Description
This hydrozoan has a well-known sexual medusa, first described in 1880, but the small solitary asexual hydroid, first described as Microhydra ryderi, was not recognized as a life stage of the same species until 1928 (Sobodkin and Bossert 1991). This introduced species is the only medusa in North America to live in pure freshwater.
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Animalia | Cnidaria | Hydrozoa | Limnomedusae | Petasidae | Craspedacusta |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1906 | Established | Expanding | Introduced | Unconfirmed | East Asia | East Asia | Ornamental(Aquatic Plant) |
History of Spread
The hydrozoan Craspedacusta sowerbii (Freshwater Jellyfish) is believed to be native to the Yangtze Valley, China (Acker 1976; Dumont 1994), but the medusa was first described from a water-lily tank in Regent Park, London in 1880 (Lankester 1880). Craspedacusta sowerbii has since been introduced to every continent except Antarctica, presumably with shipments of aquatic plants (Dumont 1994). Appearances of the medusae tend to be sporadic, but well-established populations also occur, frequently in aquaria (Schmitt 1939; Naumov 1969), and artificial ponds and reservoirs, but also in natural ponds, and in backwaters and pools of rivers (DeVries 1992; Dumont 1994).
In North America, C. sowerbii was first reported in 1885 in PA (Potts 1897), and has spread rapidly, but in a spotty fashion with new appearances in isolated locations, rather than a steady spread along river drainages (Schmitt 1939; DeVries 1992; Lytle 1962). C. sowerbii has been reported from 150+ localities in North America, with more of the occurrences in eastern North America (south ON to FL) than in the west (Schmitt 1939; DeVries 1992; Dumont 1994). It was first recorded from the Great Lakes Basin in 1933 and the Hudson Basin in 1943 (Mills et al. 1993; Mills et al. 1997).
In the Chesapeake region, this species has not been reported from tidal waters, but it has been found in adjacent ponds, pools, and backwaters near the upper limit of the tide (Schmitt 1939; Allan 1953; Rice 1958). It is likely that the medusae are occasionally washed into tidal tributaries, though they do not tolerate salinities above ~2-3 ppt (Dumont 1984; Fleming and Hazelwood 1967). The medusa of C. sowerbii has been found in the tidal Delaware River (Howells 1981).
Chesapeake Records are listed below:
James Drainage - Medusae were abundant in June-Sept. 1954-56 in Southhampton Quarry pond; '100 yards from the Williams Dam' on the James River, Richmond VA (Rice 1958).
York Drainage- Medusae were seen in Matoake Lake, Williamsburg VA (Tresselt 1950).
Potomac Drainage - Medusae of C. sowerbii were found in Washington DC, but no location was given (Hargitt 1907). More medusae were found in 1927 and 1929 in potholes and a pond adjacent to the Potomac at Great Falls VA, and again nearby in 1959 (Lytle 1962). There was also an outbreak in the Washington DC drinking-water system in 1927, and in a fishpond in Alexandria VA, 1933 (Schmitt 1939). Medusae were found in the inshore channel of the Potomac at Plummer's Island MD, just above the Fall -Line, on July 2, 1944 (Alan 1953) They were also seen in a privately owned pond in Washington County MD and in Clopper Lake (Montgomery County MD) in 1982 (Rivers 1987).
Eastern Shore Drainages - Medusae were abundant in September 1984 in Galesville Pond, Nanticoke drainage (Grogan 1989).
Upper Bay Drainages - Craspedacusta sowerbii was abundant in an impoundment of Swan Creek, Glen Burnie, Anne Arundel County, Aug-Oct. 1992 (Turek 1992). They were also found in Beaver Dam Quarry, Cockeysville MD (Baltimore County), Aug-Sept 1992, and said to reappear every year (Bagley 1993).
Delaware River - Hydroids budding off medusae, were collected in Tacony Creek, in August 1880, outside Philadelphia. Medusae were collected in tidal freshwater in May-June 1978, at Trenton and Burlington NJ, bu were not abundant (Howells 1981).
History References- Acker 1976; Allan 1953; Bagley 1993; DeVries 1992; Dumont 1994; Fleming and Hazelwood 1967; Hargitt 1907;Grogan 1989; Howells 1981; Lankester 1880; Naumov 1969; Potts 1897; Rice 1958; Rivers 1987; Schmitt 1939; Tresselt 1950; Turek 1992
Invasion Comments
Vector(s) of Introduction- Craspedacusta sowerbii produces desiccation-resistant cysts (Acker 1976; Dumont 1994), so it could be transported with boats, fishing gear, aquaria (Schmitt 1939), tools used in water, etc. Dispersal by birds is also possible (Dumont 1994).
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | 4.0 | 33.0 | 33.0 | 15.0 |
| Salinity (‰) | 0.0 | 3.0 | 0.0 | 0.0 |
| Oxygen | ||||
| pH | ||||
| Salinity Range | fresh-oligo |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | ||
| Typical Adult Size (mm) | ||
| Maximum Adult Size (mm) | ||
| Maximum Longevity (yrs) | ||
| Typical Longevity (yrs |
Reproduction
| Start | Peak | End | |
|---|---|---|---|
| Reproductive Season | |||
| Typical Number of Young Per Reproductive Event |
|||
| Sexuality Mode(s) | |||
| Mode(s) of Asexual Reproduction |
|||
| Fertilization Type(s) | |||
| More than One Reproduction Event per Year |
|||
| Reproductive Startegy | |||
| Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
Craspedacusta sowerbii (Freshwater Jellyfish) is sporadic but occasionally locally abundant, in ponds and lakes in Chesapeake drainage. However, it has no reported environmental impacts in the Bay or its watershed.
Economic Impacts Outside of Chesapeake Bay
Craspedacusta sowerbii (Freshwater Jellyfish) is an interesting experimental organism, but apparently has no economic impacts on freshwater lakes (DeVries 1992). It does does not sting swimmers but has been reported to injure Goldfishes' fins (Schmitt 1939).
References- DeVries 1992; Schmitt 1939
Ecological Impacts on Chesapeake Native Species
Craspedacusta sowerbii (Freshwater Jellyfish) has not been reported from tidal Chesapeake waters (but has been found in the tidal Delaware). If it occurs, it is probably only a stray washed over the Fall-Line. Where it is present; impacts on native biota may be small. 'As a potential competitor with other zooplanktivores, C. sowerbii medusae are not likely to be important; because in, systems that have been studied, they only consume 0.1-10% of the daily Daphnia production' (Dodson and Cooper 1976). Polyps do not appear to significantly affect zooplankton populations either (DeVries 1992).
References- DeVries 1992; Dodson and Cooper 1976
Ecological Impacts on Other Chesapeake Non-Native Species
Craspedacusta sowerbii (Freshwater Jellyfish) has not been reported from tidal Chesapeake waters (but has been found in the tidal Delaware). If it occurs, it is probably only a stray washed over the Fall-Line. If it is present, impacts on exotic biota are likely to be small.
References
Acker, Thomas S. (1976) Craspedacusta sowerbii: an analysis of an introduced species, In: Mackie, G. O.(Eds.) Coelenterate Ecology and Behavior. , New York. Pp. 219-226Acker, Thomas; Muscat, Anne M. (1976) The ecology of Craspedacusta sowerbii Lankester, a freshwater hydrozoan, American Midland Naturalist 95: 323-336
Allan, Philip (1952) Craspedacusta sowerbii in Maryland, Proceedings of the Biological Society of Washington 65: 109
Bagley, Kenneth C. (1993) Notes on the occurrence of the freshwater jellyfish Craspedacusta sowerbii Lankester, in Baltimore County, Maryland., The Maryland Naturalist 37: 1-2
Calder, Dale R. (1976) The zonation of hydroids along salinity gradients in South Carolina estuaries, In: (Eds.) Coelenterate Ecology and Behavior. , New York. Pp. 165-174
DeVries, Dennis R. (1992) The freshwater jellyfish, Craspedacusta sowerbyi: a summary of its life history, ecology, and distribution., Journal of Freshwater Ecology 7: 7-16
Dumont, Henri J. (1994) The distribution and ecology of the fresh- and brackish-water medusae of the world., Hydrobiologia 272: 1-12
Fleming, W. R.; Hazelwood, D. H. (1967) Ionic and osmoregulation in the fresh-water medusa, Craspedacusta sowerbii., Comparative Biochemistry and Physiology 23: 911-915
Grogan, William L. (1989) The freshwater jellyfish, Craspedacusta sowerbyi, on Maryland's Eastern Shore (Hydrozoa: Hydroida: Petasidae), Maryland Naturalist 33: 35-36
Hargitt, Charles W. (1907) Occurrence of the fresh-water medusa, Limnocodium, in the United States., Science 26: 638-639
Howells, Robert G. (1981) Freshwater medusa from New Jersey., Underwater Naturalist 13: 24
Hubschman, J. H.; Kishler, W. J. (1972) Craspedacusta sowerbii Lankester 1880 and Cordylophora lacustris 1871 in western Lake Erie (Coelenterata), Ohio Journal of Science 72: 318-321
Kramp, P. L. (1961) Synopsis of the medusae of the world, Journal of the Marine Biological Association of the United Kingdom 40: 7-443
Lankester, E. Ray (1880) On a new jelly-fish of the order Trachomedusae, living in fresh water, Nature 22: 147-148
Lytle, Charles F. (1962) Craspedacusta in the southeastern United States, Tulane Studies in Zoology 9: 309-314
Lytle, Charles F. (1982) Development of the freshwater medusa Craspedacusta sowerbii., In: (Eds.) Developmental Biology of Freshwater Invertebrates.. , New York. Pp. 129-150
Mills, Edward L.; Leach, Joseph H.; Carlton, James T.; Secor, Carol L. (1993) Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions., Journal of Great Lakes Research 19: 1-54
Mills, Edward L.; Scheuerell, Mark D.; Carlton, James T.; Strayer, David (1997) Biological invasions in the Hudson River: an inventory and historical analysis., New York State Museum Circular 57: 1-51
Naumov, D. V. (1969) Hydroids and Hydromedusae of the U.S.S.R., , Jerusalem. Pp.
Pennak, Robert W. (1978) Freshwater Invertebrates of the United States, , New York. Pp.
Potts, Edward (1897) A North American fresh-water jelly fish., The American Naturalist 31: 1032-1035
Rice, Nolan E. (1958) Occurrence of both sexes of the fresh-water medusa, Craspedacusta sowerbiiLankester, in the same body of water., American Midland Naturalist 59: 525-526
Rivers, S. E. (1987) The occurrence of the freshwater jellyfish Craspedacusta sowerbyi in Maryland., Maryland Naturalist 31: 37-39
Schmitt, Waldo L. (1939) Freshwater jellyfish records since 1932., The American Naturalist 73: 83-89
Slobodkin, Lawrence B.; Bossert, Patricia E. (1991) The freshwater cnidarian coelenterates., , London. Pp. 125-143
Tresselt, Ernest F. (1950) The freshwater medusa, Craspedacusta sowerbii, in Matoaka Lake, Williamsburg, Virginia., Ecology 31: 478
Turek, James G. (1992) Notes on the occurrence of the freshwater jellyfish Craspedacusta sowerbii, in Anne Arundel County, Maryland., The Maryland Naturalist 26: 41-42