Creature Feature: Pacific Lamprey (Lampetra tridentata)
The Pacific Lamprey (Lampetra tridentata)
An adult Pacific lamprey (Photo courtesy of USFWS/Freshwaters Illustrated)
Do vampires roam the Salish Sea? Of course not! But what looks like a leech on steroids with three large fangs in a circle of pointy teeth could be featured in a Halloween movie. And it may just have a few things in common with Dracula and the Cullens. These important fish may seem spooky, but do not fear- the Pacific lamprey are actually harmless to people. They are even quite fascinating! Starting with their Latin name, Lampetra tridentata . What does this tell us about this special fish? (hint: look up the meaning of each root word in Latin).
Dracula of the Pacific
Lampreys are parasitic, which means they survive by feeding on living organisms. These parasites don’t kill their hosts like some others do. In fact, as parasites go, they’re quite polite. When they find a host they dig into its skin with rows of sharp teeth in a sucker-like mouth. They may hang on for hours, days, or weeks, but they only leave a small scar behind when they take off. They prey upon other fishes and marine creatures, from salmon to sharks to rockfish. And you probably guessed it- they are after blood.
Pacific lamprey mouth. Isn’t she cute?? Photo courtesy of USFWS/Dave Herasimtschuk
Like Dracula, they are also nocturnal, but the similarities end there. These ancient fish have seven gill slits, they don’t have stomachs, and they are very long (30 in or 76 cm) and slender. Speaking of ancient, all species of lamprey (there are many) are incredibly old. How old? Millions of years old. Using radiometric dating (look that up!) scientists found that some lamprey fossils are about 450 million years old, making them one of the oldest fish species in the Pacific. Just imagine ancestors of today’s Pacific lampreys feeding on dinosaurs!
Where art thou Pacific lamprey?
As the name suggests, Pacific lampreys roam the Pacific Ocean from Japan, Alaska, Canada, and down the U.S. coast to Mexico. If you’re thinking you won’t have the chance to see lampreys because you live further inland, think again!
These lampreys are anadromous. An anadromous fish is one that is born in freshwater, migrates to the sea to grow, and then migrates back up from the salty sea to the freshwater rivers that they were born in so that they can spawn. Salmon and steelhead are other, more famous examples of anadromous fish. In fact, it is even thought that where salmon or steelhead spawn, Pacific lamprey can be lurking in the depths (or shallows), too. Though by the time salmon arrived in the Pacific 6 millions years ago, Lamprey had already been shuttling nutrients between Pacific Northwest ocean and their home streams for 444 million years.
Life in a nutshell
Both lamprey parents help build a nest for their eggs in a freshwater river. They will use their mouths and teamwork to pick up and move stones into a nest.
After about 20 days the baby Pacific lamprey hatch. These larvae, called ammocoetes, drift downstream to slower water where sand or silt settles to the bottom, that they can burrow into.
Did you say… burrow?? Yes! When the drifting ammocoetes actually are big enough to sink, they dig in and sit in a hole in the bottom. Here they sit and sieve food from the water as it goes by…for several years. They feed mostly on algae, preparing for their lifetime of sucking blood by starting out as vegetarians (no self-respecting vampire would do that).
Lamprey larvae called ammocoetes get measured under a microscope. These are less than 3 mm long (Photo courtesy of USFWS/ James Barron)
Lonely? Boring? Not ammoecetes! These cute critters actually colonize, which means that there can eventually be several little tikes of various ages in neighboring mud holes. Quite the party! They don’t move around much unless a surge of water occurs, flushing them from their burrows. Then they have to re-settle downstream.
Ammocoetes transform, or metamorphose, into juvenile lamprey when they are ready to migrate to the ocean. Besides amphibians and just two groups of bony fishes, metamorphosis is unheard of in vertebrates. It’s a lamprey superpower. They gain eyes, teeth, and a desire to travel. They even get a brand new kidney to face their new, saltwater life. Metamorphosis takes place from July-October, and between that fall and the next spring, they make their way to the ocean. Once in the ocean, they morph into adults with growing appetites.
Baby lampreys (ammocoetes) are stationary filter feeders in their home streams for several years before swimming out to sea. Photo courtesy of USGS/ Will Phinney
After about 1-3 years in the ocean feeding on the blood of other fish, the life process begins again! The adults will migrate back to their home streams and overwinter there before spawning the following spring and summer. While in freshwater, adults will not eat, and lose 20% of their weight. To compare, if you weighed 100 pounds to start, you would lose 20 pounds while waiting for winter to end!
After all that, just like salmon, they will die after they spawn. Such a sacrifice they make to bring a new generation of lamprey into the world and feed many predators and people along the way.
A river otter grabs an easy snack of an adult lamprey that has returned from the ocean to its home stream to spawn. Photo by USFWS / Talia Rose
These fatty fish have been a traditional First Food for the Coast Salish and other tribes and First Nations of the Pacific Northwest since time immemorial. Every part of the fish is eaten and oil collected for many important purposes. Now tribal peoples are leading the way to bring lamprey populations back to what they used to be. Where have lamprey gone?
Troubling News
This super important fish is struggling. Lamprey are facing many issues in their environment that are causing their populations to decline.
Dams on rivers block the lampreys from reaching their home streams to spawn. Unlike salmon, the lampreys cannot jump up fish ladders, which means when their paths are blocked, they are really blocked.
Poor water quality, invasive species, loss of habitat, and ocean pollution are also major issues that these super cool animals are facing.
Besides people, many animals eat lamprey, including seals, orcas, sturgeon, otters, and more. If there are more lamprey to eat, more salmon will also survive. Everyone wins when we all help #savethelampreys.
Salish Sea Heroes are working hard to help the Pacific lamprey. They are trying to develop safe ways for lampreys to navigate past dams to spawn and swim to the ocean, and more work is being done to restore their habitats and make sure that their waters are clean. You can help too, by using cars less and choosing stream-safe products to clean your home and make your yard nice.
Luckily, there is a lot of work being done in the Pacific Northwest to help salmon populations, and this work will also help the Pacific lamprey (and many other species). It just goes to show how so many species are tied together, or interconnected. By helping one species, we help so many more, including us!