Blue shiner

Blue shiner
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Cyprinella
Species: C. caerulea
Binomial name
Cyprinella caerulea
(D. S. Jordan, 1877)

The blue shiner (Cyprinella caerulea) is a species of shiner that is located in the southeastern area of the United States. This species of shiner is endemic to the Cahaba and Coosa River systems of the Mobile Basin in Alabama. However, it now ranges from and is restricted to the Coosa River system in northeast Alabama, northwest Georgia, and southeast Tennessee. Blue shiners can be found in second to fourth order streams with a moderate to low river current. Being sight feeders, their diet consists of terrestrial and aquatic invertebrates found in drift. The life span of this species is only 3 years.[2] Current management practices put forth by the U.S. Fish and Wildlife Service include watershed protection, monitoring the populations, reducing threats, and increasing our knowledge about the species habitat requirements. Monitoring is especially important because it tracks the possible decline or increases in the populations. The objective of this management practice is delisting the blue shiner.[3]

Geographic Distribution

C. caerulea is a species that is endemic to the southeastern United States. Specifically it is native to the Cahaba and Coosa River systems of the Mobile Basin in Alabama. However, with populations declines, it is now restricted to the Coosa River system in four disjunct populations in northeast Alabama, northwest Georgia, and southeast Tennessee.[2] Within the Coosa River system, they were native to Choccolocco Creek, the Little River, Weogufka Creek, and Big Wills Creek in Alabama; the Coosawattee River the Oostanaula River in Georgia, and the Conasauga River in Georgia and Tennessee. The exact cause of this restriction and decline isn’t currently known. However, most people believe that it is caused by the degradation of habitat and water degradation caused by urbanization, pollution, and sedimentation.[4] The extirpation from the Cahaba River in Alabama could be due to extensive urban development.[5] Efforts are currently being made to reverse the effects of habitat and water degradation. If they are successful, the blue shiner may be delisted.

Ecology

Blue shiners are temperate, freshwater fish that occupy benthopelagic zones in streams.[6] They occur in second to fourth order streams with a moderate to low river currents. They favor a substrate of sand or sand and gravel that may or may not have cobble. They tend to occupy depths of 0.15 to 1 meters. C. caerulea requires high water clarity for feeding and reproduction. In the case of feeding, this is necessary because they are visual drift feeders. Their diet consists of terrestrial and aquatic invertebrates that are found in the drift of the water column. This is why sedimentation has such an adverse effect on them. Sedimentation causes turbidity which prevents them from seeing the invertebrates that they feed on.[7] Being only about three inches long, they are very susceptible to predation. This may include larger fish, turtles, or fishing birds. They most likely compete with other fish their size that occupies the same habitat. Urban development has as adverse effect on the abundance of the blue shiner by causing water degradation. A few factors of this water degradation include high algal blooms, nitrification, and low dissolved oxygen. This all contributes to the decline in abundance.[3]

Life History

The spawning season of the blue shiner starts in early May and ends in late August. With such a large spawning season, it is possible that there can be multiple clutches within one season. C. cyprinella uses crevices in bark and woody debris that has fallen into the river. They share a very similar spawning behavior with C. trichroistia and C. gibbsi. A single male will protect a territory and about four females will wait around the crevice waiting for an opportunity to spawn. Females will spawn several times and once they are done and gone, the male will pass over the crevice as a display to females.[8] Once the display is finished the eggs are left and receive little parental care. The life span of blue shiners is three years and they reach sexual maturity around two years. These two-year-old shiners make up the majority of the spawning stock. Sedimentation is a possible cause of population decline. This is caused by the sediment filling the crevices that the eggs are located in and suffocating them. This, along with other factors, may contribute in changes in life history of the blue shiner.[2] Sedimentation may also cause turbidity in the water that could affect reproduction as well. If the water is too turbid, the females may not see the males display themselves.[3]

Current Management

With water degradation being one of the main reasons for decline, there are many things that we as humans can do to reduce impacts on the species. Homesite development may have an adverse effect on stream flow because of the high demand for water it causes. A decrease in homesite development could restore stream flow. Other ways human impacts could be reduced is to stop the building of dams, reduce loss of habitat, and reduce water pollution. Habitat loss especially affects isolated populations. In August 1995, the U.S. Fish and Wildlife Service (USFWS) implemented a recovery plan for the blue shiner. This was implemented three years after the blue shiner was put on the IUCN Red list. The USFWS has funded the Tennessee chapter of the Nature Conservancy to plan a watershed enhancement program for the Consauga River in Georgia and Tennessee. Public awareness is also being expressed through brochure sent out by the USFWS that tells how land management affects water quality. The Natural Resources Conservation Service (NRCS) is also a part of this recovery plan. Being a part of the U.S. Department of Agriculture, the NRCS has implemented a plan to reduce unfavorable effects on water quality in the Consauga River. This Recovery Plan aims to be successful through minimizing adverse effects and increasing knowledge on the different habitat requirements of the blue shiner. Watershed protection is essential to this and that is why the recovery plan is focused around them. Implementing this plan and monitoring its success is crucial to the recovery of the blue shiner.[3]

Management Recommendations

Currently, the largest population of C. caerulea is in the Conasauga River.[9] Therefore, this would be the most efficient area to sample the abundance of the species. To estimate the abundance, the best course of action would be to know the total area that a given population occupies. Then, divide that into subpopulations by equal areas that add up to the total area. Once the abundance of one subpopulation is found, the total population can be estimated by multiplying that subpopulation by the number of subpopulations within the total population. In other studies on the Cyprinella species, 700 volt AC backpack electrofishing equipment fishing was used.[10] However, using a large seine would be best when counting the subpopulations. Electrofishing wouldn’t cover as large of an area seining would. Also, the stress of getting shocked would most likely be greater than the stress of being caught in a seine. Since the blue shiner only lives for three years, it would be best to sample the population intermittently for a year or two. However, one would need to take into account the birth and death rates of the species. Currently, there is a program aimed at enhancing the Consauga River watershed. However, if improvements aren’t made soon, this watershed very well may need to be put under protection to help preserve remaining populations.

References

  1. ↑ NatureServe (2016). "Cyprinella caerulea". IUCN Red List of Threatened Species. Version 2016.3. International Union for Conservation of Nature. Retrieved 14 April 2017.
  2. 1 2 3 Stephens, C.M. and Mayden, R.L., Threatened Fishes of the World: Cyprinella caerulea Jordan, 1877 (Cyprinidae). Environmental Biology of Fishes 55(3) (1999): 264.
  3. 1 2 3 4 Stewart, J.H. and Larson, R., Blue shiner (Cyprinella caerulea) Recovery Plan. U.S. Fish and Wildlife Service (1999): 7.
  4. ↑ George, A.L., Caldieraro, J.B., Chartrand, K.M., Mayden, R.L., Population Genetics of the Blue Shiner, Cyprinella caerulea. Southeastern Naturalist 7(4) (2008): 637-638.
  5. ↑ Onorato, D., Angus, R.A., and Marion, K.R., Historical Changes in the Ichthyofaunal Asseblages of the Upper Cahaba River in Alabama Associated with Extensive Urban Development in the Watershed. Journal of Freshwater Ecology 15(1)(2000): 47
  6. ↑ Cruz, T. and Ortañez, A.K., Cyprinella caerulea (Jordan, 1877). Fishbase.org.
  7. ↑ U.S. Fish and Wildlife Service, Cyprinella caerulea. fws.gov.
  8. ↑ Johnston, C. E. and J. R. Shute., Spawning behavior of the blue shiner (Cyprinella caerulea) and the holiday darter (Etheostoma brevirostrum), two rare fishes of the Conasauga River, Georgia and Tennessee. Proc. Southeast. Fish. Count. 35 (1997): l-2.
  9. ↑ Conservation Fisheries, Inc., Cyprinella caerulea, Blue shiner. conservationfisheries.org.
  10. ↑ Nuckols, D.R., and Roghair, C.N., Presence of Altamaha shiner (Cyprinella xaenura) and Ocmulgee shiner (Cyprinella callisema) within several Chattahoochee-Oconee National Forest streams. U.S. Forest Service Southern Research Station, Center for Aquatic Technology Transfer (2003): 3
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