Researchers from Purdue University published a study in the peer-reviewed journal Proceedings of the National Academy of Sciences indicating that a small fish that is only found in New Mexico may actually be two different species.

This could have implications for the efforts to protect and conserve this unique animal.

The White Sands pupfish is only found in four springs. Two of those populations were created by humans releasing the imperiled fish into the springs. 

While it is not listed on the federal endangered species list, New Mexico considers it a threatened species and there have been efforts in the past to get the White Sands pupfish listed as endangered.

A 2009 petition cites threats to the White Sands pupfish as exotic ungulates like the introduced oryx, missile-firing activity, water withdrawal and the invasive salt cedar plants. 

The genetic research indicates that the pupfish from the Salt Creek population were taken and released to create the Lost River and Mound Spring populations.

The fourth population—found in Malpais Spring—is genetically distinct from the other three populations due to a phenomenon known as genetic drift. Essentially, about 5,000 years ago, the Carrizozo lava flow separated the Malpais Springs pupfish from the Salt Creek pupfish. Because of that separation, the two populations diverged genetically and became different species. 

Andrew Black, a study co-author, said the researchers knew there were two distinct populations—or evolutionarily significant units—with different genetics when they went into the study process. But they discovered that the genetics are so different that the pupfish found in Malpais Springs is essentially a different species.

“The separation between samples from these two ESUs was huge!” Black said in a response to questions from NM Political Report. “The point was driven home when we looked at how differentiation between these two ESUs occurred across the entire genome. We were expecting relatively low levels of differentiation, with perhaps several peaks of high differentiation associated with genes underlying local adaptations, but instead we saw an extremely high background of differentiation across the entire genome. This, I believe, is when we decided we needed to change our study design from looking at two populations of one species to two different species.”

Black had previously researched the Leon Springs pupfish during his graduate studies before he went to work on postdoctoral research at Purdue University with Professor J. Andrew DeWoody.

“I was excited to work with pupfish again,” Black said in an email response to questions from NM Political Report. “For fish, they really are pretty charismatic.”

Black described them as “small chunky fish, with cool behavior and male nuptial coloration.” He said the “discrete desert springs they typically live in makes for a really interesting model.”

And, Black said, he’s always been interested in using genetics and genomics as a tool to protect and conserve imperiled species.

Black and his team have proposed calling the pupfish found in Salt Creek, Lost River and Mound Spring the enchanted pupfish—a reference to New Mexico being known as the Land of Enchantment. Meanwhile, they propose keeping the name White Sands pupfish for the Malpais Spring population.

But, before the enchanted pupfish can be officially declared a different species, other scientists need to concur.

Mike Ruhl, the assistant chief of the research and management section for the New Mexico Department of Game and Fish’s Fisheries Management Division, said that the state is aware of the research project and the recent paper. 

“White Sands Pupfish occur entirely on U.S. Department of Defense lands and are managed through a Conservation Team that includes White Sands Missile Range, Holloman Air Force Base, the U.S. Fish and Wildlife Service and the Department,” Ruhl said in a statement. “Given its very recent publication, the management implications of the article are currently unclear and adoption of new fish species designations is a function of the Committee on Names of Fishes, a joint committee of the American Fisheries Society and the American Society of Ichthyologists and Herpetologists. The White Sands Pupfish Conservation Team will consider the research and its implications at its next meeting.”

WildEarth Guardians was behind the 2009 petition to have the pupfish listed as endangered, but it is unclear how the organization will respond to the study.

Joanna Zhang with WildEarth Guardians anticipates that the new study will have an impact.

Zhang said that if the pupfish is indeed two separate species, it means that the population found in Malpais Spring has no duplicate population. If something were to happen to Malpais Spring, the pupfish could be lost entirely. A refuge population could help provide some assurance that the rare pupfish could survive long into the future through human intervention, but, Zhang said, “ideally you don’t lose the population that’s out in the wild.”

The study also has other implications for conservation.

“Making sure that both of them have a robust population that has enough genetic diversity to remain viable in the long term, is really important,” Zhang said.

Black said that previous research and current genetic diversity estimates indicate that the White Sands pupfish has little genetic diversity.

“We showed that the genetic diversity levels of these fish are substantially lower than many other related species, close to the levels observed in several inbred lines of laboratory fish,” he said. “This is problematic as diversity is a good proxy of fitness and helps buffer environmental change.”

He said continued efforts to “ensure effective gene flow between populations of the same species” as well as conservation efforts to maintain good breeding habitat for the pupfish could help protect the genetic diversity that currently exists.

And researchers aren’t done examining the White Sands pupfish and its genetics.

One of Black’s co-authors, Erangi Heenkenda, has been sequencing the genomes of the White Sands pupfish overtime. This has involved taking genetic samples at two different time points approximately 18 years apart to examine how the species are changing.

Black said Heenkenda’s research should “be informative of the evolutionary processes occurring at a more contemporary time scale.”