Ministry of Natural Resources
Black crappie: Their distribution and potential impact on fisheries in northwestern Ontario Scott Parker The invasion of Canadian freshwaters by non-native species is potentially the greatest threat to the ecological integrity and sustainability of native fisheries (see Schindler 2001). There is relatively little information as to why an introduced species succeeds or fails in its new habitat (Kerr and Grant 2000). Similarly, the ecological consequences of introduced species is generally poorly understood and equally poorly documented. Difficulties associated with examining interactions of introduced species with native species include the lack of pre-invasion data and the effect of other stressors, such as exploitation and climate change. Rarely is the introduction of a non-native species beneficial or at best benign to its new environment. The introduction of a non-native fish will have some impact on the recipient ecosystem and immediate effects are not necessarily indicative of the long-term result (Kerr and Grant 2000). In northwestern Ontario, black crappie (Pomoxis nigromaculatus) is a valued sport fish where it occurs. Black crappie have been so widely introduced intentionally, accidentally, and illegally, that the extent of their native range is unclear. The introduction of black crappie into new waterbodies is often an attempt to provide additional angling opportunities. Historically, the distribution for black crappie is believed to have been restricted to the eastern and midwestern United States, and southeastern Canada (Scott and Crossman 1973). In Ontario, black crappie are native only to portions of southern Ontario, but their distribution has dramatically increased provincewide. In northwestern Ontario, they were first introduced into Rainy Lake by the state of Minnesota in the 1920s (Kerr and Grant 2000), and similarly into Lake of the Woods at approximately the same time (Mosindy 1995). However, most populations of black crappie in northwestern Ontario are the result of intentional but unauthorized transfers (Krishka et al. 1996) and subsequent natural dispersal through connected waterbodies. In recent years, questions have arisen regarding the affects that the introductions may have on aquatic ecosystems. Historically, black crappie were believed to be relatively sedentary. However, unlike other sunfish, they travel in small schools throughout the year (Kerr and Grant 2000) and exhibit daily vertical and horizontal movements between resting and feeding areas (McNeil 1992). Once introduced into a waterbody,
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their movement between interconnected lakes can be extensive (Parsons and Reed 2005). In a chain of lakes in central Minnesota, annual emigration of black crappie into adjacent connected lakes was as high as 92 percent (Parsons and Reed 2005). If there are no barriers, once a fish species is introduced they will eventually colonize connected waterbodies in both an upstream and downstream direction. Establishment of black crappie populations is ultimately dependant on lake characteristics and habitat availability (Krishka et al. 1996, Schiavone 1985). Black crappie prefer relatively shallow productive lakes, bays, and rivers with extensive areas of aquatic macrophytes (Kerr and Grant 2000, Scott and Crossman 1973). Crappie are generally associated with abundant cover, particularly aquatic plants found in deeper nearshore areas (McNeil 1992). They are found most often in clear, calm water and prefer summer water temperatures of 20 to 25 C (Scott and Crossman 1973, McNeil 1992). They also tolerate prolonged winter temperatures and lower dissolved oxygen levels than other members of the sunfish family (Kerr and Grant 2000). Black crappie occupy nearshore areas like other centrarchids, but they are also open-water predators (McNeil 1992). Their flexibility in habitat and omnivorous diet enable crappie to utilize a variety of physical and environmental conditions and exploit habitats similar to walleye and yellow perch (Keast 1968). Black crappie are nest builders and spawn in late spring and early summer when water temperatures reach 13 to 20 C (Scott and Crossman 1973, Kerr and Grant 2000, Holm et al. 2009). They mature at two to four years of age and may live to be eight to 10 years old (Scott and Crossman 1973) or older. Black crappie up to 14 years old have been consistently sampled in Rainy Lake in northwestern Ontario (MNR, unpublished data). Black crappie are prolific breeders with mature females producing an average of 30,000 to 137,000 eggs annually. Deposited eggs hatch in three to five days (Scott and Crossman 1973, McNeil 1992). Young are initially pelagic and are distributed horizontally near the surface in open water (Krishka et al. 1996, Kerr and Grant 2000). As they grow, fry move into vegetated littoral areas to feed on a greater variety of prey (Kerr and Grant 2000).
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Black crappie are crepuscular, feeding most often in low-light conditions near dawn and dusk (Holm et al. 2009). Black crappie feed primarily on zooplankton or a combination of zooplankton and small macroinvertebrates until they are approximately 100 mm in total length (TL) (Pine and Allen 2001, Dockendorf and Allen 2005). Black crappie as small as 60 mm have been found to feed on fish (Reid 1949), but they generally do not become piscivorous until greater than 120 mm (Keast 1968), and are primarily piscivorous by 150 mm (Ellison 1984). Black crappie may have a competitive feeding advantage over percids and other centrarchids, due to the high number of gillrakers on their first gill-arch, allowing them to feed on zooplankton when larger forage is limited (Keast and Webb 1966, Schiavone 1985). Growth of young black crappie varies greatly in relationship to density, habitat size and productivity, and prey availability (Kerr and Grant 2000). The average length of black crappie in Ontario is 21.5 cm (8.5 inches) and the maximum size is approximately 35 cm (14 in.) and 1 kg (2.2 lb.), but can be larger under the right conditions (Scott and Crossman 1973, Holm et al. 2009). The largest black crappie caught in Ontario measured 43.2 cm (17 in.) and weighed 1.7 kg (3.8 lb.) (Holm et al. 2009). The Minnesota state record, caught in the Vermillion River, was 2.3 kg (5 lb.) and 53.3 cm (21 in.) long (Minnesota DNR website). Despite the increasing number of introductions and range expansion of black crappie, few studies have examined how they interact with walleye, yellow perch, and lake trout. The research that does exist indicates that black crappie introductions may negatively impact the structure and dynamics of native fish communities, particularly yellow perch and walleye populations (McNeil 1992, Kerr and Grant 2000). The opportunistic feeding behaviour and plasticity of habitat requirements allow black crappie to disrupt existing predator-prey relationships when they are introduced to a new waterbody (McNeil 1992). Past introductions of black crappie resulted in the decline and replacement of native fish species, particularly walleye, and suppressed growth rates and recruitment of other species (McNeil 1992, Schiavone 1985, Mosindy 1995). Black crappie are thought to suppress exploited walleye populations by preying on walleye fry and fingerlings and through competition for food (Schiavone 1985, Krishka et al. 1996, Kerr and Grant 2000). In combination, these impacts can influence walleye yearclass strength and lead to walleye recruitment failures (Schiavone 1985, Mosindy 1995, Krishka et al. 1996).
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Schiavone (1985) reported that in the Indian River Lakes of New York state, walleye populations had declined, or were extirpated in 11 of 13 lakes, and that the decline was primarily the result of competition and predation from introduced black crappie. Southeastern Ontario lakes that have both black crappie and walleye, generally do not support a self-sustaining walleye population (Krishka et al. 1996). In several northern Ontario lakes, as walleye populations declined due to stresses such as the overexploitation of commercial and sport fisheries (Wepruk et al. 1992), black crappie populations expanded. Black crappie abundance may be a factor in the continued suppression of walleye stocks in these lakes. At present, approximately 90 percent of the lakes in fisheries management zone (FMZ) 5, where black crappie have been recently introduced, also contain walleye (MNR, unpublished data). Another potential issue compounding the spread of black crappie in northwestern Ontario is a rapidly changing environment. Climate warming has direct effects on fisheries as well as amplifying anthropogenic and natural stressors of aquatic ecosystems (Schindler 2001). General climatic warming in addition to an increase in environmental extremes may be particularly detrimental to northern coldwater fisheries. Warmer summer water temperatures may decrease available habitat for coldwater fish, such as lake trout, by altering the timing of lake stratification, thermocline depth, and optimal thermal habitat (Snucins and Gunn 1995, Fee et al. 1996, Dillon et al. 2003, Cahill et al. 2005). Conversely, warmer temperatures will increase available thermal habitat for non-native species such as smallmouth bass and black crappie and will potentially further stress native cool and coldwater fish communities (Shuter and Post 1990, Shuter and Meisner 1992, Schindler 2001, Jackson and Mandrak 2002, Sharma et al. 2007, Sharma et al. 2009). As waterbodies become increasingly eutrophic, black crappie populations may also increase (Olver et al. 1982), and compete for food with, and prey upon, yellow perch and walleye. Schiavone (1985) found that eutrophication resulted in highly variable yellow perch year-class strength that reduced the available forage for walleye, and with the introduction of black crappie ultimately led to the walleye population collapse in the Indian River Lakes in New York state. Conversely, black crappie failed to establish themselves in deep, thermally stratified lakes with low productivity and sparse vegetation (Schiavone 1985). The lack of suitable habitat reduced interspecific interactions and may have prevented the establishment of black crappie (Schiavone 1985). However, even a moderate change in
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environmental conditions may facilitate the expansion of black crappie into currently unfavourable or marginal habitat. Thus, the uncertainty of the effect of climate change on northwestern Ontario lakes and the potential impacts of the introduction of black crappie cannot be understated. Since 2008, 305 lakes in northwestern Ontario have been studied as part of the Ministry of Natural Resources’ (MNR) broad-scale fisheries monitoring program (BsM). This program is being conducted over a five-year period in each of northwestern Ontario’s five fisheries management zones. At the end of each five-year cycle, the program will begin again. This program will serve as a useful method for monitoring the distribution and expansion of black crappie populations in the Northwest Region over time. The MNR’s Atlas of black crappie waters in Ontario (2002) identified 34 inland waterbodies in northwestern Ontario as having black crappie present. Since that publication, an additional 80 waterbodies have been identified. The majority of new introductions of crappie have occurred in FMZ 5. Black crappie have been reported in 112 waterbodies in FMZ 5, including Rainy Lake and Lake of the Woods, both of which were intentionally stocked nearly a century
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ago. Black crappie have also been identified in two waterbodies in FMZ 6 (MNR, unpublished data). There are also reported catches of black crappie in several waterbodies in FMZ 4, such as lakes in the CedarPerrault watershed north of Vermillion Bay. At present, the total number of waterbodies in northwestern Ontario where black crappie have been identified is 114 (Figure 1); however, that number is likely greater.Black crappie populations have expanded rapidly over the past decade throughout much of FMZ 5. They are also present in FMZ 6 and have been reported by anglers in FMZ 4. Illegal fish transfers and accidental introductions from live wells and bait buckets pose a serious threat to native fisheries in northwestern Ontario. Several studies show that introduced black crappie compete for resources and habitat with walleye, yellow perch, and smallmouth bass and may have a negative effect on native fish populations. However, overexploited or stressed fish populations are at greatest risk. The relatively recent introduction of black crappie in small waterbodies in the Northwest Region and the unknown potential impact on northern boreal fisheries warrants continued monitoring.
Black Crappie Observations 65
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Figure 1. Waterbodies in northwestern Ontario where black crappie have been reported.
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Literature cited Cahill, K. L., J.M. Gunn, and M.N. Futter. 2005. Modelling ice cover, timing of spring stratification, and end-of-season mixing depth in small Precambrian Shield lakes. Canadian Journal of Fisheries and Aquatic Science 61: 2134–2142. Dockendorf, K.J., and M.S. Allen. 2005. Age-0 black crappie abundance and size in relation to zooplankton density, stock abundance, and water clarity in three Florida lakes. Transactions of the American Fisheries Society 134:172–183. Dillon, P.J., B.J. Clark, L.A. Molot, and H.E. Evans. 2003. Predicting the location of optimal habitat boundaries for lake trout (Salvelinus namaycush) in Canadian Shield lakes. Canadian Journal of Fisheries and Aquatic Science 60: 959–970. Ellison, D. 1984. Trophic dynamics of a Nebraska black crappie and white crappie population. North American Journal of Fisheries Management 4: 355– 364. Fee, E.J., R.E. Hecky, S.E.M. Kasian, and D.R. Cruikshank. 1996. Effects of lake size, water clarity, and climatic variability on mixing depth in Canadian Shield lakes. Limnology and Oceanography 41: 912– 920. Holm, E., N.E. Mandrak, and M.E. Burridge. 2009. The ROM field guide to freshwater fishes of Ontario. Royal Ontario Museum, Toronto, Ontario, Canada. 462 pp. Jackson, D.A., and N.E. Mandrak. 2002. Changing fish biodiversity: Predicting the loss of cyprinid biodiversity due to global climate change. American Fisheries Society Symposium 32. American Fisheries Society, Bethesda, MD. p. 89–90. Keast, A. 1968. Feeding biology of the black crappie, (Pomoxis nigromaculatus). Journal of the Fisheries Research Board of Canada 25(2): 285–297. Keast, A., and D. Webb. 1966. Mouth and body form relative to feeding ecology in the fish fauna of a small lake. Lake Opinicon, Ontario. Journal of the Fisheries Research Board of Canada 23(12): 1845–1874. Kerr, S.J., and R.E. Grant. 2000. Ecological Impacts of Fish Introductions: Evaluating the Risk. Fish and Wildlife Branch, Ontario Ministry of Natural Resources, Peterborough, Ontario, 473 pp. Krishka, B.A., R.F. Cholmondeley, A. J. Dextrase, and P.J. Colby. 1996. Impacts of Introductions and Removals on Ontario Percid Communities. Percid Community Synthesis. Ontario Ministry of Natural Resources. Peterborough, Ontario. 111 pp.
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McNeil, O.C. 1992. A review of the life history requirements and past introductions of black crappie. Ontario Ministry of Natural Resources, Midhurst District, Owen Sound, Ontario. 36 pp. Minnesota Department of Natural Resources. 2010. The Minnesota Department of Natural Resources Website. http://www.dnr.state.mn.us/aboutdnr/index.html Mosindy, T. 1995. Black crappie introductions in Lake of the Woods area. pp. 17–18 in P. MacMahon [ed.]. Fish: To stock or not to stock. Northwest Science and Technology Workshop Proceedings WP–003, Ontario Ministry of Natural Resources, Thunder Bay, ON. Olver, C.H., J.M. Casselman, P.J. Colby, and N.R. Payne. 1982. Report of the Georgian Bay walleye (Stizostedion vitreum) review committee. Ontario Ministry of Natural Resources. Fisheries Branch, September 1982. 68 pp. Ontario Ministry of Natural Resources. 2002. Atlas of black crappie waters in Ontario. Ontario Ministry of Natural Resources. 15 pp. Parsons, B.G., and J.R. Reed. 2005. Movement of black crappies and bluegills among interconnected lakes in Minnesota. North American Journal of Fisheries Management 25(2): 689–695. Pine, W.E., III, and M.S. Allen. 2001. Differential growth and survival of weekly age-0 black crappie cohorts in a Florida lake. Transactions of the American Fisheries Society 130: 80–91. Reid, G.K. 1949. Food of the black crappie Pomoxis nigro-maculatus (Le Sueur), in Orange Lake, Florida. Transactions of the American Fisheries Society 79: 145–154. Schiavone, A. 1985. Response of walleye populations to the introduction of the black crappie in the Indian River lakes. New York Fish and Game Journal 32(2): 114–140. Schindler, D.W. 2001. The cumulative effects of climate warming and other human stresses on Canadian freshwaters in the new millennium. Canadian Journal of Fisheries and Aquatic Sciences 58: 18–29. Scott, W.B., and E.J. Crossman. 1973. Freshwater fishes of Canada. Bulletin of the Fisheries Research Board of Canada 184: 966 pp. Sharma, S., D.A. Jackson, and C.K. Minns. 2009. Quantifying the potential effects of climate change and the invasion of smallmouth bass on native lake trout populations across Canadian lakes. Ecography 23(3): 517–525.
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Sharma, S., D.A. Jackson, C.K. Minns, and B.J. Shuter. 2007. Will northern fish populations be in hot water because of climate change? Global Change Biology 13(10): 2052–2064. Shuter, B.J. and J.D. Meisner. 1992. Tools for assessing the impact of climate change on freshwater fish populations. GeoJournal 28: 7–20. Shuter, B.J., and J.R. Post. 1990. Climate, population viability, and the zoogeography of temperate fishes. Transactions of the American Fisheries Society 119: 314–336. Snucins, E.J. and J.M. Gunn. 1995. Coping with a warm environment: Behavioural thermoregulation by lake trout. Transaction of the American Fisheries Society 124: 118–123. Wepruk, R.L., W.R. Darby, D.T. McLeod, and B.J. Jackson. 1992. An analysis of fish stock data from Rainy Lake, Ontario, with management recommendations. Ontario Ministry of Natural Resources, Fort Frances District Rep. No. 41. 196 pp.
Acknowledgements Numerous individuals contributed to the development of this report. Foremost, I would like to thank Kim Armstrong for providing his guidance, insight, and review. I would also like to thank Brian Jackson, Darryl McLeod, and Tom Mosindy who provided both data and information on black crappie in the Northwest Region, and Dan Lix for providing black crappie distribution maps. Tom Mosindy, Davis Viehbeck, and Pete Addison provided an insightful review of this report and greatly improved its clarity. Finally, many thanks go to Jessica Gagnon and Annalee McColm for desktop publishing.
Parker, S. 2011. Black Crappie: Their distribution and potential impact in fisheries in northwestern Ontario. Ont. Min. Natur. Resour., Northwest Sci. & Info, NWSI Aquatic Update 2011-4. 5 pp.
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