Chesapeake Bay Introduced Species Database


Myocastor coypus

Common name(s):
Nutria
Nutria fur coats are fetching high prices throughout the US, an economic attraction that spurred the import of Nutria to the US from their native South America (Argentina, Uruguay, Paraguay, and southern Brazil) starting in 1899. In places like Louisiana, wild populations were started with releases from fur farms, but some were deliberately released into marshes to control aquatic vegetation. In fact, the first nutria brought into Maryland came to the Fur Animal Field Station at Blackwater National Wildlife Refuge in 1939, where they were kept in outdoor enclosures in the marshes. By 1979 they were well established along the Eastern Shore of Maryland and Virginia with isolated occurrences along the Potomac River and Patuxent Rivers. Today there is a limited market for the fur, and major control efforts are underway to eliminate Nutria and protect marsh grasses in areas like Blackwater National Wildlife Refuge.
Image courtesy of Patuxent Wildlife Research Center.



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Environmental Tolerances

 
For Survival
For Reproduction
Minimum
Maximum
Minimum
Maximum
Temperature (ºC)
-10 35 null null
Salinity (‰)
0 null 0 null
Oxygen
     
pH
null null    
Salinity Range
fresh-poly


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Age and Growth

Male
Female
Minimum Adult Size (mm)
400 420
Typical Adult Size (mm)
550 525
Maximum Adult Size (mm)
635 600
Typical Longevity (yrs)
4 4
Maximum Longevity (yrs)
6 6


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Reproduction

Start
Peak
End
Reproductive Season
January July December
Typical Number of Young
per Reproductive Event
3.96
Sexuality Mode(s)
dioecious
Mode(s) of Asexual Reproduction
Fertilization Type(s)
outcross-internal
More than One Reproductive
Event per Year
yes
Reproductive Strategy
iteroparous
Egg/Seed Form
brooded


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Development

Minimum Typical Maximum
Egg/Seed Development Time (days)
null null null
Larval/Seed Development Period (days)
130 132 134
Male Maturation Age (yrs)
0.5 0.5  
Female Maturation Age (yrs)
0.5 0.5  
Larval/Seed Form  
brooded


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Locomotion and Abundance in Chesapeake

Locomotion
Abundance
Larvae
NA
Juveniles
mobile, nektonic abundant
Adults
mobile, nektonic abundant


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Habitat Preferences

Larvae
Juvenile
Adult
Primary Horizontal Habitats
nontidal freshwater; fresh (non-tidal) marsh; fresh tidal marsh; salt/brackish marsh; tidal swamp nontidal freshwater; fresh (non-tidal) marsh; fresh tidal marsh; salt/brackish marsh; tidal swamp; terrestrial
Secondary Horizontal Habitats
null null
Reproductive Horizontal Habitats
n/a n/a nontidal freshwater; fresh (non-tidal) marsh; fresh tidal marsh; salt/brackish marsh; tidal swamp
Vertical Habitats
epibenthic; nektonic; terrestrial epibenthic; nektonic; terrestrial
Substrate Type
mud; silt; vegetation mud; silt; vegetation
Tidal Height Location
supratidal; high intertidal; mid intertidal; low intertidal; subtidal terrestrial; supratidal; high intertidal; mid intertidal; low intertidal; subtidal
Wave Exposure
moderate; low; protected
Water Flow
stagnant; slow


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Trophic Interactions

Larvae
Juveniles
Adults
Trophic Status
non-feeding herbivore herbivore
Common Food/Prey Items
Brackish marsh plants (Schoenoplectus americanus [=Scirpus olneyi]; Phragmites australis; Spartina cynosuroides; Spartina patens; Panicum sp.; Allium sp.; Eleocharis palustris; Solidago sempervirens); fresh (non-tidal) marsh plants (Hydrocotyle sp.; Alternanthera philoxeroides; Bidens laevis; Eleocharis palustris; Saccolepis striata; Typha latifolia; Carex sp.; Nuphar sp.; Nympaea odorata); swamp plants (Lemna minor; Spirodela polyrhiza; grasses); corn (Zea mays); freshwater bivalves (Unionidae) Brackish marsh plants (Schoenoplectus americanus [=Scirpus olneyi]; Phragmites australis; Spartina cynosuroides; Spartina patens; Panicum sp.; Allium sp.; Eleocharis palustris; Solidago sempervirens); fresh (non-tidal) marsh plants (Hydrocotyle sp.; Alternanthera philoxeroides; Bidens laevis; Eleocharis palustris; Saccolepis striata; Typha latifolia; Carex sp.; Nuphar sp.; Nympaea odorata); swamp plants (Lemna minor; Spirodela polyrhiza; grasses); corn (Zea mays); freshwater bivalves (Unionidae)
Common Competitors
Muskrat (Onadatra zibethicus) Muskrat (Onadatra zibethicus)
Common Consumers
Humans; parasites; alligators; weather Humans; parasites; weather


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Comments

Life History: Environmental Tolerances: Temperature, Survival - Myocastor coypus is prone to frostbite in MD, and suffers frequent population crashes due to severe winter weather (Willner et al. 1979). Their fur is a good insulator, but the naked tail and feet are sites of heavy heat loss. these animals may be prone to high winter mortality because they continue to enter the water even under freezing conditions. 'Behavioral factors are therefore implicated in the high mortalities recorded during cold winters in Europe, the coypu's capacity to thermoregulate being insufficient for the kinds of activities characterisitic of their social orgnization. Dominant males that patrol their territories along water obviously incur high energetic costs in winter, a time when food resources are scarce. Although well-fed young coypus can thermoregulate at rest under cold conditions, those that remain in burrows at water level during cold spells must draw heavily on their reserves of fat and risk eventual starvation' (Doncaster et al. 1990). Myocastor coypus is prone to heatstroke at temperatures above 35 C (Doncaster et al. 1990).

Age and growth: Adult Size- The lengths given exclude tails, which were frequently damaged by frostbite, traps, etc. (Willner et al. 1983).

Reproduction: Reproductive Season - Pregnant females were found in MD in all months but April, but the occurrence of young indicated pregnancies in that month also. The frequency was highest in June and July (Willner et al. 1979).

Development Larval Period - Here, the 'larval period' is gestation.
Community Ecology: Habitat Preferences: Water Column Locations- We do not have specific data on water depths used by Myocastor coypus , but plants eaten are characteristic of intertidal zones of marshes or very shallow subtidal areas (Kinler et al. 1987; Willner et al. 1979). The absence of submersed plants in the diet indicates that there seems to be little subtidal foraging, although Gosling and Baker (1990) did mention freshwater mussels in the diet in England.


This data was last modified on Friday, January 14th, 2011.
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