Like much of the rest of North America, river otter (Lutra canadensis) were abundant in Iowa during European settlement, but unregulated trapping and hunting, and loss of habitat caused them to be essentially extirpated in the state. Wildlife managers began reintroduction efforts in the 1970’s that have helped make otters widespread in North America. Iowa’s river otter reintroduction was initiated in 1985 at Red Rock Reservoir. Sixteen otters from Louisiana were released, initiating a pilot project to determine the suitability of Iowa’s aquatic resource for otters. These otters survived normally and subsequent releases were continued until 2003.  In total 345 otter were released in Iowa between 1985 and 2005. This reintroduction coupled with wetland restoration and conservation contributed to the growth and widespread distribution of otters in Iowa.

Here are some facts about Iowa river otters:

• Adult otters weigh approximately 30 pounds.
• Most otters live to be 5 or 6, but we aged one otter at 11 years old.
• Most female otters in Iowa have litters of 5 to 6 pups.
• The annual survival rate averages between 75-85%, with females having a somewhat lower than average survival and males a somewhat higher than average rate.
• Population growth of river otters in Iowa is estimated at 7% increase per year.
• Otters prefer river and stream habitats which provide sufficient food resources such as a diversity of fish species. They are also found around wetlands and lakes.
• Estimates of linear densities of otters in Iowa range between 0.1 upwards to 0.75-1.0 otters per linear mile of shoreline.
• River otters have been sighted in all 99 counties in Iowa.
• In the fall of 2004, bow hunters recorded otter sightings most often in the east-central and northwest portion of the state.
• Between 2002 and 2004 the DNR recovered over 225 carcasses from accidentally trapped and vehicle-killed otters in Iowa.

River Otter release sites in Iowa, 1985 - 2005.

Year	Males	Females	County	Nearest Town	River / Area
1985	8	8	Marion	Runnells	Red Rock Reservoir
1986	10	10	Tama	Chelsea	Otter Creek WMA
1986	10	10	Hamilton	Stratford	Boone River
1986	10	10	Guthrie	Guthrie Center	Springbrook Park
1987	10	10	Clay	Peterson	Little Sioux River
1987	10	10	Lucas	Russell	Rathbun Reservoir
1988	10	10	Bremer	Tripoli	Sweet Marsh WMA
1988	10	10	Linn	Waubeek	Wapsipinicon River
1988	10	10	Montegomery	Morton Mills	Nodaway
1989	5	3	Mitchell	Otranto	Cedar River
1990	7	8	Mitchell	Otranto	Cedar River
1990	13	10	Cerro Gordo	Mason City	Winnebago River
1997	9	8	Linn	Cedar Rapids	Indian Creek
1997	6	6	Polk	Chichaqua	Skunk River
1998	7	5	Black Hawk	Cedar Falls	Cedar River
1998-1999*	5 sex unknown		Story	Ames	Peterson Pits
1998-1999	3 sex unknown		Sac	Reiff Park	Boyer River
1999-2000	5 sex unknown		Sac	Reiff Park	Boyer River
1999-2000	5 sex unknown		Audubon	Audubon	E. Nishnabotna River
1999-2000	3 sex unknown		Monroe	Miami Lake	Miami Lake
1999-2000	2 sex unknown		Wapello	Cedar Creek	Cedar Creek
2000-2001	5 sex unknown		Audubon	Audubon	E. Nishnabotna River
2000-2001	11 sex unknown		Hardin	Steamboat Rock	Iowa River
2001-2002	3 sex unknown		Hardin	Steamboat Rock	Iowa River
2001-2002	2 sex unknown		Clayton	Eldorado	Turkey River
2001-2002	4 sex unknown		Pottawattamie	Oakland	W. Nishnabotna River
2001-2002	2 sex unknown		Marion	Hamilton	North Cedar Creek
2001-2002	2 sex unknown		Cass	Atlantic	E. Nishnabotna River
2001-2002	5 sex unknown		Poweshiek	Brooklyn	English River
2001-2002	14 sex unknown		Worth	Northwood	Shellrock River
2002-2003	2 sex unknown		Pottawattamie	Avoka	W. Nishnabotna River
2002-2003	9 sex unknown		Grundy	Grundy Center	Blackhawk Creek

  *Coincides with the capture of otters to translocate during the succeeding
trapping seasons.   No otters were translocated during the winters of 2003-2005.

Otter sightings have been confirmed in all Iowa counties, and all but 12 Iowa counties have documented otter reproduction.

Wildlife Diversity Program
Iowa Department of Natural Resources
1436 255th St.
Boone, IA 50036-7557
phone: 515 432-2823
fax: 515 432-2835

For more information about the status of Iowa's wildlife populations,
interested persons may want to look into the Wildlife Bureau's
Trends in Iowa Wildlife Populations and Harvest.