- Количество слайдов: 38
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 (n=139) Data from Mills et al. 1993
Introduced Aquatic species in the Great Lakes Sorted by Taxonomic Group 60% 20% Data from Mills et al. 1993 18%
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 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 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.
(USFWS Ashland FRO, USGS Lake Superior Biological Station)
Ruffe density in 4 south shore tributaries to Lake Superior; 1995 -2001 (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 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 *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!