|Scientific Name:||Notropis anogenus|
|Species Authority:||Forbes, 1885|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||NatureServe (G. Hammerson)|
|Reviewer/s:||Gilbert, C., Carlson, D.M. (Freshwater Fish Red List Authority), Collen, B., Dewhurst, N. & Ram, M. (Sampled Red List Index Coordinating Team)|
Notropis anogenus has been assessed as Near Threatened due to an inferred 25% population decline as a result of habitat degradation. Further research and monitoring of the habitat status, population numbers, and potential threat processes of this species is needed to ensure a threat category is not triggered in the future.
Notropis anogenus has a disjunct distribution almost entirely confined to the Great Lakes region, primarily Wisconsin, Michigan (Becker 1983), Minnesota, and northeastern Illinois. There are still reports of a few other extant populations within other states; 1 in Iowa, 5 in New York, and a few in Ontario. It is thought that this species has been extirpated from North Dakota.
Native:Canada; United States
|Range Map:||Click here to open the map viewer and explore range.|
Notropis anogenus is represented by records from 50+ locations over a wide range, in the last 25 years. About 40 such occurrences were documented in states and provinces other than Minnesota. Minnesota is thought to have more occurrences than any other state (Phillips et al. 1982). Becker (1983) mapped about 35 collection sites in Wisconsin.
Total population size is unknown. This fish is generally rare (Lee et al. 1980; Smith 1979). Phillips et al. (1982) noted that even with intense sampling effort, only a few specimens will be collected. However, Wisconsin records indicate several sites with collections of 30-80 individuals in some years, and Becker (1983) stated that the species may be locally abundant in Wisconsin. This species is rare in Minnesota (Moyle 1975), a core part of the range. The habitat is difficult to sample effectively, so available information may underestimate abundance.
Bailey (1959:121) indicated that the species was "becoming rare in areas where it was formerly common" and that it remained most common in Michigan, Minnesota, and Wisconsin. Page and Burr (1991:158) reiterated Bailey's evaluation: "rare and becoming even less common over most of its range," but it was not clear whether or not this statement was based on new data.
The range in Michigan appears to have become more restricted. In recent decades, the species has been found in only seven of the 18 watersheds from which it was historically recorded (Derosier 2004). Latta (2005) in 1995-98 collected the species at only one of 31 sites where it had occurred in the past. However, in 1994 and 1997, he found the species at two new sites. The Michigan Department of Natural Resources (2005) recommended the species be classified as endangered.
Howell (pers. comm. 1993) reported declines in
This species has not been monitored sufficiently to clarify recent range-wide population trends, but ongoing declines seem likely.
N. anogenus is a naturally rare for reasons which have never been fully understood (C.R. Gilbert 2007 pers. comm.).
|Habitat and Ecology:||
Notropis anogenus can exclusively be found in clear, heavily vegetated glacial lakes and vegetated pools and runs of low gradient creeks and rivers. Typical substrate types include sand, mud, marl, and gravel. During the summer months, this species can be found in shallow waters, and during the winter months they move to deeper waters (Smith 1979, Lee et al. 1980, Trautman 1981, Becker 1983, Smith 1985, Page and Burr 1991).
This species is associated with two, smaller cyprinid species, the Blackchin Shiner (Notropis heterodon), and the Blacknose shiner (Notropis heterolepis). The Blackchin Shiner is said to have nearly the same distribution as that of N. anogenus, while the Blacknose Shiner has a far greater range than the other two species.
|Major Threat(s):||Declines in the population of Notropis anogenus have been attributed to increased turbidity and loss of aquatic vegetation (Herkert 1992). This loss of habitat quality is in part due to siltation, pollution, boating associated with tourism, and land use change. In North Dakota, agricultural activities have resulted in moderate to high stream turbidity (Peterka 1992). Increased turbidity has been suggested as the primary cause of the decline (Smith 1979, Trautman 1981, Parker et al. 1987). Introduction of whole-lake treatment with herbicides has also been suggested as another cause of population decline.|
|Conservation Actions:||There are no species-specific conservation measures in place for Notropis anogenus. Future conservation and management efforts would best be directed towards determining a minimum viable population, protecting spawning habitats, and water turbidity management schemes. Further research should also be directed into the impact of aquatic vegetation management, and the interaction between competitors and predators.|
|Citation:||NatureServe (G. Hammerson) 2010. Notropis anogenus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 16 April 2014.|
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