Biogeographic barriers are differentially permeable based on traits: movement of hypoxia tolerant mormyrid fish in the Lake Victoria basin (Data and code for publication)

This dataset comprises the data and code for analysis for a publication submitted to the Journal of Great Lakes Research by McGill researchers in fall 2024. Below is the abstract of the publication at submission. In the Lake Victoria Basin, Lake Nabugabo is a small satellite lake of Lake Victoria proper that is separated by deeply hypoxic swamps. These swamps form a biogeographic barrier to fish assemblages; Nabugabo hosts species not shared with Lake Victoria, and other species show high differentiation across the barrier. However, there are air-breathing fishes which show near zero genetic differentiation across this barrier. We used pooled RAD-seq to examine the degree of genetic differentiation in two species of non-air-breathing but hypoxia-tolerant mormyrid fishes, Marcusenius victoriae and Petrocephalus degeni. Since they are hypoxia-tolerant, we hypothesized that they would have low genetic differentiation across the barrier more in line with air-breathing fish rather than other species which are not air-breathing. We discovered that the genetic differentiation in our focal species was very low, with FST values of 0.02 to 0.04, as opposed to other non-air-breathing fishes in previous work that ranged from 0.05 to 0.20, mostly above 0.10. The values we found in our focal species were in fact much more comparable to obligately or facultatively air-breathing fishes that had FST values of near zero. We conclude that this barrier and other analogous ones should be understood as differentially permeable depending on the traits of the organisms crossing them, namely hypoxia tolerance in this case.