Rana catesbeiana (American bullfrog)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Distribution
- Distribution Table
- History of Introduction and Spread
- Introductions
- Risk of Introduction
- Habitat
- Habitat List
- Biology and Ecology
- Natural Food Sources
- Climate
- Latitude/Altitude Ranges
- Water Tolerances
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Social Impact
- Risk and Impact Factors
- Uses
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Gaps in Knowledge/Research Needs
- References
- Links to Websites
- Organizations
- Contributors
- Distribution Maps
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Generate reportIdentity
Top of pagePreferred Scientific Name
- Rana catesbeiana Shaw, 1802
Preferred Common Name
- American bullfrog
Other Scientific Names
- Lithobates (Aquarana) catesbeianus Dubois, 2006
- Lithobates catesbeianus Dubois, 2006
- Rana (Aquarana) catesbeiana Dubois, 1992
- Rana (Aquarana) catesbeiana Hillis, 2007
- Rana (Lithobates) catesbeiana Shaw, 1802
- Rana (Novirana) catesbeiana Hillis and Wilcox, 2005
International Common Names
- English: bullfrog; common bullfrog; North American bullfrog
- Spanish: rana mugidora; rana toro; rana toro Americana
- French: grenouille d'Amérique; grenouille taureau; grenouille-taureau americaine; ouaouaron
Local Common Names
- Brazil: rã-touro
- Germany: ochsenfrosch
- Italy: rana toro
- Netherlands: grote kikker
- Sweden: oxgroda
Summary of Invasiveness
Top of pageThe American bullfrog has been transported around the world primarily with the intention of cheaply cultivating its large and meaty hind legs for human consumption. It is also of commercial interest to biological supply houses, fish bait suppliers, the pet trade, and pond landscapers. In North America in the early 20th Century it was released outside of its natural range by wildlife agencies keen on introducing a new game species (Lannoo, 1996; Tangley, 2003). Once liberated it is extraordinarily prolific, prone to migration, and highly adaptable to new environments. It grows into a relatively large, voracious, and indiscriminate predator that can come to dominate the margins of lakes and ponds. It competes with native anurans. Larvae can have a significant impact upon benthic algae, and thus perturb aquatic community structure. Adults may be responsible for significant levels of predation on native anurans and other aquatic herpetofauna, such as snakes and turtles. The species also contributes to the spread of pathogens such as the chytrid fungus, Batrachochytrium dendrobatidis (Garner et al., 2006). R. catesbeiana has been identified by the World Conservation Union (IUCN) as one of the world’s 100 worst invasive alien species (ISSG, 2005).
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Chordata
- Subphylum: Vertebrata
- Class: Amphibia
- Order: Anura
- Family: Ranidae
- Genus: Rana
- Species: Rana catesbeiana
Notes on Taxonomy and Nomenclature
Top of pageThe American bullfrog is a member of the nearly cosmopolitan family Ranidae. For most of the past 200 years this species has been unambiguously assigned to the genus Rana and the species R. catesbeiana, Shaw, 1802. Over the past 30 years, however, advances in biochemical systematics have led to both increased knowledge and increased contention concerning how new and ever-more refined data sets should be interpreted and taxonomically expressed. Thus, there are today numerous taxonomic synonyms for R. catesbeiana, e.g. Lithobates catesbeianus,Aquarana catesbeiana, and Novirana catesbeiana, that have received varying degrees of acceptance amongst herpetological systematists and the broader zoological community (Frost 2009).
Description
Top of pageR. catesbeiana is not the largest frog species in the world but it is one of the top ten (and the largest true frog in North America) with a maximum body length slightly in excess of 200 mm (typical length 90-152 mm) and body weight up to 0.5 kg. Like most frogs, it undergoes a drastic metamorphosis during its life cycle, passing from a young aquatic life phase with branchial respiration, predominantly plankton feeding, iliophagous or herbivorous, to reach adult life as an animal with pulmonary and skin respiration and a carnivorous feeding habit (Teixeira et al., 2001). Bullfrog tadpoles are also very large by frog standards (80-150 mm) and can take from 12 to 48 months to reach metamorphosis. A bullfrog tadpole’s body can be as large as a golf ball with a relatively long, high-finned and muscular tail. The colouration of the tadpole stage is brown to light olive with small black spots scattered across the head and upper body. At metamorphosis the tadpoles resorb their gills and finned tails while transforming into juvenile miniatures of adult bullfrogs but without secondary sexual characters. The colour of adults varies from olive, green or brownish on the dorsum with vague spots or blotches; the head is lighter green, and the legs blotched or banded; the eardrums are conspicuous. The hind feet are fully webbed. The skin is mostly smooth. There are no dorsolateral folds; a short fold extends from the eye over and past the eardrum to the forearm.
Distribution
Top of pageR. catesbeiana is native to eastern North America, ranging naturally from Nova Scotia, southern Quebec and Ontario in Canada, down through the eastern United States and Mississippi drainage, and southward along the east coast of Mexico. It has been introduced to Hawaii, parts of the western USA and Canada, Mexico and the Caribbean, South America, Europe and Asia (ISSG, 2005). In the central United States it is difficult to say for certain where natural populations end and alien populations begin, but there is no disputing the fact that all occurrences west of the Rocky Mountains are the result of translocation and release during the late 19th century and throughout the 20th. (It is known that bullfrogs were introduced to areas of California and Colorado in the early 1900s -- University of Michigan Museum of Zoology, 2005).
Distribution Table
Top of pageThe distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
Last updated: 10 Feb 2022Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
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Namibia | Present | Introduced | |||||
Asia |
|||||||
China | Present | Introduced | Invasive | First reported: 1960s | |||
-Hainan | Present | Introduced | |||||
-Hubei | Present | Introduced | |||||
-Sichuan | Present | Introduced | Invasive | Feral populations have become established | |||
-Xinjiang | Present | Introduced | Invasive | Feral populations have become established | |||
-Yunnan | Present | Introduced | Invasive | Feral populations have become established | |||
-Zhejiang | Present, Localized | Introduced | Invasive | Feral populations have become established on the Zhoushan archipelago and neighbouring mainland China | |||
Hong Kong | Present, Few occurrences | Introduced | Escaped market animals have been found but no evidence yet of established populations | ||||
Indonesia | Present | Introduced | 1970 | ||||
Israel | Present | Introduced | Invasive | ||||
Japan | Present | Introduced | |||||
-Bonin Islands | Present | Introduced | |||||
-Hokkaido | Present | Introduced | Invasive | Southern Hokkaido | |||
-Honshu | Present | First reported: 1920s | |||||
-Ryukyu Islands | Present | Introduced | |||||
Laos | Present | Introduced | |||||
Malaysia | Present | Introduced | Farmed | ||||
Philippines | Present | Introduced | Farmed near Manila | ||||
Singapore | Present | Introduced | Invasive | Now common in reservoirs. Bukit Timah area & Lower Peirce Reservoir | |||
South Korea | Present | Introduced | Invasive | ||||
Sri Lanka | Present | Introduced | Invasive | ||||
Taiwan | Present | Introduced | Invasive | Imported for aquaculture in the 1950s. Feral populations have become established and are sold in pet shops; First reported: 1924 & 1951 | |||
Tajikistan | Present | Introduced | Invasive | ||||
Thailand | Present | Introduced | Began culturing bullfrogs in the early 1990s technically supported by Chulalongkom University | ||||
Vietnam | Present | Introduced | |||||
Europe |
|||||||
Austria | Absent, Formerly present | ||||||
Belgium | Present | Introduced | First reported: 1980s & 1990s | ||||
Denmark | Absent, Formerly present | First reported: 1990s | |||||
France | Present, Widespread | Introduced | Invasive | First released near Libourne then spread all over department of the Gironde, to Landes, Dordogne, Lot-et-Cher. Populations in southwest are expanding at an alarming rate; First reported: late 1800s to 2002 | |||
Germany | Present | Introduced | Invasive | First reported: 1911 to early 1990s | |||
Greece | Present, Localized | Introduced | 1997 | Crete | |||
-Crete | Present | Introduced | 1997 | As: Lithobates catesbeianus | |||
Italy | Present | Introduced | Invasive | First reported: 1935 - 1970s | |||
Netherlands | Present | Introduced | 1986 | ||||
Russia | Present | Introduced | |||||
Spain | Present | Introduced | First reported: 1880s & 2000 | ||||
-Canary Islands | Present | Introduced | 2000 | As: Lithobates catesbeianus | |||
Switzerland | Present | Introduced | 1990 | As: Lithobates catesbeianus | |||
United Kingdom | Present, Localized | Introduced | England in East Essex and Sussex - Kent border. One discovered at a home in the Scottish Borders in 2003. Patchy records from Hampshire; First reported: 1905 & 1996 | ||||
North America |
|||||||
Canada | Present | Present based on regional distribution. | |||||
-British Columbia | Present, Localized | Introduced | Southern Vancouver Island; Gulf Islands; Sunshine Coast; Lower Mainland; Osoyoos Lake; First reported: 1930s | ||||
-New Brunswick | Present | Native | |||||
-Nova Scotia | Present | Native | |||||
-Ontario | Present | Native | |||||
-Quebec | Present | Native | |||||
Costa Rica | Present | Introduced | |||||
Cuba | Present | Introduced | 1915 | ||||
Dominican Republic | Present | Introduced | 1955 | ||||
El Salvador | Present | Introduced | |||||
Guatemala | Present | Introduced | |||||
Haiti | Present | Introduced | |||||
Jamaica | Present | Introduced | 1967 | Invasive | Great Morass of the Black River | ||
Mexico | Present, Widespread | Native | Native to east coast. Introduced populations in 15 states and the Federal District. See CONABIO (2008) for more information on introductions. | ||||
Panama | Present | ||||||
Puerto Rico | Present | Introduced | 1935 | Humacao Nature Reserve | |||
United States | Present | Present based on regional distribution. | |||||
-Alabama | Present | Native | |||||
-Arizona | Present | Introduced | Established in San Bernadino Wildlife Refuge and Leslie Canyon National Wildlife Refuge in Cochise county; also in Buenos Aires National Wildlife Refuge in Pima county | ||||
-Arkansas | Present | Native | |||||
-California | Present, Widespread | Introduced | Invasive | First reported: 1896 - 1915 | |||
-Colorado | Present, Localized | Introduced | Two Ponds National Wildlife Refuge, Jefferson County; First reported: 1913 - 1914 | ||||
-Connecticut | Present | Native | |||||
-Delaware | Present | Native | |||||
-Florida | Present | Native | Original citation: University of Michigan Museum of Zoology (2005) | ||||
-Georgia | Present | Native | |||||
-Hawaii | Present, Localized | Introduced | Oahu Forest National Wildlife refuge and James Campbell National Wildlife Refuge in Honolulu county; First reported: 1897 - 1899 & 1902 | ||||
-Idaho | Present | Introduced | 1890 | ||||
-Illinois | Present | Native | |||||
-Indiana | Present | Native | |||||
-Iowa | Present | Native | Introduced in the 1930s & 1960s | ||||
-Kansas | Present | Native | |||||
-Kentucky | Present | Native | |||||
-Louisiana | Present | Native | |||||
-Maine | Present | Native | |||||
-Maryland | Present | Native | |||||
-Massachusetts | Present | Native | Wellfleet Bay Sanctuary; Normans Land Island National Wildlife Refuge, Middlesex county | ||||
-Michigan | Present | Native | |||||
-Minnesota | Present | Native | |||||
-Mississippi | Present | Native | |||||
-Missouri | Present | Native | |||||
-Montana | Present | Introduced | 1920 | ||||
-Nebraska | Present, Localized | Native | |||||
-Nevada | Present, Localized | Introduced | Pahranagat National Wildlife Refuge, Lincoln county; First reported: 1920-1938 | ||||
-New Hampshire | Present | Native | |||||
-New Jersey | Present | Native | Cape May National Wildlife Refuge, Cape May county | ||||
-New Mexico | Present | Introduced | 1885 | ||||
-New York | Present | Native | |||||
-North Carolina | Present | Native | |||||
-North Dakota | Absent, Formerly present | ||||||
-Ohio | Present | Native | |||||
-Oklahoma | Present | Native | |||||
-Oregon | Present, Widespread | Introduced | 1931 | ||||
-Pennsylvania | Present | Native | |||||
-Rhode Island | Present | Native | |||||
-South Carolina | Present | Native | |||||
-South Dakota | Present | Native | |||||
-Tennessee | Present | Native | |||||
-Texas | Present | Native | |||||
-Utah | Present, Localized | Introduced | Fish Springs National Wildlife Refuge, Juab county | ||||
-Vermont | Present | Native | |||||
-Virginia | Present | Native | |||||
-Washington | Present, Widespread | Introduced | 1910 | ||||
-West Virginia | Present | Native | |||||
-Wisconsin | Present | Native | Original citation: University of Michigan Museum of Zoology (2005) | ||||
-Wyoming | Present, Localized | Introduced | |||||
South America |
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Argentina | Present, Localized | Introduced | Present in the following provinces: Buenos Aires, Córdoba, Mendoza, Misiones, Salta, San Juan | ||||
Brazil | Present | Introduced | Invasive | Atlantic Rainforest biodiversity hotspot; First reported: 1935 - mid 1980s | |||
-Bahia | Present | Introduced | |||||
-Ceara | Present | Introduced | |||||
-Espirito Santo | Present | Introduced | |||||
-Goias | Present | Introduced | |||||
-Mato Grosso do Sul | Present | Introduced | |||||
-Minas Gerais | Present | Introduced | |||||
-Para | Present | Introduced | |||||
-Paraiba | Present | Introduced | |||||
-Parana | Present | Introduced | |||||
-Pernambuco | Present | Introduced | |||||
-Rio de Janeiro | Present | Introduced | |||||
-Rio Grande do Norte | Present | Introduced | |||||
-Rio Grande do Sul | Present | Introduced | Invasive | ||||
-Santa Catarina | Present | Introduced | |||||
-Sao Paulo | Present | Introduced | |||||
Chile | Present | Introduced | Invasive | ||||
Colombia | Present | Introduced | 1986 | Middle Magdalena Valley, north to the lowlands on the Caribbean coast. Also found in Bogotá | |||
Ecuador | Present | Introduced | First reported: late 1990s | ||||
Guyana | Present | Introduced | |||||
Peru | Present, Localized | Introduced | Established around Iquitos in central Loreto Department in the Amazon Basin, and also around Lima on the Pacific Coast | ||||
Uruguay | Present, Localized | Introduced | Invasive | Introduced in Rincón de Pando, Canelones | |||
Venezuela | Present, Localized | Introduced | An expanding population near La Azulita, in Mérida State; First reported: 1990s |
History of Introduction and Spread
Top of pageIn the late 19th and early 20th centuries bullfrogs were translocated from the eastern United States to many western states (Moyle, 1973; Bury and Whelan, 1984) and Hawaii (Pitt et al., 2005), western Canada (Orchard, 1999), the Caribbean (Kairo et al., 2003; Kraus, 2009), western Europe (Ficetola et al., 2007 -- see electronic appendix to this paper for a table with details of introductions to several European countries, mostly in the late 20th century; Lanza, 1962; Veenvliet and Veenvliet, 2003, 2004; Nehring and Klingenstein, 2008), South America (Hanselmann et al., 2004; Giovanelli et al., 2008; Laufer et al., 2008; Kraus, 2009) east Asia (Fei et al., 1999; Hirai, 2004; Wu et al., 2005; Wang et al., 2008) and southeast Asia (Hardouin, 1997). There have also been introductions to western and central Mexico, from the eastern USA and north-eastern Mexico.
Introductions
Top of pageRisk of Introduction
Top of pagePeople continue to routinely transport bullfrogs from one place to another because they appear to be an easily cultivated and profitably marketable commodity for human consumption. Bullfrogs almost inevitably escape because they are, if not impossible, then certainly impractical to confine (see Liu and Lee (2009) for information on the effects of enclosure type and other factors on the risk of escape). However even in the face of wide recognition that it is not a good thing to do, some people persist in moving this ecologically damaging species from place to place for a complex of reasons that range from genuine ignorance to wilful mischief.
Habitat
Top of pageBullfrogs will colonize a wide variety of lakes, ponds, reservoir, irrigation ditches and marshes, but there are vital characteristics for supporting a population. Permanent water is necessary because bullfrog tadpoles generally take at least 12 months and as much as 48 months to reach metamorphosis; seasonal or intermittent pools, though useful as way stations for migrating bullfrogs, will probably not permit successful reproduction. Water temperature is also important because bullfrogs reproduce only in very warm water when summer temperatures exceed 25 degrees Celsius. For this reason, lakes and ponds that are not too deep < 6 m) and have good sun-exposure around the margins provide most favourable habitat for bullfrog reproduction. Riparian thickets and an abundance of aquatic and emergent vegetation are other factors that, while not vital, are often associated with thriving bullfrog populations because they provide cover and likely a more diverse prey base. However, golf course ponds with edges denuded of most riparian plants can also support healthy bullfrog populations. Acidification of waterways has been associated with bullfrog population declines in southern Ontario (Berrill et al., 1992), but the tolerance limits of bullfrogs to water chemistry extremes and various synthetic chemicals are still being explored.
Habitat List
Top of pageCategory | Sub-Category | Habitat | Presence | Status |
---|---|---|---|---|
Terrestrial | Natural / Semi-natural | Riverbanks | Present, no further details | |
Terrestrial | Natural / Semi-natural | Wetlands | Present, no further details | |
Freshwater | Irrigation channels | Present, no further details | Harmful (pest or invasive) | |
Freshwater | Lakes | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Reservoirs | Principal habitat | Harmful (pest or invasive) | |
Freshwater | Rivers / streams | Present, no further details | Harmful (pest or invasive) | |
Freshwater | Ponds | Principal habitat | Harmful (pest or invasive) |
Biology and Ecology
Top of pageGenetics
Recent studies have looked at genetic markers to try to identify the geographical origin, number of founders, and number of introductions of alien, invasive bullfrog populations (Ficetola et al, 2008a; Austin et al., 2004). While this line of research has demonstrated success at achieving its scientific goal, it has not yet been applied to bullfrog management and eradication. These studies do highlight the fact that American bullfrogs are physiologically adaptable and behaviourally flexible when moved between environments that are markedly dissimilar, and that they can invade huge areas starting from only a small number of founder individuals.
Natural Food Sources
Top of pageFood Source | Food Source Datasheet | Life Stage | Contribution to Total Food Intake (%) | Details |
---|---|---|---|---|
algae | Aquatic|Fry | |||
amphibians | Aquatic|Adult | |||
aquatic crustaceans | Aquatic|Fry | |||
aquatic plants | Aquatic|Fry | |||
birds | Aquatic|Adult | |||
fishes | Aquatic|Adult | |||
insects | Aquatic|Adult | |||
mammals | Aquatic|Adult | |||
molluscs | Aquatic|Adult | |||
reptiles | Aquatic|Adult | |||
terrestrial non-insect arthropods | Aquatic|Adult | |||
terrestrial worms | Aquatic|Adult |
Climate
Top of pageClimate | Status | Description | Remark |
---|---|---|---|
A - Tropical/Megathermal climate | Tolerated | Average temp. of coolest month > 18°C, > 1500mm precipitation annually | |
Af - Tropical rainforest climate | Tolerated | > 60mm precipitation per month | |
Am - Tropical monsoon climate | Tolerated | Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25])) | |
Aw - Tropical wet and dry savanna climate | Tolerated | < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25]) | |
BS - Steppe climate | Tolerated | > 430mm and < 860mm annual precipitation | |
BW - Desert climate | Tolerated | < 430mm annual precipitation | |
C - Temperate/Mesothermal climate | Tolerated | Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C | |
Cf - Warm temperate climate, wet all year | Tolerated | Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year | |
Cs - Warm temperate climate with dry summer | Tolerated | Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers | |
Cw - Warm temperate climate with dry winter | Tolerated | Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters) | |
D - Continental/Microthermal climate | Tolerated | Continental/Microthermal climate (Average temp. of coldest month < 0°C, mean warmest month > 10°C) |
Latitude/Altitude Ranges
Top of pageLatitude North (°N) | Latitude South (°S) | Altitude Lower (m) | Altitude Upper (m) |
---|---|---|---|
50 | 33 |
Water Tolerances
Top of pageParameter | Minimum Value | Maximum Value | Typical Value | Status | Life Stage | Notes |
---|---|---|---|---|---|---|
Ammonia [unionised] (mg/l) | <0.5 | Optimum | Adult | |||
Ammonia [unionised] (mg/l) | <0.5 | Optimum | Egg | |||
Ammonia [unionised] (mg/l) | <0.5 | Optimum | Larval | |||
Ammonia [unionised] (mg/l) | <0.5 | Optimum | Fry | |||
Chloride (mg/l) | <7 | Optimum | Egg | |||
Chloride (mg/l) | <7 | Optimum | Larval | |||
Chloride (mg/l) | <7 | Optimum | Fry | |||
Chlorine (mg/l) | 0.02 | Optimum | Egg | |||
Chlorine (mg/l) | 0.02 | Optimum | Larval | |||
Chlorine (mg/l) | 0.02 | Optimum | Fry | |||
Dissolved oxygen (mg/l) | >3 | Optimum | Wild populations (FAO, 2005) | |||
Hardness (mg/l of Calcium Carbonate) | <40 | Optimum | Adult | |||
Hardness (mg/l of Calcium Carbonate) | <40 | Optimum | Egg | |||
Hardness (mg/l of Calcium Carbonate) | <40 | Optimum | Larval | |||
Hardness (mg/l of Calcium Carbonate) | <40 | Optimum | Fry | |||
Iron (mg/l) | <0.3 | Optimum | Egg | |||
Iron (mg/l) | <0.3 | Optimum | Larval | |||
Iron (mg/l) | <0.3 | Optimum | Fry | |||
Nitrate (mg/l) | <1.0 | Optimum | Adult | |||
Nitrate (mg/l) | <1.0 | Optimum | Egg | |||
Nitrate (mg/l) | <1.0 | Optimum | Larval | |||
Nitrate (mg/l) | <1.0 | Optimum | Fry | |||
Nitrite (mg/l) | <0.5 | Optimum | Adult | |||
Nitrite (mg/l) | <0.5 | Optimum | Egg | |||
Nitrite (mg/l) | <0.5 | Optimum | Larval | |||
Nitrite (mg/l) | <0.5 | Optimum | Fry | |||
Water pH (pH) | Optimum | May be sensitive to low pH (Berrill et al., 1992) | ||||
Water pH (pH) | 6.5 | 7.0 | Optimum | Adult | ||
Water pH (pH) | 6.5 | 7.0 | Optimum | Broodstock | ||
Water pH (pH) | 6.5 | 7.0 | Optimum | Egg | ||
Water pH (pH) | 6.5 | 7.0 | Optimum | Larval | ||
Water pH (pH) | 6.5 | 7.0 | Optimum | Fry | ||
Water temperature (ºC temperature) | >27 | Harmful | Adult | |||
Water temperature (ºC temperature) | >27 | Harmful | Broodstock | |||
Water temperature (ºC temperature) | >27 | Harmful | Egg | |||
Water temperature (ºC temperature) | >27 | Harmful | Larval | |||
Water temperature (ºC temperature) | >27 | Harmful | Fry | |||
Water temperature (ºC temperature) | 21 | 27 | Optimum | Adult | ||
Water temperature (ºC temperature) | 21 | 27 | Optimum | Broodstock | ||
Water temperature (ºC temperature) | 21 | 27 | Optimum | Egg | ||
Water temperature (ºC temperature) | 21 | 27 | Optimum | Larval | ||
Water temperature (ºC temperature) | 21 | 27 | Optimum | Fry | ||
Water temperature (ºC temperature) | 20 | 35 | Optimum | 1-42 tolerated (these values apply to wild populations rather than those in culture) |
Natural enemies
Top of pageNatural enemy | Type | Life stages | Specificity | References | Biological control in | Biological control on |
---|---|---|---|---|---|---|
Agkistrodon contortrix | Predator | All Stages | ||||
Agkistrodon piscivorus | Predator | Other|Juvenile; Aquatic|Larval | ||||
Alligator mississippiensis | Predator | All Stages; Aquatic|Larval | ||||
Ambystoma tigrinum | Predator | Aquatic|Egg; Other|Juvenile; Aquatic|Larval | ||||
Canis latrans | Predator | All Stages | ||||
Chelydra serpentina | Predator | Other|Juvenile; Aquatic|Larval | ||||
Didelphis virginiana | Predator | All Stages | ||||
Dolomedes triton | Predator | Aquatic|Larval | ||||
Homo sapiens | Predator | Other|Adult Female; Other|Adult Male | ||||
Lutra canadensis | Predator | All Stages | ||||
Mephitis mephitis | Predator | All Stages | ||||
Neovison vison | Predator | All Stages | ||||
Nerodia sipedon | Predator | All Stages | ||||
Procyon lotor | Predator | All Stages | ||||
Rana catesbeiana | Predator | Other|Juvenile; Aquatic|Larval | ||||
Saprolegnia | Pathogen | Aquatic|Egg | ||||
Thamnophis couchi | Predator | Other|Juvenile; Aquatic|Larval | ||||
Thamnophis sauritus septentrionalis | Predator | Other|Juvenile; Aquatic|Larval |
Notes on Natural Enemies
Top of pageBullfrog eggs are commonly attacked by fungi (Ruthig, 2009) and perhaps leeches (Licht 1969), while the tadpoles are preyed upon by aquatic invertebrates such as dragonfly larvae and predatory water beetles. Although fish sometimes predate bullfrog eggs, tadpoles and juveniles (Bury and Whelan, 1984; Casper and Hendricks, 2005), tadpoles avoid predation by being distasteful to many of the more widespread predatory fish, or use chemical-cued avoidance behaviour in their presence (Pearl et al., 2003). Chemical-cued avoidance behaviour is also used by bullfrog tadpoles in the presence of predatory dragonfly nymphs (Peacor, 2006). Larger aquatic-foraging garter snakes (Thamnophis spp.) might be effective predators of bullfrog tadpoles and juveniles, but garter snakes are commonly eaten by adult bullfrogs. Avian predators include herons and egrets (Ardeidae; Casper and Hendricks, 2005); various reptiles and mammals also eat bullfrogs.
Means of Movement and Dispersal
Top of pageBullfrog tadpoles will spread throughout the water bodies in which they have hatched, though they tend to seek out the warmest water. From here they can enter the inflow and outflow waterways that feed and drain lakes and ponds and therefore have a limited ability to migrate. However, because bullfrog larvae (tadpoles) are gill-breathing and entirely aquatic this life stage is unable to move out of the water on its own.
Pathway Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Animal production | Yes | Yes | ||
Aquaculture | Yes | Yes | ||
Breeding and propagation | Yes | Yes | ||
Escape from confinement or garden escape | Yes | |||
Hunting, angling, sport or racing | Yes | Yes | ||
Intentional release | Yes | Yes | ||
Pet trade | Yes | Yes | ||
Research | Yes | Yes | ||
Stocking | Yes |
Pathway Vectors
Top of pageVector | Notes | Long Distance | Local | References |
---|---|---|---|---|
Pets and aquarium species | Yes | Yes | ||
Water | Yes |
Impact Summary
Top of pageCategory | Impact |
---|---|
Economic/livelihood | Positive and negative |
Environment (generally) | Negative |
Economic Impact
Top of pageEnvironmental Impact
Top of pageBullfrogs are prolific and aggressive competitors for space and voracious predators of a very wide variety of organisms, so displacement of native species is the primary problem that they create (Bury and Whelan, 1984; Lannoo, 2005; Santos-Barrera et al., 2009). They have a much higher critical thermal maximum than most other frogs, meaning that they are able to thrive in higher water temperature, and have a longer breeding season and a higher rate of pre-metamorphic survivorship, which also allows them to be more successful than other frogs. (They also do well with changes in the environment that have occurred due to human modification).
Threatened Species
Top of pageSocial Impact
Top of pageThere have been cases of severe allergic reaction in some people who ingest the meat of bullfrogs (Hilger et al.,2002). Also, bullfrog tadpoles and metamorphs have been shown to be suitable hosts for the pathogenic bacterium Escherichia coli (Gray et al., 2007). In Japan it was found that 92% of the bullfrogs sampled were highly infected with Blastocystis, a single-celled parasite that infects the gastrointestinal tract of hosts including humans (Yoshikawa et al., 2004). The skinning of bullfrogs has been implicated in rare cases of nematode infection of humans (Quirks and Quarks, CBC Radio, Canadian Broadcasting Corporation). Studies are currently under way looking into whether bullfrogs could play a role in transmission of West Nile virus (WNV), because the virus has been isolated in many amphibian-feeding species of mosquitoes (Klenk and Komar, 2003; Danner & Phillips, 2008). An investigation of a cholera outbreak in Hunan, China, in 2006 concluded that aquatic products such as snapping turtles and bullfrogs constituted the major causes of cholera (Deng et al., 2008).
Risk and Impact Factors
Top of page- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Is a habitat generalist
- Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
- Pioneering in disturbed areas
- Capable of securing and ingesting a wide range of food
- Highly mobile locally
- Benefits from human association (i.e. it is a human commensal)
- Long lived
- Fast growing
- Has high reproductive potential
- Altered trophic level
- Conflict
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Negatively impacts aquaculture/fisheries
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
- Pest and disease transmission
- Predation
- Rapid growth
- Highly likely to be transported internationally deliberately
- Highly likely to be transported internationally illegally
- Difficult/costly to control
Uses
Top of pageIn many parts of the world where American bullfrogs are non-native, the adults are known to be hunted for food, e.g. in China. It is not known whether this utilization of bullfrogs provides an important dietary supplement or an important source of income, or is simply a recreational activity.
Uses List
Top of pageAnimal feed, fodder, forage
- Bait/attractant
General
- Botanical garden/zoo
- Capital accumulation
- Laboratory use
- Pet/aquarium trade
- Research model
- Sport (hunting, shooting, fishing, racing)
Human food and beverage
- Fresh meat
- Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)
Similarities to Other Species/Conditions
Top of pageThe average person might find it difficult to distinguish between many species in the widely distributed and speciose family Ranidae (853 described species) because so many of them are green, brown and/or olive-coloured with black irregular patterns. In any case, colour and pattern are not the most reliable of bullfrog characteristics. Size narrows the possibilities where large adult specimens are concerned – a very big specimen is likely to be a bullfrog -- but juvenile bullfrogs can easily be mistaken for other species. The low, sonorous timbre of a male bullfrog’s advertisement call is distinctive compared to that of other frogs. It sounds more in the vocal range of a cow than a frog and amounts to multiple repetitions of “Rrrungh” that vary in volume and intensity depending upon the size of the frog and the temperature of the water in which it is sitting. Juvenile bullfrogs have a distinctive escape behaviour. They produce a characteristic “MEEP” alarm call as they propel themselves into the water when frightened. This action commonly involves skipping over the water surface by rapid multiple kicks of the hind legs before submerging and swimming away.
Prevention and Control
Top of pageDue to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
Prevention
Gaps in Knowledge/Research Needs
Top of pageThere is a nearly universal agreement that American bullfrogs are one of the worst alien invasive species internationally. They are ecologically destructive and therefore eradication is acknowledged as the most desirable goal. However, there is also a collective sense of defeatism permeating all recent published discussions concerning bullfrog management (Adams and Pearl, 2007; Kraus, 2009). Adams and Pearl (2007) conclude that the “lack of obvious economic impacts” and a lack of reasonably feasible control methods inevitably translate into a lack of political will to supply the resources for large-scale management. Kraus (2009) lists some apparently successful eradication case studies that have been carried out in Europe, but then concludes that these may be exceptions to the general pattern of eradication failure. However, Kraus also observes that large-scale ecological problems are beyond the capabilities and outside the skill sets of the average volunteer organization or institutional research lab, though these are most often the people who are expected to take the initiative. In fact, eradication programs are more akin to military operations. The strategies, tactics and techniques for an effective eradication are to out-flank, out-pace, and ultimately to overwhelm your foe. Traditionally, biologists are trained to study a problem, collect data, and publish results but eradication is something quite different in the degree of dedication and improvisation required. It also needs sufficient long-term commitments from funding agencies as well as adequate support staff.
References
Top of pageAlbinati RCB, Lima SL, Tafuri ML, Donzele JL, 2000. Digestibilidade aparente de dois alimentos protéicos e três energéticos para girinos de rã-touro (Rana catesbeiana, Shaw, 1802). R. Bras. Zootec., 29(6):2154-2156.
Austin JD, Lougheed SC, Boag PT, 2004. Controlling for the effects of history and nonequilibrium conditions in gene flow estimates in northern bullfrog (Rana catesbeiana) populations. Genetics, 168:1491-1506.
Bury RB, Whelan JA, 1984. Ecology and management of the bullfrog. USFWS Resource Pub., 155:1-23.
CaliforniaHerps, 2005. Rana catebeiana-American Bullfrog. Online at www.californiaherps.com/frogs/frogs.html. Accessed 1 June 2005.
Culley Jr DD, Meyers SP, 1972. Frog culture and ration development. Feedstuffs, 44(31):26-27.
DIAS, 2004. FAO Database on Introductions of Aquatic Species. Online at www.fao.org/figis/. Accessed 25 February 2005.
Gans C, 1974. Biomechanics. Philadelphia, USA: J. B. Lippincott Co., 272 pp.
Hammerson GA, 1982. Amphibians and reptiles in Colorado. Colorado Division of Wildlife, Denver, 131 pp.
Hayes MP, Jennings MR, 1986. Decline of ranid frog species in western North America: are bullfrogs (Rana catesbeiana) responsible? J. Herpetol., 20:490-509.
Hecnar SJ, M’Closkey RT, 1997. Changes in the composition of a ranid frog community following bullfrog extinction. American Midland Naturalist, 137:145-150.
Henley J, 2009. Why we shouldn't eat frogs' legs. The Guardian. http://www.guardian.co.uk
ISSG, 2005. Global Invasive Species Database (GISD). University of Auckland, New Zealand. http://www.issg.org/database
Jim J, 1995. Ecologia das rãs. In: Proceedings of the First International Meeting on Frog Research and Technology, February 1995. Viçosa – MG, Brasil: ABETRA/UFV, 167-190.
Kiesecker JM, Blaustein AR, 1998. Effects of introduced bullfrogs and smallmouth bass on microhabitat use, growth, and survival of native red-legged frogs (Rana Aurora). Conservation Biology, 12:776-787.
Kraus F, 2009. Invading nature: Springer series in invasion ecology 4. Springer, 563 pp.
Kusrini MD, Alford RA, 2006. Indonesia's exports of frogs' legs. TRAFFIC Bulletin, 21(1):13-28.
Licht LE, 1969. Palatability of Rana and Hyla eggs. American Midland Naturalist, 82:292-298.
Lima SL, Agostinho CA, 1988. A criação de rãs. Rio de Janeiro: Globo, 187pp.
Lima SL, Agostinho CA, 1995. A tecnologia de criação de rãs. Viçosa: Impr. Univ., 166pp.
Lima SL, Cruz TA, Moura OM, 1999. Ranicultura: análise da cadeia produtiva. Viçosa: Ed. Folha fr Viçosa, 172 pp.
Liu X, Li YM, 2009. Aquaculture enclosures relate to the establishment of feral populations of introduced species. PLoS ONE, 4:E6199.
Marcantonio AS, Lui JF, Stéfani MV, 2002. Estudo citogenético da rã-touro (Rana catesbeiana Shaw, 1802). Ars Veterinária, 18(2):174-178.
NatureServe, 2005. Comprehensive Report Species – Rana catesbeiana. Online at www.natureserve.org/explorer/. Accessed 1 June 2005.
Ryan MJ, 1980. The reproductive behavior of the bullfrog (Rana catesbeiana). Copeia, 1980:108-114.
Sanabria E, Debandi G, Quiroga L, Martínez F, Corbalán V, 2011. First record of the American bullfrog Lithobates catesbeianus (Shaw, 1802) in Mendoza province, Argentina. Cuadernos de Herpetología, 25(2):55-58.
Sanabria E, Ripoll Y, Jordan M, Quiroga L, Ariza M, Guillemain M, Pérez M, Chávez H, 2011. A new record for American Bullfrog (Lithobates catesbeianus) in San Juan, Argentina. Revista Mexicana de Biodiversidad, 82:311-313.
Sanabria EA, Quiroga LB, Acosta JC, 2005. Introduction of Rana catesbeiana Shaw (bullfrog) in pre-Andean environments of San Juan province, Argentina. (Introducción de Rana catesbeiana Shaw (rana toro), en ambientes precordilleranos de la Provincia de San Juan, Argentina.) Multequina, 14:67-70.
Souder W, 2000. A plague of frogs: the horrifying true story. New York, USA: Hyperion, 299 pp.
Storer TI, Usinger RL, 1965. General Zoology. Fourth edition. McGraw-Hill, 741 pp.
Tangley L, 2003. A plague of aliens. National Wildlife, 41(2):42.
Teixeira RD, Pereira Mello SCR, Lima dos Santos CAM, 2001. The world market for frog legs. FAO/GLOBEFISH Research Programme, 68:44 pp.
University of Michigan Museum of Zoology, 2005. Animal Diversity Web. Online at http://animaldiversity.ummz.umich.edu/site/index.html. Accessed 1 June 2005.
Villee CA, Walker W, Smith FE, 1963. General Zoology. Third edition. WB Saunders, 844 pp.
Zavod Symbiosis, 2005. Bullfrogs. Online at www.zavod-symbiosis.si/. Accessed 1 June 2005.
Distribution References
Banks B, Foster J, Langton T, Morgan K, 2000. British bullfrogs? British Wildlife. 327-330.
Bury RB, Whelan JA, 1984. Ecology and management of the bullfrog. In: USFWS Resource Pub. 155 1-23.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
DIAS, 2004. FAO Database on Introductions of Aquatic Species., http://www.fao.org/figis/
ISSG, 2005. Global Invasive Species Database (GISD)., New Zealand: University of Auckland. http://www.issg.org/database
Kellog R, 1932. Bulletin of the U.S. National Museum, Washington, DC, USA: U.S. National Museum.
Kusrini M D, Alford R A, 2006. Indonesia's exports of frogs' legs. TRAFFIC Bulletin. 21 (1), 13-28.
Lima SL, Cruz TA, Moura OM, 1999. (Ranicultura: análise da cadeia produtiva)., Viçosa, Ed Folha fr Viçosa. 172 pp.
NatureServe, 2005. Comprehensive Report Species - Rana catesbeiana., http://www.natureserve.org/explorer/
Sanabria E, Debandi G, Quiroga L, Martínez F, Corbalán V, 2011. First record of the American bullfrog Lithobates catesbeianus (Shaw, 1802) in Mendoza province, Argentina. In: Cuadernos de Herpetología, 25 (2) 55-58.
Sanabria E, Ripoll Y, Jordan M, Quiroga L, Ariza M, Guillemain M, Pérez M, Chávez H, 2011a. A new record for American Bullfrog (Lithobates catesbeianus) in San Juan, Argentina. In: Revista Mexicana de Biodiversidad, 82 311-313.
Sanabria EA, Quiroga LB, Acosta JC, 2005. Introduction of Rana catesbeiana Shaw (bullfrog) in pre-Andean environments of San Juan province, Argentina. (Introducción de Rana catesbeiana Shaw (rana toro), en ambientes precordilleranos de la Provincia de San Juan, Argentina). In: Multequina, 14 67-70.
Tan B C, Tan K S, 2002. Invasive alien species in Singapore: a review. ASEAN Biodiversity. 33-34.
Teixeira RD, Pereira Mello SCR, Lima dos Santos CAM, 2001. The world market for frog legs. In: FAO/GLOBEFISH Research Programme, 68 44 pp.
Zavod Symbiosis, 2005. Bullfrogs., http://www.zavod-symbiosis.si/
Links to Websites
Top of pageWebsite | URL | Comment |
---|---|---|
AmphibiaWeb | http://amphibiaweb.org/ | |
BullfrogControl.com.Inc | http://www.bullfrogcontrol.com | |
FAO: Cultured Aquatic Species Information Programme | http://www.fao.org/fishery/culturedspecies/Rana_catesbeiana/en | |
ISSG database global Invasive Species Database) | http://www.issg.org | |
IUCN Red List | http://www.redlist.org |
Organizations
Top of pageWorld: Invasive Species Specialist Group (ISSG), Web based, http://www.issg.org/contact.htm
World: IUCN/SSC Global Amphibian Assessment, IUCN/SSC, International, http://www.issg.org
Italy: FAO (Food and Agriculture Organization of the United Nations), Viale delle Terme di Caracalla, 00100 Rome, http://www.fao.org/
Mexico: CONABIO - National Commission for Knowledge and Use of Biodiversity, Liga Periférico - Insurgentes Sur, Núm. 4903, Col. Parques del Pedregal, Delegación Tlalpan, 14010, http://www.conabio.gob.mx
USA: US Geological Survey - USGS, USGS National Center 12201 Sunrise Valley Drive, Reston, VA 20192, http://nas.er.usgs.gov
Contributors
Top of page08/12/2009 Original text (Invasive Species Compendium) by:
Stan Orchard, BullfrogControl.com Inc., 69A Burnside Road West, Victoria, British Columbia, V9A 1B6, Canada
04/05/2005 Original text (Aquaculture Compendium) by:
Marta Stéfani, Departamento de Zootecnia da FCAV/Unesp Jaboticabal, Via de Ac. Prof. Paulo Donato Castellane, s/n Jaboticabal - SP - 14884-900, Brazil
Distribution Maps
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