Within the province, Pumpkinseeds are present in Christina Lake, Kootenay Lake, Boldue Lake and Osoyoos Lake on the mainland, and in Beaver, Elk, Prospect, Landford, Blenkinsoop (Swan), Glen, Glintz, Young, and possibly other small lakes on Vancouver Island. They are also found in Colquitz Creek, draining Beaver and Elk Lakes. There appears to be no authoritative record of the introduction of this fish into the Northwest. Lampmam (1949) states that adult largemouth bass and small fry of "various sunfish" were released into the Willamette River in 1893 by the United States Fish Commission, and it is assumed that Pumpkinseeds were included. In any case, they became widespread in Oregon and Washington at a fairly early date, and it is possible that those in the mainland lakes of British Columbia originated from this source by natural spread up the Columbia River and its tributaries.
On the other hand, it has been suggested that Pumpkinseeds were introduced accidentally into the British Columbia lakes along with Black Bass fry. This seems the most likely explanation for their presence on Vancouver Island, where they are found in lakes that also contain Smallmouth Bass.
They are considered an invasive species here. There are huge issues with them being illegally stocked as a way to initiate bass fishery in our province. The idea is they serve as food for bass. I am not sure you can legally transport them live to a pond and release them. It is a shame that they are so invasive in our northern climates because they are very pretty.