Date of the first record
The date of the first documented record of the species occurrence in a country/country region.
Date fields usage example:
| Date to be specified | Date From | Date To |
| Exact 1985 | 1985 | 1985 |
| 18th century | 1701 | 1800 |
| before 1700 | 1700 | |
| after 2001 | 2001 |
Environmental position
Environment(s) occupied by a species throughout its life cycle.
OPTIONS:
Biofouling. Assemblage of organisms on wetted artificial substrates.
Commensal. An organism in a symbiotic relationship, in which one benefits while the other is not adversely affected.
Demersal. Synonyms: hyperbenthic, benthopelagic, nektobenthic. An organism living at, in or near the bottom of the sea, but having the ability to swim.
Ectoparasite. A parasite living on the surface of its host.
Endoparasite. A parasite living within the organs or tissues of its host.
Epifaunal. Synonym: epibenthic. An animal inhabiting the surface of the seabed, submerged plants and animals.
Epilithic. An organism living on the surface of rock or other hard inorganic substrata.
Epiphytic. An organism living on the surface of a plant, non-parasitic.
Epizoic. An organism living on the surface of an animal, non-parasitic.
Infaunal. Synonym: endobenthic. An animal living within the seabed sediments.
Interstitial. An organism (< 1 mm) living in the spaces between sediment particles.
Lithotomous. An organism burrowing into rock.
Neustonic. An organism living on (epineuston) or under (hyponeuston) the surface film of water bodies.
Pelagic. An organism inhabiting the water column.
Pleustonic. An organism inhabiting the water surface due to their own buoyancy, normally positioned partly in the water and partly in the air.
Habitat type
Estuary. River mouth, transition zone between riverine and marine environments, subject to influences from both.
Lagoon. Shallow, enclosed water body separated from the sea by barrier islands, narrow spit or reefs.
Offshore. Areas located at least 50 nautical miles from the shore.
Open coast. A coast not sheltered from the sea.
Strait/Sound. Channels between the mainland and an island or between two islands which are open at both ends to the open coast (it does not refer to similar features or narrows within marine inlets).
Sheltered coastal area. Coastal area partly surrounded by land (e.g., bay, inlet, fjord).
Ports. A location on a coast or shore containing one or more harbours where ships can dock and transfer people or cargo to or from land.
Port vicinity. The area near a port where ballast water operations may occur, including areas where vessels may conduct ballast water discharge or uptake operations when approaching a port or leaving it, e.g., port approaches, anchorage areas and designated ballast water exchange areas. The dimension is port specific.
Marina. A specially designed harbour for pleasure craft and small boats.
Aquaculture sites. Areas set out for the purpose of farming aquatic organisms.
Marine Protected Area (MPA). Defined marine area where natural resources are given greater protection than the surrounding waters. Different categories exist depending on the level of protection afforded by legislation.
Migration pattern
Diurnal. Movements between alternative habitats over day and night, e.g. vertical migration.
Life-time. One time migration between different habitats during the life cycle, e.g. anadromus migration.
Not relevant. No evidence of any life history cycle stages to migrate.
Seasonal. Movements between alternative habitats during a specific time of a year (e.g., spawning and feeding migrations).
Pathway / Vector
Pathway
A pathway is the route a NIS takes to enter or spread through a non-native ecosystem e.g. vessels. Each pathway may have a number of vectors.
VectorA vector is a transfer mechanism and is the physical means by which species are transported from one geographic region to another. More than one vector within a pathway may be involved in a transfer of species.
Pathways and vectors included:| Pathway | Vector |
| Aquarium trade | Intentional organism release Transported water Waste discharge |
| Culture activities | Aquaculture equipment Associated water & packaging material Intercontinental stock movement Regional stock movement Unintentional release & escapees |
| Leisure activities | Angling catch Cultural releases Live bait Live souvenirs Sport equipment Stocking for angling Waste discharge |
| Live food trade | Intentional organism release Transported water Waste discharge |
| Management | Biological habitat management Construction equipment Construction materials Release for biological control |
| Natural spread from neighboring countries | Other natural vectors Water currents |
| Other canals | Canal de Midi (linking the Bay of Biscay with the Mediterranean Sea) Kiel Canal (linking the North Sea with the Baltic) Northern waterway (linking the Baltic with the Ponto-Caspian region through Volga river canal system) Rhone waterway (linking the North Sea with the Mediterranean) Southern waterway (linking the North Sea with the Black Sea through Danube river canal system) Central waterway (linking the Baltic Sea with the Black Sea through the Dnieper river canal system) Other waterways Irrigation canals |
| Research and education | Gear movement Intentional releases Unintentional release & escapees Waste discharge |
| Suez Canal | |
| Vessels | Anchor and anchor chain Ballast tank sediments Ballast water Ship’s hull Sea chest Others |
| Wild fisheries | Discard of by-catch Fishing gear Live bait release Live packaging material Processed live material Stock movements Transported water |
Pathway / Vector – Levels of certainty:
| Level | Criteria | Examples |
| Direct evidence | The species was actually found associated with the specific vector(s) of a pathway at the time of introduction to a particular locality within a country/country region. | Documented evidence of an introduction: release to the wild for stocking or biological control; escape/release of live food; import of cultured species and documented findings of their associate organisms, parasites and diseases on transmission; appearance of organisms by hull fouling, ballast water discharge sampling or other ship vectors documented upon an arrival with appropriate scientific methods. |
| Very likely | The species appears for the first time in a locality where a single pathway/vector(s) is known to operate and where there is no other explanation that can be argued for its presence except by this likely pathway/vector(s). | A highly localized distribution of a species in an area adjacent to an isolated port or other locality where the only pathway is vessels and its vector(s) (ballast water, hull fouling, etc). This often involves geographically discontinuous distributions. It may be a continuous spread as in case of introduction by canals or by natural means. The conclusion is deduced from the analysis of the invasion event and species distribution patterns. |
| Possible | The species cannot be convincingly ascribed to a single pathway, but is known to be introduced by this pathway(s) elsewhere. | There may be more than one pathway involved in the introduction within a country/country region. Arrival of a species known to have taken place elsewhere by the same pathway(s) which operates in an area. A conclusion is made by expert judgment based on pathways currently or historically present. |
| Unknown | Invasion of a given alien species cannot be clearly explained. | Where no rational explanation for the appearance of a species in a given country/region. |
Population status
Population status (the lowest level of certainty):
Population status (the moderate level of certainty):
Recipient region
The country/region for which introduction is recorded.
References.
References should follow the standard of Biological invasions:
Journal article
Gamelin FX, Baquet G, Berthoin S, Thevenet D, Nourry C, Nottin S, Bosquet L (2009) Effect of high intensity intermittent training on heart rate variability in prepubescent children. Eur J Appl Physiol 105:731-738. doi: 10.1007/s00421-008-0955-8
Ideally, the names of all authors should be provided, but the usage of “et al” in long author lists will also be accepted:
Smith J, Jones M Jr, Houghton L et al (1999) Future of health insurance. N Engl J Med 965:325–329
Article by DOI
Slifka MK, Whitton JL (2000) Clinical implications of dysregulated cytokine production. J Mol Med. doi:10.1007/s001090000086
Book
South J, Blass B (2001) The future of modern genomics. Blackwell, London
Book chapter
Brown B, Aaron M (2001) The politics of nature. In: Smith J (ed) The rise of modern genomics, 3rd edn. Wiley, New York, pp 230-257
Online document
Cartwright J (2007) Big stars have weather too. IOP Publishing PhysicsWeb. http://physicsweb.org/articles/news/11/6/16/1. Accessed 26 June 2007
Dissertation
Trent JW (1975) Experimental acute renal failure. Dissertation, University of California
Reproductive duration
Long. Breeds in one or more discrete periods, each longer than three months.
Medium. Breeds in one or more discrete periods, each longer than a week and less than three months.
Short. Breeds in one or more discrete periods within a week.
Reproductive seasonality
Months for a species known to reproduce in the invaded site.
Salinity range
The exact salinity range if known (psu), else salinity zone(s) according to the Venice system:
1. Limnetic [<0.5psu]
2. β-Oligohaline [0.5-3psu]
3. α-Oligohaline [3-5psu]
4. β-Mesohaline [5-10psu]
5. α-Mesohaline [10-18psu]
6. Polymixohaline [18-30psu]
7. Euhaline [30-40psu]
8. Hypersaline [>40psu]
Source region
The area the species was introduced from to the recipient country/country region. Depending on the information availability may be ascribed to a particular locality (e.g. port), a country, a LME or a larger Ocean region.
CAUTION: in many cases the source area will be not the same as the area of native origin which is defined in the SPECIES block of the database.
Species status
Non-indigenous species. Non-indigenous species (synonyms: alien, exotic, non-native, allochthonous, introduced) are species, subspecies or lower taxa (such as a variety, form) introduced outside of their natural range (past or present) and outside of their natural dispersal potential. This includes any propagule of a NIS, such as a gamete, seed or resting spore, a gravid female or a pair of individuals of different sexes (in sexual reproduction), or a vegetative reproductive organ and section of tissue (in asexual reproduction), which might survive, reproduce and subsequently form a population. It also includes hybrids between an alien species and an indigenous species, fertile polyploid organisms and artificially hybridized species irrespective of their natural range or dispersal potential.
Cryptogenic. Cryptogenic species are such species which cannot be reliably demonstrated as being either introduced or native. In some cases the true origin of a species remains obscure because of either insufficient taxonomic knowledge or due to a lack of records from the time they became introduced, or for other reasons.
Temperature range
Indicate min. and max. annual temperature range in the area where a species is known to maintain an established (reproducing) population.
Wave exposure
Exposed. Open coastline facing prevailing wind and receiving both wind-driven waves and swell.
Semi exposed. Generally open coasts facing away from prevailing winds or sheltered by offshore reefs/structures.
Sheltered. Coasts with a restricted fetch (<20 km) and lacking persistent swell.
Zonation
Ecological zone(s) occupied by a species throughout its life cycle.
Benthic - Bathyal. Synonym: continental slope. The seafloor between the edge of the continental shelf and abyssal plain (200-4000 m).
Benthic - Littoral. Synonym: intertidal. The shore between the high and low water marks.
Benthic - Sublittoral beyond photic zone. Synonym: lower circalittoral. The lower part of the continental shelf, where photosynthesis cannot take place.
Benthic - Sublittoral within photic zone. Synonyms: subtidal, infralittoral. The shallow part of sublittoral where photosynthesis can occur.
Benthic - Supralittoral. Synonyms: splash zone, spray zone, supratidal zone. The area above the spring high tide line, subject spray or splash.
Pelagic - Littoral. Water mass within littoral zone.
Pelagic - Neritic. Water mass above the continental shelf.
Pelagic - Offshore. Synonym: oceanic. Water mass beyond the continental shelf.
Public domain: Introduction event account
| Species | Didemnum vexillum | |
| Date of the first record (?) | 2005 |
| Recipient region (?) | Country: United Kingdom (Britain) LME: 24. Celtic-Biscay Shelf LME sub-region: English Channel |
|
| Source region (?) | Not entered |
| Pathway / Vector (?) | Level of certainty: Highly likely Pathway: Vessels Vector: (Highly likely) Ship’s hull Comments: Initial introduction is almost certainly associated with hull fouling on vessels. However, there is some evidence in Europe to suggest that Culture activities involving the transfer of stock might be involved in its further spread. |
| Habitat type (?) | Not entered | |
| Wave exposure (?) | Not entered | |
| Salinity range (?) | Not entered | |
| Temperature range (?) | Not entered |
| Zonation / Substratum (?) | Not entered | |
| Reproductive duration (?) | Not entered | |
| Reproductive seasonality (?) | Not entered | |
| Migration pattern (?) | Not entered |
| Population status (?) | Not entered | |
| Species status (?) | Non-indigenous species References (not structured): SR Jenkins & JDD Bishop, unpublished data Holt RHF, Ramsay K, Mowat S, Kent FEA, Griffith K. 2008. Survey of a non native ascidian (sea squirt) Didemnum vexillum in Holyhead Marina. Field Report: December 2008. CCW Marine Monitoring Report No: 67. Stefaniak L, Lambert G, Gittenberger A, Zhang H, Lin S, Whitlatch RB. 2009. Genetic consecificity of the worldwide populations of Didemnum vexillum Kott, 2002. Aquatic Invasions 4(1): 29-44. |
| Created by | Dan Minchin |
| Last update by | Dan Minchin, 2016-03-03 |
Support: FP7-ENVIRONMENT VECTORS