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\"Describes the habits and nature of river otters at night\"-- Provided by publisher.

While reintroducing extirpated species is an important approach for restoring self-regulating biodiverse ecosystems, previous studies have shown that public support and understanding are indispensable for the success of such projects. In this study, the attitudes of university students toward species that have already been reintroduced in Japan (oriental storks) and those that have not yet been reintroduced (river otters) were compared. A questionnaire survey was conducted in a private university in Japan, and the results (n = 360) revealed that the students more likely supported the reintroduction of oriental storks than that of river otters. A majority did not know the reasons accounting for the extirpation of these species, and a text mining analysis revealed that those who saw the news about reintroduction of oriental stork showed a higher likelihood to support the project. Thus, the participants' attitudes toward species reintroduction were not necessarily affected by their knowledge regarding the concerned species, but by the transient experiences, such as watching news about the project.

Otter video overview for BOLSE. Animals, sea otters, river otters, mammals.

Lutra lutra (Linnaeus, 1758), commonly known as the Eurasian otter, is the most widely distributed of the lutrinids (otters). L. lutra is primarily a piscivorous predator but also preys on amphibians, crustaceans, small mammals, birds, and reptiles. Extant populations of this semiaquatic mustelid occur in a wide variety of aquatic freshwater and marine habitats throughout Asia, all of Europe, and parts of northern Africa. Despite the large distribution, habitat loss has led to dwindling L. lutra populations, particularly in Asia, and the species is currently listed as “Near Threatened” by the International Union for Conservation and Nature and Natural Resources.

River otters (Lontra canadensis) are key predators in North Carolina's aquatic systems, but they are often seen as competitors by anglers and fish hatcheries. River otter diets typically consist of fish and crayfish, but also include occasional herpetofauna, mammals, and birds. While standard diet studies focus on identification of prey through manual examination of stomach contents and feces, metabarcoding DNA analysis has become more popular to determine the presence or frequency of species that are often missed, misidentified, or underestimated. We collected river otter carcasses from licensed trappers and fur dealers across North Carolina from the 2009–10 trapping season through the 2015–16 season. We conducted necropsies and analyzed the stomach contents using standard observational methods and metabarcoding DNA analysis. We manually examined 522 river otter stomachs, of which 377 contained prey items. Decapods (crustaceans) were identified in 41% of stomachs and made up similar percentages within each Furbearer Management Unit (FMU). The order Perciformes composed the majority (62%) of fish prey across all stomach samples. Coastal Plain river otters primarily consumed crustaceans (50%) and fish (40%). Piedmont and Mountain river otters consumed fish (32% and 42%, respectively) most often followed by crustaceans (62% and 50%, respectively). Prey selection was similar between the sexes. Out of 368 samples, metabarcoding DNA examination was able to reliably match 164 prey items to species, 5 classes, 18 orders, 25 families, and 42 genera. Fishes made up 33% of the identifications, particularly Perciformes (13%), Cypriniformes (7%), and Siluriformes (5%). Twelve percent of identifications was made up by Amphibia, split evenly by Anura and Urodela. No birds or reptiles were detected in the Mountain or Piedmont FMUs, and no mammals were detected in the Coastal Plain or Mountain FMU. Overall, river otters in North Carolina consume a large variety of prey that varied regionally. The manual examination provided identifications that were not provided by the DNA examination (i.e., crayfish, brown snakes), while the DNA examination provided a more accurate identification of the broad array of prey items. To understand the composition of annual river otter diets we encourage managers to expand research to evaluate river otter diets year-round and incorporate additional noninvasive methods (e.g., scat surveys) throughout the year.

E. coli was isolated from the Salish Sea (Puget Sound) ecosystem, including samples of marine and fresh water, and wildlife dependent on this environment. E. coli isolates were assessed for phenotypic and genotypic resistance to antibiotics. A total of 305 E. coli isolates was characterized from samples collected from: marine water obtained in four quadrants of the Salish Sea; select locations near beaches; fresh water from streams near marine beaches; and fecal samples from harbor porpoises (Phocoena phocoena), harbor seals (Phoca vitulina), river otters (Lontra canadensis), and English sole (Parophrys vetulus). Isolates were evaluated using antimicrobial susceptibility typing, whole-genome sequencing, fumC, and multilocus sequence typing. Resistance and virulence genes were identified from sequence data. Of the 305 isolates from Salish Sea samples, 20 (6.6%) of the E. coli were intermediate, and 31 (10.2%) were resistant to ≥1 class of antibiotics, with 26.9% of nonsusceptible (resistant and intermediate resistant) E. coli isolates from marine mammals and 70% from river otters. The proportion of nonsusceptible isolates from animals was significantly higher than samples taken from marine water (p < 0.0001). A total of 196 unique STs was identified including 37 extraintestinal pathogenic E. coli (ExPEC)-associated STs [ST10, ST38, ST58, ST69, ST73, ST117, ST131, and ST405]. The study suggests that animals may be potential sentinels for antibiotic-resistant and ExPEC E. coli in the Salish Sea ecosystem.

River otters (Lontra canadensis) are widespread in the United States and are managed for sustainable fur harvest throughout much of their range in the United States. Despite their widespread distribution, river otters can be difficult to monitor due to their cryptic nature and the inaccessible habitats they often occupy. Additionally, there has been little research conducted to quantify winter habitat selection patterns of river otters. We used 4 years of aerial survey data conducted during the winter to quantify habitat selection patterns of river otters inWisconsin, USA, and to determine factors associated with survey efficacy. We used a mixed-effects logistic regression framework to evaluate habitat and anthropogenic factors at 2 spatial scales. We found that river otters were positively associated with the amount of forested and wetland habitat within a 1 km buffer around sampling locations, but that no factors we measured were influential at a local (100 m) scale. River otters were more likely to be detected when ice cover was only partial as opposed to when ice coverage was complete or when it was completely absent. Our results suggested that river otter habitat selection in Wisconsin is not strongly affected by anthropogenic influences but instead by broad-scale habitat configuration. Furthermore, our results suggested that aerial survey approaches for river otters can be optimized by conducting surveys during periods when ice coverage is sufficient to allow for clear tracking substrate without being prevalent enough to limit movements into and out of corresponding aquatic habitats.

The North American river otter Lontra canadensis is a semi‐aquatic furbearer species that historically ranged throughout North America. Starting in the mid‐1800s and continuing through the early 1900s, the negative effects associated with anthropogenic disturbances (i.e. overharvest, development and ultimately habitat alternation) led to local extinctions. Researchers debate whether current land use patterns are affecting river otter occupancy. New Jersey is the most densely populated state in the United States, thus it provides a perfect study area to test potential anthropogenic effects on river otters. Using occupancy modeling to examine river otter habitat preferences, we measured presence/absence at 244 low order streams from January–April 2011–2012 along with 19 corresponding site/landscape covariates in both northern and southern New Jersey. In southern New Jersey, we detected otters at 83/141 sites (58.9%) with a detection probability of 97.7% across repeat visits and a predicted occupancy of 59.4 ± 0.04%. In northern New Jersey we detected otters at 31/103 sites (30.1%) with a detection probability of 44.5% across repeat visits and a predicted occupancy of 58.8 ± 0.04%. We determined the influence of habitat covariates on otter occupancy and found that water depth, water quality, stream width and mink presence were positively correlated with otter occupancy. The % commercial, industrial, transportation and recreational habitat, % low intensity development, bank slope, and distance to lake were negatively correlated with otter occupancy. Knowing the location of occupied stream and latrine sites will assist biologists in their efforts to monitor river otter populations and help estimate river otter density for harvest and conservation efforts.

Research studies that shed light on cognitive and perceptual abilities in otters can utilize tasks that provide environmental, structural, food-based, sensory, or cognitive enrichment. The current study examined the use of the novel object recognition task, a task commonly used to study memory in non-human animals, as a form of sensory enrichment. The subject of the current study was an adult male otter that resided at the Seneca Park Zoo in Rochester, NY, USA. The stimulus pairs for this task were multisensory (3D objects and odorants). In this study, three memory intervals were investigated: 10 min, 1 h, and 24 h (each memory interval included 10 sessions). The otter spent only 15% of his time near the stimulus pairs and engaged in very few explorations, suggesting that this was not an effective form of sensory enrichment and did not provide any evidence for long-term memory. These results contrast strongly with our previous studies with otters using a two-alternative forced-choice task that provided engaging cognitive enrichment. We suggest that cognitive enrichment, including enrichment via training (and food-based enrichment), may be more effective for otters than sensory enrichment. Future research should further investigate cognitive phenomena in otters using tasks involving cognitive enrichment. These types of studies can improve enrichment practices and promote positive welfare for otters in zoos, inform conservation efforts, and grow our limited knowledge of otter perception and cognition.

Monitoring the demographics and genetics of reintroduced populations is critical to evaluating reintroduction success, but species ecology and the landscapes that they inhabit often present challenges for accurate assessments. If suitable habitats are restricted to hierarchical dendritic networks, such as river systems, animal movements are typically constrained and may violate assumptions of methods commonly used to estimate demographic parameters. Using genetic detection data collected via fecal sampling at latrines, we demonstrate applicability of the spatial capture–recapture (SCR) network distance function for estimating the size and density of a recently reintroduced North American river otter (Lontra canadensis) population in the Upper Rio Grande River dendritic network in the southwestern United States, and we also evaluated the genetic outcomes of using a small founder group (n = 33 otters) for reintroduction. Estimated population density was 0.23–0.28 otter/km, or 1 otter/3.57–4.35 km, with weak evidence of density increasing with northerly latitude (β = 0.33). Estimated population size was 83–104 total otters in 359 km of riverine dendritic network, which corresponded to average annual exponential population growth of 1.12–1.15/year since reintroduction. Growth was ≥40% lower than most reintroduced river otter populations and strong evidence of a founder effect existed 8–10 years post‐reintroduction, including 13–21% genetic diversity loss, 84%–87% genetic effective population size decline, and rapid divergence from the source population (FST accumulation = 0.06/generation). Consequently, genetic restoration via translocation of additional otters from other populations may be necessary to mitigate deleterious genetic effects in this small, isolated population. Combined with non‐invasive genetic sampling, the SCR network distance approach is likely widely applicable to demogenetic assessments of both reintroduced and established populations of multiple mustelid species that inhabit aquatic dendritic networks, many of which are regionally or globally imperiled and may warrant reintroduction or augmentation efforts. Monitoring the demographics and genetics of reintroduced populations is critical to evaluating reintroduction success, but species ecology and the landscapes that they inhabit often present challenges for accurate assessments. Using genetic detection data collected via fecal sampling at latrines, we demonstrate applicability of the spatial capture–recapture (SCR) network distance function for estimating the size and density of a recently reintroduced North American river otter (Lontra canadensis) population in the Upper Rio Grande River dendritic network in the southwestern United States, and we also evaluated the genetic outcomes of using a small founder group for reintroduction. Combined with noninvasive genetic sampling, the SCR network distance approach is likely widely applicable to demogenetic assessments of both reintroduced and established populations of multiple mustelid species that inhabit aquatic dendritic networks, many of which are regionally or globally imperiled and may warrant reintroduction or augmentation efforts.