It's really important to consider the long-term cumulative effects of changes in the aquatic ecosystems, for example, especially in a highly urban and developed area like Vancouver and Burrard Inlet.
Herring as a mid-level forage fish used to be incredibly abundant in Burrard Inlet. In 1882, a commercial herring fishery was opened by early European settlers. They primarily fished with dynamite. They would see a school of herring, throw dynamite in the water and scoop the herring out, so by 1898 herring were totally extirpated from Burrard Inlet and never came back.
For one thing, the archeological record shows that in some parts of Burrard Inlet herring made up upwards of 50% of the Tsleil-Waututh fish diet. As well, it's an incredibly important food source for chinook salmon and chum salmon and the things the whales eat.