Transcript Unintentional Introductions of Non

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
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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
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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
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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
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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
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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)
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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!