January 18, 2022

Salmon, science and good sense

As a graduate of the University of Maine at Machias and a former volunteer at the Pleasant River salmon hatchery, I took great interest in Andrew Goode’s Dec. 13 commentary. Goode questioned Gov. Angus King’s use of scientific information to publicly oppose the effort by U.S. Fish and Wildlife Service and the National Marine Fisheries Service (NMFS) to list Maine’s wild Atlantic salmon as endangered.

The governor’s position is that there has been considerable homogenization of wild salmon stocks due to the federal government’s 100-plus-year-old stocking program among rivers. The governor contends that the federal government hatchery stock supplementation makes the assumption of a DPS — distinct population segment — null and void. I believe the governor’s position is based on both valid scientific information and common sense.

As a Ph.D. candidate studying animal genetics at the University of California at Davis, I know there is no scientific literature containing the “gold-standard” for what constitutes either a DPS or an ESU — evolutionary significnt unit. If you were to ask 10 geneticists what data is needed to delineate either designation, you would get 10 different answers.

These terms were created by NMFS so they could list smaller and smaller groups of populations under the Endangered Species Act. The terms are intentionally vague, ensuring that it is virtually impossible to argue against a proposed DPS listing under ESA. In fact, you will not find a mention of DPS or ESU in the original text of the ESA, they were added after the fact, giving environmental groups the perfect tool to force the federal government to list any select group of populations.

Goode claimed the governor’s position is not supported by any scientific studies. This could not be further from the truth. While Goode mentions that the governor’s “theory is contradicted by numerous scientific studies,” he only mentions one such study, which is Dr. Tim King’s latest genetics study issued by the U.S. Geological Survey. Interestingly, printed boldly on the cover of Dr. King’s report is the following statement: “Not to be cited without prior permission of the authors.”

The authors know their work has yet to be completed and peer-reviewed. I have thoroughly reviewed Dr. King’s report. The quotes Goode used in his column are obviously biased in favor of the DPS and are a misrepresentation of Dr. King’s position.

In addition, Goode’s assertion that Gov. King’s theory is not supported by other research is false. There have been several genetic studies covering these issues, all using different molecular genetics techniques. Each offers very little scientific support to the structure of the proposed DPS. Also, to claim the set of rivers to be “wild” is also false. Using the North Atlantic Salmon Conservation Organization’s (NASCO) definition of “wild” as having spent two complete generations without human interference, these rivers are hardly wild, as they are federal hatchery-supported, the product of the river-specific inbreeding program.

If you take a salmon from one of these rivers, you can not confidently assert that it is wild. There is some chance that it was born in the river, but more than likely, it was stocked from the hatcheries. Ironically, if we use NASCO’s definition, then a European hybrid aquaculture salmon could be protected under ESA if it escapes, spawns successfully in a river, and produces offspring that return to that river to spawn.

Addressing the question of the distinctness of an individual river or of the DPS as a whole, the small population sizes of these rivers play an enormous role in affecting the outcome of any study. The genetics studies completed to date rely on genetic marker frequency differences between rivers to determine whether or not the rivers are different from one another. As the population sizes of each river become smaller, the frequency differences observed between rivers become more and more affected by the random sampling of genetic material from one generation to the next, a process known as genetic drift.

The science of genetics is not static. Unlike other scientific disciplines, geneticists study moving targets because the genetic make-up of all species is constantly evolving in nature. In fact, the markers that are used in the most current studies on salmon genetics are said to be neutral in that their frequencies are unaffected by natural selection (and hence local adaptation). Yet differences in frequencies of these markers are used by the federal government to claim that local adaptation is occurring.

This is a gross misuse and misrepresentation of the science of population genetics. Since these are neutral markers and the population sizes of these rivers are so low (hence the proposed listing), frequency differences between rivers are most likely due to the effect of the small size of the broodstock used in the federal government’s river-specific program and in no way are related to local adaptation of individual river stocks.

Considering all the alliances the Atlantic Salmon Federation and Goode have with environmental groups, are you willing to trust an organization closely allied with advocacy-based environmentalism to present objective science? Or would you prefer to listen to scientists and common sense? It’s your choice. It’s your state.

Jeff Rodzen is a graduate of the University of Maine at Machias and a doctoral candidate in animal genetics at the University of California at Davis.

Have feedback? Want to know more? Send us ideas for follow-up stories.

comments for this post are closed

You may also like