Use of non-invasive techniques to determine population size of marine otter Lontra felina in two locations of Peru

Abstract

Marine otters (Lontra felina) are very difficult to observe and census. Currently, there is no reliable information on the population size of marine otters. Between June and August 2012 we collected 258 samples of marine otter feces from 7 localities in Peru. All locations were visited four times. 141 samples (55%) were successfully amplified at five to seven loci. We identified a minimum of 79 individuals across all locations from the genetic data for a density estimate of 4.4 otters per km. CAPWIRE estimates of N were greater than the minimum estimated from the genetic data (11 otters/km) and were almost 2-6X higher than previous estimates based on sightings. There was a strong relationship between the number of fresh scat and the number of detected otters, suggesting scat counts might be used to estimate the number of otters at a site.