aquatic invasive species n.
Skip this Video
Loading SlideShow in 5 Seconds..
Aquatic Invasive Species PowerPoint Presentation
Download Presentation
Aquatic Invasive Species

Aquatic Invasive Species

279 Vues Download Presentation
Télécharger la présentation

Aquatic Invasive Species

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Aquatic Invasive Species Laura Fogt EEES 4730

  2. Outline • Objective • Background information • Problem and causes • Consequences to aquatic systems • Solutions • Research publication

  3. Objective • To discuss the ecological impacts of aquatic invasive species and propose some possible solutions.

  4. Invasive Species • Definition • Where they are found • In and around bodies of water

  5. Problem • Thousands of aquatic species have been dispersed or transplanted across the globe through human interaction

  6. Causes • Humans have played dominant role in species transport across the globe through man-made pathways • Intentional • Ex: intended movement of living seeds, whole plants or pets • Unintentional • Ex: ballast water discharge

  7. Ballast Water Discharge

  8. Other methods of transport • Ships and boats • Organisms attach themselves to hulls of vessels • Canal construction • Intentional release • Food sources • Sport fishing • 7 out of the 8 fish on the “One Hundred of the World’s Worst Invasive Alien Species” were introduced for sport (Cambray, 2003)

  9. More methods • Shipping • Oyster transfer considered the primary vector for the spread of invasive macroalgae in the Mediterranean (Roman, 2010) • Algal packing material used for shipping live seafood and bait may contain juvenile crabs, snails, mussels, and other organisms often discarded near shore(Roman, 2010) • Aquaculture • In one single incident in 2000, the population of salmon in Maine was elevated by 1000 times when approximately 100,000 fish escaped (Anonymous, 2011) • Ornamental fish trade

  10. Consequences • Ecological changes • Extinctions through competitive exclusion • 1/3 of endangered and threatened species in US are listed, in part, due to the action of invasive species (Cambray, 2003) • Trophic alterations (predation, competition, food web alteration) • Threat to aquatic biodiversity conservation • Biotic homogenization • Zoogeographic pollution • Hybridization and introgression • Occurs among fish species due to introductions for sport or commercial fishing, biological control, or through accidental introductions of bait species (Rhymer et al, 1996) • The average similarity of fish faunas among the US has increased by 7.2% (Rahel, 2007) • Diseases and parasites • Habitat and spatial alterations

  11. Solutions • Strict penalties for violations • More than 50 national and international laws and regulations are in place to restrict the transport of nonnative species. Few of these carry stiff penalties for noncompliance (Roman, 2010) • Ballast-water exchange • 1996 National Invasive Species Act following Zebra mussel spread in Great Lakes • Voluntary in many coastal areas

  12. Solutions • Follow guidelines • Aquatic Nuisance Species Handbook • Identification and control of invasive species in Michigan • Northeast Aquatic Nuisance Species Panel website (NEANS) • Gives mechanical, chemical and biological methods to control each aquatic invasive species • Prevention is the best way to deal with invasive species rather than eradication • Prohibitive legislation (Lacey Act in US) • Prohibits trade in wildlife, fish, and plants that have been illegally taken, possessed, transported or sold • Regulation of high risk activities such as ballast water transfer • Education

  13. Research • Impacts of alien invasive species on freshwater fauna at risk in Canada • Alan Dextrase and Nicholas Mandrak, 2003 • Examines threat factors contributing to the endangerment of freshwater fishes and molluscs in Canada and the nature of alien invasive species introductions affecting aquatic species at risk

  14. Background • In Canada, species have been assigned status designations since 1978 by the Committee on the Status of Species at Risk in Canada (COSEWIC) • Status designations • Extinct, Extirpated, Endangered, Threatened, Special Concern • COSEWIC meets regularly to assign status designations at risk using status reports that summarize biological information, population and habitat trends, limiting factors and threats

  15. Background • Freshwater fish fauna of Canada consists of 230 species, including 23 alien species. • 34% of native species designated at risk • Freshwater molluscan fauna consists of 180 species, including 12 alien species • 7% of native species designated at risk

  16. Area of study

  17. Materials and Methods • Threat factors compiled for each Canadian freshwater fish and mollusc species designated Extinct, Extirpated, Endangered or Threatened by COSEWIC • Special concern excluded from analysis because they are not immediately imperilled and threat factors are often poorly understood • Threats that occurred in the past, are currently occurring, and expected to occur all considered in analysis • Threats assigned to various categories identified by the World Conservation Union • Threats sub-divided into two groups and classified as primary or secondary • The vector of introduction was determined when alien invasive species were a factor contributing to decline or endangerment

  18. Fish Results • 42 taxa of freshwater fishes reviewed • Alien invasive species was second only to habitat loss as a threat factor • Threat factor for 26 out of 41 taxa, 63% • Primary factor for 14 out of the 26 • Primary factor in 4 out of 5 extinctions

  19. Threat factors identified in COSEWIC status reports for freshwater fishes at risk

  20. Mollusc Results • Alien invasive species cited as primary threat factor for 6 of 11 species (55%) • All cases due to impacts of zebra mussels • All result of ballast water discharge

  21. Threat factors identified in COSEWIC status reports for freshwater molluscs at risk in Canada

  22. Vectors-Freshwater Fish • Seven different pathways • 65% related to sport fishing • Also introduced through ballast discharge, aquarium fish releases, canals, movement of recreational boats, aquaculture and horticulture escapes • Of the 17 species introductions related to sport fishing, only 2 authorized

  23. Discussion • In >75% of cases, listed species face multiple threat factors • Largest numbers of listed fishes in Great Lakes-Western St. Lawrence and Pacific Islands Ecological areas. • Highest native species richness • Highest human impact

  24. Solutions • Species at Risk Act in 2003 • Enacted to prevent extinction of Canadian wildlife species • Provides legal protection to listed species and their habitats • Mandate development of recovery strategies within specified time frames

  25. References • Anonymous. 2011. Accessed online from on October 30, 2011 • Cambray, J. 2003. Impact on indigenous species biodiversity caused by the globalization of alien recreational freshwater fisheries. Hydrobiologia. 500: 217-230 • Dextrase, A. and N. Mandrak. 2004. Impacts of alien invasive species on freshwater fauna at risk in canada. Biological invasions. 8: 13-24 • Northeast Aquatic Nuisance Species Panel, 2011. Accessed online on October 30, 2011. • Rahel, F. 2007. Biogeographic barriers, connectivity and homogenization of freshwater faunas: it’s a small world after all. Freshwater biology. 52: pp 696-710 • Rhymer, J. and Simberloff, D. 1996. Extinction by hybridization and introgression. Ecology, evolution, and systematics. 27: 83-109. Referenced from Accessed on October 29, 2011. • Roman, J. 2010. Aquatic invasive species. The encyclopedia of earth. Accessed from on October 30, 2011.