What was the impact of gold mining on the Fraser River salmon stock?

• A. Salmon stocks increased due to mining
• B. Gold mining caused salmon stock to leave the river
• C. No impact
• D. Salmon became the primary export

Answer: (B)

The question tests how resource extraction in the 19th century affected river fisheries, specifically the Fraser River salmon. Gold mining disrupted the river environment in ways that hurt salmon: mining methods like hydraulic mining and dredging stirred up enormous amounts of sediment, filled in spawning gravels, and introduced pollutants. This sediment and pollution damaged the areas where salmon lay eggs and where young fish develop, and it also altered the river’s channels, making it harder for salmon to migrate to their upstream spawning grounds. As a result, salmon populations declined, and fish effectively left or avoided the most affected parts of the river. So the best description is that gold mining caused the salmon stock to leave the river or, more generally, to decline due to habitat destruction and pollution. The other options don’t fit: mining did not increase stocks, there was a clear impact, and salmon were not simply exported as a primary outcome of mining.