Lecture 20- Community change: Introduced marine species Flashcards Preview

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Flashcards in Lecture 20- Community change: Introduced marine species Deck (31):

What is the definition of an introduced species?

-species transported by human activities into region in which they did not occur in historical time and are now reproducing in the wild; not native to the area -also called non-indigenous, exotic, alien


What is the definition of a cryptogenic species?

-species not demonstrably native or introduced -suspected of being introduced but cannot prove it as there isn't a record of their presence/absence in the past


What is the definition of an invasive species?

-species that spread from their point of introduction and cause environmental damage -have negative effect on the environment -can be introduced or not


What is the definition of a weed?

-plant growing in an area where it is not wanted


What is the definition of a pest?

-organism considered harmful to human activities (including plants)


What is Port Philip Bay full of?

-introduced species -2003=99 introduced =61 cryptogenic (suspected introductions) -in 2010- 1 more introduction and 2 more possible


How many introduced marine species are there in Australia? (roughly)



What are the four most damaging introduced species in Port Philip Bay?

1. Northern Pacific Seastar 2. Green alga Codium fragile 3. Polychaete worm= feed by filtering larvae, impact on reproduction of other species 4. Brown alga Unidaria pinnatifida= outcompetes native species for light and substrate


Why should we be concerned about the introduced species?

-Human-mediated biological invasions a major threat to native biodiversity -Threat to habitats, ecosystem function -Economic impacts -there is a high biodiversity in Australia, lot of endemism, would be a shame to lose it


Are the introduced species a global problem?


-eg. Unidaria pinnatifida

-japanese kelp

-worldwide problem

-native in Japan, Korea

-initially in Tasmania (from vessels probably),then spread more

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What are the impacts of the Northern Pacific Seastar? (Asterias amurensis)

-voracious predator - In Derwent Estuary 1986 –now dominant benthic invertebrate predator -Northern hemisphere = damage to commercial shellfish including oysters, cockles, scallops -tube feeding -eats bivalves -generalist predator -will change habits depending on what is available -firts in Derwen Estuary a -keystone species -now problematic -australia


What are the impacts of the green alga Caulerpa taxifolia? (aqarium caulerpa)

-In Mediterranean Sea –large monospecific meadows – reduced commercial fish catches –accumulation of toxins in fish flesh –entangling of nets and boat propellers -grows incredibly fast -outcompetes everything else -produces toxin that affects fish -toxin has flow on effects= ends up in fish flesh -a guy knew it was there and was reported = could have been prevented


What are the impacts of the comb jelly?

-Mnemiopsis ledyi –predator of zooplankton including fish eggs and larvae –native to Atlantic coast of N and S America -In Black Sea, early 1980s –ballast water introduction –no predators/competitors – anchovy fishery collapsed problematic when billions of them -extremely abundant, feed on larvae= kill off the other species as cannot grow


What is ballast water?

- water in a ship to keep the boat stable when it is traveling without load


What is the process of invasion?


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What is the tens rule?

-all of these filter

-only about 10% of the propagules that end up on a vector will survive to get to a place

-only 10% of those will establish

-of those only 10% will have a serious impact on the assemblages

-only 1 in 1000 species transported from A to B will end up as a problem

-just a statistic

-may differ

-more transport then more species transported

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What are the potential vectors for transport of species? (6)

1. International shipping -fouling (hull, sea chests...) 2. Aquaculture- may be intentional 3. Aquarium trade 4. Domestic shipping 5. Commercial shipping 6. Recreational boating (transport of water -sea chests= water intake for water -hard to clean -if clean less likely to transport -domestic shipping=local fishing gear can also transport it -recreational= can be local and international =anchors can pick up shit)


What are the most important vectors?

-biofouling and ballast water are the most important vectors

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What is the policy with ballast water of ships coming to Melbourne?

ballast water= from the North must dump it in the tropics and then collect new one and dump here= limit the potential of dispersal = reason is that tropical species are less likely to survive in temperate waters


How are most goods transported in the world?

-by sea -mostly bulk dry carriers, container ships & oil tankers


What are the two examples of aquaculture introductions?

1=Deliberate introductions –Undaria to Atlantic coast of France, 1983 –Pacific oyster Crassostrea gigas to Tas, Vic, SA, WA –outgrows Sydney rock oyster, outcompetes it 2=Accidental introductions –Undaria to Mediterranean in 1971, probably on oysters –Herpes virus possibly with imported feed stock for sea-caged tuna


What are some examples of other vectors?

-packing for live bait •misc. maritime activities –e.g. construction, drifting infrastructure 1. European crab= both sides of the atlantic -appeared in California -wrapped stuff in seaweed and thus transported to California 2. dock broke off and across the pacific -transported its entire ecosystem


What are second innoculations?

-when introduced in one spot and then further transported from there by other vectors -spread further along the coast -keep the boat clean so you don't spread the propagules -often on boats


What is propagule pressure?

-more propagules arrive the more likely it is that they will settle -how you increase propagule pressure= more arrivals, more propagules per arrival


What makes a successful invader? (5)

1.Short life cycle 2.Rapid growth 3.Early onset of reproduction 4.High fecundity 5.Ability to colonise new/disturbed substrates -species traits -these make it more likely to be a good invader -ability to settle on variety of substrates


What is the relationship of disturbance and invasion?

-Disturbed environments may be more prone to invasion, -if you have a native community in good shape= no clear substrate= less likely to have an invasion


What is a tracker species?

- is a species is good at invading clear substrate


What is a driver species?

actively clears substrate to grow on


What are the management issues with introduced species?

1.Eradication of established pests very difficult –Black-striped mussel in Darwin =over $2.6 million (successful) –Northern Pacific seastar from Inverloch 2.- Preventing arrival a much better option –Anti-fouling paints –Ballast water management


What are the recent issues in Victorian waters?

1.Undaria pinnatifida, spreading 2.Grateloupia turuturu 3.Late 2011: Asterias amurensis in Western Port •Mid 2012: at Wilsons Prom


What can you do to help?

-If you see Undaria outside PPB or Apollo Bay harbour, report it ! • Only Undaria has midrib & sporophyll