For the Love of Lampreys By Dave’y Lumley Yakama Nation Pacific Lamprey Project

The Yakama Nation Fisheries Pacific Lamprey Project works to study lamprey throughout the Yakima River and its tributaries. There are over 40 species of lamprey found throughout the world and the Yakima River Basin is home to three of them; the Pacific Lamprey, the Western Brook Lamprey, and the Western River Lamprey. Although data is collected on all three species, the Pacific Lamprey is very important and is a main focus of study. Not a lot of people know of these amazing fish, what they do, or why they are ecologically and culturally important.

Lamprey have a very unique anatomy that distinguishes them from other fishes. Lamprey do not have bones, scales, paired fins, or jaws. Instead they have a notochord, which is a long thick cartilaginous rod lying ventral to the neural tube, an oral hood / suction-disc mouth, only two dorsal and caudal fins, and they have gill pores/slits instead of gill arches. Due to how efficient this body style is, they haven't needed to evolve their overall anatomy much over the past 450 million years and have been around for about 200 million years longer than the dinosaurs! 

You could say their entire body is almost like one giant muscle. Its body consists of a head, trunk, and tail and their life stages consist of a larval stage (aka ammocoete), juvenile stage (aka macrophthalmia), and an adult stage. Some lamprey are residential and spend their entire life living in one river system, or they can be anadromous and will spend part of their life in freshwater and part in salt water. As an ammocoete, they are blind filter/deposit feeders and burrow in the fine sediment where they feed on decomposing organic matter (similar to an earthworm in a garden) and algae. They help to break down organic matter buildup which keeps river systems healthy and riparian areas healthy. Due to their slender physique, they are able to glide through the fine sediment very easily and in turn help to aerate and churn the sediment; they are our river’s ecological engineer. At this stage they are also food for birds, small mammals, and many freshwater fishes. During their ammocoete stage, they can range from 1 – 8 inches in size. 

The next stage is their migratory phase, and the larval lamprey transforms from a blind filter/deposit feeder to an eyed parasitic feeder. Their oral hood develops into a suction disc with teeth. After their transformation (aka complete metamorphosis), they migrate from freshwater to saltwater along with salmon smolts. By traveling together, both species act as a buffer for each other. This allows predators who wish to feed on them to eat one which allows the other to escape; this allows both migrating species to make it to the ocean. They will spend a few to several years parasitically feeding on other fishes. 

Unlike Arctic Lamprey that are known to feed considerably on salmon, Pacific Lamprey focus on fish species that live closer to the floor of the ocean, such as Pacific hake, sole, halibut, cod, shark, and even some whale species. Lamprey are opportunistic feeders, so they will feed on whatever is easy to find and abundant. Unlike some other species that are known to chew through tissue, Pacific lamprey are primarily blood- and body-fluid feeders, so host fishes can often survive the feeding. 

Once they reach adulthood, lamprey begin their migration to freshwater and travel upstream until they find suitable habitat and spawning cohorts. Adult lamprey are not the strongest swimmers so they rely on their suction disc to hold onto rocks to rest and cling-and-climb upstream. Adult Pacific Lamprey can use their muscular body to climb fish ladders and waterfalls as well. As long as water is flowing down the surface, the lamprey will be able to climb. Not all lamprey species are capable of climbing. Only two species can accomplish this; the Pacific Lamprey and the Kana Kana (pouched lamprey) found in New Zealand. Adult lamprey also uses their suction disc to build their redds (spawning nests) by physically sucking onto a rock and carrying it out of the nest area. Once the adult lamprey spawn, they will die and in doing so they deposit all those oceanic nutrients into the freshwater system. Their life span is likely 10-15 years and they spend about half in freshwater and half in the ocean.

Like many fish species, there are threats to lamprey survival including dams, irrigation screens, pollution, and increased water temperatures. Fish ladders were developed to help salmon get past dams. Salmon have a big powerful tail to swim quickly and jump up the ladders. But Pacific Lamprey are slow swimmers and rely on using their suction disc to suction onto smooth surfaces and climb. This can be difficult on those ladders. The fish ladders are a series of short waterfalls that reach from the highest water point above the dam to the lowest water point below the dam. When constructed, fish ladders have 90 degree corners. Lamprey cannot successfully attach to sharp angles and this can cause the lamprey to try over and over again eventually tiring and causing them to become susceptible to predators. 

It is estimated that only 50% of the migrating lamprey population will make it past each dam traveling from the Pacific Ocean up the Columbia River system. This does not mean that 50% of all lamprey die, but they don’t pass the dam and may turn back and go into other systems. This results in less genetic diversity traveling upstream. To help tackle this issue, lamprey passage structures have been developed and installed on some of the dams. These passage structures are a series of chutes and ramps with water flow that help lamprey to navigate more safely over the barriers. When installed, lamprey passage numbers increase. The Pacific Lamprey Project staff also travels annually to the lower three Columbia River Dams to collect adult lamprey and drive them by truck to upstream tributaries. 

Another major threat to larval and juvenile lamprey is water pollution from agricultural land uses and the related increases in water temperature. Across the region, screened irrigation canals divert water for agriculture. The screens slow the water entering the canal and block fish species as well, but sediment can collect behind the screens. This slow water and thick sediment is very attractive to larval lamprey. Unfortunately, larval lamprey can be very small in their first year (0.25-1 inch in length) and can fit through those screens. To help save as many stuck lamprey as possible, the Pacific Lamprey Project staff use an electro-backpack-fisher to remove lamprey from the sediment and place them back into the river or creek. 

The Pacific Lamprey are not only important for the environment but are also culturally important to the tribes along the Columbia River as they have been harvested just as long as salmon. They have a special place within each tribe and are served during special events and ceremonies. Historically, lamprey would be harvested at waterfalls, but dams have removed most of the waterfalls from our riverways. Today, the majority of Pacific Lamprey are harvested at Willamette Falls, in Oregon City, OR. By helping to restore the lamprey numbers it can help increase the availability to all tribal members and also increase their presence in the ecosystem.

Lamprey are such amazing creatures and Education Outreach is very important for their survival. Any chance we get, the Pacific Lamprey Project staff teaches the public about lamprey and their importance by showing historical photos and bringing live fish to events, bringing lamprey to the classrooms, hatchery tours, and hosting adult release events. We will be at KEEN’s Get Intimate with the Shrub-Steppe on May 10-12, 2024. We hope you will join us and learn about these amazing creatures. Register here.

Lamprey have survived in this world for hundreds of millions of years. They have survived 4-5 mass extinctions, but they need our help now. We are learning more techniques and tricks every day to help increase their survival and we need your help!

Learn more about KEEN's Get Intimate with the Shrub-Steppe here https://www.ycic.org/giss