Alien Species
Invasive
species are non-indigenous organisms introduced into an ecosystem that is not
their native habitat either by accident or intentionally.
While some alien species may have little impact within their new habitat, others can become invasive and pose a serious threat to marine biodiversity, coastal economies, local cultures and livelihoods, and human health.
The threat of alien invasive species continues to grow as global trade, travel, and tourism allow species to be transported over increased distances to areas that were not previously accessible to them. Areas subjected to the worst pollution, intensive fisheries and/or bottom trawling, and major shipping routes are likely to be the most seriously impacted by the invasion of non-native species.
The approximately 3–5 billion tons of ballast water from large ships transferred throughout the world each year by large ships (Raaymakers, 2002) is believed to be the main vector for the spread of invasive aquatic species today, with an estimated 7,000 species transported each day (Carlton, 2001). Large numbers of alien species are also transported as ‘hitchikers’ attached to the hulls of ships or on floating objects such as marine trash.
While some alien species may have little impact within their new habitat, others can become invasive and pose a serious threat to marine biodiversity, coastal economies, local cultures and livelihoods, and human health.
The threat of alien invasive species continues to grow as global trade, travel, and tourism allow species to be transported over increased distances to areas that were not previously accessible to them. Areas subjected to the worst pollution, intensive fisheries and/or bottom trawling, and major shipping routes are likely to be the most seriously impacted by the invasion of non-native species.
The approximately 3–5 billion tons of ballast water from large ships transferred throughout the world each year by large ships (Raaymakers, 2002) is believed to be the main vector for the spread of invasive aquatic species today, with an estimated 7,000 species transported each day (Carlton, 2001). Large numbers of alien species are also transported as ‘hitchikers’ attached to the hulls of ships or on floating objects such as marine trash.
Origins & Pathways of Invasive Marine Species
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Which Goals Does This Affect?
How Do We Measure It?
The Ocean Health Index utilized
total counts of all invasive species according to data from the Global Invasive
Species Database (GISD). The database reports the number and type of alien
species in each marine ecoregion, with species types categorized as invasive
and harmful invasive species.
Total count of all invasive species was used. Ecoregion based data were re-aggregated to match the Ocean Health Index’s EEZ-based reporting region. The sum of all invasive species within each reporting unit was then rescaled to the maximum global value. It was not possible to predict the full potential impact of alien species, because high-resolution data are not yet available on where these species exist, how far they have spread, and exactly what parts of the ecosystem or food web they affect. Harmful effects would need to be evaluated separately for each goal. That is not yet possible globally, but it might be done for smaller case-studies where such information could be obtained.
Total count of all invasive species was used. Ecoregion based data were re-aggregated to match the Ocean Health Index’s EEZ-based reporting region. The sum of all invasive species within each reporting unit was then rescaled to the maximum global value. It was not possible to predict the full potential impact of alien species, because high-resolution data are not yet available on where these species exist, how far they have spread, and exactly what parts of the ecosystem or food web they affect. Harmful effects would need to be evaluated separately for each goal. That is not yet possible globally, but it might be done for smaller case-studies where such information could be obtained.
What Are The Impacts?
ECOLOGICAL IMPACT
Invasive alien species can harm
environments by
preying upon or parasitizing native species or competing with them for
resources.
HUMAN HEALTH IMPACT
Invasive species can introduce
harmful microbes and associated bacteria that are transferable to local seafood
and bivalve populations, increasing the risk of cholera or other communicable
diseases or epidemics.
A South American strain of human cholera bacteria was found in ballast tanks in the port of Mobile, Alabama in 1991. Cholera strains were also found in oyster and fin-fish samples in Mobile Bay, resulting in a public health advisory to avoid handling or eating raw oysters or seafood (Habitattitude 2009).
A South American strain of human cholera bacteria was found in ballast tanks in the port of Mobile, Alabama in 1991. Cholera strains were also found in oyster and fin-fish samples in Mobile Bay, resulting in a public health advisory to avoid handling or eating raw oysters or seafood (Habitattitude 2009).
ECONOMIC IMPACT
Eradicating
or controlling an invasive alien species is costly and can have significant
economic impacts.
In 2000, New Zealand spent $3.5 million to remove a species of invasive seaweed, Undaria pinnatifida, from the fouled hull of a single vessel that sank offshore.
Invasive alien species can decrease the number of visitors to a coastal area and reduce revenue from coastal tourism and recreational activities.
In 2000, New Zealand spent $3.5 million to remove a species of invasive seaweed, Undaria pinnatifida, from the fouled hull of a single vessel that sank offshore.
Invasive alien species can decrease the number of visitors to a coastal area and reduce revenue from coastal tourism and recreational activities.
What Has Been Done?
Lionfish Derby Series in the Caribbean
The
lionfish was introduced to South Florida waters in the early 1990’s and has
been rapidly spreading throughout the Caribbean.
Because it is a natural predator to most reef fish in the area, the lionfish
has the potential to significantly decrease populations of ecologically
important native species.
To combat the lionfish, the United States’ NOAA’s Florida Keys National Marine Sanctuary, in partnership with Reef Environmental Education Foundation (REEF), hosted a series of lionfish derbies. Divers who removed lionfish from sanctuary waters were eligible for more than $10,000 in cash and prizes.
To combat the lionfish, the United States’ NOAA’s Florida Keys National Marine Sanctuary, in partnership with Reef Environmental Education Foundation (REEF), hosted a series of lionfish derbies. Divers who removed lionfish from sanctuary waters were eligible for more than $10,000 in cash and prizes.
Mr.KIO/Marine Photobank
Get More Information
The Global Invasive Species Database (GISD)
The GISD aims to increase awareness
and facilitate the prevention and management of invasive alien species.
Invasive Species Specialist Group (ISSG)
A network of scientific and policy
experts that works to reduce the threats of invasive species by raising
awareness and introducing measures to prevent and control alien populations.
The International Union for Conservation of Nature (IUCN)
This booklet provides detailed,
accessible information on the marine invasive species issue, and 15 case
studies of particularly damaging or costly bioinvasions.
GloBallast Partnerships: GEF/UNDP/IMO Global Ballast Water Management Programme
GloBallast works with developing
countries to reduce the transfer of invasive species in ballast water and
implement the International Maritime Organization (IMO) ballast water
guidelines.
The National Invasive Species Council
Established in the United States by
Executive Order 13112, the council ensures that the Federal programs being
implemented to prevent and control invasive species are effective.
References
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Altonn, H. Cut Throat Coral An invasive species first seen 31 years ago now threatens black coral beds off Maui. Honolulu Star Bulletin (2003).
Australian Quarantine and
Inspection Service. 2005. AQIS Fact Sheet.
Bergendorf, David. 2005 Aquatic
Nuisance Project Fact Sheet. US Fish and Wildlife Service. Stockton, California
Burgiel, Stas, Foote, Greg, Orellana, Marcos & Perrault, Anne Invasive Alien Species and Trade: Integrating Prevention Measures and International Trade Rules. (Center for International Environmental Law and Defenders of Wildlife: Washington D.C., 2006).
Carlton, J. T. & Commission, P. O. Introduced species in U.S. coastal waters: environmental impacts and management priorities. 80 (Pew Oceans Commission: 2001).
Marine Menace: Alien invasive species in the marine environment. 30 (International Union for Conservation of Nature: Gland, Switzerland, 2009).
ECES (Earth Crash Earth Spirit). Snowflake coral introduced from the Caribbean is killing Hawaii's black
coral. (February 17, 2004.)
Molnar, J. L., Gamboa, R. L., Revenga, C. & Spalding, M. D. Assessing the global threat of invasive species to marine biodiversity. Frontiers in Ecology and the Environment 6, 485–492 (2008).
Godwin, L. S. Hull fouling of maritime vessels as a pathway for marine species invasions to the Hawaiian Islands. Biofouling 19 Suppl, 123–131 (2003).
Grigg, R. W. Harvesting Impacts and Invasion by an Alien Species Decrease Estimates of Black Coral Yield off Maui, Hawai’i. Pacific Science 58, 1–6 (2004).
Lafferty, K. D. & Kuris, A. M. Biological Control of Marine Pests. Ecology 77, 1989–2000 (1996).
Raaymakers, S. The
ballast water problem: Global Ecological, economic and human impacts.
Proceedings of the RESCO/IMO Joint Seminar on Tankers Ballast Water Management
and Technologies. (Dubai, 2002).
Padilla, D. K. & Williams, Susan L. Beyond Ballast water: aquarium and ornamental trades as sources of invasive species in aquatic ecosystems. Front Ecol Environment 2, 131–138 (2004).
Sanin, S. L. Components of Marine De-pollution in the Mediterranean Region. 4 (Environmental Engineering Department Hacettepe University: Ankara, Turkey, 2009).
Savarese, J. Preventing and Managing Hull Fouling International, Federal and Sate Laws and Policies. (2005).
Toonen, R. 2004. Reproduction
and developmental characteristics of an alien soft coral (Carijoa riisei) in
Hawaii (FY 2004-2005). Hawai’i Institute of Marine Biology.
PHOTO(S): © Keith A. Ellenbogen