On both coasts of North America, salmon have long symbolized speed, power and abundance in nature. But today salmon populations are plummeting for a variety of reasons. Aquaculture, or fish farming, seems to offer a way to satisfy the exploding demand for fresh fish. But it's controversial. David Suzuki is among the critics who question the current practices of this young industry. To explore this important issue in Europe and North America we joined forces with the BBC.