Document Type

Article

Publication Date

3-19-2019

DOI

10.1093/jhered/esz016

Publication Title

Journal of Heredity

Abstract

An understanding of the genetic composition of populations across management boundaries is vital to developing successful strategies for sustaining biodiversity and food resources. This is especially important in ecosystems where habitat fragmentation has altered baseline patterns of gene flow, dividing natural populations into smaller sub-populations and increasing potential loss of genetic variation through genetic drift. River systems can be highly fragmented by dams built for flow regulation and hydropower. We used reduced-representation sequencing to examine genomic patterns in an exploited catfish, Hemibagrus spilopterus, in a hotspot of biodiversity and hydropower development- the Mekong River basin. Our results revealed the presence of two highly-divergent coexisting genetic lineages which may be cryptic species. Within the lineage with the greatest sample sizes, pairwise FST values, principal components analysis, and a STRUCTURE analysis all suggest that long-distance migration is not common across the Lower Mekong Basin, even in areas where flood-pulse hydrology has limited genetic divergence. In tributaries, effective population size estimates were at least an order of magnitude lower than in the Mekong mainstream indicating these populations may be more vulnerable to perturbations such as human-induced fragmentation. Fish isolated upstream of several dams in one tributary exhibited particularly low genetic diversity, high amounts of relatedness, and a level of inbreeding (GIS = 0.51) that has been associated with inbreeding depression in other outcrossing species. Our results highlight the importance of assessing genetic structure and diversity in riverine fisheries populations across proposed dam development sites for the preservation of these critically-important resources.

Comments

This is a pre-copyedited, author-produced version of an article accepted for publication in Journal of Heredity following peer review. The version of record

Ackiss, A. S., Dang, B. T., Bird, C. E., Biesack, E. E., Chheng, P., Phounvisouk, L., . . . Carpenter, K. E. (2019). Cryptic lineages and a population dammed to incipient extinction? Insights into the genetic structure of a Mekong River catfish. Journal of Heredity. doi:10.1093/jhered/esz016

is available online at: https://doi.org/10.1093/jhered/esz016.

Original Publication Citation

Ackiss, A. S., Dang, B. T., Bird, C. E., Biesack, E. E., Chheng, P., Phounvisouk, L., ... Carpenter, K. E. (2019). Cryptic lineages and a population dammed to incipient extinction? Insights into the genetic structure of a Mekong River catfish. Journal of Heredity. doi:10.1093/jhered/esz016

ORCID

0000-0002-8726-7423 (Ackiss); 0000-0001-7932-9471 (Biesack)

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