this change. Since this is an 'EXCEPT' question, four options will provide a plausible cause for the decrease, while the correct answer will not. We should look for an answer that is either irrelevant to the bass population or suggests that the fishing should have actually improved or stayed the same.