Which of the following are “exotic species”?

1. Which of the following are “exotic species”? Wheat in Kansas Steelhead trout in Lake Michigan Bluegrass in Kentucky Zebra mussels in Lake Erie

2. Steps to become an invasive species….. Disperse from native range to somewhere else Survive in new habitat Reproduce in new habitat Naturalize (establish permanent population) Become a problem (immigrant vs invasive spp)

3. lag phase when not know if spp will become invasive

4. Some conditions can promote invasiveness Vacant “niches”: ecosystems with few species Escape from predators and competators Disturbance of ecosystem

5. Consequences of invasion: Great Lakes case study

6. Great Lakes Introductions increase over time Ricciardi et al 2001

7. Routes of introduction  Canals  (sea lamprey)  alewife  Ballast water importation  zebra mussels  spiny water flea  goby  ruffe  Aquaculture and aquarium trade and intentional release  carp

8. The Sea Lamprey (Petromyzon marinus) Primative (jawless) fish Native to Atlantic Ocean Adults predatory on large fish

9.  Probably entered Great Lakes via the Hudson River and its artificial extension, the Erie Canal (opened to Lake Ontario in 1819) Erie Canal Hudson

10.  Gained access to Lake Erie through Welland Canal around Niagara Falls (completed 1829), but not noted in Lake Erie until 1921  Thereafter invasion quickened; found in Lake Huron in 1932, Lake Michigan in 1936, and Lake Superior in 1946.

11.  Lampreys devastated lake trout populations in Great Lakes Removal of top predator allowed smaller fish such as alewife (also introduced through canals) to boom http://www.glfc.org/slft.htm  Lamprey control (pesticide applied to juvenile form in streams)- continues today  Coho & Chinook salmon easier to grow in hatcheries than lake trout. These exotic species were heavily stocked

12. Alewife •  Euryhaline species •  Traveled through canals (maybe native to Ontario)  Population expanded when lake trout died  Efficient zooplankton eater, changed zooplankton and contribute to decline of native fish (e.g. bloater)

13. Sea Lamprey Pacific Salmon Phytoplankton Lake Trout Bloater Alewife Whitefish Small zooplankton Large zooplankton

14. Ballast-mediated species Introduction discharge uptake transport

15. Water is used for ballast, but sediments accumulate too Can contain resting stages or live animals

16. http://www.earthwave.org/zmussel.htm Dreissenid Mussels History Ponto-Caspian origin  Ballast transport  First found in Lake St. Clair Biology  Adults attach to substrate  Planktonic larvae  High population density  High filtration rate

17. Zebra mussel covering hard substrate and spreading over soft sediment in Oneida Lake, NY

18. Total coverage of sediments in St Lawrence Seaway Covering hard objects

20.  Increase in water clarity in Oneida Lake, NY 5 zebra mussels 4 Secchi depth (m) 3 2 1975 1980 1985 1990 1995 2000

21. Lake Erken; P. Eklov, Uppsala U. Bay of Quinte; S. Millard, DFO Western Lake Erie; S. Ludsin Naroch Lakes chain; L. Brulakova & A. Karatayev, Austin St. U. Onieda Lake; CBFS

22. 90 7 pre zebra mussel post zebra mussel 80 6 pre zebra mussel 70 5 60 4 50 Mean pre-zebra mussel TP (ug/L) Mean annual Secchi depth (m) 40 3 30 2 20 1 10 0 0 Naroch Oneida Erie Erken Quinte N Quinte B Myastro Batorino Lake

23. Dreissena and Unionid Clams Some species extremely long lived, > 100 years Do not mature for relatively long time ~> 10 years Populations already hurt by water quality problems and dams Zebra mussels encrust unionid shells. Interference competition  Native clams usually disappear w/ in 5 yr of zebra mussel introduction

24. Bythotrephes http://www.miseagrant.org/ans/zoo.html short vs. long spine big vs. small body http://ebiomedia.com/gall/classics/Daphnia/feature_main.html  A native of Great Britain and northern Europe  Discovered in Lake Huron in 1984  Spread to all the Great Lakes and some inland lakes. Native Daphnia spp.

25. http://www.miseagrant.org/ans/zoo.html http://ebiomedia.com/gall/classics/Daphnia/feature_main.html Which would fish rather eat??  Feeds on smaller zooplankton in the Great Lakes  May be reducing food for native plankton and fish species

26. Round Goby http://www.miseagrant.org/ans/fish.html  Eat zebra mussels  May compete with native darters or sculpins  May consume eggs of natives (lake trout)

27. Eurasian Ruffe European perch family discovered in Duluth harbor in 1985. http://www.miseagrant.org/ans/fish.html Have spread around Lakes Superior and have established a population in Thunder Bay near Alpena, Michigan. In some areas, explosive population growth and displace native species such as y.p. and emerald shiners Sharp spines make them difficult for larger fish to eat

28. Aquaculture Releases Carp European settlers for food and fishing well established population Asian Carp Southern fish farms

29. Knocking on the door: Asian carp  several species, accidentally released from aquaculture facility.  ~ 40 mi from Lake Michigan.  Electrical barrier in place in Chicago.

30. http://www.glfc.org/fishmgmt/carp.asp

31. Economics of electrical barrier Construction cost? Maintenance cost? Will it work? MN proposing bubble and sound curtain 57% effective

32. Sea Lamprey Pacific Salmon Lake Trout Bloater Alewife Whitefish goby Spiny flea Small zooplankton Large zooplankton Asian carp Zebra mussels Benthic algae Phytoplankton

33. Invasional Meltdown Theory that suggests that current invasions may facilitate future invasions Exotics don’t necessarily compete with one another, may make it easier for others to get in. Compare to “biotic resistance” or “empty niche” theories described in reading

34. Prevention and Control Prevent entry: International trade treaties International and interstate commerce Examples: Garden plants, pets, aquarium fish, agricultural species Shipping industry regulations Examples: all GL species Very difficult to predict which species will become invasive How to decide which species cannot be imported

35. Eradication Possible if detected early Biology of species important, ex. it has slow dispersal or depends on few other spp. for survival Long-term effort: funding for eradication program is not cut Public support

36. Maintenance Control Keep population at low level to avoid ecological damage Some successful examples