When we think of beautiful places in the world, I think many of us tend to forget about the places right in our backyard. Living in Minnesota, I know, for me at least, this much is true. In our developed society, it sometimes becomes difficult to recall the wildlife that depended on our land before us and with much of our surrounding area on private land, it is a challenge to appreciate land you can’t discover for yourself. After going big for my last species, today we are going to travel back home to explore a tiny creature whose health is reflective of how we take care of our Earth’s most fertile and economically valued ecosystem: prairies.
Guaranteed to not be any longer than your pinky finger, the Topeka shiner is a small, orange-finned, minnow-sized fish found in prairie streams in Iowa, Kansas, Minnesota, Missouri, and South Dakota. Although the Topeka shiner varies considerably in size by sex and location, this small animal will almost surely go unseen unless you are purposefully on the hunt. The largest documented males can reach 2.8 to 3 inches and weigh a little over 0.18 oz (which is still just a little over what a U.S. dime weighs!). The largest females reach 2.4 to 2.6 inches and a little over 0.11 oz. They can typically reach about 2 years of age, but some can live up to 3 years. In most cases, Topeka shiners grow to maturity sometime during the spring or summer of their second year (at 11-13 months of age).
As nonthreatening as this little fish is, one would imagine it is a herbivore and only feeds on aquatic plant material, but the Topeka shiner is actually an opportunistic omnivore, meaning they will eat pretty much any animal or plant material that is small enough to fit in its mouth. One study conducted in Minnesota, even found over 25 different food groups inside the shiner’s stomachs! This included everything from insects, to snails, to clams, water mites, worms, freshwater sponge, mosses, algae, seeds, and even fish larvae.
In my investigation on this species, I made the assumption that Topeka shiners would be an easy snack for any larger fish. However, it appears that this isn’t ordinary as they were only found in the stomachs of a few individual fish out of hundreds of stomachs examined in one study. They investigated all of the species in which scientists assumed could be native predators to the shiners (i.e. larger creek chubs, black bullheads, yellow perch) and it appears that fish don’t have much of a taste for shiners. However, this excludes the cases of the invasive species of these streams. In Kansas and Missouri, largemouth bass that have been introduced in ponds and traversed into Topeka shiner habitat where they are now a major predator and may be partly responsible for Topeka shiner decline in those states.
Topeka shiners are primarily found in gentle, slow-moving streams that are naturally winding. The winding nature of these streams is essential because curves create oxbows, pools and runs of water where the shiner resides. It has recently been noted that the shiners may prefer pools of water outside of the main channel courses, probably because they are in contact with groundwater and usually contain vegetation and areas of exposed gravel. The substrate of these streams often contain a deep layer of silt with sand and gravel on top. The Topeka shiner relies on streams with this substrate as well as good water quality and cool to moderate temperatures. It is likely that channels and oxbows that are seasonally flooded connect the water table and are responsible for keeping summer water temperatures and dissolved oxygen concentrations low during hot and dry summer months in addition to preventing freezing of pools in the winter months, which would cut off habitat.
Topeka shiners have an obligate relationship with many fish species as they are almost always found with sand shiners, orange-spotted or green sunfish, fathead minnows, white suckers, and black bullheads. The spawning season is 8-10 weeks long during the summer and is dependent on orange-spotted or green sunfish to share a nest with. It is believed that the shiners don’t build their own nests, but instead spawn in the water above a sunfish nest because this provides a form of protection. Evidence for this lies in the fact that juvenile shiners remain near this mixed-species nests during their first summer.
In contrast to humans, for mating to occur in shiners, the females have to be persistent and aggressively (and repeatedly) try to enter a male’s nest territory to be accepted. Throughout a season, female Topeka shiners can lay several clutches of eggs sometimes as large as 800 eggs!
Up next we will discuss the environmental issues that the Topeka shiner faces: Topeka shiner: our prairie home companion in need of some saving — The Environmental Issue
If you would like to check out more animals on the Endangered Species List on your own, please visit the U.S. Fish and Wildlife Service’s list of Threaten/Endangered Species in the U.S. and Foreign Countries.
References: U.S. Fish and Wildlife Service. Threatened and Endangered Species. Questions and Answers about the Topeda Shiner in Minnesota. Department of the Interior. U.S. Fish and Wildlife Service. [Online] 2016 https://www.fws.gov/midwest/endangered/fishes/TopekaShiner/tosh_mn.html (accessed Mar 28, 2017). NatureServe. 2014. Notropis topeka (Topeka shiner). The IUCN Red List of Threatened Species 2014. [Online] 2014 http://dx.doi.org/10.2305/IUCN.UK.2014-3.RLTS.T184092A19034321.en. (accessed Mar 28, 2017). U.S. Fish and Wildlife Service. Threatened and Endangered Species. Topeka Shiner (Notropis topeka). Department of the Interior. U.S. Fish and Wildlife Service. [Online] 2017 https://www.fws.gov/midwest/endangered/fishes/TopekaShiner/index.html (accessed Mar 28, 2017). Images: Image 1: Rothert, J. 36-07-2016.jpg. https://mdc.mo.gov/sites/default/files/media/magazine/36-07-2016.jpg (accessed Mar 28, 2017). Image 2: Tomelleri, J. Topeka Shiner - MDC Discover Nature. https://nature.mdc.mo.gov/sites/default/files/media/images/2015/02/topeka_shiner_2-27-15.jpg (accessed Mar 28, 2017). Image 3: Larson, D. Distribution Map of Tokepa shiner. pers. comm. (given Mar 27, 2017). Image 4: Morrison, L. Oxbows cut nitrates in farm drainage water. http://www.cornandsoybeandigest.com/sites/cornandsoybeandigest.com/files/uploads/2015/07/jones-sterling-oxbow-3.jpg (accessed Mar 28, 2017). Image 5: Rather, J. 15_02-2011.jpg. https://mdc.mo.gov/sites/default/files/media/images/2011/01/15_02-2011.jpg (accessed Mar 28, 2017).