Thomas L. Serfass

Microsatellite variation in the reintroduced Pennsylvania elk herd

Relocation programs have restored elk (Cervus elaphus) to portions of its vast historical range. We examine the consequences of these relocation programs by assessing variation at 10 microsatellite loci in three elk herds, a source herd (Yellowstone National Park), a large herd reintroduced from Yellowstone (Custer State Park) and a bottlenecked herd reintroduced from both Yellowstone and Custer (the Pennsylvania herd). Observed single locus heterozygosities ranged from 0.000 to 0.739. Multi‐locus heterozygosities ranged from 0.222 to 0.589. Although significant differences were detected among all three herds, the Yellowstone National Park and Custer State Park herds possessed similar levels of variation and heterozygosity, and the genetic distance between these two herds was small. The Pennsylvania herd, on the other hand, experienced a 61.5% decrease in heterozygosity relative to its source herds, possessed no unique and few rare alleles, and the genetic distances between the Pennsylvania herd and its sources were large. Simulations were performed to identify bottleneck scenarios in agreement with levels of variation in the Pennsylvania herd. Our data confirm that the rate of population growth post‐relocation may have important genetic consequences and indicate that theoretical predictions regarding the maintenance of genetic variation during relocation events must be viewed with caution when small numbers of a polygynous species are released.

ASSESSMENT OF GENETIC VARIANCE AMONG SOURCE AND REINTRODUCED FISHER POPULATIONS

Abstract A series of reintroduction programs have reestablished fisher (Martes pennanti) populations to a large part of their former range. Horizontal starch-gel electrophoresis of 20 presumptive gene loci was used from 1996 to 1998 to investigate gene dynamics in 4 remnant fisher populations (sources) and 4 reintroduced fisher populations from the northeastern and Great Lakes regions of the United States. Mean multilocus heterozygosities, mean number of alleles per locus, and percentage polymorphic loci were 0.027–0.090, 1.2–1.6, and 10.0–30.0, respectively, in the 8 populations surveyed. Significant allelic frequency differentiation was detected among the 4 source populations and among the 4 reintroduced populations, but a significant proportion of the genetic variance was partitioned only among the 4 reintroduced populations. Pairwise comparisons between each source and its associated reintroduced population indicated that only older reintroductions have attained significant differentiation of allelic frequency from their sources. Significant heterozygotic deficiencies were detected for statewide populations and regional populations within states, suggesting that breeding biology of the fisher, presumably among females, is creating levels of fine-scale genetic structure within populations.

Genetic Variation among Populations of River Otters in North America: Considerations for Reintroduction Projects

Horizontal starch gel electrophoresis was used to assess variability at 23 presumptive gene loci of 732 river otters obtained from fur-trappers in 18 states and three Canadian provinces. States and provinces providing otters were sorted into eight geographic regions for genetic comparisons. Multilocus heterozygosity and polymorphism ranged from 0.018 to 0.032 and 0.044 to 0.087, respectively. One locus, esterase-2, (EST-2) demonstrated a high level of polymorphism throughout all regions. Malate dehydrogenase-1 (MDH-1) was polymorphic throughout the Mississippi drainage but not elsewhere. Heterozygosity, occurrence of rare alleles, and mean number of alleles per locus were associated positively with estimated population sizes. Average heterozygosity and polymorphism values for otters within regions were lower than overall averages reported for mammals but similar to the range of those observed in other mammalian carnivores. Patterns of gene flow suggested by the distribution of polymorphism at the MDH-1 locus do not concur with the current taxonomic classification of river otters. Levels of genetic variation detected in this investigation present a positive outlook for the maintenance of genetic diversity in river otter populations, if sound management principles are applied for reintroductions.

Visitation Patterns and Behavior of Nearctic River Otters (Lontra canadensis) at Latrines

Abstract Little is known about the visitation patterns of Lontra canadensis (Nearctic river otter) at latrines. We used remote camera and video camera systems manufactured by TrailMaster® to determine when Lontra canadensis (river otters) occupying riverine habitats in Pennsylvania and Maryland visit latrines, what the group composition is during visits, and if either variable changes by season. We documented 173 visits to latrines by river otters. The majority of visits (102) were by single river otters. One hundred fifty of the total visits occurred at night. Most (111) lasted <1 min. The largest peak in visitation to latrines occurred immediately prior to and during the breeding season (February/March).

Survival and Post-release Movements of River Otters Translocated to Western New York

Abstract Survival and post-release movements of individuals translocated for reintroduction purposes have implications for intra-specific interactions, which are essential for reproduction, and, ultimately, for the success of the reintroduction effort. Between 1997–1998, 28 (14M:14F) Lontra canadensis (river otters) were translocated to the Genesee River, NY, to restore extirpated populations. Otters were implanted with transmitters to determine survival, cause of mortality, and post-release movements. Five (3M:2F) otters died during the study: three (2M:1F) mortalities were caused by collisions with vehicles and two (1M:1F) were from unknown causes. Survival rate during the first year was 0.89 (95% CI = 0.78–1.00); annual survival rate was 0.92 (95% CI = 0.79–1.00) and 0.86 (95% CI = 0.70–1.00) for males and females, respectively. Post-release dispersal distance of 22 (11M: 11F) otters ranged from 1.2 to 54.0 km (mean = 12.5 km, 95% CI = 8.5–23.7 km). Dispersal distance of females was greater than that of males by a mean of 8.7 km (95% CI = 0.1–19.2 km). River otters that dispersed >15 km from the release site experienced higher mortality.

Using Fecal Glucocorticoids to Assess Stress Levels in Captive River Otters

Abstract Reintroduction projects often expose animals to a series of acute stressors that may cause chronic stress and lead to the stress response. The stress response results in the release of glucocorticoids that, when excessive, can cause detrimental effects to the animal. Glucocorticoids can be extracted from feces and quantified as an effective method for assessing stress levels. We collected scats from 10 river otters (Lontra canadensis; 3 from MD and 7 from NY, USA) held captive for the Pennsylvania River Otter Reintroduction Project (PRORP). We used these scats to verify the use of the Correlate-EIATM Corticosterone Enzyme Immunoassay Kit (Assay Designs, Inc., Ann Arbor, MI) to evaluate stress levels in otters. We also determined trends in stress levels during the initial 10–12 days otters were in PRORP captivity, and compared glucocorticoid levels for 5 of the New York otters the morning before, the morning of, and the morning after veterinary examinations to determine if associated procedures (e.g., physical and chemical restraint) caused increased stress levels. Glucocorticoid concentrations declined from time 1 to time 2 for the 3 otters from Maryland (an average decline of about 6-fold) and for 5 of 7 otters from New York. Among otters evaluated for stress associated with veterinary examinations, average glucocorticoid concentrations were increased the morning of and the morning after veterinary examinations from the day before the veterinary examinations. We demonstrated that fecal glucocorticoids are an effective method for assessing stress levels in otters and that PRORPs captive management program did not contribute to increasing stress during the 10–12-day evaluation period. Fecal glucocorticoid assays could be used to evaluate stress levels of zoo or permanently captive otters, determine the most effective husbandry techniques for housing otters, and evaluate effects of both management practices and environmental conditions in the wild and in captivity.

Food Habits and Fish Prey Size Selection of a Newly Colonizing Population of River Otters (Lontra canadensis) in Eastern North Dakota

Abstract The food habits of river otters (Lontra canadensis) on three rivers in the Red River of the North drainage of eastern North Dakota were evaluated using an analysis of 569 scats collected between 4 Oct. 2006 and 26 Nov. 2007. Fish and crayfish were the primary prey items, occurring in 83.0% and 51.1% of scats, respectively. Other prey included insects (26.7%), birds (7.9%), amphibians (6.7%), mammals (6.0%) and freshwater mussels (0.2%). Fish of Cyprinidae (carp and minnows) were the most prominent fish in the diet, occurring in 64.7% of scats. Other relatively common fish in the diet included Ictaluridae (catfish, 17.4% frequency of occurrence), Catostomidae (suckers, 13.0%), and Centrarchidae (sunfish, 11.2%). The diet of river otters changed seasonally, including a decline in the frequency of fish in the summer diet, and a corresponding increase in the occurrence of crayfish. Consumed fish ranged from 3.5 to 71.0 cm total length, with a mean of 20.7 cm (se ± 0.5, n  =  658). Fish 10.1–20.0 cm were the most frequently consumed size class (36.5% relative frequency), with the majority of other consumed fish being ≤10.0 cm (24.6%), 20.1–30.0 cm (14.1%), 30.1–40.0 cm (14.0%), or 40.1–50.0 cm (8.2%). The size of consumed fish changed seasonally, with spring having the largest mean prey size.

The Influence of Habitat Quality on the Detection of River Otter (Lontra canadensis) Latrines Near Bridges

Abstract Riparian sign surveys near bridge crossings are commonly used to detect the presence of river otters. However, the efficacy of using such surveys for determining river otter presence has not been evaluated relative to habitat conditions. We conducted surveys to detect latrines (locations where scats are deposited in riparian areas) from reintroduced populations of river otters at 26 bridge-suites in northern Pennsylvania. A bridge-suite consisted of a bridge site, a random site and a selected site (i.e., high quality site based on several habitat variables), <2.5 km upstream or downstream from the bridge. Sites consisted of both shorelines along a 200-m section of stream or river. Site quality was determined by applying a modified Pattern Recognition model (PATREC) previously developed to provide a probabilistic assessment for predicting the occurrence of river otter latrines based on the presence or absence of certain riparian and riverine habitat features. Sites were surveyed in fall 2003 and spring 2004. Latrines were detected at 19 (73.1%) of the 26 bridge-suites. Of these 19 bridge-suites, 17 (65.3%) were positive for latrines in spring, 15 (57.7%) in the fall and 13 (50.0%) in both seasons. Among the 78 survey sites (i.e., 3 sites per bridge-suite), 32 (41.0%) were positive for latrines [21 sites (26.9%) in spring and 22 sites (28.2%) sites in fall]. Repeated measures logistic regression was used to assess the influence of the covariates season (spring or fall), type of site (i.e., site type: bridge, random or selected) and quality of site (site score) on the probability of detecting latrines. Two models were useful in describing the occurrence of a positive site (i.e., a site with ≥1 latrine), and both included site type as a variable. The odds of a selected site being positive ranged from 7.8 to 9.3 times the odds of random or bridge sites being positive. We concluded that monitoring the presence of river otters based on searching for latrines at bridge or random sites was considerably less effective than by using the a priori selection of surveys areas based on riparian habitat features.

CHEMICAL RESTRAINT OF FISHERS (MARTES PENNANTI) WITH KETAMINE AND MEDETOMIDINE–KETAMINE

Abstract We chemically restrained fishers (Martes pennanti) as part of a captive-management protocol designed to facilitate veterinary evaluation and treatment, and conditioning on a high-calorie diet before reintroduction in Pennsylvania. We compared the safety and efficacy of ketamine (KET) and medetomidine–ketamine (MED–KET) by monitoring immobilization intervals (induction time, down time, alert time, and recovery time) and physiologic responses (pulse rate, respiration rate, rectal temperature, blood pressure, oxygen saturation, and mean arterial pressure) during restraint. We administered MED–KET at 0.4 mg MED combined with 20.0 mg KET to males and at 0.2 mg MED combined with 10.0 mg KET to females. The x̄ ± SD dosages were MED 0.07 ± 0.008 mg/kg + KET 3.7 ± 0.5 mg/kg for males and MED 0.07 ± 0.007 mg/kg + KET 3.6 ± 0.3 mg/kg for females. KET alone was administered at 100.0 mg to males and at 50.0 mg to females, resulting in x̄ ± SD dosages of 18.7 ± 1.8 mg/kg for males and 19.2 ± 2.2 mg/kg for females. Mean induction time did not differ between fishers restrained with MED–KET (4.6 min) and KET (4.5 min). However, compared with KET, MED–KET resulted in longer mean down time (36.2 vs. 142.2 min), alert time (40.8 vs. 146.8), and recovery time (81.1 vs. 199.4 min). Fishers that received MED–KET were mildly bradycardic and hypertensive compared with those that received KET. Although KET resulted in increased muscle tension and labored respiration, it would be effective for performing brief, noninvasive procedures for fishers because induction was rapid, recovery was short and calm, anesthesia was not profound, and physiologic response was generally expected on the basis of known drug pharmacology. Medetomidine–ketamine also immobilized fishers effectively, providing rapid induction, physiologic response typical to α2 agonism, calm recovery, and possibly a plane of anesthesia adequate for invasive procedures such as tooth removal or surgery.

Genetic Polymorphisms in Fishers (Martes pennanti)

Abstract Genetic polymorphisms were investigated in fishers (Martes pennanti) using horizontal starch gel electrophoresis of allozymes. During the 1996–1997 fisher trapping season muscle and liver samples were collected from animals in New Hampshire, New York, Wisconsin, and West Virginia, whereas blood samples were collected from New Hampshire and New York animals only. A total of 30 gene loci were resolved from muscle, liver and blood samples. For the entire pooled sample, the mean multilocus heterozygosity (direct count) was 0.047 and the percentages of loci polymorphic (0.95 criterion and 0.99 criterion) were 20.8 and 45.8, respectively.