Description
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Animalia | Mollusca | Gastropoda | Basommatophora | Ellobiidae | Melampus |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1894 | Established | Expanding | Cryptogenic | Regular Resident | Western Atlantic | Western Atlantic | Shipping(Dry Ballast) |
History of Spread
The salt marsh snail Melampus floridanus was first described from the Myakka River, FL, in 1856 (Martins 1996). Its present range is NJ to Mexico (Morrison 1951; Rosenberg 1995). In 1889, Dall listed its range as 'west Florida' and 'Florida Keys' (Dall 1889), but in 1894 Vanatta (1898) collected some Melampus spp. near Chestertown MD which were subsequently identified as M. floridanus: 'May not other collections have this Floridian species from northern localities?' (Vanatta 1898). Subsequently, M. floridanus (usually under the name of Detracia floridana) has been collected from the Gulf Coast (FL-LA) (Morrison 1951) and SC (Shoemaker et al. 1978), and in Chesapeake and Delaware Bays. Morrison (1951) attributed the apparent scarcity of specimens between FL and the Chesapeake to the lack of collecting in low-salinity marsh habitats. The dramatic range extension of M. floridanus could represent an introduction of this high marsh, semi-terrestrial snail, most likely on dry ballast. On the other hand, this tiny (6-8 mm) species is easily overlooked, and is easily confused with the similar M. bidentatus, considered native.
Atlantic Coast records:
FL - Melampus floridanus was described in 1856, and was listed for FL Keys and West FL (Gulf Coast) by Dall (1889).
Chesapeake Bay - The first Chesapeake Bay collection was in 1894 (Vanatta 1898).
Delaware Bay - Morrison (1954), collected this snail in Bombay Hook National Wildlife Refuge, DE, but it was not subsequently found by Leathem and Maurer (1975).
NJ Coastal Bays- Melampus floridanus was common to abundant in Phragmites australis (Common Reed) and Spartina spp. (Cordgrass) marshes in the Mullica River, Great Bay NJ (Angradi et al. 2001).
Chesapeake Bay records:
Lower Bay- Norfolk VA (Burch 1950); Poropotank Marsh; York River (Wass 1972); Accomack County VA; Pocomoke River (1 snail to 2.5 cm2; an estimated 4 billion per square mile (Morrison 1951).
Potomac River- Potomac Beach VA (1938); Cobb Island (MD; 1937); Breton Bay VA (1958) (United States National Museum of Natural History collections).
Patuxent River- Broomes Island to Solomons MD (1939, 1948) (United States National Museum of Natural History collections).
Upper Bay- Queen Anne's County MD; opposite Chestertown on Chester River 1894 (Vanatta 1898); Galesville MD, West River (1948-54), 'present in abundance' (Allen 1954b); Deale; MD, Herring Bay (1952) (Morrison 1952); Chesapeake Beach MD; Dorchester County MD, Head of Little Choptank River.
History References - Allen 1954b; Angradi et al. 2001; Burch 1950; Dall 1889; Martins 1996; Morrison 1951; Morrison 1952; Morrison 1954; United States National Museum of Natural History collections; Rosenberg 1995; Vanatta 1898; Wass 1972
Invasion Comments
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | ||||
| Salinity (‰) | 0.0 | |||
| Oxygen | ||||
| pH | ||||
| Salinity Range | oligo-poly |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | 5.0 | 5.0 |
| Typical Adult Size (mm) | 6.0 | 6.0 |
| Maximum Adult Size (mm) | 7.0 | 7.0 |
| Maximum Longevity (yrs) | 2.0 | 2.0 |
| 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
The salt marsh snail Melampus floridanus has no known economic impacts in the Chesapeake Bay region.
Economic Impacts Outside of Chesapeake Bay
The salt marsh snail Melampus floridanus has no reported economic impacts over its range.
Ecological Impacts on Chesapeake Native Species
The salt marsh snail Melampus floridanus appears to be somewhat local in its distribution. Competition with Melampus bidentatus (Eastern Melampus) is possible, but may be limited by differing habitat preferences, since M. floridanus ranges further from the water and higher above the mean high-tide line (Allen 1954b). No ecological impacts on native biota have been reported for this species, throughout its range.
References- Allen 1954b
Ecological Impacts on Other Chesapeake Non-Native Species
Competition between the Melampus floridanus with introduced and cryptogenic high- salt marsh snails, the introduced Myosetella myosotis and the cryptogenic Assiminea succinea, has not been documented and is probably limited by the fairly localized distribution of all three species.
References
Allen, J. Frances (1954) Notes on the gastropods collected in the vicinity of Crisfield, Maryland, The Nautilus 67: 92-94Allen, J. Frances (1954) Notes on the molluscan fauna of Galesville, Md., The Nautilus 67: 108-112
Angradi, T.R.; Hagan, S. M.; Able, K. W. (2001) Vegetation type and the intertidal macroinvertebrate fauna of the brackish marsh: Phragmites vs. Spartina., Wetlands 21: 75-92
Berman, Jody; Carlton, James T. (1991) Marine invasion processes: Interactions between native and introduced marsh snails, Journal of Experimental Marine Biology and Ecology 150: 267-281
Burch, Paul R. (1950) Mollusks, In: (Eds.) The James River Basin. , Richmond. Pp. 129-137
Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America, , Davis. Pp. 1-904
Dall, William Healey (1889) A preliminary catalogue of the shell-bearing marine mollusks and brachiopods of the south-eastern coast of the United States, Bulletin of the United States National Museum 37: 1-221
Martins, Antonio M. (1996) Anatomy and systematics of the Western Atlantic Ellobiidae (Gastropoda, Pulmonata)., Malacologia 37: 163-332
Morrison, J. P. E. (1951) Two new Western Atlantic species of pulmonate mollusks of the genus Detracia and two old ones (Family Ellobiidae)., Journal of the Washington Academy of Sciences 41: 17-20
Morrison, J.P.E. (1954) Some zoogeographic problems among brackish water mollusks, The American Malacological Union Annual Report 20: 7-10
Morrison, Joseph P. E. (1952) Demonstration of the egg-masses and eggs of Detracia floridana., American Malacological Union Annual Report 18: 15-16
Morrison, Joseph P. E. (1958) The primitive life history of some salt marsh snails, American Malacological Union Annual Report 24: 25-26
Porter, Hugh J. (1974) The North Carolina Marine and Estuarine Mollusca: An Atlas of Occurrence, , Morehead City. Pp.
1995-2023 Malacolog 4.1. http://www.acnatsci.org
Shoemaker, A. H., Porter, H. J., Boothe, B., Petit, R. E., Eyster, L. S. (1978) Marine mollusks., , Columbia. Pp. 123-135
Vanatta, K. G. (1898) Melampus floridanus Shuttl., Nautilus 12: 107
Wass, Melvin L. (1972) A checklist of the biota of lower Chesapeake Bay, Special Scientific Report, Virginia Institute of Marine Science 65: 1-290