BIOL Fishes Exam 3
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Great Lakes “HOMES”
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Huron, Ontario, Michigan, Erie, Superior
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Bathymetry
- refers to the depth of the water
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Laker Erie a very shallow lake
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Speciation
- not much in the past 10,000 years
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African Cichlids
- most speciose group known on earth.
Species Flock
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Lake Victoria
- massive amount of species.
Pollution, overfishing decreased speciation.
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Nile Perch was introduced and the population of Cichlids fell off dramatically.
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Atlantic Salmon
- first fish lost in the Great Lakes due to human activity, overfishing
Natural Migration Pattern
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Barriers
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In the US mountain ranges run from North to South, as opposed to Europe where they run East
to West.
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In the us this did not cut off species migration due to glaciation as it did on the European
continent.
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Migration
- anywhere from geographic time and space to fish lifetime or season.
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Pleistocene Period
- advances of
ice sheets, glaciers
and movement caused a great deal of
changes and migration.
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Glaciers
- glaciated/unglaciated, complex and dynamic magins at the edges.
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Ohio
- was
glaciated
⅔
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Refugia
-
a location which supports an isolated or relict population of a once more widespread
species.
An area in which a population of organisms can survive through a period of
unfavorable conditions, especially glaciation.
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Glacial melting causes water masses to become connected allowing migration.
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Connections outside of the Great Lakes, disappeared over time
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Mississippi Refugium
- 80-90% of fish from Mississippi River drainage.
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Warm water taxa
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Connections from glacial refugium caused diversity that shouldn't be there.
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Gars, Sturgeons, ancient lineages that were present there
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Centrarchids, Perchids, Cyprinids
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Atlantic Refugium
- migration to Lake Ontario
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Sea Lamprey to Lake Ontario
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Alewife, Herring
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Atlantic Salmon
- from Atlantic seaboard migration
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1st species lost from Great Lakes due to human activity
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Landlocked in Ontario because of
blocked spawning migrations via mill dams
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Arctic Refugium
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Cold water taxa
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Lake Trout
Human Mediated Migration Pattern
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3 Methods
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Ballast Water
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Navigation Canals
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Fish Stocking
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Ballast Water Invasions
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Human induced invasions
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Most invasive species are bad for the ecosystem
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Ships can carry invasive species in their ballast water
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Ballast Water
- used to change buoyancy of ship, picked up invasive species of fish
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Eurasian Rulf
- invaded Lake Superior via ballast water
1
BIOL Fishes Exam 3
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Round Goby
- invaded Great Lakes via ballast water.
Not aggressive until they invaded
the Great Lakes where they thrived.
