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Aquatic Invasive Species. Laura Fogt EEES 4730. Outline. Objective Background information Problem and causes Consequences to aquatic systems Solutions Research publication. Objective. To discuss the ecological impacts of aquatic invasive species and propose some possible solutions.

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Aquatic invasive species

Aquatic Invasive Species

Laura Fogt

EEES 4730


  • Objective

  • Background information

  • Problem and causes

  • Consequences to aquatic systems

  • Solutions

  • Research publication


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

Invasive species
Invasive Species

  • Definition

  • Where they are found

    • In and around bodies of water


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


  • 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

Ballast water discharge
Ballast Water Discharge

Other methods of transport
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)

More methods
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


  • 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


  • 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


  • 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


  • 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


  • 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


  • 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

Materials and methods
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

Fish results
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

Mollusc results
Mollusc Results freshwater fishes at risk

  • 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

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

Vectors freshwater fish
Vectors-Freshwater Fish freshwater molluscs at risk in Canada

  • 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

Discussion freshwater molluscs at risk in Canada

  • 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

Solutions freshwater molluscs at risk in Canada

  • 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

References freshwater molluscs at risk in Canada

  • 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.