Lecture 20- Community change: Introduced marine species Flashcards
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)
-300
What are the four most damaging introduced species in Port Philip Bay?
- 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?
- yes
- eg. Unidaria pinnatifida
- japanese kelp
- worldwide problem
- native in Japan, Korea
- initially in Tasmania (from vessels probably),then spread more
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?
-
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
What are the potential vectors for transport of species? (6)
- 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
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
