The Feasibility of River Otter Reintroduction in Northern Utah

The purpose of this thesis is to document river otter (Lutra canadensis) distribution and reintroduction potential in northern Utah. Distribution was studied using data from 3 sources: 1) otter sighting records from Utah Division of Wildlife Resources; 2) surveys of Utah furbearer trappers and natural resources personnel; and 3) searches of streams for otter sign. Potential for river otter habitat/reintroduction was evaluated by assessing food, cover, and reintroduction attributes. Streams were ranked using an evaluation system based on data from the otter literature. Forty-six positive otter sightings were made in Utah by trappers, natural resources personnel, and the public, 1964-1988. Only 1.3% of 844.4 km of northern Utah streams had otter sign during winter and summer searches. General characteristics of northern Utah streams such as habitat type and stream gradient are suitable for river otters. However, stream alterations and livestock grazing have negatively impacted potential otter habitat. Ninety-four percent of the studied streams are presently unacceptable for reintroductions. Escape cover is the most limited habitat attribute, but food appears to be available in adequate quantities. We recommend no otter reintroductions be made until riparian zones are rehabilitated and protected. Reestablishment of stream bank vegetation is essential to provide escape cover for reintroduced otters. We also recommend control of pollution inputs and no further construction of reservoirs. Surveys of otter distribution and evaluation of potential reintroduction should be done on the Colorado River drainage in Utah