Common name: Rudd
Synonyms and Other Names: pearl roach
available through www.itis.gov
Identification: The rudd is a somewhat stocky, deep-bodied fish with a forked tail, and the mouth is distinct with a steeply angled protruding lower lip. The scales are robustly marked, the back is dark greenish-brown, and the sides are brassy yellow tapering to a whitish belly. The pectoral, pelvic, and anal fins are bright reddish-orange, and the dorsal and tail fins are reddish-brown (PA Sea Grant 2013). Berg (1949); Maitland (1977); Muus and Dahlstrom (1978); Wheeler (1978); Smith (1985); Burkhead and Williams (1991); Page and Burr (1991); Crossman et al. (1992); Pflieger (1997). Burkhead and Williams (1991) provided diagnostic characters for the recognition of rudd x golden shiner crosses.
Rudd can be distinguished from all native North American minnows (Cyprinidae) by the presense of a scaled keel along the belly between the pelvic and anal fins, along with a deep compressed body. Rudd is superficially similar to the native Golden Shiner (Notemigonus crysoleucas), and can be distinguished by the following characters (Howells 1990; Page and Burr 2011)
| || Rudd || Golden Shiner |
| Dorsal fin rays || 9-11 || 7-9 |
| Anal fin rays || 10-11 || 8-19 |
| Gill rakers on 1st arch || 10-13 || 17-19 |
| Pharyngeal teeth || 3,5-5,3 || 0,5-5,0 |
| Lateral line scales || 36-45 || 44-54 |
| Ventral keel || Scaled || Unscaled |
| Eyes || Red or gold with red spot || Yellow-green |
| Fin color || Bright red || Yellow-green |
(except in spawning adults
and southern population)
Size: 48 cm TL
Native Range: Western Europe to the Caspian and Aral sea basins (Berg 1949; Robins et al. 1991b).
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Scardinius erythrophthalmus are found here.
Table last updated 2/25/2021
† Populations may not be currently present.
Ecology: Rudd is a benthic cyprinid fish with omnivorous feeding habits and a lifespan of up to 15 years. Nurminen et al. (2003) found the rudd diet to primarily contain various macrophytes, bryophytes, and filamentous algae along with some animal material and detritus. Rudd was more zooplanktivorous in spring and autumn and less in summer and show a size-dependent diet shift from microcrustaceans while small, to macroinvertebrates at larger sizes (Garcia-Berthou and Moreno-Amich 2000). Guinan et al. (2015) showed a diet switch from piscivory in early spring towards herbivory in summer/fall coinciding with increased macrophyte abundance.
Reproduction occurs from April to August. Adhesive eggs are laid among vegetation. Fecundity ranges from 3500–232000 eggs. Maturation is at 2–3 years, 90–150 mm TL. Males are smaller with fine tubercles on head and body.
Means of Introduction: Bait bucket release seems to be the primary mechanism by which rudd have gained access into open waters. However, the history of its introduction is complex and only partly known. The species apparently entered the United States during two widely separated periods of introduction. It was initially brought to this country either in the late 1800s or early 1900s. A second period of introduction presumably began in the late 1960s or early 1970s. According to Courtenay and Williams (1992) and Gilbert (1998), rudd first appeared in the United States during the late 1800s. Main support for their conclusion is based on a footnote of Hubbs (1921). In his footnote, reference is made to a brief description by Bean (1897) of a variety of golden shiner Notemigonus crysoleucas from Central Park Lake, New York City, which Hubbs concluded to be, in reality, introduced Scardinius erythrophthalmus. Hubbs' opinion was based on the "permanent vermilion color of the pectorals, ventrals and anal" described by Bean for specimens apparently held in the New York Aquarium. Later, Bean (1903), repeating the same description as in the 1897 paper, elevated the race to a subspecies (i.e., Abramis chrysoleucas roseus). The principal character on which the new form was based was the blood red pigmentation of the fins (hence the name roseus). In his investigation on the history of rudd in the United States, Burkhead (personal communication) was unable to locate types for the subspecies, but he did find a single N. crysoleucas, dated 1894, from Central Park Lake which he examined and concluded as typical in every respect. According to Burkhead, the available information does not support or refute Hubbs' comments. Furthermore, since Hubbs' remarks presumably are based solely on Bean's color description, Burkhead concluded that it seems prudent to discard Hubbs' inference. The first verifiable U.S. record dates to 1916. In that year, some 300 specimens obtained from the New York aquarium by B. O. Webster, the Wisconsin superintendent of fisheries, were transplanted to Lake Oconomowoc, Wisconsin (Cahn 1927; Greene 1935). Myers (1925) reported on a population in Central Park Lake in New York City. The Central Park population, now extirpated, may have originated from Copake Lake, Roeliff-Jansen Kill system, which also supported a population in 1916 and possibly earlier (M. N. Feinberg, personal communication to Burkhead). The origin of the very first New York fish is not known; however, because rudd is popular in Europe as a food and game species, it may have been introduced for both purposes. The Central Park population also may have been the source for the transplant to a New Jersey park just across the Hudson (Myers 1925; Greeley 1937). The early 1950s capture of rudd by C. R. Robins in Cascadilla Creek, Tompkins County, New York, appears to be the only and last known record from the creek (Courtenay et al. 1984; Smith 1985). The origin of this population is not documented, but the relatively close Roeliff-Jansen Kill population is a logical possibility. The earliest of the more recent records is a 1973 capture of rudd from Cobboseecontee Lake in Maine. Neither year nor origin of the Maine introduction is known. At about the same time, a bait dealer in Suffolk, Virginia, began rearing rudd for bait. The source of the Suffolk, Virginia fish farmer's stock is uncertain. The interest in bait culture of rudd dramatically intensified in the early 1980s. The central Arkansas region of Lonoke and Prairie counties, an area known for its active fish farming industry, apparently became the largest producer of rudd in the United States. It appears that the greatest dispersal of rudd has been through interstate traffic rather than direct European import. In fact, much of its recent culture and spread can be attributed to its popularity as a bait among striped bass Morone saxatilis anglers. As a result, rudd have been widely introduced through a combination of bait bucket releases, escapes from aquaculture facilities and farm ponds, and, presumably, by dispersal from various points of introduction (e.g., Burkhead and Williams 1991). Although many rudd introductions are considered accidental, it is likely that rudd also have been intentionally released into public waters during the past few decades.
Status: This species has been recorded as introduced to 20 states. In a numbers of other states it has been used as a bait fish, but there is as yet no record of it being found in open waters. Available data indicate established populations still survive in Maine and New York, and, more recently, evidence indicates it is established in Massachusetts, Nebraska, and South Dakota. The species had breeding populations in New Jersey, Wisconsin, and Kansas, but it is apparently no longer extant in these states. It has been established in Lake Cobboseecontee, Maine, since 1973 (Courtenay et al. 1984; Burkhead and Williams 1991; Kircheis 1994). It has been established in the Roeliff-Jansen Kill drainage, New York, since the first half of the 1900s (Smith 1985). Probably in reference to that region, Schmidt (1986) listed rudd as present in the Hudson River drainage in the northern Appalachian region. Other New York populations are considered extirpated (Courtenay et al. 1984; Smith 1985); however, Mills et al. (1993) stated that an established population was discovered in Oneida Lake, New York, in the Lake Ontario drainage, in 1990. It may also be established in the St. Lawrence River and Lake Ontario, but that conclusion awaits confirmation. Hartel et al. (1996) stated that the presence of both young and adults over several years indicated that it is reproducing in the lower Charles River in Massachusetts. According to Zadina (personal communication), rudd is considered to be established in one or more lakes in Nebraska as of 1998. Presumably this includes Lake Ogallala. There also is evidence of rudd reproduction in parts of western South Dakota; during the summer of 1997 several year classes were discovered in Pactola Reservoir, Sheraton Lake, and Newall Lake (Unkenholz, personal communication). The species was established and later became extirpated in New Jersey and Wisconsin (Becker 1983; Courtenay et al. 1984; Courtenay and Williams 1992). There has been at least one established population in Kansas. In Spring 1996, a large breeding population was discovered in a 0.6-acre farm pond in the Deep Creek-Kansas River drainage near Manhattan, Riley County. However, that population was exterminated by Kansas Department of Wildlife and Parks personnel in Summer of 1996; as of early 1998, there has been no record of rudd in sites downstream of the pond (Bever, personal communication). Although they mapped its distribution in Kansas, Cross and Collins (1995) did not provide information on reproductive status. In general, the past literature on rudd distribution and status is fragmentary and somewhat contradictory. Courtenay et al. (1986, 1991), Courtenay and Stauffer (1990), and Courtenay and Williams (1992) considered it established in Maine and New York. Similarly, Page and Burr (1991) stated that it was established in Maine and in the lower Hudson River drainage in New York. In a relatively recent work, Courtenay (1993) indicated that the rudd was established in Maine, New York, Kansas, and presumably Nebraska (postal abbreviation given as NB). Jenkins and Burkhead (1994), citing unpublished information, stated that rudd had become established in Indiana, New York, and Maine. However, we have found no evidence that the rudd was ever introduced to Indiana waters. It is likely that inclusion of Indiana was an error (Burkhead, personal communication). Muoneke (1990) incorrectly cited unpublished information in stating that rudd apparently had become established in Alabama. In many states it has been recorded but not known to be reproducing. For instance, Jenkins and Burkhead (1994) stated that it is unknown whether escapees have established a population in Virginia. Although it has been reported from several reservoirs in Missouri, Pflieger (1997) stated there is no evidence yet that rudd is established in the state. Although we have a relatively recent report of this species from Connecticut (Jones, personal communication; Whitworth (1996) stated that the species has not been found in that state. Biologists in Arkansas say it is not established in that state (N. Stone and S. Barkley, pers. comm. 2007).
Impact of Introduction: Largely unknown. In a laboratory setting, Burkhead and Williams (1991) demonstrated that rudd readily hybridize with native golden shiner, Notemigonus crysoleucas, a primary forage species of many native game fishes. As such, the probability exists that rudd introduced to open waters will hybridize with golden shiner, with unknown consequences to wild populations of the native species. First generation hybrids offspring should show heterosis (or hybrid vigor), but the "genetic pollution" in subsequent generations could prove detrimental due to a variety of factors, for instance spawning behavior and recruitment success, and general loss of fitness (Burkhead and Williams 1991; Courtenay and Williams 1992). Nevertheless, the interactions of the two species in nature are not known (Burkhead, personal communication). Cadwallader (1977) reviewed the potential impacts of the rudd in waters of the North Island of New Zealand. He concluded, in part, that rudd can be expected to compete for invertebrate food sources with native fishes. In addition, being omnivorous, the rudd can shift its diet to plants, unlike most native fishes. Because rudd are fairly hardy, Cadwallader also indicated that the fish will fare better than many native fishes in waters that are eutrophic or polluted.
References: (click for full references)
Aprill, D. 2002. The rudd - another invasive species worth watching. Press Republican, Plattsburg, NY. May 12, 2002.
Burkhead, N.M. - U.S. Geological Survey, Gainesville, FL.
Burkhead, N.M., and J.D. Williams. 1991. An intergeneric hybrid of a native minnow, the golden shiner, and an exotic minnow, the rudd. Transactions of the American Fisheries Society 120:781-795.
Cadwallader, P.L. 1977. Introduction of rudd Scardinius erythrophthalmus into New Zealand. Part 1. Review of the ecology of rudd and the implications of its introduction into New Zealand. New Zealand Ministry of Agriculture and Fisheries, Fisheries Technical Report 147:1-18.
Clearwater, S.J., C.W. Hickey, and M.L. Martin. 2008. Overview of potential piscicides and molluscicides for controlling aquatic pest species in New Zealand. Science & Technical Publishing, New Zealand Department of Conservation, Wellington, New Zealand.
Courtenay, W.R., Jr., and J.D. Williams. 1992. Dispersal of exotic species from aquaculture sources, with emphasis on freshwater fishes. In Rosenfield, A., and R. Mann (Eds.). Dispersal of Living Organisms into Aquatic Ecosystems. Maryland Sea Grant Publication, College Park, MD. pp. 49-81.
Garcia-Berthou, E., and R. Moreno-Amich. 2000. Rudd (Scardinius erythrophthalmus) introduced to the Iberian Peninsula: feeding ecology in Lake Banyoles. Hydrobiologia 436:159-164.
GLMRIS. 2012. Appendix C: Inventory of Available Controls for Aquatic Nuisance Species of Concern, Chicago Area Waterway System. U.S. Army Corps of Engineers.
Guinan, M.E., Jr., K.L. Kapuscinski, and M.A. Teece. 2015. Seasonal diet shifts and trophic position of an invasive cyprinid, the rudd Scardinius erythrophthalmus (Linnaeus, 1758), in the upper Niagara River. Aquatic Invasions 10(2):217-225. http://dx.doi.org/10.3391/ai.2015.10.2.10
Hicks, B.J. 2003. Biology and potential impacts of rudd (Scardinius erythrophthalmus L.). In Invasive Freshwater Fish in New Zealand, Department of Conservation, Hamilton, NZ, pp. 49-58.
Lake, M.D., B.J. Hicks, R.D.S. Wells, and T.M. Dugdale. 2002. Consumption of submerged aquatic macrophytes by rudd (Scardinius erythrophthalmus L.) in New Zealand. Hydrobiologia 470(1-3):13-22.
Ling, N. 2005. Rotenone--a review of its toxicity and use for fisheries management. New Zealand Department of Conservation, Wellington, New Zealand.
Litvak, M.K., and N.E. Mandrak. 1993. Ecology of freshwater baitfish use in Canada and the United States. Fisheries 18(12):6-13.
Marsden, J.E., and M. Hauser. 2009. Exotic species in Lake Champlain. Journal of Great Lakes Research 35(2):250-265.
Neilson, K., R. Kelleher, G. Barnes, D. Speirs, and J. Kelly. 2004. Use of fine-mesh monofilament gill nets for the removal of rudd (Scardinius erythrophthalmus) from a small lake complex in Waikato, New Zealand. New Zealand Journal of Marine and Freshwater Research 38(3):525-539.
Nurminen, L., J. Horppila, J. Lappalainen, and T. Malinen. 2003. Implications of rudd (Scardinius erythrophthalmus) herbivory on submerged macrophytes in a shallow eutrophic lake. Hydrobiologia 506-509:511-518.
Page, L.M., and B.M. Burr. 2011. Peterson field guide to freshwater fishes of North America north of Mexico. 2nd edition. Houghton Mifflin Harcourt, Boston, MA.
Pigg, J., R. Gibbs, and J. Stahl. 1992. Distribution records for three new introduced species of the ichthyofauna of Oklahoma waters. Proceedings of the Oklahoma Academy of Science 72: 1-2.
Rasmussen, J.L. 1998. Aquatic nuisance species of the Mississippi River basin. 60th Midwest Fish and Wildlife Conference, Aquatic Nuisance Species Symposium, Dec. 7, 1998, Cincinnati OH.
Tilmant, J.T. 1999. Management of nonindigenous aquatic fish in the U.S. National Park System. National Park Service. 50 pp.
Whittier, T.R., D.B. Halliwell, and R.A. Daniels. 2000. Distributions of lake fishes in the Northeast - II. The Minnows (Cyprinidae). Northeastern Naturalist 7(2):131-156.
Nico, L., P. Fuller, G. Jacobs, J. Larson, T.H. Makled, A. Fusaro, and M. Neilson
Revision Date: 9/29/2020
Peer Review Date: 3/13/2015
Nico, L., P. Fuller, G. Jacobs, J. Larson, T.H. Makled, A. Fusaro, and M. Neilson, 2021, Scardinius erythrophthalmus (Linnaeus, 1758): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=648, Revision Date: 9/29/2020, Peer Review Date: 3/13/2015, Access Date: 2/25/2021
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.