In addition, the Fraser River is one of the greatest salmon rivers in the world. All five species of Pacific salmon are found in the Heart of the Fraser River – pink, chinook, coho, sockeye, and chum – at various stages of their life cycle.
The largest population of pink salmon (over 10 million) are known to spawn right in the mainstem of the gravel reach in the Heart of the Fraser. Sockeye have been known to rear in the mainstem, side channels and sloughs of the lower Fraser River. Chum salmon (over 1 million) are known to spawn in the side channels of the Fraser such as the side channel besides Herrling island. Ocean-going coastal cutthroat trout are known to inhabit the gravel reach where they forage and spawn in the mainstem and side channels. Juvenile chinook are known to use the side channels and riverine habitats to rear and hunt as they make their way down to the ocean.
The flooded islands provide important habitat for these small fish to retreat and seek refuge from the rushing mainstem of the Fraser during spring freshet. Recently the Committee On the Status of Endangered Wildlife in Canada (COSEWIC) declared half of assessed chinook populations are endangered with some populations possibly being wiped out in the next 20 years. Protecting the gravel reach of the Fraser is one important puzzle piece in supporting these chinook populations on the brink of extinction.