AL North American River Otter Hunting Guide

Also known as: River otter

The North American river otter, also known as the northern river otter and river otter, is a semiaquatic mammal that is endemic to the North American continent throughout most of Canada and along the coasts of the United States and its inland waterways. An adult North American river otter can weigh between 5 and 14 kilograms (11–31 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur.

Habitat & Range

The North American river otter is found throughout North America, inhabiting inland waterways and coastal areas in Canada, thePacific Northwest, theAtlantic states, and states on theGulf of Mexico. They also inhabit the forested regions near thePacific coastin North America. The species is also present throughout Alaska, including theAleutian Islands, and the north slope of theBrooks Range. Urbanization and pollution, though, have resulted in a reduction in the otters' range in the United States.[1]They are now absent or rare in Arizona, Kansas, Nebraska, New Mexico, North Dakota, Ohio, Oklahoma, South Dakota, and Tennessee. Reintroduction projects have expanded their distribution in recent years, such as in West Virginia,[27]and especially in theMidwestern United States. Since their reintroduction to Kentucky in the early 1990s, the otters have recovered to the point that a trapping season was implemented in 2006, and the species is now found in all of the state's major waterways.[28]In 2010, the Colorado Department of Wildlife reported the river otter, reintroduced to the state in the 1980s, was "thriving" and recommended its protection status be reconsidered.[29]In late 2012, a river otter nicknamed Sutro Sam took up residence around the former site of theSutro BathsinSan Francisco, the first river otter sighting in that city since the 1950s.[30]North American river otters occupy all Canadian provinces and territories, except until recently,Prince Edward Island.[1]Otters have recently begun re-establishing themselves on Prince Edward Island.[31]InMinnesota, otter populations have rebounded due to reintroduction efforts in the 1980s,[32]improvements in water quality, habitat restoration, and harvest regulation.[33]While river otters are most common in northern Minnesota,[34]they can be seen in urban areas including theTwin Cities.[35] Historical records indicate North American river otters were once populous throughout most major drainages in the continental United States and Canada prior to European settlement. North America's largest populations were found in areas with an abundance and diversity of aquatic habitats, such as coastal marshes, theGreat Lakesregion, andglaciatedareas ofNew England. In addition,riverinehabitats in interior regions supported smaller otter populations.[1]The North American river otter existed on all parts of the Pacific Coast, including the seashore and inland streams and lakes.[36]In Mexico, North American river otters lived in theRio GrandeandColorado River Deltas.[23] Although commonly called a "river otter", the North American river otter is found in a wide variety of aquatic habitats, both freshwater and coastal marine, including lakes, rivers, inland wetlands, coastal shorelines, marshes, and estuaries. It can tolerate a great range of temperature and elevations. Aquatic life ties them almost exclusively to permanent watersheds.[17]Their main requirements are a steady food supply and easy access to a body of water, but they are sensitive to pollution and disappear from tainted areas.[23] Like other otters, the North American river otter lives in a holt, or den, constructed in the burrows of other animals, or in natural hollows, such as under a log or in riverbanks. An entrance, which may be under water or above ground, leads to a nest chamber lined with leaves, grass, moss, bark, and hair.[23]

Life History

L. c. canadensis; L. c. kodiacensis; L. c. lataxina; L. c. mira; L. c. pacifica; L. c. periclyzomae; L. c. sonora Lutra canadensis TheNorth American river otter(Lontra canadensis), also known as thenorthern river otterandriver otter, is asemiaquaticmammalthat isendemicto the North American continent throughout most ofCanadaand along the coasts of the United States and its inland waterways. An adult North American river otter can weigh between 5 and 14 kilograms (11–31 lb). The river otter is protected and insulated by a thick, water-repellent coat of fur. The North American river otter, a member of the subfamilyLutrinaein theweasel family(Mustelidae), is equally versatile in the water and on land. It establishes aburrowclose to the water's edge in river, lake, swamp, coastal shoreline, tidal flat, orestuaryecosystems. The den typically has many tunnel openings, one of which generally allows the otter to enter and exit the body of water. Females give birth in these burrows, producing litters of one to six young.[2] North American river otters, like most predators, prey upon the most readily accessible species.Fishis a favored food among the otters, but they also consume variousamphibians(such assalamandersandfrogs),[3]freshwater clams,mussels,snails, smallturtles, andcrayfish. The most common fish consumed areperch,suckers, andcatfish.[4]Occasional reports also show the river otter eating other small animals, such as mice, squirrels, birds, and even dogs that they have attacked and drowned.[5][6][7] The range of the North American river otter has been significantly reduced byhabitat loss, beginning with theEuropean colonization of the Americas. In some regions, though, their population is controlled to allow the trapping and harvesting of otters for theirfur. North American river otters are very susceptible to the effects ofenvironmental pollution, which is a likely factor in the continued decline of their numbers. A number of reintroduction projects have been initiated to help halt the reduction in their overall population.[8] The North American river otter has long and thinwhiskersthat are used to detect prey in dark waters.[19][17]An average adult male weighs about 11.3 kilograms (25 lb) against the female's average of 8.3 kg (18 lb). Its body length ranges from 66 to 107 cm (26–42 in).[20]About one-third of the animal's total length consists of a long, tapered tail.[17]Tail lengths range from 30 to 50 cm (12–20 in).[20]Large males can exceed a weight of 15 kg (33 lb).[21]It differs from theEurasian otterby its longer neck, narrower visage, the smaller space between the ears, and shorter tail.[22] Males and female river otters showdifferent nonsexual physical characteristics,[23]with males typically being larger.[17] North American river otters can live 21–25 years in captivity,[23][17]or 8–13 years in the wild.[23][17] North American river otters only settle in areas that consist of vegetation, rock piles, and sufficient coverage.[37] The diet of the North American River otters is extensive and mostly consists of fish, frogs, crayfish, turtles, insects, and some small mammals. They are known to hunt in pairs or alone and can hunt on both land and in the water.Lontra canadensisis a predator adapted to hunting in water, feeding on aquatic and semiaquatic animals. The vulnerability and seasonal availability of prey animals primarily determine their food habits and prey preferences.[54] North American river otters consume an extensive assortment of fish species ranging in size from 2 to 50 cm (0.79–19.69 in) that impart sufficient caloric intake for a minute amount of energy expenditure.[40]They generally feed on prey that is in good supply and easy to catch. As a result, slow-swimming fish are consumed more often thangame fisheswhen both are equally available.[42][46]Slow-moving species include suckers (Catostomidae),catfish, sunfish andbass(Centrarchidae), daces,carp, and shiners (Cyprinidae).[39]For instance, Catostomidae are the primary dietary component of North American river otters in Colorado's Upper Colorado River Basin.[55]Likewise, thecommon carp(Cyprinus carpio) is a preferred fish species for them in other regions of Colorado.[55]Fish species frequently found in the diets of the North American river otters include: Catostomidae, which consists of suckers (Catostomusspp.) andredhorses(Moxostomaspp.); Cyprinidae, made up of carp (Cyprinusspp.),chubs(Semotilusspp.), daces (Rhinichthysspp.), shiners (NotropisandRichardsoniusspp.), and squawfishes (Ptychocheilusspp.); andIctaluridae, which consists ofbullheadsandcatfish(Ictalurusspp.).[26]Other fish an integral part of the North American river otters' diets are those that are often plentiful and found in large schools: sunfish (Lepomisspp.);darters(Etheostomaspp.); andperches(Percaspp.).[26][42][43]Bottom-dwelling species, which have the tendency to remain immobile until a predator is very close, are susceptible to North American river otters. These includeCentral mudminnows(Umbra limi) andsculpins(Cottusspp.).[26][42][43]Game fish, such astrout(Salmonidae) andpike(Esocidae), are not a significant component of their diets.[40][42]They are less likely to be prey for the North American river otters since they are fast-swimming and can find good escape cover.[40]However, river otters will prey on trout, pike,walleye(Sander vitreus vitreus),salmon(Oncorhynchusspp.), and other game fish duringspawning.[43]Otters have been found to consume invasive Asian carp.[56] Adult North American river otters are capable of consuming 1.0–1.5 kilograms (2.2–3.3 lb) of fish per day.[46]A study conducted on captive otters revealed they preferred larger fish, ranging from 15 to 17 cm (5.9–6.7 in), more than smaller fish, ranging from 8 to 10 cm (3.1–3.9 in), and they had difficulty catching fish species less than 10 cm (3.9 in) or larger than 17 cm (6.7 in).[38]Otters are known to take larger fish on land to eat, whereas smaller fish are consumed in the water.[46] North American river otters may prefer to feed oncrustaceans, especiallycrayfish(Cambarus,Pacifasticus, and others) andcrabsmore than fish where they are locally and seasonally plentiful.[23][39]In Georgia, crayfish accounted for two-thirds of the prey in the summer diet, and their remnants were present in 98% of the summerspraint. In the winter, crayfish made up one-third of the North American river otter's diet.[57]A study conducted on North American river otters in a southwestern Arkansas swamp identified a correlation between crayfish consumption, fish consumption, and water levels.[58] During the winter and spring, when the water levels were higher, North American river otters had a greater tendency to prey upon crayfish (73% of scats had crayfish remains) rather than fish.[58]When water levels are lower, though, crayfish seek out shelter while fish become more highly concentrated and susceptible to predation. Therefore, fish are more vulnerable to being preyed upon by otters because the crayfish have become more difficult to obtain.[39] Amphibians, where regionally accessible, have been found in the North American river otter's diet during the spring and summer, as indicated in many of the food habit studies.[42][44]The most common amphibians and reptiles recognized werefrogs(RanaandHyla).[43]Specific species of reptiles and amphibians prey include:boreal chorus frogs(Pseudacris maculata);Canadian toads(Bufo hemiophrys);wood frogs(Rana sylvatica);[44]American bullfrogs(Rana catesbeiana);green frogs(Rana clamitans);[46]northwestern salamanders(Ambystoma gracile);California giant salamander(Dicamptodon ensatus);rough-skinned newt(Taricha granulosa);[43]andgarter snakes(Thamnophis).[26][43] Amphibians and reptiles are more obtainable by the North American river otter during the spring and summer as a result of breeding activity, appropriate temperatures, and water supply for the prey.[58] Waterfowl,rails, and some colonial nesting birds are preyed upon by North American river otters in various areas.[42][55]Susceptibility of these species is greatest during the summer (when waterfowl broods are vulnerable) and autumn.[42]The North American river otters have also been known to catch and consumemoultingAmerican wigeon(Mareca americana) andgreen-winged teal(Anas crecca).[44]Other species of birds found within their diets include:northern pintail(Anas carolinensis);mallard(Anas platyrhynchos);canvasback(Aythya valisineria);ruddy duck(Oxyura jamaicensis); and theAmerican coot(Fulica americana).[43] Although they consume birds, North American river otters do not feed on bird eggs.[38] Aquatic invertebrateshave been recognized as an integral part of the North American river otter's diet.[26][44][46][55]Otters consume more aquatic insects in the summer as the populations increase and specific life stages heighten their susceptibility.[44]Most aquatic invertebrates preyed upon by the otters are from the orders Odonata (dragonfly nymphs), Plecoptera (stonefly nymphs), and Coleoptera (adult beetles).[44][55]Invertebrates discovered within scats or digestive tracts could most likely be a secondary food item, first being consumed by the fish that are subsequently preyed upon by the North American river otters.[41][43] Mammals are rarely consumed by North American river otters, and are not a major dietary component.[40][41]Mammals preyed upon by North American river otters are characteristically small or are a type species found inriparian zones.[55]The few occurrences of mammals found in the North American river otter's diet include remains of themuskrat(Ondatra zibethicus);meadow vole(Microtus pennsylvanicus);eastern cottontail(Sylvilagus floridanus); andsnowshoe hare(Lepus americanus).[44][46][59] Records of North American otters preying upon North American beavers (Castor canadensis) vary; it has been reported in the southern boreal forest of Manitoba.[60]Trappers in Alberta, Canada commonly assert North American river otters are major predators of North American beavers.[44]A 1994 river otter study reported findings of beaver remains in 27 of 1,191 scats analyzed.[44]However, many other studies did not report any findings of North American beaver remains in the scat sampled.[58][61]

Status, Trends & Threats

Threats to North American river otter populations in North America vary regionally. North American river otter inhabitation is affected by type, distribution, and density of aquatic habitats and characteristics of human activities. Preceding the settlement of North America by Europeans, North American river otters were prevalent among aquatic habitats throughout most of the continent. Trapping, loss or degradation of aquatic habitats through filling of wetlands, and development of coal, oil, gas, tanning, timber, and other industries, resulted inlocal extinctionsor population declines in North American river otter populations in many areas. In 1980, an examination conducted on U.S. river otter populations determined they were locally extinct in 11 states, and lost significant population in 9 other states. The most severe population declines occurred in interior regions where fewer aquatic habitats supported fewer otter populations. Although the distribution became reduced in some regions of southern Canada, the only province-wide extinction occurred onPrince Edward Island.[1] During the 1970s, improvements in natural resource management techniques emerged, along with increased concerns about North American river otter population declines in North America. Consequently, many wildlife management agencies developed strategies to restore or enhance otter populations, including the use of reintroduction projects. Since 1976, over 4,000 otters have been reintroduced in 21 U.S. states. All Canadian provinces except Prince Edward Island and 29 U.S. states have viable populations that sustain annual harvests. While current harvest strategies do not pose a threat to maintaining otter populations, harvest may limit expansion of otter populations in some areas.[1] Oil spillspresent a localized threat to otter populations, especially in coastal areas.Water pollutionand other diminution of aquatic and wetland habitats may limit distribution and pose long-term threats if the enforcement of water quality standards is not upheld.Acid drainagefromcoal minesis a persistent water quality issue in some areas, as it eliminates otter prey. This dilemma prevents, and consequently inhibits, recolonization or growth of North American river otter populations. Recently, long-term genetic consequences of reintroduction projects on remnant North American river otter populations has been discussed. Similarly, many perceived threats to North American river otters, such as pollution and habitat alterations, have not been rigorously evaluated. Little effort has gone into assessing the threat of disease to wild North American river otter populations, so it is poorly understood and documented.[1] Lontra canadensisis listed in Appendix II of theConvention on International Trade in Endangered Species of Wild Fauna and Flora(CITES). They have been virtually eliminated through many parts of their range, especially around heavily populated areas in the midwestern and eastern United States.[67]Appendix II lists species that are not necessarily threatened with extinction currently, but may become so unless trade is closely controlled.[68] The North American river otter is considered a species ofleast concernaccording to theIUCN Red List, as it is not currently declining at a rate sufficient for a threat category. By the early 1900s, North American river otter populations had declined throughout large portions of their historic range in North America. However, improvements in water quality (through enactment of clean water regulations) and furbearer management techniques have permitted river otters to regain portions of their range in many areas. Reintroduction projects have been particularly valuable in restoring populations in many areas of the United States. However, North American river otters remain rare or absent in the southwestern United States. Water quality and development inhibit recovery of populations in some areas. The species is widely distributed throughout its range. In many places, the populations have re-established themselves because of conservation initiatives. Reintroduction of river otters may present a problem in that it may contaminate the genetic structure of the native population.[1]

Hunting Season

Nov 15 - Feb 28.

References

• Alabama — North American River Otter