Japanese Bubble Snail
Haminoea japonica
Description 5
Like other members of this genus in California, H. japonica is well-camouflaged and appears nondescript in a natural setting, but is quite compelling on close inspection. While this Japanese native has been reported from nonnative oyster beds in Washington, as Gosliner and Behrens (2006) describe, it was first detected in the San Francisco Bay in 1999 as a part of the SFBay2K survey. It can now be found in many parts of the Bay, including Albany Bulb and Lake Merritt.
As Gosliner and Behrens describe, it can be distinguished from the other species of Haminoea in California (H. vesicula and H. virescens) by the "deeply divided posterior lobes of the headshield while those of the other two species are only shallowly notched."
Habitat 5
Invaded inner bays and harbors.
Comprehensive description 6
Haminoea bubble snails are marine mollusks with thin, fragile shells. These snails are herbivorous, apparently feeding mainly on diatoms(Malaquias et al. 2004, 2009).
There has been some confusion over the identity and correct name of the bubble snail described from Washington State, U.S.A., in 1989 as Haminoea callidegenita (Gibson and Chia 1989). This is now considered to be a junior (and thus invalid) synonym of the valid name H. japonica (Gosliner and Behrens 2006). (see Systematics and Taxonomy, below)
Haminoea japonica is unusual in that it produces some offspring that are swimming, non-feeding veliger larvae and others that metamorphose into crawling juveniles prior to hatching (Gibson and Chia 1989, 1995).
Development 7
Haminoea japonica has poecilogonous development (i.e. it produces more than one type of offspring). Gibson and Chia (1989, 1995, as H.callidegenita) found that swimming non-feeding (lecithotrophic) veligers (typical mollusk larvae) and crawling juveniles were simultaneously released from nearly every egg mass observed, indicating that development mode varied not only within the population, but even among the offspring of single individuals. Development of all offspring from an egg mass appeared to be identical until just prior to hatching, when approximately half of the siblings metamorphosed and hatched as juveniles (these capsular metamorphic larvae underwent development, including a veliger stage, within the egg capsule, before hatching). The remaining siblings hatched as veligers and metamorphosed after a planktonic period ranging from 1 to 30 days. The percentage of juvenile hatchlings was highly variable among egg masses (ranging from 4 to 100%, with most egg masses having 50 to 70% of total hatchlings emerging as juveniles). Variability in hatchling type occurred among clutches, populations, and years. The percentage of juveniles released per egg mass was not influenced by a variety of factors tested, including physical egg mass characteristics, female reproductive traits (fecundity, female size, egg size), time of year, source of metamorphic inducer, and culture conditions. (Gibson and Chia 1995)
Distribution 8
Haminoea japonica (=H. callidegenita) is apparently native to the northwestern Pacific, but has been introduced to (at least) the eastern Pacific, the Atlantic coast of Spain, and the Mediterranean (Gosliner and Behrens 2006 and references therein).
Risk statement 9
In June 2005 at Crown Beach (San Francisco Bay) in Alameda, California (U.S.A.), over 90 people, primarily schoolchildren, reported rashes after wading in the water. The cause of this problem was apparently a schistosome (a parasitic trematode worm) in the genus Gigantobilharzia, carried by the recently introduced Japanese Bubble Snail, Haminoea japonica. (Cohen 2005) Although this parasite likely cannot complete its life cycle in humans or other mammals, requiring a bird host instead, accidental infection can cause an unpleasant dermatitis in humans.
Sources and Credits
- (c) Robin Agarwal (ANudibranchMom on iNaturalist), some rights reserved (CC BY-NC), https://www.flickr.com/photos/30314434@N06/19767819438/
- (c) Ken-ichi Ueda, some rights reserved (CC BY), http://www.flickr.com/photos/18024068@N00/3495795856
- (c) Robin Agarwal (ANudibranchMom on iNaturalist), some rights reserved (CC BY-NC), https://www.flickr.com/photos/30314434@N06/19955876765/
- (c) Robin Agarwal (ANudibranchMom on iNaturalist), some rights reserved (CC BY-NC), https://www.flickr.com/photos/30314434@N06/19247904234/
- (c) Ken-ichi Ueda, some rights reserved (CC BY-SA)
- (c) Shapiro, Leo, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/17763544
- (c) Shapiro, Leo, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11290048
- (c) Shapiro, Leo, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11290051
- (c) Shapiro, Leo, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/17763545
More Info
iNat Map
| Color | brown |
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