Corella inflata is a solitary tunicate with an oblong-oval body, which is distorted by a greatly enlarged atrial chamber, giving it a roughly cubical shape. For a time, its identity was confused with Corella willmeriana, but in 1981 they were distinguished as two species. Its native range spans Alaska, British Columbia and Puget Sound, Washington. Introduced populations have been reported from Coos Bay, Oregon, and Humbolt Bay and San Francisco Bay in California. The most likely transport vector for these introduced populations is ship or boat fouling. Specific impacts of C. inflata have not been reported.
Image Credit: Christina Simkanin, Univeristy of Victoria, B.C. Canada
|Bioregion||Region Name||Year||Invasion Status||Population Status|
|NEP-III||Alaskan panhandle to N. of Puget Sound||0||Native||Estab|
|P292||_CDA_P292 (San Juan Islands)||0||Native||Estab|
|NEP-II||Alaska south of Aluetians to the Alaskan panhandle||0||Native||Estab|
|NEP-IV||Puget Sound to Northern California||2003||Def||Estab|
|P293||_CDA_P293 (Strait of Georgia)||0||Native||Estab|
|NEP-V||Northern California to Mid Channel Islands||2008||Def||Estab|
|P090||San Francisco Bay||2008||Def||Estab|
The solitary tunicate Corella inflata has an oblong-oval body, distorted by a greatly enlarged atrial chamber, giving it a roughly cubical outline. The test is more or less transparent or translucent. The oral and atrial apertures open at the same level at the anterior end, and have poorly developed siphons. The rectum, sperm duct, and oviduct are short, about half the body length, and end at the base of the expanded atrial chamber. In C. willmeriana, which has a very small atrial chamber, the rectum, sperm duct and oviduct extend the full body length to the atrial siphon. The eggs are spawned into the dorsal atrial chamber, and are brooded there in a floating mass due to their very large ammonium-filled follicle cells, until several hours after the tadpoles hatch. The filiform oral tentacles are in one row, and vary in number from 35 to 65, while those in C. willmeriana are sometimes in two or three rows, and range from 45 to 95. The oral musculature in C. inflata is weak, and the body is flaccid when removed from the tunic, while in C. willmeriana it is more developed, and often contracts in preservation, making it difficult to count the tentacles. Body length and width of C. inflata are about equal, reaching about 30 mm (Van Name 1945; Lambert et al. 1981).
Corella inflata was described from southern British Columbia (Huntsman 1912, cited by Lambert et al. 1981), but later considered conspecific with C. willmeriana by Van Name (1945). Lambert et al. (1981) compared and distinguished the two species, noting differences in range. Corella wilmeriana was known to range from Alaska to central California, while C. inflata was known only from southern British Columbia to Puget Sound. In recent surveys, it was found north to Prince William Sound (Hines and Ruiz 2000; Ruiz et al., unpublished data), and the Chukchi Sea, north of Alaska (USNM 1116525, US National Museum of Natural History 2012). Since 2003, it has been found in Coos Bay OR (Chang 2009; Onuma 2011), Humboldt Bay CA (Wilson 2011), and San Francisco Bay CA (Chang 2009; Ruiz et al., unpublished data; Steve Foss, personal communication). These southern occurrences are definite introductions, probably due to ship or boat fouling.
In 2003, Corella inflata appeared in Coos Bay, Oregon, but disappeared following heavy rains in 2006 (R. Emlet and J. T. Carlton, pers. comm., cited by Chang 2009). It reappeared later in Coos Bay, and settling larvae were photographed by Onuma (2011). Corella inflata was common in Humboldt Bay in 2009, during a study of fouling organisms (Wilson 2011), but was not found in 2011 samples (Gretchen Lambert, personal communication). In 2008, C. inflata was abundant in San Francisco Bay at San Francisco Marina and Sausalito Marine Harbor (Chang 2009), and in additional locations in a 2010 survey (Richardson Bay and St. Francis Yacht Harbor, Steve Foss, personal communication).
A solitary tunicate is ovoid, elongate or vase-like in shape, with two openings or siphons. Most solitary tunicates attach to substrates by their side or base, but some attach with a conspicuous stalk. They are sessile filter feeders and have 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.
Solitary ascidians are hermaphroditic, meaning that both eggs and sperm are released to the atrial chamber. Eggs may be self-fertilized or fertilized by sperm from nearby animals, but many species have a partial block to self-fertilization. Depending on species, eggs may be externally or internally fertilized. In external fertilizers, eggs and sperm are released through the atrial siphon into the surrounding water column were fertilization takes place. 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. Swimming periods are usually less than a day and some larvae settle immediately after release, but the larval period can be longer at lower temperatures. Once settled, the tail is absorbed, the gill basket expands, and the tunicate begins to feed by filtering (Barnes 1983).
|General Habitat||Marinas & Docks|
|General Habitat||Grass Bed|
|Salinity Range||Polyhaline||18-30 PSU|
|Salinity Range||Euhaline||30-40 PSU|
|Minimum Salinity (‰)||20||Chang et al. 2020|
|Maximum Height (mm)||30||Lambert and Lambert 1981|
|Broad Temperature Range||Cold-temperate|
|Broad Salinity Range||Poly-euhaline|