Description: Coregonus artedi or cisco, also referred to as tullibee or lake herring have a streamlined and elongated body. They appear shiny with their silver scales and grayish fins. Coregonus artedi’s upper and lower jaws meet in a terminal position (tip of the mouth) and the tail is deeply forked. An adipose fin is present as they are members of Salmonidae. An adipose fin is a smaller fin found behind or posterior to the dorsal fin on the fish’s dorsal side (back of fish). Coregonus artedi exhibit polymorphism, which means they can display many body forms. A study in Canada found that C. artedi in Great Slave Lake in the Northwest Territories of Canada have a wide range of morphological differences and life histories among this one taxon. They can be put into three categories adfluvial cisco, lacustrine cisco, and bigeye cisco (Muir et al. 2012). The average lengths of this fish are 157.79 mm, 200.83 mm and 146.06 mm, respectively (Muir et al. 2012). The lacustrine cisco is the morphology and life history that is most common among its native range in North America and will be the focus of this paper. This body form of C. artedi has been found to have anywhere from 36 to 57 gill rakers, 9-14 dorsal rays, and 10-15 anal rays (Muir et al. 2012).
In Minnesota, they are commonly mistaken for lake whitefish (Coregonus clupeaformis) or mooneye (Hiodon tergisus). The Minnesota Department of Natural Resources (DNR) gives a guide on how to differentiate between these three (“Identifying Lake Whitefish, Cisco, and Mooneye - Minnesota DNR.” 2019). For lake whitefish and C. artedi, lake whitefish have a sub-terminal mouth (mouth located below anterior most portion of head) as opposed to the C. artedi’s terminal mouth. To tell the difference between mooneye and C. artedi, the anal fin on the mooneye is longer and the origin will be even with the origin of the dorsal fin. C. artedi’s will be shorter, and the origin of the dorsal fin will be anterior to the origin of the anal fin.Systematics: Coregonus artedi taxonomy goes as follows; Kingdom-Animalia, Phylum-Chordata, Class-Actinopterygii, Order-Salmoniformes, Family-Salmonidae, Subfamily-Coregoninae, Genus-Coregonus. Within the genera Coregonus, fish can be split into two groups: whitefish and cisco. The fact that these are closely related has remained consistent through the years (Bernatchez et al.1991; Crête-Lafrenière et al. 2012). The exact relationships have changed. One study found that C. artedi are an outgroup to many other cisco species within Coregonus (Bernatchez et al.1991). More recent genetic work plus the addition of more Coregonus species has found that these relationships are different than previously thought. Coregonus artedi is sister taxon to four others extant Coregonus species, C. zenethicus, C. nigripinnis, C. kiyi, C. hoyi. (Crête-Lafrenière et al. 2012). This means that these species are more closely related than previously thought. While the fossil record for C. artedi is unavailable, Coregonus fossils have been dated back to the early Pleistocene (Harington 2011). These fossils include two extinct Coregonus spp. and one unidentified Coregonus sp.
Habitat & Range: Coregonus artedi are distributed through the great lakes and deep inland lakes of North America (Scott & Crossman 1973). They inhabit the pelagic zone (open water) in lakes and their habitat can be narrowed down to two main factors: temperature and oxygen. Coregonus artedi prefer cold water, 12.5-16.5 degrees Celsius. They prefer high levels of dissolved oxygen (DO), 6 mg/L. They avoid water when 20-21 degrees Celsius or 4-4.5 mg/L DO (Jacobson et al. 2010). Temperature and DO levels become lethal to C. artedi when it reaches over 23.8 degrees Celsius or 3 mg/L DO. They can tolerate higher temperatures when more DO is available and lower DO levels when temperature is lower (Jacobson et al. 2010). Using data about temperature and DO plus the relationship between these two factors and C. artedi, spatial models have been created for C. artedi (Jacobson et al. 2010). These models show where in the water column C. artedi can be found throughout the year.Food:
Coregonus artedi are carnivorous fish that primarily feed on zooplankton. They have been observed to feed on smaller fish when they are adults (Johnson et al. 2004). Their diet of zooplankton is diverse, according to a feeding study done out of Lake Superior (Johnson et al. 2004). This study found 24 different species across many genera in the stomachs of C. artedi. The top three species found making up about 70% were: Diaptomus sicilis, Ostracoda spp. and Daphnia galeata mendotae. Another feeding study done in Lake Superior during the winter found that C. artedi predominantly feed on Diaptomus sicilis (Link et al. 1995). They took it a step further and compared percent make-up of diet to present abundance for zooplankton. They found that selection does occur, and diet make-up is not proportional to relative abundance in the ecosystem. They hypothesized that selection of diet for the C. artedi was based on size (Link et al 1995). This eludes to that selection in their diets has to do with is the right size rather than a preference or abundance of a particular species.
Reproduction: Coregonus artedi move into rivers during the fall to spawn, their eggs remain in the river overwinter and hatch the next spring. Coregonus artedi broadcast spawn in shallow waters, 1-3 meters over rocky and vegetative substrate (Savino et al. 1994). These fish exhibit no particular parental care and have not been documented displaying breeding colors. The optimum temperature for C. artedi eggs is found to be between 2 and 8 degrees Celsius (Colby and Brooke 1970). A study (Savino et al. 1994) observing the impacts of sediment and turbidity found that they had little impact on egg incubation. That study suggested that oxygen levels play a large role in egg hatching rates. Turbidity and sediment type only impact incubation when it directly impacts oxygen. Coregonus artedi are generally fall spawning fish there are some populations that have been observed to spawn in the spring (Hnault et al 1991).
Other Interesting Facts:
The name Coregonus translates in Latin to “angle eye”. The name Artedi refers to famous ichthyologist Petrus Artedi. The USDA actually allows for this fish to be sold under all three of its names: Cisco, Tullibee, and Lake Herring. The name lake herring is misleading in that it is not a member of the herring family (“Cisco (Lake Herring).” 2019). From personal experience these fish do not taste good when cooked like most other Minnesota game fish (walleye, bluegill, perch). However, they are great when smoked. The Minnesota state record for cisco is 5 lbs. 11.8 ounces or 2.6 kg (“Identifying Lake Whitefish, Cisco, and Mooneye - Minnesota DNR.” 2019).
Conservation & Economic Importance:
Coregonus artedi have a history of being commercially fished for in the Great Lakes (Ebener et al. 2008). Commercial harvest peaked between 1883 and 1908, reaching up to 9 million kg annually. Coregonus artedi numbers in the great lakes declined to an estimated .02% of their maximum (Claramunt et al. 2019). Today, the populations of C. artedi have rebounded and are much higher. Across the great lakes they are still commercially harvested but with many restrictions and at lower numbers (Ebener et al. 2008).
There is some recreational fishing for cisco, but it is not be a significant factor on population. In Minnesota, walleye (Sander vitrues) is the center of attention for conservation and economic importance. Coregonus artedi is an incredibly important food source for walleye. They have been shown to promote faster growth and larger maximum sizes in walleye (Morgan et al. 2009). This study found that C. artedi are a higher energy food source than other food for walleye. When they are abundant and present for walleye, they provide lots of energy at low cost and allows for more energy to be used for growth (Morgan et al. 2009). The state of Minnesota has designated Cisco as a “rough fish”. Until recently there were no limits for the number of ciscoes one could harvest, this has been changed to 50 per day. The limit on Mille Lacs lake is stricter at 10 per day. There is evidence to support that climate change may negatively impact their populations in the future (Martell et al. 2013). This study found that higher temperature resulted in lower carrying capacities. This ultimately leads to a lower population in impacted lakes.
Resources:
MDNR 2019. “Identifying Lake Whitefish, Cisco, and Mooneye - Minnesota DNR.” Minnesota Department of Natural Resources, 23 June 2019, www.dnr.state.mn.us/areas/fisheries/baudette/whitefish.html.
Bernatchez, L., Colombani, F., & Dodson, J. J. 1991. Phylogenetic relationships among the subfamily Coregoninae as revealed by mitochondrial DNA restriction analysis. Journal of Fish Biology, 39, 283-290.
Claramunt, Randall M, Smith, Jason, Donner, Kevin, Povolo, Annalise, Herbert, Matthew E, Galarowicz, Tracy, . . . Jonas, Jory L. 2019. Resurgence of Cisco (Coregonus artedi) in Lake Michigan. Journal of Great Lakes Research, 45(4), 821-829.
Colby, P. J., & Brooke, L. T. 1970. Survival and development of lake herring (Coregonus artedii) eggs at various incubation temperatures.
Crête-Lafrenière, A., Weir, L. K., & Bernatchez, L. 2012. Framing the Salmonidae family phylogenetic portrait: a more complete picture from increased taxon sampling. PloS one, 7(10), e46662.
Ebener, Mark P., 2008. "Status of cisco (Coregonus artedi) in Lake Superior during 1970-2006 and management and research considerations." Gt. Lakes Fish. Comm., Lake Superior Tech. Rep 1 (2008): 126.
Harington, C. 2011. Pleistocene vertebrates of the Yukon Territory. Quaternary Science Reviews, 30(17), 2341-2354.
Hnault, M., & Fortin, R. 1991. Early life stages, growth, and reproduction of spring-spawning ciscoes ( Coregonus artedii ) in Lac des corces, Quebec. Canadian Journal of Zoology, 69(6), 1644-1652.
Jacobson, P. C., Stefan, H. G., & Pereira, D. L. 2010. Coldwater fish oxythermal habitat in Minnesota lakes: influence of total phosphorus, July air temperature, and relative depth. Canadian Journal of Fisheries and Aquatic Sciences, 67(12), 2002-2013.
Johnson, T. B., Brown, W. P., Corry, T. D., Hoff, M. H., Scharold, J. V., & Trebitz, A. S. 2004. Lake herring (Coregonus artedi) and rainbow smelt (Osmerus mordax) diets in western Lake Superior. Journal of Great Lakes Research, 30, 407-413.
Link, J., Selgeby, J. H., Hoff, M. H., & Haskell, C. 1995. Winter diet of lake herring (Coregonus artedi) in western Lake Superior. Journal of Great Lakes Research, 21(3), 395-399.
Martell, Steven J., Pitcher, Tony J., & Varkey, Divya A. 2013. Temperature-Driven Decline of a Cisco Population in Mille Lacs Lake, Minnesota. North American Journal of Fisheries Management., 33(4), 669-681.
“Mille Lacs Lake Fishing Regulations - Minnesota DNR.” Minnesota Department of NaturalResources, 27 Sept. 2019, www.dnr.state.mn.us/fishing/millelacs.html.
Muir, A. M., Vecsei, P., Power, M., Krueger, C. C., & Reist, J. D. 2014. Morphology and life history of the Great Slave Lake ciscoes (Salmoniformes: Coregonidae). Ecology of freshwater fish, 23(3), 453-469.
Morgan, George E., Gunn, John M., Kaufman, Scott D, Morgan, George E, & Gunn, John M. 2009. The Role of Ciscoes as Prey in the Trophy Growth Potential of Walleyes. North American Journal of Fisheries Management., 29(2), 468-477.
Savino, J. F., Blouin, M. A., Davis, B. M., Hudson, P. L., Todd, T. N., & Fleischer, G. W. 1994. Effects of pulsed turbidity and vessel traffic on lake herring eggs and larvae. Journal of Great Lakes Research, 20(2), 366-376.