Pacific Lamprey: Salmon’s underappreciated neighbor

Guest Blogger: Erin Hanson

The following guest post was voted best in the class for an undergraduate assignment on communicating science from Humboldt State University’s Fall 2020 Fish Conservation and Management course taught by Dr. Andre Buchheister. The assignment required students to find a peer-reviewed article on a fisheries management topic that interests them and to communicate the issue in a blog format to a general audience.

The west coast of the United States is home to numerous important fisheries, however, most of the time, the conversation is monopolized by a few popular species such as the Coho and Chinook Salmon. So, what about some of those that are less well known? Well, mainstream popularity certainly isn’t everything, and no species proves that better than the Pacific Lamprey, Entosphenus tridentatus.

Some consider Pacific Lamprey to have an “intimidating” and “alien” look (photo credit: Jeremy Monroe, Freshwaters Illustrated via FWS OFWO).

Due to its eel-like body and intimidating sucker-like mouth, European settlers treated this fish as a pest rather than a valuable resource (Columbia River Inter-Tribal Fish Commission 2011). However, the Indigenous peoples of the west coast have always understood the immense importance of lamprey not only for the ecology of their ecosystems, but also for their subsistence and spirituality (Simpson 2019). Lamprey are considered to be one of the “First Foods” along with things like salmon, deer, and huckleberries. These foods play a central role in ceremonies as well as being incredibly important for food security and survival (Columbia River Inter-Tribal Fish Commission 2011).

In the 1970s, Indigenous communities noticed a sharp decline in the number of lampreys returning to the Columbia River basin (Columbia River Inter-Tribal Fish Commission 2011). After centuries of disregard for the lamprey, the California Department of Fish and Wildlife is finally protecting this unique fish after consistent pressure and collaboration from Indigenous communities. Thankfully, steps are now being taken to address the numerous factors that prevent Pacific Lamprey from flourishing. Some of the most pressing concerns raised by Indigenous communities include habitat destruction, water contamination, and dams (Columbia River Inter-Tribal Fish Commission 2011).

What is a Lamprey?

            Pacific Lamprey, Entosphenus tridentatus, are part of an ancient group of jawless fishes called Agnathans. Lamprey, like many salmonid species, are anadromous, meaning that they spawn in freshwater and then spend a majority of their adult life in marine environments. Juvenile lamprey are called ammocoetes and spend up to seven years maturing in rivers and tributaries before heading to saltwater as an adult (Lampman 2017). Lamprey are unique from most other fishes because they lack paired fins, scales, bones, vertebrae, and a swim bladder (USFWS 2019). Pacific Lamprey generally gets a bad reputation due to the fact that they are parasitic, feeding off larger fish species and even marine mammals (Columbia River Inter-Tribal Fish Commission 2011). They also can look quite “intimidating” and “alien” with their oral sucker and three cuspid teeth which are used to cling to their hosts during feeding  (USFWS 2019). However, Pacific Lamprey pose no threat to humans.

Pacific Lamprey have an oral sucker disk and three cuspid teeth which are used to cling to their hosts during feeding (photo credit: Oregon Zoo).

What Caused the Decline of the Pacific Lamprey?

Current Pacific Lamprey populations in the Pacific Northwest are estimated to be only about five to ten percent of what was recorded in 1960s (Shultz 2015). Pacific Lamprey populations are in peril due to an increasing lack of access to streams and tributaries that they rely on for reproduction, particularly on the Klamath, Snake, and Columbia Rivers. A large reason for this lack of access is dams and water diversions (Simpson 2019). Dams generally have fish ladders in place for salmon passage; however, Pacific Lamprey are not able to use traditional fish ladders, meaning that they are often caught in screen and killed before they are able to complete their journey to or from the ocean (USFWS 2019).  If Pacific Lamprey are unable to pass over dams, the likelihood of them reproducing successfully greatly diminishes (Lampman 2017). Other factors in their population declines are contaminants, reduced prey numbers, and overfishing for use as bait (USFWS 2019).

How Can the Pacific Lamprey Fishery be Restored?

In 2011, Indigenous Tribes from the Columbia River Basin created a comprehensive restoration plan for the Pacific Lamprey with the help of Tribal and non-Tribal biologists (Columbia River Inter-Tribal Fish Commission 2011). This plan details the many steps required to bring the Pacific Lamprey populations back to sustainable levels. As only 50% of adult lamprey can pass over dams without specialized passage (Columbia River Inter-Tribal Fish Commission 2011), fish passage one of the major goals of the restoration plan. This can be achieved by modifying existing dams to reduce water velocity, adding specialized lamprey ladders to aid in fish migration (Columbia River Inter-Tribal Fish Commission 2011), and improving fishways with refuge boxes, lamprey ladders, and adjusting fishway base flow (Lampman 2017). For example, the Bonneville Dam on the Columbia River has added “refuge boxes” to the auxiliary water channel to help protect the lamprey from predation and to give them shelter from the hot sun during the day (Lampman 2017).

Video still of Pacific Lamprey passage over a dam (video credit: NOAA Fisheries via Columbia River Inter-Tribal Fish Commission). To view the full video of the Pacific Lamprey ladder, click on the image or visit:

Public outreach and education about the Pacific Lamprey are also vital for continued restoration efforts. I decided to write about this topic for that very reason. The general (non-Indigenous) public has very little knowledge about Pacific Lamprey and, as we know, public interest can be a large driving force when it comes to implementing change for conservation. For instance, many people do not understand how lamprey actually help the salmon populations despite being parasitic. They act as a “prey buffer” for salmon against predators, therefore increasing adult salmon survival (Columbia River Inter-Tribal Fish Commission 2011). A “prey buffer” means that when lamprey and salmon are in the river together, they are both targeted by predators which keeps one species from being picked off more than the other (Columbia River Inter-Tribal Fish Commission 2011). People certainly love and appreciate salmon and linking the two species together in people’s minds may help get people more inspired to protect the, perhaps less charismatic, but equally important lamprey. Increased outreach can help non-Indigenous communities become more engaged and invested in Pacific Lamprey conservation and help herald the important role they play environmentally.

It is vital that Indigenous communities continue to lead this conservation effort. Their communities have been the most affected by the decline in Pacific Lamprey and they have knowledge on the species dating back hundreds and hundreds of years. Eurocentric management of natural resources has not saved this struggling species, and, in some cases, it has even hindered its success. However, more recent efforts to work alongside Indigenous communities have proven to be far more effective in restoring Pacific Lamprey back towards 1960s population levels (Shultz 2015). With the support of Indigenous communities and biologists, the Pacific Lamprey, salmon’s underappreciated neighbor, may once again thrive in the Pacific Northwest.

For other Humboldt State student posts, please see:

About the Author:

Hello! My name is Erin Hanson and I am a current Marine Fisheries major at Humboldt State University. Very early on in my life, I knew that studying fish and marine life was the right career path for myself. As a child, I spent a lot of time at the Oregon Coast Aquarium where I first developed my love for marine creatures great and small.  I graduated from the Oregon Coast Community College Aquarium Science Program in Newport, Oregon in 2016. Through this program, I developed my skills as an aquarist and became passionate about public aquarium work and animal husbandry. I am currently working at the Humboldt State University Telonicher Marine Laboratory in Trinidad, California as a lab technician taking care of local northern California fish and invertebrates. Besides animal husbandry, I am also passionate about preserving diversity of freshwater and marine fish and invertebrates. I hope to combine both my passions in a career where I can help educate and inspire the next generation of fisheries scientists and aquarists.


US Fish and Wildlife Service (USFWS). 2019. Pacific Lamprey.  

Lampman, R. 2017. Practical Guidelines for Incorporating Adult Pacific Lamprey Passage at Fishways. U.S Fish and Wildlife.

Simpson, K. 2019. Overlooked fisheries of Baduwa’t: An oral history study exploring the environmental and cultural histories of eulachon and Pacific Lamprey in the Mad River Basin, a Wiyot watershed. Humboldt State University Thesis.

Columbia River Inter-Tribal Fish Commission. 2011. Tribal Pacific Lamprey Restoration Plan for the Columbia River Basin.

Shultz, L. 10 February 2015. Study finds lamprey decline continues with loss of habitat in Oregon. Oregon State University Press Release.

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