What Caspian Lamprey Are and Where They Live
Caspian lamprey are jawless fish that look more like eels than typical fish—long, cylindrical bodies with a circular mouth ringed with horn-like teeth. They are parasitic feeders, attaching to other fish and rasping away tissue and blood. In North America, they are found primarily in the Pacific Northwest, particularly in the Columbia River system, where they migrate upstream from the ocean to spawn in freshwater.
These fish spend most of their adult lives in saltwater or brackish environments but return to rivers to reproduce. The Columbia River from the Pacific coast inland to Idaho and Oregon supports the largest populations. Smaller populations exist in other Pacific Northwest river systems, including the Snake River and tributaries. Unlike many other lamprey species, Caspian lamprey do not establish landlocked populations in lakes—they are anadromous, meaning they must return to the sea to mature.
Caspian lamprey are not a primary target for recreational fishing in North America, though they are harvested commercially and by tribal fisheries in the Pacific Northwest. Most anglers encounter them incidentally while fishing for salmon, steelhead, or other species in the Columbia River system.
Key Takeaways
- Caspian lamprey are anadromous parasitic fish found mainly in the Columbia River system and other Pacific Northwest rivers.
- They spend their adult lives in the ocean or estuary and return to freshwater only to spawn, typically in spring and early summer.
- Recreational fishing for Caspian lamprey is uncommon; most encounters happen while fishing for salmon or steelhead.
- Tribal and commercial fisheries harvest Caspian lamprey in the Pacific Northwest, but regulations and seasons vary by state and tribe.
Seasonal Timing and Migration Patterns
Caspian lamprey begin their upstream migration in spring, typically from April through June, though timing varies depending on water temperature and flow. They move through the Columbia River system in waves, with peak activity usually occurring in May and June. Unlike Pacific salmon, which stop feeding once they enter freshwater, Caspian lamprey continue to feed on other fish during their spawning migration, making them visible to anglers throughout their river stay.
Spawning occurs in gravel beds in smaller tributaries and upper river sections, usually from June through August. After spawning, adults die—they do not return to the ocean. Juveniles, called ammocoetes, remain in freshwater for several years (typically 3 to 7 years) before transforming into parasitic adults and migrating to the ocean. This long freshwater juvenile stage means young lamprey are present year-round in spawning tributaries, though they are rarely encountered by anglers because they burrow in soft substrate and are nocturnal.
Where to Fish for Caspian Lamprey in the Columbia River System
The Columbia River mainstem from the Pacific coast to the Bonneville Dam is the primary zone where migrating adult Caspian lamprey are encountered. Dams on the Columbia—Bonneville, The Dalles, John Day, and McNary—create barriers that slow lamprey movement and concentrate them in tailrace areas and below dam structures. These zones are accessible from public boat launches and shore access points managed by the U.S. Army Corps of Engineers.
The Snake River, a major tributary of the Columbia, also supports Caspian lamprey populations. Lamprey move upstream through the Snake into Idaho, particularly in spring and early summer. Access points exist at various public areas managed by state wildlife agencies and the Corps of Engineers, though some sections require permits or have seasonal closures.
Smaller tributaries such as the Cowlitz River (Washington), Willamette River (Oregon), and Umatilla River (Oregon) receive spawning runs of Caspian lamprey. These rivers are more accessible to shore anglers and offer quieter fishing than the mainstem Columbia. Check with the Washington Department of Fish and Wildlife or Oregon Department of Fish and Wildlife for current access conditions and any seasonal restrictions on specific tributaries.
Regulations and Seasons by State
Recreational fishing for Caspian lamprey is not a standard category in most state fishing regulations. Washington and Oregon do not list Caspian lamprey in their standard sport fish regulations, and there are no established recreational seasons or bag limits for them. This means they are not legally protected as a game fish, but they are also not typically the focus of recreational harvest.
Tribal fisheries in the Columbia River Basin—including the Yakama Nation, Nez Perce Tribe, Umatilla Tribes, and others—conduct commercial and subsistence harvests of Caspian lamprey under separate agreements with state and federal agencies. These harvests are managed under tribal fishing rights and are not open to the general public.
If you catch a Caspian lamprey while fishing for other species, check your state's current fishing guide to confirm whether it must be released. Regulations change, and some states have begun tracking lamprey populations more closely. Contact your state wildlife agency before your trip to confirm the current status.
How to Identify Caspian Lamprey
Caspian lamprey are unmistakable once you know what to look for. Adults are dark gray to brown on the back and lighter on the belly, typically 24 to 30 inches long, though some reach 36 inches. Their most distinctive feature is the circular mouth, which is lined with concentric rings of horn-like teeth arranged around a central piston-like tongue. When attached to another fish, they rasp away tissue using this tongue.
Unlike eels, lamprey have no scales and no paired fins (pectoral or pelvic fins). They have two dorsal fins on their back and a tail fin, but these are small and not prominent. Their eyes are positioned on the sides of their head, and they have seven gill openings in a line behind the eye on each side of the body.
Juvenile lamprey (ammocoetes) look completely different—they are small (usually under 6 inches), pale, and have a sucker-like mouth rather than a circular toothed one. They are rarely seen by anglers because they live buried in soft substrate in spawning tributaries.
Incidental Encounters While Fishing for Other Species
Most anglers in the Pacific Northwest encounter Caspian lamprey while fishing for salmon or steelhead in the Columbia River system. If you hook one, it will fight hard and thrash violently, which can be startling if you are not expecting it. Lamprey are strong swimmers and can break light tackle, so use steady pressure and avoid jerking.
If you land a Caspian lamprey and want to release it, handle it carefully—they are slippery and can injure themselves if thrashed on rocks or gravel. Wet your hands before handling, and return it to the water quickly. Do not attempt to remove it from the water by hand unless you are certain of your state's current regulations.
Caspian lamprey are not dangerous to humans, though their appearance can be alarming. They do not bite people and are not aggressive toward anglers. If you see one in the water or catch one, you are witnessing a fish that has traveled hundreds of miles from the ocean to spawn—a remarkable migration that few anglers get to observe.
Ecological Role and Conservation Status
Caspian lamprey are native to the Pacific Northwest and play a role in the river ecosystem as both predators and prey. Adult lamprey feed on salmon, steelhead, and other fish, which can affect populations of those species. At the same time, lamprey are food for larger predators, including birds, seals, and larger fish. Their presence in the Columbia River system is monitored by fisheries managers as part of broader efforts to understand river health and fish populations.
Unlike sea lamprey, which are invasive in the Great Lakes and cause significant damage to fish populations, Caspian lamprey are not considered a conservation problem in their native range. However, dams and habitat loss have reduced their historical populations. Some river restoration efforts in the Pacific Northwest include provisions to help lamprey pass upstream, recognizing their role in the ecosystem and their cultural importance to tribal nations.
Frequently Asked Questions
Can I keep a Caspian lamprey if I catch one?
Recreational fishing for Caspian lamprey is not regulated as a game fish in Washington or Oregon, so there are no standard bag limits or seasons. However, regulations can change, so check your state's current fishing guide or contact your state wildlife agency before your trip. Tribal fisheries do harvest lamprey commercially and for subsistence, but those fisheries are not open to the general public.
Are Caspian lamprey dangerous?
Caspian lamprey are not dangerous to humans. They do not bite people and are not aggressive. They feed on fish by attaching to them with their circular mouth, but they have no interest in anglers. If you catch one, you can handle it safely by keeping your hands wet and returning it to the water quickly.
Where do Caspian lamprey go in winter?
Adult Caspian lamprey that have not yet spawned remain in the river during winter, though they are less active in cold water. Spawning occurs in summer, and adults die after reproduction. Juveniles (ammocoetes) spend several years in freshwater tributaries, buried in soft substrate, before transforming and migrating to the ocean.
How do I tell a Caspian lamprey from a sea lamprey?
Sea lamprey are not native to the Pacific Northwest and are not found in the Columbia River system. Caspian lamprey are the only lamprey species you are likely to encounter while fishing in Pacific Northwest rivers. If you catch a lamprey in the Great Lakes or Atlantic coast, it is likely a sea lamprey, which is invasive and should be reported to your state wildlife agency.
Why do dams affect Caspian lamprey migration?
Dams block or slow the upstream movement of migrating lamprey, concentrating them in tailrace areas below the dam. Some lamprey can pass through dam spillways or fish ladders, but many are delayed or diverted. This affects their ability to reach spawning habitat in upper tributaries and can reduce reproductive success for the population.