Wednesday June 15, 2022
Daily Fly —
Folks that grew up playing and fishing the banks of Idaho’s salmon and steelhead rivers 50 years ago may remember digging in the sand for handfuls of worm-like creatures they could use as bait.
Once very common across the Columbia River basin, Pacific Lamprey are native to the Pacific Northwest and have declined substantially, mainly because it is very difficult for them to navigate dams and reservoirs. Unless one knows where to look, most people will not see Lamprey in the wild today. Young fish or larvae known as ammocoetes can spend up to seven years in the sand filtering water for food. They then emerge and migrate downstream in rivers carrying them to the ocean.
As they migrate downstream, they change color from dark brown to silver and develop eyes to see. As their body changes, they no longer filter water for food but become parasitic, latching on to other fish or mammals like whales that will provide them with food and also give them a ride as they grow in the ocean. When they are ready, adults make their way back to rivers and streams to spawn before they die, much like salmon except they do not necessarily home in to the specific stream they were born in.