AquaNISInformation system on aquatic non-indigenous and cryptogenic species |
Species | Ascidiella aspersa [WoRMS] | |
Authority | (Müller, 1776) | |
Family | Ascidiidae | |
Order | Phlebobranchia | |
Class | Ascidiacea | |
Phylum | Chordata | |
Synonym (?) | European Sea Squirt | |
Sub-species level (?) | Not entered |
Native origin (?) | Ocean: Atlantic --> Ocean region: NE Atlantic References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. Comments: Baltic sea Norway Irish Sea English Channel Mediterranean Sea Northwest African coasts |
Life form / Life stage (?) |
Comments: In internal fertilizers, eggs are brooded and fertilized within the atrial chamber and then released into the water column upon hatching. Fertilized eggs hatch into a tadpole larva with a muscular tail, notochord, eyespots, and a set of adhesive papillae. The lecithotrophic (non-feeding, yolk-dependent) larva swims briefly before settlement. |
Sociability / Life stage (?) |
References (not structured): Lynch, S. A., Darmody, G., O'Dwyer, K., Gallagher, M. C., Nolan, S., McAllen, R., Culloty, S. C. 2016. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load. Estuarine, Coastal and Shelf Science, 181, pp. 249-255. Comments: A. aspersa has a life span of 18 months and is a solitary tunicate but often forms unfused colonies in close association with each other on hard surfaces such as rocks. |
Reproductive frequency (?) | Iteroparous |
Reproductive type (?) | Sexual References: Lynch, S. A., Darmody, G., O'Dwyer, K., Gallagher, M. C., Nolan, S., McAllen, R., Culloty, S. C. 2016. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load. Estuarine, Coastal and Shelf Science, 181, pp. 249-255. Comments: A. aspersa are hermaphroditic and contain both an ovary and a testis, but previous studies indicated that they are protandic meaning that the male reproductive organs mature before the female ones. |
Developmental trait (?) | Lecithotrophy Spawning References: Niermann-Kerkenberg, E., Hofmann, D. K. 1989. Fertilization and normal development in Ascidiella aspersa (Tunicata) studied with Nomarski-optics. Helgoländer Meeresuntersuchungen, 43, pp. 245-258. Comments: Eggs and sperm are released into the ambient water, where fertilization takes place. Upon reaching a size of 30 mm, male gonads are mature while at 40 mm both sex organs are fully mature. Ascidians exhibit variations in reproductive cycle patterns, fluctuating between a strict seasonal spawning per year to a continuous gamete release throughout the year. |
Characteristic feeding method / Life stage (?) |
Comments: hey are sessile filter feeders with two siphons, an oral and an atrial siphon. Water is pumped in through the oral siphon, where phytoplankton and detritus is filtered by the gills, and passed on mucus strings to the stomach and intestines. Waste is then expelled in the outgoing atrial water. |
Mobility / Life stage (?) |
References (not structured): Niermann-Kerkenberg, E., Hofmann, D. K. 1989. Fertilization and normal development in Ascidiella aspersa (Tunicata) studied with Nomarski-optics. Helgoländer Meeresuntersuchungen, 43, pp. 245-258. |
Salinity tolerance range (?) | Exact range: 18 - 40 References: Lynch, S. A., Darmody, G., O'Dwyer, K., Gallagher, M. C., Nolan, S., McAllen, R., Culloty, S. C. 2016. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load. Estuarine, Coastal and Shelf Science, 181, pp. 249-255. Comments: A. aspersa is euryhaline, tolerating salinities from 18 to 40 ppt. |
Habitat modifying ability potential (?) | Autogenic ecosystem engineers |
Toxicity / Life stage (?) | Not relevant |
Bioaccumulation association (?) | Anthropogenic chemical compounds References: Bell, M. V., Pirie, B. J. S., McPhail, D. B., Goodman, B. A., Falk-Petersen, I. B., Sargent, J. R. 1982. Contents of vanadium and sulphur in the blood cells of Ascidia mentula and Ascidiella aspersa. Journal of the Marine Biological Association of the United Kingdom, 62(3), pp. 709-716. |
Known human health impact? | Known Comments: Harmless. |
Known economic impact? | Known References: Nagai, H., Shibahara, S., Matsushima, R., Uchida, H., Kanamori, M., Nogata, Y., Kamio, M. 2021. Hemolytic compound 3, 7, 11, 15-tetramethyl-hexadecan-1, 19-disulfate found in the invasive European sea squirt Ascidiella aspersa. Fisheries Science, 87, pp. 145-150. Lynch, S. A., Darmody, G., O'Dwyer, K., Gallagher, M. C., Nolan, S., McAllen, R., Culloty, S. C. 2016. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load. Estuarine, Coastal and Shelf Science, 181, pp. 249-255. Comments: This biofouling pest when introduced to new locations also directly competes with other native filter-feeding fauna of economic importance like scallops, mussels and oysters. |
Known measurable environmental impact? | Known References: Lynch, S. A., Darmody, G., O'Dwyer, K., Gallagher, M. C., Nolan, S., McAllen, R., Culloty, S. C. 2016. Biology of the invasive ascidian Ascidiella aspersa in its native habitat: Reproductive patterns and parasite load. Estuarine, Coastal and Shelf Science, 181, pp. 249-255. Comments: A. aspersa has the potential to be a successful invader because of its rapid growth rate and tolerance to a wide range of environmental conditions. Outside of its native range A. aspersa has impacted on the environment by forming large populations and subsequent high amounts of biomass suspension feeding on a significant proportion of plankton in the water column. Due to the large quantities of water that A. aspersa filters, it can potentially act as a carrier or reservoir of parasites for other host species and facilitate the introduction of disease such as the protistan parasite Bonamia ostreae, which is the causative agent of bonamiosis a fatal disease of the native European oyster Ostrea edulis. |
Included in the Target Species list? | No References: HELCOM, 2009. Alien Species and Ballast Water [PDF] Available at: https://archive.iwlearn.net/helcom.fi/stc/files/shipping/Table_2_Alienspecies_%20lists_2009.pdf [Accessed 1 July 2024]. |
Association with vessel vectors (?) | Biofouling References: Hewitt, C. L., Campbell, M. L., Thresher, R. E., Martin, R. B., Boyd, S., Cohen, B. F., ... & Lockett, M. M. (2004). Introduced and cryptogenic species in port Phillip bay, Victoria, Australia. Marine biology, 144(1), 183-202. Comments: Modes of introduction to new locations include unintentional movement with aquaculture materials, ship ballast water and ship or boat hull fouling. |
Created by | Aleksas Narščius, 2017-06-01 |
Last update by | Sandra Gečaitė, 2024-08-02 |