Taxonomy
Botrylloides violaceus
Distribution
Status
Conservation status
Not Assessed
Native status
Non-native
First reported in the wild
2006
Invasiveness
Invasive species - risk of Medium Impact
Irish status
Present in the wild
Introduction pathways - 1
Transport Stowaway
Introduction pathways subclass - 1
Ship/boat hull fouling
Invasive score
14
NAPRA Ireland risk assessed
No
Species Biology
Identification
Colonial ascidian that forms thick mats on pontoons, ropes and boats in marinas (Minchin,2007a). Difficult to identify to species.
Ecology
No impacts documented for this species in Ireland. Can survive attached to hulls of moving vessels (Murray et al., 2012) so has the potential to spread within and between marinas in Ireland, coating boats and increasing drag and fuel consumption. May be mal-adapted to invade natural marine communities due to biotic resistance (Simkanin et al., 2013) but can coat surfaces excluding native benthic species. Likely to displace the native star ascidian Botryllus schlosseri in some habitats (Gittenberger & Moons, 2011), however may be outcompeted itself by Didenum vexillum with rising sea temperatures (Lord & Whitlatch, 2015).
Habitat
Marine
Reproduction
Hermaphroditic, ovoviviparous (internal fertilisation and give birth to live young but young are nourished by an egg yolk rather than by a placenta as in mammals) but may reproduce by asexually by budding (Simkanin et al., 2013).
Pathway and vector description
May have been introduced to Europe from North America or directly from its native range in the Pacific North west. There are a number of potential pathways for introduction to Ireland, from continental Europe, Britain, North America, but it likely arrived as a fouling organism on boats (Minchin, 2007b).
Mechanism of impact
Competition, Bio-fouling
Broad environment
Marine
Habitat description
Generally found in marinas, harbours and sheltered man made bays (Simkanin et al., 2013).
Species group
Vertebrate
Native region
North America
Distribution
World distribution(GBIF)
Irish distribution
Found at Carlingford and Malahide marinas in 2007 (Minchin, 2007a), the exact distribution of this species in Ireland is unknown but is thought to have established in Ireland (Minchin, 2007b).
Native distribution
Native to North West Pacific (Minchin, 2007b).
Temporal change
Date of first record category
2001-2010
Fifty year date category
2001-2050
Records submitted to Data Centre in 2024
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How can you help
Report any sightings to the National Biodiversity Data Centre.
References
Publications
Gittenberger, A., & Moons, J. J. S. (2011). Settlement and possible competition for space between the invasive violet tunicate Botrylloides violaceus and the native star tunicate Botryllus schlosseri in The Netherlands. In Aquatic Invasions (Vol. 6, No. 4, pp. 435-440). Regional Euro-Asian Biological Invasions Centre (REABIC).
Lord, J., & Whitlatch, R. (2015). Predicting competitive shifts and responses to climate change based on latitudinal distributions of species assemblages. Ecology, 96(5), 1264-1274.
Minchin, D. (2007a). Rapid coastal survey for targeted alien species associated with floating pontoons in Ireland. Aquatic Invasions, 2(1), 63-70.
Minchin, D, (2007b). A checklist of alien and cryptogenic aquatic species in Ireland. Aquatic Invasions, 2(4), 341-366.
Murray, C. C., Therriault, T. W., & Martone, P. T. (2012). Adapted for invasion? Comparing attachment, drag and dislodgment of native and nonindigenous hull fouling species. Biological Invasions, 14(8), 1651-1663.
Simkanin, C., Dower, J. F., Filip, N., Jamieson, G., & Therriault, T. W. (2013). Biotic resistance to the infiltration of natural benthic habitats: examining the role of predation in the distribution of the invasive ascidian Botrylloides violaceus. Journal of Experimental Marine Biology and Ecology, 439, 76-83.