Slackwater Darter

The Slackwater Darter (Etheostoma boschungi) is endangered and decreasing (NatureServe, 2013). These little darters live relatively short lives, have only limited windows each year to breed successfully, and have drastically reduced seasonal breeding habitat. If something disrupts their habitat or access to the habitat during their critical spawning season, the population can quickly decline, leaving little chance for recovery. If they can't breed, the species will recede.

Slackwater Darters spend most of their life in slow-flowing, gravel-bottomed creek beds. They engage in annual migrations to spawn (Wall and Williams, 1974). They travel upstream in the winter to spawn in shallow tributaries and fields (Boschung, 1976). However, these migrations are highly localized and specific. Migrations rely on certain traditional paths easily disrupted by roads, farmland expansion, or urban development. If their routes become blocked, the fish often can't find alternative paths, severely impacting their reproduction ability (Roy et al., 2019). 

Their reproductive strategy and spawning habitat are perhaps their greatest vulnerability. Slackwater Darters depend almost exclusively on ephemeral wetlands and shallow vegetated streams, areas frequently disturbed by humans. Activities like draining wetlands for agriculture, expanding urban areas, or even subtle changes in land use or groundwater can rapidly degrade or eliminate these habitats, leaving the darters with nowhere suitable to breed or survive. Nearly all known breeding sites now occur on either developed or agricultural land, so land-use changes within the Slackwater Darter's natural range lead to extirpation and species-level decline (Utz et al. 2010).

Their small body size also makes them inherently vulnerable. Being small severely limits their ability to disperse to new habitats if their location is compromised. These little fish can't quickly relocate if their environment deteriorates, trapping them in increasingly unsuitable habitats (Johnson et al., 2013).

These traits—short lifespans, specialized migrations, sensitive physiology, exclusive habitat needs, limited body size, and fragile reproductive cycle—make the Slackwater Darter particularly vulnerable to human-caused environmental changes. These traits highlight why conservation efforts must prioritize existing habitat protection, habitat connectivity, and restoration.

References:

Boschung, H. T. (1976). An evaluation of the Slackwater Darter (Etheostoma boschungi), relative to its range, critical habitat, and reproductive habits in the Cypress Creek watershed and adjacent stream systems; An assessment of the probable impacts of the Cypress Creek watershed project on the Slackwater Darter and its critical habitat [Report]. Auburn, AL.

NatureServe. (2013). Etheostoma boschungi. The IUCN Red List of Threatened Species 2013: e.T8110A13305507. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T8110A13305507.enLinks to an external site.

Johnston, C. E., Henderson, A. R., & Hartup, W. W. (2013). Precipitous decline and conservation of Slackwater Darter (Etheostoma boschungi) in tributaries of the Tennessee River, Tennessee and Alabama. Biodiversity and Conservation, 22(13–14), 3247–3259. https://doi.org/10.1007/s10531-013-0568-3Links to an external site.

Roy, M. B., Johnston, C. E., & Janosik, A. (2019). A habitat risk assessment and breeding site projection for Slackwater Darter (Etheostoma boschungi) (Percidae) in Alabama and Tennessee, USA. Environmental Biology of Fishes, 102(4), 685–703. https://doi.org/10.1007/s10641-019-00862-xLinks to an external site.

Utz, R. M., Hilderbrand, R. H., & Raesly, R. L. (2010). Regional differences in patterns of fish species loss with changing land use. Biological Conservation, 143(3), 688–699. https://doi.org/10.1016/j.biocon.2009.12.006

Wall, B. R., & Williams, J. D. (1974). Etheostoma boschungi, a new percid fish from the Tennessee drainage in northern Alabama and western Tennessee. Tulane Studies in Zoology, 18, 172.