Two temporally and morphologically distinct trap types were utilized, and the shift from the Winged Heart trap type to the Winged Chevron trap type about 700 years ago appears abrupt and closely coincident with Little Ice Age climatic conditions and increased importance of salmon at Aboriginal village sites on west coast Vancouver Island, at Haida Gwaii (Queen Charlotte Islands) and south coast Alaska.

England’s monarchs were sacrificing to Woden and persecuting Christian missionaries when First Nations managed a vast, highly-productive, industrial-scale fish harvesting complex in the estuary of the Courtenay River.
At first, the elaborate arrangement of 300 ingenious traps on the sandy flats of the river mouth harvested herring, which still mass to spawn off the east coast of Vancouver Island every March.
But 700 years ago, perhaps in response to climate change, the technology was altered to exploit pink, chum, coho, chinook and possibly sockeye salmon.