Northern Prairie Wildlife Research Center
Until recently, the only species of silvery minnow to had been recorded in North Dakota was the western silvery minnow (Hybognathus argyritis). However, fish surveys by Kelsch (1993) on the Little Missouri River in southwestern North Dakota and by Kelsch and DeKrey (1997) and Peterka (1991) on the Pembina River in northeastern North Dakota have produced Hybognathus nuchalis (Mississippi or central silvery minnow). For purposes of this paper, both species will be considered present in North Dakota until taxonomists re-address the classification and identification problems common to this genera.
Central stonerollers were first recorded in North Dakota during a fish survey of the James River near Jamestown in 1892 (Woolman 1896); however, subsequent surveys have failed to recover stonerollers in North Dakota's portion of the James River. Central stonerollers were also collected in tributaries to the Red River in the 1960's (Copes and Tubbs 1966). However, recent fisheries investigations of the same eastern North Dakota rivers have documented only the largescale stoneroller (Peterka and Koel 1996; Steve Kelsch, Univ of North Dakota, pers comm). As a result of this finding, review of older, vouchered central stoneroller specimens at the University of North Dakota revealed the species to actually be largescale stonerollers. Whether the genera Campostoma is represented by one or two species in North Dakota is unclear. It is possible the central stoneroller has been extirpated from the James River Basin (at least in North Dakota) and never existed in the Red River Basin. Until further basin-specific fish surveys are conducted, two species of Campostoma will be considered as to have inhabited North Dakota. The addition of the largescale stoneroller is the only species difference between 1994 (Fishes of the Dakotas 1994) and 1997 (Table 1).
The apparent extirpation of the lake sturgeon and lake chubsucker coupled with the cessation of a stocking program for six introduced species, leaves 95 fish species (and four known hybrids) that currently inhabit North Dakota's lakes, reservoirs, rivers and streams. This includes 81 native species, none of which are endemic, and 14 introduced species, seven of which are ‘naturalized' (i.e., widespread natural reproduction occurs). In addition, four naturally occurring hybrids have been documented in North Dakota (Table 1). Twenty-one families of fish are present (15 exclusively native, three with both native and introduced species, and three introduced) with Cyprinidae (32 native species) and Catostomidae (11 native species) the most common families. The three, exclusive introduced families are Salmonidae (six species), Percichthyidae (two species) and Osmeridae (one species).
A number of other species reside in adjacent border waters but have never been documented in North Dakota. For example, eight species are considered native and present in the Red River drainage in Minnesota (Underhill et al. 1997) but have not been captured in North Dakotas portion of the basin.
Native Species: Despite 85% of fish species in the state are native, North Dakota is considered relatively species poor compared to southern and eastern states (Warren and Burr 1994). For example, Alabama harbors 257 native fish species. In contrast, Arizona and Utah are home to only 26 species. North Dakota's 81 native fish species compares with 57 in Montana, 90 in South Dakota, 135 in Minnesota, and a national statewide average of 125 (Page and Burr 1991, Fishes of the Dakotas 1994, Horak 1995).
Introduced Species: Over forty percent (six of 14) of the introduced species currently in North Dakota were first documented between 1964 (Dotson 1964) and 1977 (Ryckman 1981). It was during this general time period when the North Dakota Game and Fish Department introduced numerous coldwater species into the Missouri River system in hopes of creating a recreational fishery. During the past 20 years, only two new introduced species (i.e., zander which was stocked into Spiritwood Lake in 1989 with no apparent recruitment noted, and more recently cisco, which migrated downstream into the Missouri River system from Ft. Peck Reservoir, Montana. Reproduction of cisco has been noted (N.D. Game and Fish Dept., unpubl. data)) have been documented.
Seven of the current 14 introduced species have been naturalized (Table 1). Natural reproduction of two other species, grass carp and striped bass (Steinwand et al. 1996), has never been documented in North Dakota though adult grass carp continue to be observed in Spiritwood Lake. The last documented striped bass was a 20 pound fish caught in 1993 by an angler in Devils Lake. One other species, the zander, was recently determined to likely no longer exist in North Dakota. The last zander, a yearling, was documented in 1990 in Spiritwood Lake. The other five species and one hybrid (tiger muskie) do not naturally reproduce thus must be stocked to provide a recreational fishery.
Past non-native introductions, intentional or unintentional, have generally enhanced North Dakota's recreational fishery. Only the common carp, which was introduced into the United States in the 1870's for fish cultivation (Fritz 1987), has proven detrimental and continues to plague fish communities within numerous water bodies throughout the country (Panek 1987) and the state (nine targeted eradications in North Dakota during the 1990's have resulted in the removal of 1,877,000 pounds of carp (N.D. Game and Fish Dept., unpubl. data)).
On the other hand, introduced fish such as rainbow trout, brown trout, smallmouth bass, largemouth bass and white bass, and others have greatly increased recreational fishing opportunities throughout the state. Introduced species presently account for approximately 15% of the statewide fish harvest and nearly $30 million in annual angler expenditures (N.D. Game and Fish Dept., unpubl. data). The success of introduced species in North Dakota was predicated on the fact that over two-thirds of the states water bodies managed for fisheries are reservoirs and more than 95% of all fishable water bodies have been altered by man. In addition, other than in the Missouri River system, most of the introduced species inhabit lakes and reservoirs where species diversity is typically low. The mean number of all species sampled per lake/reservoir (n=128) in 1996 was 5.7 (N.D. Game and Fish Dept., unpubl. data).
The percent of introduced species present in North Dakota (16%) is relatively low compared to many other western states. For example, the number of fish species in Arizona has nearly tripled as a result of introductions of non-native species (Rinne 1990). In Montana, 30 of 85 (35%) fish species were introduced (Fredenberg and Gould, no date) but the introduced species support 85% of the recreational fishery (Horak 1995). North Dakota's 14 introduced fish species ranks considerably lower than the national statewide average of 24 introduced species (Horak 1995). Of the 14 introduced species present in North Dakota, most (12) were intentionally introduced by the North Dakota Game and Fish Department. In comparison, only 27 of the 58 taxa deliberately introduced into California waters were by the California fish agency (Dill and Cordone 1997).
Frequently Observed Species: In 1996, the most commonly sampled adult species in lakes and reservoirs, in order by frequency of occurrence, were yellow perch (71%), northern pike (65%), walleye (56%), fathead minnow (43%), white sucker (42%), bluegill (41%), black bullhead (28%), and brook stickleback (24%) (Power 1997). Though percentages vary slightly between years, the general species composition and occurrence is representative for North Dakota's lakes and reservoirs.
In contrast to the lake and reservoir surveys, 94% of the river/stream surveys from 1950 to 1994 yielded more than five species (Fig. 1). In fact, 54% of the river/stream surveys produced more than 15 species. The following are, in order, the most frequently occurring species sampled from North Dakota rivers and streams: white sucker, fathead minnow, brook stickleback, black bullhead, northern pike, common carp (introduced), and creek chub (N.D. Game and Fish Dept., unpubl. data).
Species of Concern: After a review of fish surveys, the statewide population status of nine native species was deemed of immediate concern (Table 2) due to documented or suspected long-term population decline. Six of these nine species generally inhabit only the Missouri River system. The status of another 13 species may be of some concern although the distribution of many of these species appears to be more peripheral, with good populations in other parts of their range. The status of the remaining 59 native species is currently of no immediate concern, but certainly of no less importance. The most recent federal listing of North Dakota fish species is also included in Table 2. Currently, the pallid sturgeon is the only federally listed endangered fish species in North Dakota.
All rare species of concern listed in Table 2 prefer riverine conditions. This is consistent with a nationwide trend; most threatened and endangered fish species were associated with lotic rather than lentic systems (Flather et al. 1994). In North Dakota, the rare fish species of concern tend to be either small cyprinids (i.e., pearl dace, northern redbelly dace and pugnose shiner) that are found in the clear, cool waters of headwater streams, or an assemblage of species (i.e., pallid sturgeon, paddlefish, sicklefin chub, sturgeon chub, flathead chub and blue sucker) that are predominantly found in large, turbid rivers (i.e., the Yellowstone River and that portion of the Missouri River between the confluence of the Yellowstone River and Lake Sakakawea).
Nationally, habitat loss has been identified as the single most important factor for species endangerment (Flather et al. 1994). The creation and operation of six mainstem dams on the Missouri River (including Garrison Dam in North Dakota) along with channelization, are the common causes cited for the decline of a number of native species (USFWS 1994) including six of the rare species of concern listed by the Dakota Chapter of the American Fisheries Society (Table 2). In addition, abuses to the riparian corridor (e.g., excessive grazing) and subsequent loss of aquatic habitat due to sedimentation, as well as non-point pollution, have likely contributed to the decline of a number of native minnow species. Though specific, long-term databases are lacking for rivers and streams throughout North Dakota, the State Department of Health is in the process of collecting information that will establish baseline data in hopes of developing indices of biological integrity (IBI).
Changes in reservoirs can exemplify the deterioration of the watershed. For example, three randomly-chosen small reservoirs (located on small streams and separated by more than 200 miles and numerous sub-basins) exhibited volume reductions, due to sedimentation, of 18% to 35% between 1970 and 1990 (N.D. Game and Fish Dept., unpubl. data). Correspondingly, each of these reservoirs have reported a decline in the recreational fishery and a reduction in species diversity. Undoubtedly, the health of the respective fisheries is directly related to the health of the riparian and aquatic habitats.
In addition, long-term changes to riverine habitat have likely allowed for colonization of species into different drainages. For example, a fish survey conducted in the Pembina River in 1996 recorded the first-time presence of seven species (Kelsch 1997). A similar 1996 fish survey on the Knife River documented the first time appearance of the following species: johnny darter, red shiner, and spottail shiner (Peterka and Koel 1997). In many of these instances, land use changes and patterns may be the ultimate cause for these new species occurrences.
Recreational Fishery: North Dakota's recreational fishery includes an annual statewide fishing harvest estimate that exceeds 2.5 million fish (Baltezore et al. 1994). In addition, estimates of annual angler expenditures range between $83 million (American Sportfishing Association 1997) and $257 million (Baltezore and Leitch 1992). Fishing licence sales (licences required for individuals 16 years of age and older) during the 1996-97 fishing season totaled 133,600 (N.D. Game and Fish Dept., unpubl. data). North Dakota continues to be near the top in angler participation on a per capita basis as nearly one in every four North Dakotans 16 years of age or older bought a fishing licence in 1996 (USFWS 1997). Three native species, walleye (76%), yellow perch (13%), and northern pike (10%), were the most preferred species to catch in 1990 (Power 1992). Fathead minnows compose the vast majority of the live bait fish sold in North Dakota (N.D. Game and Fish Dept., unpubl. data).
Essentially all species that are of recreational significance are widely transported and stocked throughout the state. For example, the following is the 1996 North Dakota hatchery production of fingerlings/smolts (all in millions): 7.8 walleye, 2.9 northern pike, 0.6 largemouth bass, 0.6 smallmouth bass, 0.6 yellow perch, 0.5 chinook salmon, 0.4 saugeye, 0.2 rainbow trout, 0.1 brown trout and 0.1 hybrid muskie (Weigel 1997).
In some states, species endangerment has been attributed to recreational fishery programs including the introduction and stocking of non-native species (Williams et al. 1989). However, in North Dakota, there have been no major conflicts between protecting native fish and maintaining a recreational fishery.
Conclusion/Recomendations: The principal challenge for North Dakota fishery managers and other resource professionals into the next millennium will be to maintain the state's recreational fishery while providing adequate protection for native fish populations. This will be a formidable task in light of ongoing environmental degradation of the state's riverine habitats.
Developing and implementing a statewide ‘Native Fish Program' would ensure some additional consideration for numerous species in the future. In addition, earmarking funding specifically for protecting fish habitat would provide long-term benefits and a national excise tax on select recreational gear could be an important avenue for supporting a 'Native Fish Program'. Lastly, a drainage (site-specific) distributional study of all fishes in North Dakota would provide valuable information.