Insights into marine otter (Lontra felina) distribution along the Peru coastline

The marine otter (Lontra felina) has a patchy distribution associated with rocky coastlines along the Pacific coast of South America. In Peru marine otters are found from La Libertad (8°04′S) to Tacna (18°09′S), however, few studies have assessed its population and conservation status. To assess marine otters' current distribution along the Peru coastline, we conducted visual surveys and collected environmental characteristics such as human presence and habitat type. We surveyed 20 locations from five regions where otter presence was based on signs of detection (spraints, food leftovers, tracks, or direct observations). In addition, data on human presence, habitat type, and geographic location were also collected. Across the 20 locations, 268 sections were scanned, and marine otters were detected in 90% (n = 18) of locations and in 19% (n = 52) of sections. Spraints were the most frequent sign detected while direct observations occurred only in seven locations. Our analysis indicates habitat features play an important role in marine otter presence, with habitats with large rocks providing preferred conditions. Our study provides information on marine otter distribution along the Peru coastline that can assist in the identification of locations for focused conservation initiatives and strategies, which should be coordinated among regions to strengthen their design and implementation.     

The marine otter Lontra felina (): A review of its present status and implications for future conservation

The marine otter Lontra felina is an endangered and little known species living in a fragmented habitat: the coast of Peru and Chile. The smallest marine mammal's presence is unclear in Argentina and southern Tierra del Fuego and the current limits of the distribution are still under discussion. Recent population genetic studies suggest certain levels of gene flow despite a disjunct population. In the 20th century intensive hunting was the major threat to L. felina. This top predator still faces an uncertain future due to the impact of human activities (urbanization, pollution, and intensive fisheries). There is a need of further studies deepening the knowledge on population genetics, population numbers and migration behavior. Environmental education work, law enforcement and monitoring of protected areas are suggested to secure the survival of the species.     

Variation in digestive efficiency of captive North American river otters (Lontra canadensis) on various diets

Energy content, proximate nutrient values, passage rate, and digestive efficiency associated with various diet types and factors affecting these parameters have not been quantified for the North American river otter (Lontra canadensis). We measured energy digestive efficiency (DEff) and intestinal passage rate of three captive river otters on their regular diet (a combination of polar bear diet, cat food, and feline diet) and on test diets consisting of the constituent components of their regular diet. Gross energy, crude protein, crude fat, and crude fiber varied appreciably among diet components. Caloric DEff values were high (cat food and polar bear diet combination: 83.11%; regular diet: 86.62%; feline diet: 90.22%) indicating diets high in fat and protein permit greater energy absorption. Passage rates ranged from 167–188 minutes and were influenced by level of activity such that passage rate was more rapid at higher levels of activity. Coefficients of variation (CV) from DEff (CV=1.51) and digesta passage rates (CV=7.35) were dissimilar, indicating that a direct measure may yield a more precise estimate of absorption over digesta passage rates. To further understand energy handling by river otters on diets used in zoologic institutions and to better provide the nutrient dense diets this active species requires, additional studies quantifying energetic parameters for captive otters of various genders, ages, and reproductive conditions on other diet types are needed. Zoo Biol 0: 1–10, 2007. © 2006 Wiley‐Liss, Inc.     

Cryptosporidium and Giardia in marine-foraging river otters (Lontra canadensis) from the Puget Sound Georgia Basin ecosystem

Species of Cryptosporidium and Giardia can infect humans and wildlife and have the potential to be transmitted between these 2 groups; yet, very little is known about these protozoans in marine wildlife. Feces of river otters (Lontra canadensis), a common marine wildlife species in the Puget Sound Georgia Basin, were examined for species of Cryptosporidium and Giardia to determine their role in the epidemiology of these pathogens. Using ZnSO4 flotation and immunomagnetic separation, followed by direct immunofluorescent antibody detection (IMS/DFA), we identified Cryptosporidium sp. oocysts in 9 fecal samples from 6 locations and Giardia sp. cysts in 11 fecal samples from 7 locations. The putative risk factors of proximate human population and degree of anthropogenic shoreline modification were not associated with the detection of Cryptosporidium or Giardia spp. in river otter feces. Amplification of DNA from the IMS/DFA slide scrapings was successful for 1 sample containing > 500 Cryptosporidium sp. oocysts. Sequences from the Cryptosporidium 18S rRNA and the COWP loci were most similar to the ferret Cryptosporidium sp. genotype. River otters could serve as reservoirs for Cryptosporidium and Giardia species in marine ecosystems. More work is needed to better understand the zoonotic potential of the genotypes they carry as well as their implications for river otter health.     

Development of polymorphic microsatellite loci for North American river otters (Lontra canadensis) and amplification in related Mustelids

In order to complement ecological research on native and reintroduced populations of the North American river otter (Lontra canadensis), we developed 10 polymorphic microsatellite loci that would permit us to evaluate population genetic structure and conduct fecal DNA analyses. The number of alleles per locus ranged from 3 to 14 and observed heterozygosity ranged from 0.23 to 0.68. Preliminary screening revealed that primers were polymorphic in a subset of other Mustelids.     

Ten new polymorphic microsatellite loci for North American river otters (Lontra canadensis) and their utility in related mustelids

We describe 10 novel North American river otter (Lontra canadensis) polymorphic microsatellite loci. Individuals from two river drainages in New York were sampled, and the number of alleles per locus ranged from two to 12 (Drainage 1) and two to 10 (Drainage 2). Observed heterozygosities ranged from 0.21 to 0.83 (Drainage 1) and 0.20 to 0.80 (Drainage 2). Preliminary screening revealed that loci amplified in five other mustelids [Martes pennanti (n = 6), Martes fiona (n = 8), Mustela frenata (n = 8), Mustela erminea (n = 8) and Mustela vison (n = 5)].     

Spacing and foraging of otters (Lutra lutra) in a marine habitat

The distribution of otter dens (holts) and otter droppings (spraints) which also function as scent markers, is described for an area of coast in north-west Scotland, and some observations are presented of the otters' movements and foraging. Otter holts were spaced out at an average distance of 11 km, and spraints were concentrated around the holts. The foraging areas were probably used communally, and the difference between this utilization and that observed elsewhere is discussed.     

Field implantation of intraperitoneal radiotransmitters in Eastern Wolf (Canis lycaon ) pups using inhalation anesthesia with sevoflurane

In a study of wolf pup survival, intraperitoneal radio transmitters were surgically implanted in 53 (27 male and 26 female) 3.5- to 8-wk-old Eastern wolf (Canis lycaon) pups at den sites in Algonquin Provincial Park, Ontario, Canada, over two whelping seasons (2004 and 2005). Pups were manually removed from dens and initially injected with butorphanol at a dosage of 0.1 mg/kg for sedation and intra-operative analgesia. Anesthesia was induced and maintained with 3% sevoflurane in oxygen via a face mask. Meloxicam (0.3 mg/kg intramuscularly) was given to provide additional analgesia. All surgeries were completed without complications, and pups were readily accepted back into the packs. No postoperative complications were identified, but two pups from a single litter drowned as a result of being moved by the pack to a flooded den following the surgery. In five pups necropsied following natural deaths, transmitters were found lying free within the peritoneal cavity, and there was no evidence of infection at the surgical site or peritonitis. Inhalation anesthesia provided extremely rapid induction (1 min) and recovery (<3 min) and was completely controllable with no residual anesthetic effects. The equipment for inhalation anesthesia was readily portable in field packs, and it has considerable advantages over injectable drugs for small and very young animals such as wolf pups. The utility of the procedure is demonstrated by the minimal effect it had on subsequent pup survival, the rapid recovery of pups following surgery, and the lack of long-term complications as determined by necropsies of pups following natural deaths.     

TECHNICAL ADVANCES: Effects of genotyping protocols on success and errors in identifying individual river otters (Lontra canadensis) from their faeces

In noninvasive genetic sampling, when genotyping error rates are high and recapture rates are low, misidentification of individuals can lead to overestimation of population size. Thus, estimating genotyping errors is imperative. Nonetheless, conducting multiple polymerase chain reactions (PCRs) at multiple loci is time-consuming and costly. To address the controversy regarding the minimum number of PCRs required for obtaining a consensus genotype, we compared consumer-style the performance of two genotyping protocols (multiple-tubes and 'comparative method') in respect to genotyping success and error rates. Our results from 48 faecal samples of river otters (Lontra canadensis) collected in Wyoming in 2003, and from blood samples of five captive river otters amplified with four different primers, suggest that use of the comparative genotyping protocol can minimize the number of PCRs per locus. For all but five samples at one locus, the same consensus genotypes were reached with fewer PCRs and with reduced error rates with this protocol compared to the multiple-tubes method. This finding is reassuring because genotyping errors can occur at relatively high rates even in tissues such as blood and hair. In addition, we found that loci that amplify readily and yield consensus genotypes, may still exhibit high error rates (7-32%) and that amplification with different primers resulted in different types and rates of error. Thus, assigning a genotype based on a single PCR for several loci could result in misidentification of individuals. We recommend that programs designed to statistically assign consensus genotypes should be modified to allow the different treatment of heterozygotes and homozygotes intrinsic to the comparative method.     

Population variability in the genusTrichocereus (Cactaceae) in central Chile

Trichocereus has 4 species in central Chile. Population analyses indicate that introgressive hybridization has occurred betweenT. chilensis andT. litoralis in the Valparaíso and Santiago coast ranges. A taxonomic key is presented.     

Ecological effects of harvesting Lessonia (Laminariales,Phaeophyta) in central Chile

Lessonia nigrescens and L. trabeculata are economically important canopy-forming kelps in Chile. Experimental harvesting of stipes above the first dichotomy reduces stipe movement and inter-stipe friction, allowing the development of a heavy epiphytic load and increased grazing. Complete stipe removal leads to holdfast death as neither species is able to simultaneously regenerate all stipes. The invertebrate fauna inside the holdfast does not respond to upper canopy changes, but mortality does occur in partial or complete plant removals. Kelp removal also affects inter-plant distances, results in increased access of grazers to the outside and inside of kelp holdfasts, reduces recruitment of other algal species, and modifies the morphology of L. trabeculata such that the plants become more susceptible to removal by water movement.     

Corynosoma strumosum (Acanthocephala) infection in marine foraging mink (Neogale vison) and river otter (Lontra canadensis) and associated peritonitis in a juvenile mink

Corynosoma strumosum (Acanthocephala), a widespread parasite of pinnipeds, is reported in marine foraging North American mink (Neogale vison) and river otter (Lontra canadensis) on Vancouver Island, British Columbia. This is the first confirmed case of infection by C. strumosum in river otters on the west coast of North America and may be the first confirmed case of infection in wild North American mink; C. strumosum has previously been reported in river otters in Europe (Lutra lutra) and in farmed mink fed with marine fish. We also detected a case of acanthocephalan associated peritonitis in a juvenile mink. Furthermore, though infections with Corynosoma spp. are often assumed to be accidental in mustelids, some C. strumosum individuals found in mink showed signs of reproductive activity. These findings indicate that mink may be a competent definitive host and represent a reservoir in coastal habitats although further research is needed to confirm this. Investigating whether river otters may be competent hosts and determine the prevalence of infection in coastal populations would determine the potential implications of C. strumosum for coastal otters and minks. Our report indicates that mink and possibly river otter living in coastal areas are vulnerable to this previously unreported parasitic infection with mortality risk, at least in juvenile individuals.     

Diet of otters (Lutra lutra) in closely associated freshwater, brackish and marine habitats in south-west Portugal

The diet of otters was studied in closely associated freshwater, brackish and marine habitats, from spraints collected on the Portuguese south-west coast over an 18-month period. In areas where marine prey was the only available resource, diet was dominated by blennies, wrasses and gobies, but other prey was taken in areas near coastal lagoons, marshes and estuaries. Eels and amphibians were considered the typical prey of freshwater habitats, and grey mullet the typical prey of brackish water habitats. If the inland habitats near the coast were large enough, otters preferred to forage there rather than in the sea. In one area where otters alternatively used marine and inland habitats, the former were used most extensively in autumn and winter, and the latter in spring and summer. It is suggested that otters prefer to forage inland rather than in the sea.     

Two new species of Ascarophis (Nematoda: Cystidicolidae) in marine fishes from Chile

In this study, we describe 2 new species of Ascarophis van Beneden, 1871 (Nematoda: Cystidicolidae), found in fishes from southern Chile. Ascarophis carvajali n. sp. was found in Austrolycus depressiceps and Patagonotothen cornucola, whereas Ascarophis draconi n. sp. was taken from Champsocephalus gunnari. These new Ascarophis species differ from other species in a combination of several morphometric and morphological characteristics. Although A. carvajali n. sp. was morphologically close to Ascarophis minuta, the new species has a larger ratio between glandular and muscular esophagus, filaments on both egg poles, and a shorter right spicule than A. minuta. Ascarophis draconi n. sp. was morphologically similar to Ascarophis adioryx and Ascarophisfiliformis. However, A. adioryx has eggs without filaments, a smaller ratio between glandular and muscular esophagus length, and a smaller ratio between left and right spicule lengths in contrast to A. draconi n. sp., whereas A. filiformis has a shorter glandular esophagus and left spicule length than A. draconi n. sp. Only 1 Ascarophis species has been recorded in a single fish from Chile (i.e., Ascarophis sebastodis in Sebastes capensis). Consequently, this study constitutes not only new species and records of Ascarophis in fishes from Chile, but also new records for the Pacific coast of South America.     

The influence of wave exposure on the foraging activity of marine otter, <Emphasis Type="Italic">Lontra felina</Emphasis> (Molina, 1782) (Carnivora: Mustelidae) in northern Chile

The marine otter Lontra felina has been said to prefer wave-exposed habitats over more protected sites in response to a greater prey abundance in exposed habitat. We examined how the foraging activity of L. felina is affected by the regime of wave exposure and prey availability at Isla Choros, northern Chile. Through focal sampling we recorded time spent by otters in foraging, the duration of dives, and the hunting success on a wave-exposed and a wave-protected site on the island. In addition, we quantified the abundance of prey in both habitats. Marine otters spent more time foraging in the wave-protected site compared with the wave-exposed habitat. Successful dives reached 26.9% in the wave-exposed habitats, and 38.2% in the wave-protected habitat. Foraging dives were 18% shorter in wave-exposed as compared with wave-protected habitat. Numerically, available prey did not differ significantly with habitat. Our results are more consistent with the hypothesis that wave-exposed habitats represent a sub-optimal habitat to foraging marine otters. Marine otters’ use of wave-exposed patches through northern and central Chile coastal areas probably reflects a low availability of suitable protected areas and greater human disturbance of more protected habitat.     

Grooming and resting of otters Lutra lutra in a marine habitat

The weight gain in lactating harbour seal pups and sex-specific growth curves are described. The relationship between body length, body weight and age were derived by regression analysis based on length and age data from 365 seals, and weight values from 136 seals. The asymptotic values of the curves describing body length were 148.0 cm and 147.2 cm in females and 153.9 cm and 155.5 cm in males using Gompertz and von Bertalanffy, respectively. The corresponding body weight values were 72.8 kg and 76.7 kg in females and 90.7 kg and 88.4 kg in males.     

Predicting reproduction in captive sea otters (Enhydra lutris)

The sea otter (Enhydra lutris) is a threatened species. It is also a popular exhibit animal in many zoos and aquariums worldwide. Unfortunately, sea otters reproduce successfully in only a small number of facilities. Pregnancies vary in duration, and are thought to involve a delayed implantation of about 2–3 months, followed by an implanted phase of 4–5 months. In this study we attempted to identify estrus and pregnancy states, and predict the date of birth in one female sea otter (Mali) housed at the Lisbon Oceanarium. We used different techniques to evaluate her reproductive status, including monitoring behavior to determine estrus, assessing weight changes to determine pregnancy and parturition date, and analyzing fecal hormone samples to determine estrus, pregnancy, and parturition date. During this study, Mali became pregnant four times. Her gestational length varied between 188–255 days. Weight increases >29 kg or 15% above baseline weight suggested pregnancy, and parturition was estimated to occur approximately 3 months thereafter. Fecal hormone (progestagens and estrogen) metabolite data gathered during two of her pregnancies showed that Mali's delayed implantation phase of pregnancy lasted 43–109 days (a typical duration in other sea otters is 100–110 days). Mali's implanted phase lasted a relatively long time (140–145 days compared to an average of 117 days in other sea otters). The combination of the three measurements was a powerful tool that enabled us to determine pregnancy and anticipate the arrival of a new sea otter pup. Zoo Biol 24:73–81, 2005. © 2005 Wiley‐Liss, Inc.     

A new species of Pomphorhynchus (Acanthocephala: Palaeacanthocephala) in freshwater fishes from central Chile

This study describes a new species of Pomphorhynchus collected from Percilia gillissi Girard, 1855 from the Za?artu canal, between the sister basins of the Itata and Laja rivers, in central Chile. Pomphorhynchus moyanoi n. sp. is characterized by an asymmetrical, well-differentiated subspherical bulb and 12-14 longitudinal rows of 13-14 hooks; the third and the fourth hook in each row are stout. Among South American species, P. moyanoi n. sp. shows some similarities to the Chilean species P. yamagutii Schmidt & Hugghins, 1973, but it differs in having a longer neck, larger bulb, and different proboscis armature arrangement. Pomphorhynchus moyanoi n. sp. differs from P. patagonicus Ortubay, Ubeda, Semenas & Kennedy 1991, in the bulb shape (protuberances), number of rows, fourth hook size and basal hook size. Pomphorhynchus moyanoi n. sp. also differs from P. sphaericus in the arrangement of hooks (number of rows and hooks per row), length and width of the proboscis, neck width, and symmetry of the bulb.     

The spatial organization of otters (Lutra lutra) in Shetland

The dispersion of otters Lutra lutra was studied along the coasts of an area of Shetland. The population was relatively stable, with about one adult otter per kilometre of coast. They fished diurnally in a strip of water usually within 100 m of the shore. Females lived in exclusive group ranges, occupied by up to four females, with well-defined boundaries which were respected by successive occupants. For two groups, where relatively complete information was available, range size was 4.7 and 6.4 km, occupied by two and four females, respectively; a third range was about 14 km, with possibly 4–5 females. Within the group ranges individual females moved on their own or with their cubs. Each had a core area, where they were observed > 50% of the time; these core areas were separate from each other, although each individual used the entire group range. Several or all females in each range bred in any one summer. Male ranges were larger than those of females, and overlapped with two or more female group ranges; there were several resident males along each section of coast, but the information on males was incomplete. The habitats of the sexes were different; males spent more time on exposed coasts than did females. There were frequent visits to all coasts from non-resident otters of both sexes.
Behavioural interactions related to territoriality are described; otters showed little overt aggression, except between adult males, but there was some individual avoidance. It is argued that the survival value of this spatial organization can be understood in terms of resource dispersion, but several types of resources have to be considered (including prey and fresh water), and detailed predictions of spatial organization from resource dispersion are unwarranted.