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Status of Unintentionally Introduced Non-native Aquatic Species in Lake Superior, 2002 Mark P. Dryer & Gary Czypinski USFWS-Ashland Fishery Resources Office Douglas A. Jensen Minnesota Sea Grant Program Cumulative Number of Nonnative Species Introduced into the Great Lakes, 1993 10 20 90 19 70 19 50 19 30 19 10 19 90 18 70 18 50 Animals - 56 Plants - 83 18 18 30 90 80 70 60 50 40 30 20 10 0 (n=139) Data from Mills et al. 1993 Introduced Aquatic species in the Great Lakes Sorted by Taxonomic Group 90 83 80 60% 70 60 50 40 20% 26 30 25 18% 20 10 3 0 Plants & Algae Invertebrates Fish Data from Mills et al. 1993 Diseases Pathogens Fish Community Objectives for Lake Superior 1. Prevent the introduction of any non-indigenous aquatic nuisance species. 2. Prevent or delay the spread of non-indigenous aquatic nuisance species, where feasible. 3. Eliminate or reduce populations of nonindigenous nuisance species, where feasible. Source: Public Discussion draft, March 2001 Proportion of native and introduced fish species in the Great Lakes 140 17 60 40 15 16 100 80 17 14 120 114 99 113 112 Erie Ontario Exotic fish Native fish 67 20 0 Superior Michigan Huron Based on Mills et al. 1993, D.A. Jensen (manuscript in prep 2000) Lake Superior Non-native Species - 32 • • • • 17 fish (53%) 5 aquatic invertebrates (16%) 4 diseases and parasites* (12%) 6 aquatic plants (19%) 61% arrived since 1960 Jensen, D.A. Manuscript in Preparation 2000 Sources of non-native species in Lake Superior Sources of releases:* 10 ballast water 7 unintentional stocks 6 intentional stocks 5 canals and diversions 4 bait bucket/recreation boats 3 nursery/cultivar 1 biological supply house/aquarium release 1 unknown Total: 32 (8 intentional, 23 unintentional, 1 unknown) * total number >32 because of multiple pathways for several species Ship ballast, hulls and hull sediments are the primary source of unintentionally introduced nonnative species in Lake Superior Ballast Water Management Progress • • • • • • Great Lakes shipping industry voluntary guidelines. Michigan enacted legislation. Legislation under consideration in Wisconsin. U.S. Coast Guard regulations for ocean vessels. Great Lakes Panel on ANS, Policy Statement Ballast management technology demonstrations. Unintentionally Introduced Fish (9) in Lake Superior • • • • • • • • • Ruffe Fourspine stickleback Threespine stickleback Round goby Tubenose goby White perch American eel Sea lamprey Alewife ship ballast ship ballast ship ballast ship ballast ship ballast ship ballast canals canals canals/ballast Ruffe (Gymnocephalus cernuus) • Lake Superior – west half • Lake Huron – at Alpena, MI Threats and Impacts • • • • Grows rapidly. High reproductive output. Aggressive feeding habits. In St. Louis River, yellow perch, emerald shiner, and trout perch declined. • Yellow perch growth slower in competition w/ruffe. Number/hectare in trawls St. Louis River, WI/MN 2500 2000 1500 1000 500 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year (USFWS Ashland FRO, USGS Lake Superior Biological Station) Ruffe density in 4 south shore tributaries to Lake Superior; 1995-2001 1200 Number per hectare in trawls 1000 800 Amnicon R Iron R Flag R Ontonagon R 600 400 200 0 1995 1996 1997 1998 1999 2000 2001 Year (USFWS Ashland FRO, USGS Lake Superior Biological Station) Round goby (Neogobius melanostomus) Tubenose goby (Proterorhinus marmoratus) Round goby Tubenose goby Threats and Impacts • • • • • Dominates spawning sites of other fish. Spawns numerous times . Tolerates low DO for several days. Aggressive feeding habits. Feeds on eggs of sculpin, darters, and logperch. • Displaces native bottom-dwelling fish. Round goby Round Goby Abundance in the SLRE Number/hectare in trawls 30 25 20 15 10 5 0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Year Source: USGS Lake Superior Biological Station Threespine stickleback (Gasterosteus aculeatus) • Marquette Harbor •Black Bay •MN, WI, MI tributary estuaries Threats and Impacts • Impacts largely unknown, but may compete w/native sticklebacks. • Feed on zooplankton, oligochaetes and chironomids. • Inhabits shallow, sandy-bottomed shoreline habitats. Fourspine stickleback (Apeltes quadracus) • Thunder Bay Harbor White perch (Morone americana) • St. Louis R. estuary • Wisconsin tributary estuaries • Chequamegon Bay •Michigan tributary estuaries Threats and Impacts • Eggs are an important diet component. • Yellow perch growth rates declined in some areas where co-exist. • Hybridize with native white bass in Lake Erie. • Known to overpopulate habitats of native fishes and become stunted. Alewife (Alosa pseudoharengus) •Widespread but scarce Threats and Impacts • A diet rich in alewifes may result in a thiamine deficiency in predators disrupting their reproduction. • Effective predators of lake trout fry. • Populations can explode without predation. American eel (Anguilla rostrata) • St. Louis R. estuary • Nemadji R. • Black Bay Unintentionally Introduced Invertebrates in Lake Superior (5) • • • • • Zebra mussel Spiny waterflea Rusty crayfish Asiatic clam Aquatic oligochaete* ship hull ship ballast multiple ship ballast ship ballast *widespread in other Great Lakes but not confirmed in Lake Superior. Zebra mussel (Dreissena polymorpha) • Harbors and sheltered bays Threats and Impacts • Clog intake pipes; foul ships, shores, docks and rocks. • Caused millions dollars in economic damage to industry and recreation. • Threaten native mussels. Spiny waterflea (Bythotrephes cederstroemi=longimanus) • Throughout Lake Superior Threats and Impacts • Rapid reproductive rate compete with young fish for food. • Nuisance to recreational and charter fishers. Rusty crayfish (Orconectes rusticus) • St. Louis R. • Pidgeon R. • Thunder Bay • Inland lakes along U.S. shore Threats and Impacts • More aggressive than native crayfish, out competing them for habitat. • Reduce aquatic plant abundance and diversity. • Less susceptible to predation than native crayfish. Recommendation • Prevent the future introduction of any non-native species to Lake Superior. To support recommendation(s) • Develop and support policy. • Implement management. • Conduct research, assessments and monitoring. • Conduct aggressive public education. For Endangered Species, Extinction is Forever For Invasive Species, Introduction is Forever No Control is 100% Effective; There is No Silver Bullet!