Scientists reveal the secret world of fish nations that divide Arkansas

Scientists reveal the secret world of fish nations that divide Arkansas

Animals may not respect the lines drawn by humans along our borders, but that doesn’t mean they don’t have their own complex societies.

By studying the White River Basin in Arkansas, biologists from the University of Arkansas have mapped what they describe as fish “countries,” which they hope will help future conservation and ecosystem management plans.

“Just as our ancestors were more likely to have close relatives, so too did they have fish, thus creating regionally distinct genetic ‘countries’, shaped by unique environments,” said Zach Zbinden, a postdoctoral research associate who conducted the research as part of the study. . He said in his doctoral thesis statement.

The White River originates in northwest Arkansas in the Boston Mountains and eventually connects with the Mississippi River. The river basin can be divided into several sub-basins consisting of different sub-regions.

To analyze these “fish countries,” Zbinden and his team surveyed 31 fish species from 75 sites along the river basin, and examined the degree of genetic variation within different species. By studying this genetic diversity, the team revealed consistent genetic boundaries between fish populations in these different locations.

Arkansas brown trout
Photo of a brown trout in the White River in Arkansas. New research suggests that the river basin is divided into fish “nations” with their own distinct genetic makeup.
Steve Cleaver/Getty

These genetic limits could be caused by limited dispersal between subpopulations or different environmental pressures, leading to different adaptations.

Evaluating several species allowed the team to confirm that this genetic differentiation was consistent between different species at different sites, demonstrating the existence of these invisible boundaries and subpopulations within the river ecosystem.

The team hopes that highlighting these distinct subgroups will help guide future conservation strategies for fish populations in the White River Basin and beyond.

Arkansas’ native fish face many threats. These factors include overfishing, habitat degradation, development, pollution, climate change, and the introduction of non-native fish species, according to the Native Fish Alliance.

Analyzing genetic variation in individual species is a common practice in conservation to analyze population sizes and justify funding. This multi-species approach allows for a more comprehensive understanding of the complexity of river network structures.

The data also highlights the importance of independent management of this population. For example, boosting fish stocks in one country with fish from another may do more harm than good, possibly displacing a subspecies of another.

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