Lamprey are pretty interesting critter. Here in PNW we have 3 species (the Pacific, river and western brook). The Pacific and river are anadromous with the pacific being the more common and likely the species that Dave say the other day. The brook lamprey is strictly freshwater species whose adult phase in non-parasitic (AP - that likely is the species you saw in the Whatcom tribs).

Up to 30 years lampreys were common through out the PNW and often seen in our local rivers. They are spring spawners with a timing similar to that of steelhead. They also construct redds that at least superfically look like steelhead redds.

As mentioned they were quite numerous but in recent decades their populations have crashed and headed to ESA listing across the region; likely for much the same reasons that our steelhead populations have fallen on hard times.

Now if we can just get the State to go to selective fisheries with Wild Lamprey Release (WLR) management, end those lamprey hatchery programs and get rid of the lamprey gill net fisheries (both treaty and non-treaty) we will see populations quickly rebounding to carrying capacity (very much t.i.c.).

Tight lines
Curt