Laura FogtEEES 4730

OutlineObjectiveBackground informationProblem and causesConsequences to aquatic systemsSolutionsResearch publication

ObjectiveTo discuss the ecological impacts of aquatic

invasive species and propose some possible solutions.

Invasive SpeciesDefinitionWhere they are found

In and around bodies of water

http://www.invasivespeciesinfo.gov/aquatics/main.shtml

ProblemThousands of aquatic species have been

dispersed or transplanted across the globe through human interaction

CausesHumans have played dominant role in species

transport across the globe through man-made pathwaysIntentional

Ex: intended movement of living seeds, whole plants or pets

Unintentional Ex: ballast water discharge

Ballast Water Discharge

http://www.eoearth.org/article/Aquatic_invasive_species

Other methods of transportShips and boats

Organisms attach themselves to hulls of vessels

Canal constructionIntentional release

Food sourcesSport 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 methodsShipping

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)

AquacultureIn 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

ConsequencesEcological 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 parasitesHabitat and spatial alterations

SolutionsStrict 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 exchange1996 National Invasive Species Act following Zebra

mussel spread in Great LakesVoluntary in many coastal areas

SolutionsFollow 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 eradicationProhibitive 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

ResearchImpacts of alien invasive species on

freshwater fauna at risk in CanadaAlan 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

BackgroundIn 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

BackgroundFreshwater 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 species7% of native species designated at risk

Area of study

Materials and MethodsThreat factors compiled for each Canadian freshwater

fish and mollusc species designated Extinct, Extirpated, Endangered or Threatened by COSEWICSpecial 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 Results42 taxa of freshwater fishes reviewedAlien invasive species was second only to

habitat loss as a threat factorThreat factor for 26 out of 41 taxa, 63%Primary factor for 14 out of the 26Primary factor in 4 out of 5 extinctions

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

Mollusc ResultsAlien 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

Common nameCOSEWIC status Threat factor

Habitat loss/ degredation

Invasive alien species Pollution

Changes in native species dynamics

Human disturbance

Lake Winnipeg physa Endangered P PBanff Springs snail Endangered P S Photwater physa Endangered P Pdwarf wedgemussel Extirpated Pnorthern riffleshell Endangered P P P Ssnuffbox Endangered P P P Swavy-rayed lampmussel Endangered P P P S Sround hickorynut Endangered P P P Skidneyshell Endangered P P P Smudpuppy mussel Endangered P P P Srayed bean Endangered P P

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

Vectors-Freshwater FishSeven different pathways

65% related to sport fishingAlso 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

DiscussionIn >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 richnessHighest human impact

SolutionsSpecies 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 Anonymous. 2011. Accessed online from

http://see-the-sea.org/topics/species/invasive_species.htm. 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 http://www.northeastans.org 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 http://www.annualreviews.org/doi/pdf/10.1146/annurev.ecolsys.27.1.83. Accessed on October 29, 2011.

Roman, J. 2010. Aquatic invasive species. The encyclopedia of earth. Accessed from http://www.eoearth.org/article/Aquatic_invasive_species on October 30, 2011.