Marine bio invasion
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  • Do know all this suspects.
  • Today marine biologist main challenges is Global scale impacts Over-fishing,Invasive species,Climate change, Pollution. But in that subject area limited studies going on rather than other topics.
  • Today’s my topic is one newly image problem is marine biological invasion.
  • This are definition of invasive species- An alien species whose establishment and spread threatens ecosystems, habitats, or species with economic or environmental harm.U must know related simple term to define otherwise confuse other term.“Invasive species” are those introduced species that cause measurable economic or ecological damage (most do not)Federal Executive Order 13112 states: “invasive species” is defined as a species that is (1) non-native (or alien) to the ecosystem under consideration and (2) whose introduction causes or is likely to cause economic or environmental harm or harm to human healthWe often use the words invasive, alien, and exotic synonymsly"Invasive species" means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health. "Alien species" means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem. “exotic species” An organism that exists in the free state in an area but is not native to that area. Also refers to animals from outside the country in which they are held in captive or free-ranging populations. The first two invasive and alien come from the Official U.S. definitions regarding invasive species were provided in Executive Order 13112 signed by President William Clinton on February 3, 1999. native/indigenous – living naturally in a given area prior to colonization by humansexotique/non indigenous/alien – introduced out sideits native range (generallyimplieshumaninvolvement)naturalized – non-native species that is established (implies acceptance of species in new area by humans)nuisance – speciesthat has adverse impacts on humanactivities (does not implythatitisexotic)invasive –spreadingrapidly in numbers and in space
  • The establishment new marine environment of a species outside of its natural range. All introduce species not invasive species. Most introduced species are not invasive. A species may be invasive in some regions but not others.Dr. A. Ricciardi, lecture slides from Ecology of Species Invasions (BIOL540, McGill University)What is an ‘invasive’ species?An introduced species that spreads rapidly.Note: ‘Invasive’ is a relative term. Most introduced species are not invasive. A species may be invasive in some regions but not others.
  • Let’s look at species become to alien to invasive.Fortunately, an alien species do not always progress to invasive species. Very few organisms survive and are able to maintain a steady population to the point of becoming invasive.Plasticity and adaptive evolution can lead to greater invasiveness- Sexton et al. 2002. Ecological Applications 12:1652-1660
  • Common invasive species traits include: The ability to reproduce both asexually and sexually Fast growth Rapid reproduction High dispersal ability Phenotypic plasticity(the ability to alter one’s growth form to suit current conditions) Tolerance of a wide range of environmental conditions (generalist) Ability to live off of a wide range of food types (generalist) Association with humans
  • 1st figure show’s world distribution of the Invasive marine species pathways and origins. 2nd figure show to invasive marine species hotspots. Now u can see European water, north Americans water, Meditarion water, can be sea in highly infected area. Highly potential singapore, around srilanka area become invasive hotspots area. Trans-oceanic route connecting east and west, and Colombo harbor being a world famous commercial sea port.
  • Marine invasion mainly divided on intentional introduction and unintentional introduction
  • Intentional Introductions-Fish species released to increase local catches,Predators/parasites have been introduced for bio-control of agricultural pests (never in a marine system though),Plants (ex. seaweed culture ) have been brought into to provide forage for animals or for restoration purposes
  • Shellfish(ex: oysters) have been introduced to create new fisheries, Plants introduced for mudflat or dune management, Mari culture (farming of oysters,salmon, etc), Aquarium use, Live seafood trade, Live fish bait trade, Seaweeds used in packaging (e.g. of bait)
  • Unintentional Introductions-Ballast water transport of larvae form,Hull Fouling,Canals, Water diversion schemes, Fouling of buoys,Transport on fishing or diving gear,Transport on pleasure craft or other small boats,Docks, barges and oilrigs with fouling can introduce organismsDepending on conditions, extra water may be taken up in different areas so the water in any one ship’s ballast tanks may have come from a number of sources. Ballast water can contain a huge variety of organisms from microscopic plankton to 12 cm-long fish. Now adays, samples of ballast water find an amazing variety of life and hundreds of life forms, from cholera and botulism bacteria to plankton, invertebrates and fish. Ballast water transfer is considered the primary cause of introductions today.
  • Alien pathogens in shellfish and other aquaculture introductions,live food trade of oysters and lobsters or bait,Research use,Released pets,Secondary dispersal by currents,Traps, ropes, anchors, buoys, etc. all can transport species to new areas,Escape from backyard ornamental ponds
  • This are the famous marine invasive species. Every species have story. I have to tell one of sad story Divers around Florida are being exposed to a new hazard—the beautiful but poisonous lionfish (Pteroisvolitans). This species was first noticed after a hurricane in 1994; it probably escaped from an aquarium destroyed in the hurricane. The rate at which marine organisms are being introduced worldwide is accelerating rapidly due to the increased volumes of trade and shipping, as well as the ever-increasing connectivity of ports and harbors.
  • This are man made invasion pathways divided Transportation, living industries, miscellaneous pathways
  • Ballast waterShipping is the most common invasion pathway, carrying invasive species in ballast or as fouling organisms and has contributed to 69% of all marine introductions.over 12 billion tons of ballast water is moved across vast coastal and oceanic domains annually.Ballast water can contain a huge variety of organisms from microscopic plankton to 12 cm-long fish.
  • Treatment systems available to date can be placed into one of three categories: • Systems that do not require or produce biocide chemicals. Systems in this category include filtration plus UV, oxygen stripping and pH reduction, and magnetic filtration.• Systems that use advanced oxidation, electrolysis or oxidative chemical dosing modules to produce short-lived radicals (OH', O3, ClO-) that decay without producing long-lived toxic end-products.• Systems that generate chloride ions – typically by electro-chlorination – that can produce long-lived end-products at potentially toxic concentrations, therefore requiring adequate decay time or sulphite treatment, particularly if the organic content is high.
  • Aquaculture (Mari culture)Aquaculture is the second largest contributor to marine species invasions 41% of marine invasive species.introduced from aquaculture practices Individuals escape or are released. Exotic marine fishes or invertebrates will often be introduced to a region via aquaculture practices as an economical investment.Example:The Atlantic Salmon from the eastern USA is found in farms from Chile to Norway. If the salmon escape, genetic swapping with native species will occur
  • Plastic Flotsam Stranding in oceanThe vast amounts of waterborne debris is almost certainly drastically changing.opportunities for many marine organisms to travel and thus for exotic invaders to spread. Canal modificationReport that 17% of marine invasive species occur via the construction of canals. Canals typically connect two biogeographically distinct bodies of water, creating the high potential for species interchanges. The Mediterranean Sea maintains many international trade routes and is also connected to the biologically diverse Red Sea via the Suez Canal.
  • Marine Bio invasions and Climate ChangeClimatically driven changes may affect both local dispersal mechanisms, The alteration of current patterns, Competitive interactions between NIS and native species, The onset of new thermal optima and/or different carbonate chemistry. Latitudinal range expansions of species correlated with changing temperature conditions, Effects on species richness and the correlated extinction of native species, Some invasions may provoke multiple effects which involve overall ecosystem functioning
  • Ocean in motion, Ocean AcidificationStress species then they disruption of recruitment could facilitate the establishment of invasive species as newly opened areas will be vulnerable to the introduction of these opportunistic species. The introduction of competitive non-native species into an ecosystem may have a substantial, and often irreversible, influence on biodiversity, habitat quality, and ecosystem functioning.Changes to SalinityMajor shifts in the abiotic environment will result in a change in the existing species composition as there will be some organisms that will be unable to adapt to their new environment; therefore these species will be forced to disperse to adjacent habitats or become extinct. This loss of biodiversity may facilitate the establishment of new weedy / invasive species that are able to thrive in the changing environment. Higher survival rates will increase the probable number of individuals released at a given place at a given time as well as the number of transported organisms that are capable of survival and reproduction following release. Sea Level RiseA rise in sea level of less than 1m would submerge an estimated 10,000 square miles of land. Existing wetland and salt marshes will be flooded and die, calling into question the types of communities that will replace these lost ecosystems. Inundation could also disrupt groundwater flow from aquifers to ocean by altering the water table level relative to the sea level, potentially diminishing the delivery of essential nutrients to at least, tropical reef communities and disrupting coastal wetland Native marine species will likely be subjected to increased turbidity and pollution resulting from runoff from the land. Although some native species will be able to adapt to the newly created habitats, the high level of disturbance caused by sea level rise will render marine communities particularly vulnerable to the introduction of opportunistic invasive species.Ocean in motionSpecies that depend on ocean currents for reproduction and migration will also be affected. many coral and fish species rely on dispersal of their larvae by currents; therefore, changes in circulation will result in lower recruitment into new areas, reducing species dispersal as well as overall habitat diversity. The disruption of recruitment could facilitate the establishment of invasive species as newly opened areas will be vulnerable to the introduction of these opportunistic species.Ocean AcidificationCalcifying species include corals, mollusks, crustaceans, and coralline algae that provide critical habitat and food sources for other organisms. Declining number and/or abundances of these species may promote the success of existing invaders or the colonization of new invaders - namely fleshy/non-calcified algae. The introduction of competitive non-native species into an ecosystem may have a substantial, and often irreversible, influence on biodiversity, habitat quality, and ecosystem functioning
  • Changes to Salinity, Sea Level RiseMajor shifts in the abiotic environment will result in a change in the existing species composition as there will be some organisms that will be unable to adapt to their new environment; therefore these species will be forced to disperse to adjacent habitats or become extinct. This loss of biodiversity may facilitate the establishment of new weedy / invasive species that are able to thrive in the changing environment. Higher survival rates will increase the probable number of individuals released at a given place at a given time as well as the number of transported organisms that are capable of survival and reproduction following release.
  • Now let’s look at Environmental impacts-Preying upon native species,Decreased habitat availability for native species,Additional competition,Parasites and disease,Smothering and overgrowth,Hybridization, causing genetic dilution,Changes to ecosystem function,Changes in nutrient cycles,Decreased water quality
  • Now let’s look at Economic impact-financial costs for management, Cost and damages incurred due to fouling of equipment and vessels, Aesthetic and/or recreation impacts, Actual losses relative to impacts to fishery or aquaculture resources. Interference with fisheries (e.g. fouling or tearing of nets),Disruption to tourism,Damage to infrastructure (through fouling of pipes, wharves, buoys etc.),Costs of clean up or control,Costs of treatment or quarantine
  • Public Health Impacts-Parasites and disease, sometimes lethal - Harmful Algal Blooms (HAB),Decreased recreational opportunities, eg.algal slicks, overgrowth of aquifers and smothering of beaches. ex:AlexandriumminutumCultural impacts-Competition with native species used for subsistence harvesting,Degradation of culturally-important habitats and resources such as water ways.
  • Action and responsesIn contrast with terrestrial invasions, govern­ment and other agents have been slow to recognize marine introductions as an issue, primarily due to a lack of information and demonstrable impacts to human health, ecosystems, and economies. Responses exist on several scales; there are numerous international and national efforts relative to invasive species in addition to regional and local initiatives. While some efforts include a regulatory component, the bulk of management approaches to marine invasive species are voluntary.
  • Once a species has been introduced to an area it is important to locate it and take action quickly before it has a chance to establish and spread. This can be challenging given the open nature of the marine environment. But if an invader is found while it is still in a relatively small containable area, it may be eradicated if the response is quick enough. This is why surveys are so important.
  • Since Sri Lanka is located in the middle of the trans-oceanic route connecting east and west, and Colombo harbor being a world famous commercial sea port, there is a huge potential of alien plankton being introduced into the Sri Lankan coastal zone via ballast water of the ships calling there.Altogether 159 taxa of plankton were found in the samples. In the ballast water samples alone, there were 56 different taxa of which 50% of them were totally alien to the local coastal zone.Even though 28 totally alien planktonic taxa were found in the five cargo ships sampled in the present study, the introduction potential of alien plankton into Sri Lankan coastal zone would be undoubtedly massive given the fact that the Colombo harbor receives approximately 5000 ships annually. Ballast waters offer conducive situation for microorganisms such as bacteria, viruses and dinoflagellates to translocate into far away regions and cause deleterious effects to local flora and fauna through their toxigenic, proliferative and over-competitive characteristics.• Further studies should be carried out to identify alien invasive species in ballast water of ships visited other ports in Sri Lanka• Baseline studies should be carried out to identify current plankton species in Hambantota port and other ports in Sri Lanka• Further studies should be carried out using more local sites along the northwestern coastline• Plankton analysis of the ballast water of ships visiting Colombo harbor other than Indian ocean, Pacific ocean and Arabic seaBased on the findings, alien marine zooplankton are introduced to Sri Lankan coastal environment through ballast water• There are tendencies of spreading alien marine zoo-plankton with the north bound ocean currents
  • Fund Research Programs: Dedicated research programs across a diversity of regions (e.g. high, mid and low latitude sites) must be developed and adequately funded to detect species movements and likely interspecies interactions, in order to predict, and possibly prevent, the impact of invasion resulting from global climate change.Increased Coordination: Build partnerships among federal agencies and academic institutions to enhance capacity for detecting, responding to, and managing invasive species.Develop Rapid Response Plans: Risk assessments are needed to prioritize species that deserve rapid responses. Strategies need to be developed for rapid response to these speciesVector Management: These scenarios of the “ghost of Christmas future” support the need to strikingly enhance vector management policies to prevent future invasions.Expand Educational and Outreach Programs. It is imperative for the public to understand the implications of their actions, with or without the climate change message.National strategy for monitoring. Global climate change will result in the loss of species; yet without adequate monitoring the extent of this loss may not be known.

Transcript

  • 1. Today’s marine biologist challenges Global scale impacts  Over-fishing  Invasive species  Climate change  Pollution
  • 2. Marine Biological Invasion R.R.De Zoysa/As 2009029/Aquatic Science (Sp)
  • 3. 1) Introduction 2) Biological invention & natural theory 3) Marine Bio invasion & climate change 4) Impact of invasive species 5) Type of invasion 6) Intentional introduction 7) Unintentional introduction 8) Sri Lanka status 9) Invasive species list 10)Action and response 11)Organizational and country role 12)Recommendation 13)Reference’s
  • 4. Definitions Invasive Species An alien species whose establishment and spread threatens ecosystems, habitats, or species with economic or environmental harm. What are invasive Species? Invasive Species implies exotic and a threat to native species Exotic Species from another part of the world Introduced Species implies introduction but not a threat Alien Species Implies introduction to a particular ecosystem
  • 5. Classical Model of Invasion Natural Colonization Natural colonization and humanmediated invasion Establishment requires dispersal across barriers, colonization in acceptable number, and successful reproduction
  • 6. Marine Biological invasion: The establishment new marine environment of a species outside of its natural range. Geographic (or physiological) barrier Introduces species Invasive species •Most introduced species are not invasive. • A species may be invasive in some regions but not others.
  • 7. Alien to Invasive Fortunately, an alien species do not always progress to invasive species  Very few organisms survive and are able to maintain a steady population to the point of becoming invasive From Alien To Invasive Many die en route to a new locale Many die immediately upon arrival by physical and biotic agents Naturalization Lag Phase Exponential Growth Phase
  • 8. Common invasive species traits include: The ability to reproduce both asexually and sexually Fast growth Rapid reproduction High dispersal ability Phenotypic plasticity(the ability to alter one’s growth form to suit current conditions)  Tolerance of a wide range of environmental conditions (generalist)  Ability to live off of a wide range of food types (generalist)  Association with humans     
  • 9. Intentional Introductions Unintentional Introductions
  • 10. Intentional Introductions Fish species released to increase local catches Predators/parasites have been introduced for bio-control of agricultural pests Plants (ex. seaweed culture ) have been brought into to provide forage for animals or for restoration purposes Shellfish have been introduced to create new fisheries Plants introduced for mudflat or dune management
  • 11. Intentional Introductions Mari culture (farming of oysters, salmon, etc) Aquarium use Live seafood trade Live fish bait trade Seaweeds used in packaging (e.g. of bait) Pterois volitans Fisheries, Including Marine Aquaculture (Mariculture)
  • 12. Unintentional Introductions Ballast water transport of larvae form Ships Hull Fouling Canals Water diversion schemes Fouling of buoys Transport on fishing or diving gear Transport on pleasure craft or other small boats Canals Docks, barges and oilrigs with fouling can introduce organisms Dry Docks Drilling platforms Amphibious planes, Seaplanes
  • 13. Unintentional Introductions Alien pathogens in shellfish and other aquaculture introductions live food trade of oysters and lobsters or bait Research use Released pets Secondary dispersal by currents Traps, ropes, anchors, buoys, etc. all can transport species to new areas Escape from backyard ornamental ponds Navigational buoys & Marina Floats Recreational equipment Floating marine debris Research
  • 14. Famous Ex: marine invasive species Vibrio cholerae Red tide Comb jelly North Pacific seastar Zebra Green crab mussel Lion fish Mitten crab Asian kelp Colonial tunicate
  • 15. Ballast water  Shipping is the most common invasion pathway, carrying invasive species in ballast or as fouling organisms and has contributed to 69% of all marine introductions.  over 12 billion tons of ballast water is moved across vast coastal and oceanic domains annually.  Ballast water can contain a huge variety of organisms from microscopic plankton to 12 cm-long fish.
  • 16. Ballast water treatment systems
  • 17. Aquaculture (Mari culture) • Aquaculture is the second largest contributor to marine species invasions 41% of marine invasive species . • introduced from aquaculture practices Individuals escape or are released. • Exotic marine fishes or invertebrates will often be introduced to a region via aquaculture practices as an economical investment. Example: The Atlantic Salmon from the eastern USA is found in farms from Chile to Norway. If the salmon escape, genetic swapping with native species will occur
  • 18. Plastic Flotsam Stranding in ocean The vast amounts of waterborne debris is almost certainly drastically changing opportunities for many marine organisms to travel and thus for exotic invaders to spread. Canal modification Report that 17% of marine invasive species occur via the construction of canals. Canals typically connect two biogeographically distinct bodies of water, creating the high potential for species interchanges. The Mediterranean Sea maintains many international trade routes and is also connected to the biologically diverse Red Sea via the Suez Canal.
  • 19. Marine Bio invasions and Climate Change  Climatically driven changes may affect both local dispersal mechanisms,  The alteration of current patterns,  Competitive interactions between NIS and native species,  The onset of new thermal optima and/or different carbonate chemistry.  Latitudinal range expansions of species correlated with changing temperature conditions,  Effects on species richness and the correlated extinction of native species,  Some invasions may provoke multiple effects which involve overall ecosystem functioning
  • 20. Changes To Salinity, Ocean Motion, Ocean Acidification  Result in a change in the existing species composition  Unable to adapt to their new environment  Therefore these species will be forced to disperse to adjacent habitats or become extinct.  Loss of biodiversity may facilitate the establishment of new weedy / invasive species That are able to thrive in the changing environment  Higher survival rates will increase the probable number of individuals released at a given place at a given time
  • 21. Sea Level Rise  Existing wetland and salt marshes will be flooded and die, calling into question the types of communities that will replace these lost ecosystems.  increased turbidity and pollution resulting from runoff from the land. Although some native species will be able to adapt to the newly created habitats,  the high level of disturbance caused by sea level rise will render marine communities particularly vulnerable to the introduction of opportunistic invasive species.
  • 22. Environmental impacts          Preying upon native species Decreased habitat availability for native species Additional competition Parasites and disease Smothering and overgrowth Hybridization, causing genetic dilution Changes to ecosystem function Changes in nutrient cycles Decreased water quality
  • 23. Economic impact          Monetary costs for management, Cost and damages incurred due to fouling of equipment and vessels, Aesthetic and/or recreation impacts, and Actual losses relative to impacts to fishery or aquaculture resources. Interference with fisheries (e.g. fouling or tearing of nets) Disruption to tourism Damage to infrastructure (through fouling of pipes, wharves, buoys etc.) Costs of clean up or control Costs of treatment or quarantine
  • 24. Public Health Impacts  Parasites and disease, sometimes lethal - Harmful Algal Blooms (HAB)  Decreased recreational opportunities, e.g. algal slicks, overgrowth of aquifers and smothering of beaches ex: Alexandrium minutum Harmful algal bloom Red Tide Cultural impacts  Competition with native species used for subsistence harvesting  Degradation of culturally-important habitats and resources such as waterways
  • 25. Actions and Responses
  • 26. Sri Lankan status Sri Lanka is located in the middle of the trans-oceanic route connecting east and west, and Colombo harbor being a world famous commercial sea port, there is a huge potential of alien 159 taxa of plankton were found in the samples. In the ballast water samples alone, there were 56 different taxa of which 50% of them were totally alien to the local coastal zone. Ballast waters offer conducive situation for microorganisms such as bacteria, viruses and dinoflagellates to translocate into far away regions and cause deleterious effects to local flora and fauna through their toxigenic, proliferative and over-competitive characteristics. Caulerpa taxifolia and Undaria pinnatifida among the list of 100 most invasive species’. Of late, an exotic marine algal species is on the verge of becoming invasive in Southern India. Can be observed in Sri Lanka.
  • 27. Sri Lanka marine water recorded invasive species Annelids Pelagobia longicirrata Cephalachordates Larva of Amphioxus Coelenterates Aurelia aurita Copepods Acartia erythaea Oncaea spp. Paracalanus aculeatus Naupli of Parechaeta norvegia Acartia hamta Augaptilus longicaudatus Calanopia aurivilli Candacia furcatus Disseta palumboi Euchaeta marina Eurydice pulchra Metridica vensuta Crustaceans Alvinia puncture Zoea of Scylla serrate Foraminifers Globigerinella adamsi Hydrozoa Loripe tetraphylla Mollusks Baby Squid Rotifers Cephalodella spp. Tintinnids Favella panamensis Ormosella trachelium Parafavella obtusa Tintinninae vitreus Tunicates Tadpole larva of sea squirt
  • 28. Responsible agency           International Maritime Organization Ministry of Environment Central Environmental Authority Sri Lanka Ports Authority NARA Directorate of Merchant Shipping Coast Conservation Department Coast Guard Department Disaster Management Centre Sri Lanka Navy
  • 29. Recommendations Fund Research Programs: Dedicated research programs across a diversity of regions (e.g. high, mid and low latitude sites) must be developed and adequately funded to detect species movements and likely interspecies interactions, in order to predict, and possibly prevent, the impact of invasion resulting from global climate change. Increased Coordination: Build partnerships among federal agencies and academic institutions to enhance capacity for detecting, responding to, and managing invasive species. Develop Rapid Response Plans: Risk assessments are needed to prioritize species that deserve rapid responses. Strategies need to be developed for rapid response to these species Vector Management: These scenarios of the “ghost of Christmas future” support the need to strikingly enhance vector management policies to prevent future invasions. Expand Educational and Outreach Programs. It is imperative for the public to understand the implications of their actions, with or without the climate change message. National strategy for monitoring. Global climate change will result in the loss of species; yet without adequate monitoring the extent of this loss may not be known.
  • 30. Reference's Occhipinti-Ambrogi, D. Savini (2003) Biological invasions as a component of global change in stressed marine ecosystems, www.elsevier.com/locate/marpolbul: Section of Ecology, Department of Genetics and Microbiology. Safra Altman, Robert B. Whitlatch (2006) Effects of small-scale disturbance on invasion success in marine communities, 1st edn., Journal of Experimental Marine Biology and Ecology: Daleo P, Alberti J, Iribarne O (2009) Biological invasions and the neutral theory, 1st edn., Diversity and Distributions: Blackwell Publishing Ltd. Semmens, B.X., Buhle, E.R., Salomon, A.K., and Pattengill-Semmens, C.V. 2004. A hotspot of non-native marine fishes: evidence for the aquarium trade as an invasion pathway. Marine Ecology Progress Series 266: (239-244.) Stachowicz, J.J., Whitlach, R.B., & Osman, R.W. 1999.Species diversity and invasion resistance in a marine ecosystem. Science 286: 1577-1579. Stephens, P.A. and Sutherland, W.J. 1999. Consequences of the Allee effect for behaviour, ecology, and conservation. Trends in Ecology and Evolution 14(10): 401-405. Randall, J.E. 1987. Introduction of marine fishes to the Hawaiian Islands. Bulletin of Marine Science 41(2): 490-502.
  • 31. O’Shea, S. and Cangelosi, A. 1996. Trojan horses in our harbors: biological contamination from ballast water discharge. U Tol. L. Rev. 27: 381. Molnar, J.L., Gamboa, R.L., Revenga, C., and Spalding, M.D. 2008. Assessing the global threat of invasive species to marine biodiversity. Frontiers in Ecology and Environment 6(9): 485-492. Drake, J.M. and Lodge, D.M. 2007. Hull-fouling is a risk factor for intercontinental species exchange in aquatic ecosystems. Aquatic Invasions 2(2): 121-131. Byers, J.E. 2002. Impact of a non-indigenous species on natives enhanced by anthropogenic alteration of selection regimes. OIKOS 97(3): 449-457. Molnar, J.L., Gamboa, R.L., Revenga, C., and Spalding, M.D. 2008. Assessing the global threat of invasive species to marine biodiversity. Frontiers in Ecology and Environment Bax, N. Williamson, A. Aguero, M., Gonzalez, E., & Geeves, W. 2003. Marine invasive alien species: a threat to global biodiversity. Marine Policy 27(4): 313-323. W. U. CHANDRASEKERA, M. A. S. T. FERNANDO (2009) Accidental introduction of alien plankton into the Sri Lankan coastal zone through ballast water of cargo ships, 1st edn., Sri Lanka J. Aquat. Sci 14: Senanayake S.A.M.A.I.K, Ranathunga R.R.M.P.K.,Gunasekara.A.J.M., N.Priyadarshana (2010) The Occurrence Of Marine Organisms - In Ballast Water Of Ship Visiting Colombo Harbour., 1st edn., 15th International Forestry and Environment Symposium:
  • 32. "Invasive marine species are one of the four greatest threats to the world's oceans! Unlike other forms of marine pollution, such as oil spills, where ameliorative action can be taken and from which the environment will eventually recover, the impacts of invasive marine species are most often irreversible!“ Source: International Maritime Organization (2007)