Pacific salmon, especially Chinook and Chum, reside and feed in estuaries during downstream migrations. But the extent to which they rely on estuaries, and which habitats within estuaries, is not well understood. We need to understand this complexity if we are going to enact effective conservation policies. This is especially important in urban systems where habitat loss is ongoing, and at different rates across the estuarine mosaic. The Fraser River estuary, for example, supports a multitude of fish species…