Growing a 'First Fish'
(Edited and taken from the Spring 2021 issue of Fish & Wildlife News)

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Over the past decade, Abernathy Fish Technology Center has been working with colleagues and a team of tribal and federal scientists to generate groundbreaking studies to help establish the nation’s first Pacific lamprey aquaculture programs.

The work touches on four things: hatchery programs, the collaborative nature of Pacific lamprey research, why the fish is vital to West Coast tribes, and the unique life cycle that makes raising them in captivity complex.

“The long duration of the larval life stage, typically 3-9 years, makes the continuous production of larval lamprey a long-term project that requires a lot of rearing tank space,” says Ralph Lampman, a Yakama Indian Nation Pacific lamprey project biologist.

Creating lamprey hatchery programs in a region where hatchery operations are dominated by salmonid culture, has been another difficulty. Pacific salmon and steelhead hatcheries have existed since the late 1800s.

Not so for Pacific lamprey, which are anadromous like salmon and steelhead but live twice as long and spend most of their lives in their larval and early juvenile stages.

No hatchery program for Pacific lamprey exists throughout their entire range, which extends from Alaska to the Mexico border.

“Overcoming salmon-centric thinking both within the research community and our funders has been a challenge,” says Dr. Mary Moser, a research fish biologist with NOAA Fisheries. “Lamprey culture is a long-term commitment. This information also gives insights into lamprey biology needed for management of wild lamprey populations.”

Tribes have been sounding alarm bells for decades about declining lamprey populations. Their concern is personal. Pacific lamprey is a culture ambassador that provides an opportunity to pass knowledge of an appreciation for a “First Food” from one generation to another.

“Working to develop artificial propagation for lamprey provides the opportunity to investigate different strategies to save this imperiled species,” says Aaron Jackson, project leader for the Confederated Tribes of the Umatilla Indian Reservation’s Pacific Lamprey Project.

That’s how Abernathy, and partners Jackson Lampman, Moser, and Dr. Alexa Maine, the Umatilla Tribes’ aquatic propagations lab manager, ultimately joined forces.

Using Abernathy’s resources, in 2012 Abernathy led a team that investigated larval lamprey growth and survival rates through diets.

Findings indicated that a larval lamprey feeding regimen with a slurry of dry yeast and commercial fish feed was most effective. Algae, which is part of wild larval lampreys’ diet, surprisingly was not.

Abernathy was fortunate to have the partners it did. The partners had already figured out how to spawn adults and incubate the eggs – a huge task. Abernathy was able to begin its work focused on rearing the young lamprey starting before they begin to feed and still have a yolk sac.”

Conducting the diet research was difficult. The delicate larval lamprey don’t grow more than a few centimeters the first year of their lives. They also spend their entire larval and early juvenile periods buried in aquatic substrate, filter-feeding. Most of the time they’re virtually invisible.

“The lamprey don’t often do what you expect them to, so we tried a lot of things by running multiple trials,” says Ann Gannam, PhD, who supervises Abernathy’s lamprey research.

Besides key diet clues, that first study generated something equally valuable: awareness that tribal and federal scientists could together tackle tough questions, share results, and safeguard everyone’s research by independently maintaining young lamprey refugia populations.

“The unique assets that each of our partners brought together made it possible to collaborate in a way that would not have been possible if we tackled this problem alone, and was the seed of success,” Lampman says. “Another benefit is that we don’t put all the eggs in the same basket, figuratively and literally speaking.”

In 2013 and 2014, using fish provided by the Yakama Nation, Abernathy investigated the effects of various ration sizes and rearing densities on young lamprey growth.

The research not only helped tribal partners refine their own nascent Pacific lamprey aquaculture programs, but got the attention of others. In 2015, Chelan County Public Utility District (PUD) which operates three Columbia River dams in Washington State, provided multiyear funding to continue research including a challenge to grow larval lamprey into juveniles to help support future PUD studies.

The district’s investment allowed the researchers to tackle bigger questions: when should the critical first feeding period begin, and at what fish size could scientists safely and humanely implant tracking tags to monitor the movements of larvae or transformed juveniles that would stay in place to facilitate accurate data collection?

The 2015 research achieved breakthroughs on both fronts.

Studies indicated that larval lamprey first fed between 16 and 24 days post-hatch seemed to survive and grow the fastest. The timing of the first feed was not only vital for early development but increased the likelihood that the young fish would grow rapidly enough to survive fluctuating environmental conditions.

Meanwhile, the tagging research demonstrated two commonly used tags could be implanted even in tiny lamprey. A third tag, which required more invasive surgical techniques, be safely implanted in fish as small as three inches long.

Trust between the scientists deepened with every successive research phase. Decades of mistrust over salmon management, without their input and broken treaties over two centuries have left tribes understandably wary when working with the federal government. Twenty-first century Pacific lamprey conservation, fundamentally collaborative in nature, is a pronounced contrast to that history.

“This process has provided the opportunity to build meaningful relationships between the federal government and tribal governments,” says Jackson, an enrolled Umatilla tribal member.

The team analyzed and refined their handling techniques with each study and provided each other with valuable peer review. The stepping-stone research revealed other surprises: alfalfa pellet supplements improved the growth of larger larvae. However, handling the larvae and keeping the study tanks clean was proving extremely complicated without stressing the fish and potentially amplifying mortality. The partners tackled the problem together, learning from each other’s successes and setbacks.

“One of the main challenges presented when culturing lamprey is substrate. They need it,” Gannam says. But it completely hides the lamprey from view so you cannot really see what is going on from day to day. Carefully separating out the delicate animals from heavy sand is very labor intensive. Over time, the substrate develops its own ecosystem and requires specialized cleaning and maintenance to keep the lamprey going.”

Between 2016 and 2018, the team’s efforts focused on new variables influencing larval lamprey behavior and survival: water turnover, substrate particle sizes, tank cleaning techniques, photoperiods, feeding frequency variation, and optimal rearing densities.

Then, in 2019, another breakthrough occurred. 

The lamprey in both Abernathy’s and the Yakama Nation’s study did what no other captive-raised Pacific lamprey had ever done.

They metamorphosed from tiny larvae to juvenile lamprey. Their eyes developed. Their skin color began changing from the dun brown suited for camouflage in substrate to the pale silver better suited to conceal them in a water column. Their mouths began to curve into an oral disc with rows of small, circular posterior teeth, and the three large anterior teeth that give Entosphenus tridentatus its “three-toothed” binomial name.

The collaborators were elated.

“We are one of only two groups of people in history that have ever succeeded in production of eyed juvenile lamprey from artificial propagation,” Lampman notes.

In 2019 and 2020, the team was able to conduct studies to help answer important questions about rearing juvenile fish in different hatchery rearing environments and see how those promoted or inhibited metamorphosis.

They did so without removing a single fish from the wild.

Today, Abernathy raises thousands of lamprey across four different year classes. In 2021, the researchers are exploring cues that trigger larval transformation to juveniles, helping lamprey culturalists prepare for this pivotal lifecycle moment. The Yakama and Umatilla Pacific Lamprey Projects are using the canon of studies to eventually ramp up full-cycle Pacific lamprey hatchery programs.

It's something lamprey advocates have been hoping to see for years. Now it’s closer than ever, thanks to nearly a decade of effort by a group of persistent scientists.

The next step is convincing others to invest in Pacific lamprey artificial propagation programs. After all, research proves they can operate.

For Abernathy, the knowledge that the fish are continuing to help close knowledge gaps is highly satisfying.

“Even when you don’t get the result you expect you are still learning something, kind of like finding pieces to a puzzle,” Gannam says. “That is one of the most rewarding aspects of this work – and practicing science. When you reveal something new, and get that answer for the first time, you reveal a universal truth that no one before has ever known.”

(written by Sean Connolly, Fish and Aquatic Conservation Program, Columbia-Pacific Northwest Region)