Lutra Maculicollis Research Articles

Stakeholder perceptions of human–predator conflict in the South African fly‐fishing industry

AbstractHuman–wildlife conflict in African aquaculture and fisheries is poorly understood. We investigated this conflict through a questionnaire aimed at owners and managers of fly‐fishing properties in South Africa. While perceptions of losses varied, all respondents reported losses to predators. Resulting mitigation measures, including lethal control, were employed mostly against cormorants (Phalacrocorax spp.) and otters (Aonyx capensis and Hydrictis maculicollis). Given that fly‐fishing properties potentially provide valuable habitat for protected species such as otters, our results highlight a need for improved mitigation measures and exploring alternative options of potentially generating income from tourism associated with the presence of charismatic predators.

The extirpation of medium and large mammal species from the Ehotilé Islands National Park, south-eastern Côte d’Ivoire

Abstract In West Africa, high deforestation rates and poaching have induced dramatic declines of mammal’s populations and local extinctions. Due to their isolation, island species are more vulnerable than mainland species. The premises of that scenario are perceptible in the Ehotilé Islands National Park, south-eastern Côte d’Ivoire, but have not been documented. This study aimed to update the diversity and conservation status of medium and large mammals in that protected area. Several surveys were conducted between 2019 and 2021, using ethno-zoological interviews and individual surveys with local populations, as well as reconnaissance walks and camera trapping to collect data on the presence or absence of mammals. From interviews with local populations and literature review, a list of 27 species of mammals that were potentially present in the park in the past was established. Most “lost” species are large mammals, especially primates that are globally threatened. A total of 11 species were pictorially identified, including two Near threatened species (Aonyx capensis and Hydrictis maculicollis) and one Vulnerable species (Cercopithecus lowei). The study confirms a trend of population decline and the erosion of mammal diversity in the park, hence highlighting the need for urgent conservation actions.

The Determinants of Mesocarnivore Activity Patterns in Highveld Grassland and Riparian Habitats

Despite the diversity of mesocarnivores and the broad geographic ranges of these species, our understanding of their behaviour and ecology at multi-species and community levels is limited. Our study was conducted between April and mid-July 2015 and used data collected over 105 days from 39 camera traps to quantify activity patterns of sympatric mesocarnivores in riparian and grassland habitats of Telperion Nature Reserve, South Africa. A total of 13 mesocarnivore species were detected within this relatively small (∼7350 ha) reserve. Sufficient records (≥10 records) were obtained for rusty-spotted genet (Genetta maculata), black-backed jackal (Canis mesomelas), otter species (African clawless otter, Aonyx capensis, and spotted-necked otter, Hydrictis maculicollis), serval (Leptailurus serval ), slender mongoose (Galerella sanguinea), yellow mongoose (Cynictis penicillata) and marsh mongoose (Atilax paludinosus). Generalized linear models were used to investigate whether species ID, temperature, vegetation characteristics or moon phase best predicted temporal activity. To assess which species had the highest potential for competitive interaction, we also quantified the coefficient of activity overlap. Our results show that species ID and temperature were the best predictors of mesocarnivore activity. Slender and yellow mongooses displayed the highest coefficient of activity overlap (0.90), followed by marsh mongoose and rusty-spotted genet (0.80), and serval and rusty-spotted genet (0.79). These species are likely to have the highest potential for competitive interactions, but preferences for different vegetation characteristics and variations in the estimated relative abundance may point to coexistence through spatial and fine-scale temporal partitioning. The other species exhibited lower coefficients of activity overlap with each other, suggesting they may coexist through temporal partitioning of resources.

The diving behavior of African clawless and spotted-necked otters in freshwater environments

Abstract Understanding the diving behavior of semiaquatic mammals, particularly in relation to estimated aerobic dive limits and diet, is important to understand their adaptability and potential vulnerability to changes in prey type and distribution. The diving behavior of African clawless otters, Aonyx capensis, and spotted-necked otters, Hydrictis maculicollis, is poorly known, and no estimates of their dive performance in relation to targeted prey and calculated dive limits have been reported previously for freshwater environments. We investigated the diving behavior of both these otter species in freshwater environments within South Africa through video recordings of direct observations and subsequent video analyses where dive and recovery durations and dive function were recorded. African clawless otters were found to perform longer dives (mean ± SD = 26.9 ± 12.2 s), compared to spotted-necked otters (8.5 ± 7.6 s). African clawless otters showed substantial variation in dive durations, with the shortest dives sometimes lasting < 5 s, and the longest recorded dive being 70 s. The majority of spotted-necked otter dives lasted < 10 s, with the shortest recorded dive lasting 0.66 s and the longest recorded dive lasting 50.9 s. Spotted-necked otters performed different dive types that were evidently dependent on prey targeted, with dives targeting crabs (16.10 ± 1.91 s) being longer than dives targeting rainbow trout, Oncorhynchus mykiss (5.58 ± 0.17 s). The theoretical dive durations of African clawless otters were exceeded during play dives, while spotted-necked otters sometimes exceeded their theoretical dive durations when performing successful foraging dives. The results of this study suggest that spotted-necked otters can vary behavior in relation to prey and exceed theoretical dive duration during successful foraging dives to maximize the net rate of energy gain. Furthermore, when considering known individual-level dietary specialization and plasticity in these species, it may be predicted that dive behaviors are likely to vary substantially among individuals, and in relation to prey availability and localized habitat conditions.

The diet of spotted-necked otters foraging in trout-stocked waters in Mpumalanga, South Africa

Human-wildlife conflict is likely to increase as urbanisation increases. African clawless otters, Aonyx capensis, and spotted-necked otters, Hydrictis maculicollis, are illegally persecuted for their perceived role in reducing trout in artificially stocked habitats in South Africa. The diet of African clawless otters has been investigated, but little is known about the diet of spotted-necked otters in these habitats. Using stable isotope techniques, we investigated the diet of spotted-necked otters occupying habitats artificially stocked with trout. Stable isotope analyses revealed that the diet of spotted-necked otters included equal proportions of crab and trout followed by frog. Diet was found to vary between, as well as within, individuals suggesting individual dietary plasticity. Temporal variation in foraging areas was evident for some otters. These results suggest that individual animals specialise on trout when available. However, this was not consistent between individuals. The resulting conflict with freshwater fisheries may, therefore, be primarily due to individual animals adapting to diets consisting largely of farmed trout. The extent of spotted-necked otter influence on stocked trout, however, needs further investigation.

Complete mitochondrial genomes of the African clawless (Aonyx capensis) and spotted necked (Hydrictis maculicollis) otter: structure, annotation, and interspecies variation

Otters are flagship species for pristine habitats and their southernmost distribution in Africa includes two species; Aonyx capensis and Hydrictis maculicollis. Here, we present novel full mitochondrial genomes of these otter species. The comparable mitogenomes consist of 36 genes including 13 protein-coding genes, 2 ribosomal RNAs, and 22 tRNAs including a hypervariable region. Only 19 out of the 36 genes showed some level of variation between species with the smallest being trnV (68 bp difference) and the biggest being nad5 (1830 bp difference). Such variations may provide guidance in selecting gene regions during marker development for phylogenetic assessments.

More than range exposure: Global otter vulnerability to climate change

Climate change impact on species is commonly assessed by predicting species' range change, a measure of a species' extrinsic exposure. However, this is only one dimension of species' vulnerability to climate change. Spatial arrangement of suitable habitats (e.g., fragmentation), their degree of protection or human disturbance, as well as species' intrinsic sensitivity, such as climatic tolerances, are often neglected. Here, we consider components of species' intrinsic sensitivity to climate change (climatic niche specialization and marginality) together with components of extrinsic exposure (changes in range extent, fragmentation, coverage of protected areas, and human footprint) to develop an integrated vulnerability index to climate change for world's freshwater otters. As top freshwater predators, otters are among the most vulnerable mammals, with most species being threatened by habitat loss and degradation. All dimensions of climate change exposure were based on present and future predictions of species distributions. Annual mean temperature, mean diurnal temperature range, mean temperature of the wettest quarter, precipitation during the wettest quarter, and precipitation seasonality prove the most important variables for otters. All species are vulnerable to climate change, with global vulnerability index ranging from −0.19 for Lontra longicaudis to −36,9 for Aonyx congicus. However, we found that, for a given species, climate change can have both positive and negative effects on different components of extrinsic exposure, and that measures of species' sensitivity are not necessarily congruent with measures of exposure. For instance, the range of all African species would be negatively affected by climate change, but their different sensitivity offers a more (Hydrictis maculicollis, Aonyx capensis) or less (Aonyx congicus) pessimistic perspective on their ability to cope with climate change. Also, highly sensitive species like the South-American Pteronura brasiliensis, Lontra provocax, and Lutra perspicillata might face no exposure to climate change. For the Asian Lutra sumatrana, climate change would instead lead to an increased, less fragmented, and more protected range extent, but the range extent would also be shifted into areas with higher human disturbances. Our study represents a balanced example of how to develop an index aimed at comparatively evaluating vulnerability to climate change of different species by combining different aspects of sensitivity and exposure, providing additional information on which to base more efficient conservation strategies.

Conflict between spotted-necked otters and fishermen in Hlan River, Benin

The spotted-necked otter (Lutra maculicollis) is believed to be declining across its range and, in Benin, has recently been listed as endangered. In Benin, the spotted-necked otter is largely restricted to the south of the country, where it is threatened by a number of factors, including conflict with fishermen. Understanding the nature and extent of this conflict, and the impact that it has on local fishermen, as well as identifying feasible mitigation strategies, represents a critical challenge for conservation managers.This study documents otter damage experienced by 30 fishermen in the Hlan River, in the Southern Benin wetlands. We performed hierarchical classification analysis using Ward distances to categorize fish species according to the level of otter damage suffered, and used generalized linear models to identify predictors that best explained otter damage. Our results suggest that of the 16 fish species commonly caught by fishermen in the Hlan River, otters favored the most valuable species (but these were also the most abundant in the catch). However, although otter damage was extensive, monthly total income loss attributable to spotted-necked otter damage (including fish loss and damage to equipment) was estimated at only 9% per fishermen (considerably lower than the 30% reported by a preliminary survey of 163 fishermen in the same area). Our model showed that otter damage increased significantly with the number of adult fish captured by fisherman while the cost of otter damage increased with the length of time that the fishing equipment was left unattended. We suggest that otter damage could be reduced if fishing equipment were checked at least twice a day by fishermen, and recommend a maximum interval between checks of 700min (12h). Long-term sustainable management of these conflicts will require an integrated approach taking into account socio-economic, political and environmental dimensions.

Differentiation of two South African otter species (Aonyx capensis and Lutra maculicollis) from spraint based on partial CytB primer sets

Accurate species identification based on visual cues can be challenging due to morphological similarities and the cryptic nature of certain species. Thus a more conclusive method of identification is required, namely DNA barcoding. This is the case regarding two South African otter species, Cape Clawless otter (Aonyx capensis) and the spotted necked otter (Lutra maculicollis). Due to the cryptic nature of these animals faecal samples, known as spraints, are the easiest way of confirming the presence of the animal in an area. In this study, we compared results obtained for universal and partial CytB primer sets on collected spraint and tissue control samples. Universal CytB primers revealed a low percentage of amplified otter species from faecal samples (species specific amplification success of 10.9%) whereas, the partial CytB primer set resulted in successful amplification of 45 out of 55 (82%) samples. We were thus able to positively differentiate between the two otter species using the partial CytB primer set developed in this study. The ability to accurately identify species using partial DNA will be beneficial in understanding numerous aspects of the behaviour and ecological importance of animals in their environment.

Pliocene Carnivora (Mammalia) from the Hadar Formation at Dikika, Lower Awash Valley, Ethiopia

We report here on further study of the Carnivora collected by the Dikika Research Project at Dikika, in the Hadar Formation south of the type locality since 2000. The Canidae and the otter Enhydriodon have been described elsewhere, so we focus here on the other Mustelidae and on the Felidae and Hyaenidae. All Hyaenidae are referred to Crocuta, but differences in size and tooth proportions suggest two species that might belong to distinct lineages. An associated set of upper and lower teeth is made the type of a new species of Lutra that must be close to the divergence of Lutra palaeindica, Lutra lutra, and Hydrictis maculicollis. Sample size is still small, but the Dikika assemblage differs from others of similar age in the abundance of hyenas relative to felids.

Preliminary report on the behavior of spotted‐necked otter (Lutra maculicollis, Lichtenstein, 1835) living in a lentic ecosystem

Little is known of spotted-necked otter behavior, particularly in lentic ecosystems. In 2005, the Association of Zoos and Aquariums (AZA) selected this species for management under the Small Carnivore Taxonomic Regional Collection Plan (SCTAG). In 2012, the AZA Otter group recommended this species for Red SSP status. As a result of the paucity of information on natural behaviors and the requirement of thoroughly understanding a species' behavior to properly manage ex-situ populations this study was initiated. Behavioral data was recorded on Rubondo Island National Park, Tanzania between 2006 and 2009. Data was collected on habitat use as well as general behavior. Additionally, a complete catalogue of observed behaviors was maintained for future ethogram construction. Latrines, where scat is deposited, were predominantly located on projections and scattered in 20 m areas. The majority of latrines were located along forest edge habitats. Females routinely used key core areas for denning and extensive intra- and inter-sex overlapping of ranges was evident. Forest-edge habitat was used for denning; foraging and resting occurred along both forest-edge and emergent wetland shorelines. Behavioral results indicate this species is cathemeral on RINP. Average group size recorded was 1.99 with a range of 1-12. Group composition consisted of singletons or females with young. These basic groups often coalesced into packs which occasionally joined to form temporary larger schools. The results of this study will provide valuable information for the design and implementation of ex-situ spotted-necked otter management in the future.

Enhancing tourist opportunities to view spotted‐necked otters (Lutra maculicollis) at Rubondo Island National Park: can the apriori location of latrines simplify identifying best viewing areas?

AbstractWe observed spotted‐necked otters (Lutra maculicollis) along a 5.17‐km section of shoreline at Rubondo Island National Park, Tanzania, during May 2008 and February, June–August 2009 to determine whether their activity areas were associated with latrine site (places along the shoreline where spotted‐necked otters scent mark by depositing scats and urine) as part of an assessment to determine how tourists or researchers can best view the species. For this assessment, we compared the distance of spotted‐necked otters sightings associated with the shoreline (n = 207) with the distance between an equal number of geographical information system (GIS)‐generated random points to the nearest latrine for each of the respective points. The mean distances for locations of spotted‐necked otter sightings to the nearest latrine differed from the mean distance of random points to latrines [171.9 m (SE = 11.30) and 66.1 m (SE = 8.16), respectively; t = −9.23, df = 412, P < 0.001]. Sightings also were much (2.6 times) closer to latrines that occurred in groups than those that were isolated (single). Establishing viewing sites at or near latrines (particularly those occurring in clusters) would thus seem an effective way to maximize opportunities to see spotted‐necked otters.

Preventive Medicine Success: Thymoma Removal in an African Spot-Necked Otter (Lutra maculicollis)

During a preventive medicine examination on a 13-yr-old intact female African spot-necked otter (Lutra maculicollis), radiographs were obtained and a cranial thoracic mass was noted. Cytology from an ultrasound-guided fine-needle aspirate was suggestive of a thymoma. Surgical removal was performed and this diagnosis was confirmed by histopathology. At a recheck examination 6 mo postsurgery, there was no evidence of recurrence. This case highlights the value of a comprehensive preventive medicine program that resulted in the early detection of a subclinical thymoma and its successful removal.

Spotted-Necked Otter in the Lower Orange River, Northern Cape, South Africa

An out-of-range sighting of a spotted-necked otter, Lutra maculicollis, was recorded on the lower Orange River at Senderling's drift (28°7′S; 16°53′E), in the Ais/Ais Richtersveld Transfrontier Park. Notes are provided on its observed behaviour, which corresponds with that of its known biology. This record is 1200 km downstream from the known distribution. Mammal species inventories need to be more meticulously undertaken so as not to overlook any species, and particularly larger mammals.

Re-evaluation of the species composition of Bashkirovitrema Skrjabin, 1944 (Digenea: Echinostomatidae), with the description of two new species of this genus and the proposal of Kostadinovatrema novaeguiniense n. g., n. sp.

A comparison of specimens previously identified as Bashkirovitrema incrassatum (Diesing, 1850) from the African or cape clawless otter Aonyx capensis, and the speckle-throated or spotted-throated otter Hydrictis maculicollis from the Old World with specimens and descriptions of B. incrassatum from the New World showed that those from Africa (Bashkirovitrema africanum n. sp.) had a more extensive distribution of the vitelline fields than either B. canadense n. sp. from the northern river otter Lontra canadensis and the American mink Neovison vison (North America) and B. incrassatum from the Neotropical river otter Lontra longicaudis (South America). B. africanum n. sp. further differs from B. canadense n. sp. by having a smaller body, shorter forebody, smaller oral sucker, longer cirrus, shorter intertesticular space, shorter post-testicular space and longer eggs. B. canadense n. sp. can be distinguished from B. incrassatum by having a longer body, longer forebody, smaller sucker ratio, smaller testes, greater distance between the ventral sucker and the ovary, shorter cirrus-sac, longer post-testicular space and narrower eggs. B. africanum n. sp. differs from B. incrassatum by having a smaller ventral sucker, larger ovary, shorter cirrus-sac, smaller intertesticular space, larger post-testicular space and longer eggs that are not as wide. Kostadinovatrema n. g., as represented by K. novaeguiniense n. sp., can be separated from species of Bashkirovitrema Skrjabin, 1944 by having a wider body width to length profile, a head collar that is narrower than the forebody and armed with 33 rather than 27 collar spines, an ovary that is further removed anteriorly from the testes, and a dorso-ventrally flattened hindbody that is nearly as broad as the forebody. The new genus differs from Hypoderaeum Dietz, 1909 and Moliniella Hübner, 1939 by having 33 head collar spines.

Distribution and habitat of otters (Aonyx capensis and Lutra maculicollis) in southern Nigeria

We report new data on the distribution and habitat of two otter species, Aonyx capensis and Lutra maculicollis, from southern Nigeria. Although preliminary, our investigations suggest that these two species may use the available habitat differently. Lutra maculicollis appears more linked to freshwater streams and Aonyx capensis is mainly restricted to brackish water streams (with mangrove vegetation along the banks) and, more occasionally, to transitional habitats between freshwater and brackish‐water environments. The possible reasons explaining habitat partitioning are discussed.

Seasonal variations and changes in the diet of southern river otter in different freshwater habitats in Chile

The diet of southern river otter Lutra prouocax Thomas, 1908 was determined from 605 scats collected from four sites in Southern Chile between 1990-1991. Crustacean remains were the most common item found in scats. Crustacean species that were the most common in scats collected from lakes, became less important in the river outlets. Fish remains were all from fish less than 100 mm in length and were found more frequently in scats collected at the river sites than at the lake sites. Differences in the diet between otter's scats collected in lakes and their river outlets may be related to prey availability and vulnerability. Diet was more diverse in river habitats than in the lakes. The diet of southern river otter appears to be closer to that described for Aonyx capensis and Lutra maculicollis in South Africa. The southern river otter is heavily dependent on the abundance of three crustacean species. Differences in the diets observed between lake and their river outlets suggest important differences in habitat conditions. This may have future implications for prioritising habitat protection in the conservation of southern river otter.

Regulation of lipoprotein secretion by the human liver: Importance of intracellular APOB degradation

Climate change impact on species is commonly assessed by predicting species' range change, a measure of a species' extrinsic exposure. However, this is only one dimension of species' vulnerability to climate change. Spatial arrangement of suitable habitats (e.g., fragmentation), their degree of protection or human disturbance, as well as species' intrinsic sensitivity, such as climatic tolerances, are often neglected. Here, we consider components of species' intrinsic sensitivity to climate change (climatic niche specialization and marginality) together with components of extrinsic exposure (changes in range extent, fragmentation, coverage of protected areas, and human footprint) to develop an integrated vulnerability index to climate change for world's freshwater otters. As top freshwater predators, otters are among the most vulnerable mammals, with most species being threatened by habitat loss and degradation. All dimensions of climate change exposure were based on present and future predictions of species distributions. Annual mean temperature, mean diurnal temperature range, mean temperature of the wettest quarter, precipitation during the wettest quarter, and precipitation seasonality prove the most important variables for otters. All species are vulnerable to climate change, with global vulnerability index ranging from −0.19 for Lontra longicaudis to −36,9 for Aonyx congicus. However, we found that, for a given species, climate change can have both positive and negative effects on different components of extrinsic exposure, and that measures of species' sensitivity are not necessarily congruent with measures of exposure. For instance, the range of all African species would be negatively affected by climate change, but their different sensitivity offers a more (Hydrictis maculicollis, Aonyx capensis) or less (Aonyx congicus) pessimistic perspective on their ability to cope with climate change. Also, highly sensitive species like the South-American Pteronura brasiliensis, Lontra provocax, and Lutra perspicillata might face no exposure to climate change. For the Asian Lutra sumatrana, climate change would instead lead to an increased, less fragmented, and more protected range extent, but the range extent would also be shifted into areas with higher human disturbances. Our study represents a balanced example of how to develop an index aimed at comparatively evaluating vulnerability to climate change of different species by combining different aspects of sensitivity and exposure, providing additional information on which to base more efficient conservation strategies.

Trophic overlap between three syntopic semi‐aquatic carnivores: Cape clawless otter, spotted‐necked otter and water mongoose

SummaryDrought conditions in the Eastern Cape Province, South Africa, from 1990 to 1993 caused much of the Bushmans River to dry up, thus forcing Cape clawless otters Aonyx capensis (Schinz), spotted‐necked otters Lutra maculicollis (Lichtenstein) and water mongooses Atilax paludinosus (Cuvier) to coexist in restricted ranges. The diet of the three carnivores was compared by analysing their scats to determine the amount of trophic overlap. Expressed as relative percentage frequency, the three most common prey categories found in Cape clawless otter scats were crab Potamonautes perlatus (Milne Edwards) (51%), insect (19%) and fish Tilapia sparrmanii (Smith) (18%). In spotted‐necked otter scats, fish (47%), crab (38%) and frog (8%) were the most common, while in water mongoose scats, insect (28%), crab (26%) and mammal (15%) were most abundant. Water mongooses and spotted‐necked otters ate similar sizes of crabs, significantly larger than those eaten by the Cape clawless otters. Cape clawless otters ate a wide range of crab sizes, including specimens much larger than those taken by the other two carnivores. Cape clawless otters and water mongooses ate similar size fish, significantly smaller than spotted‐necked otters. The results show that even during enforced cohabitation in a relatively small range during drought conditions, there is separation of diets in these three carnivores.RésuméLes conditions de sécheresse qui ont sévi dans la Province du Cap oriental, en Afrique du Sud, entre 1990 et 1993, ont causé l'assèchement d'une grande partie de la Bushman River, obligeant les loutres à joues blanches, Aonyx capensis (Schinz), les loutres à cou tacheté, Lutra maculicollis (Lichtenstein) et les mangoustes aquatiques, Atilax paludinosus (Cuvier), à coexister dans des aires resteintes. En analysant les déjections, on a comparé le régime alimentaire des trois carnivores pour déterminer le taux de recouvrement trophique. Exprimé en pourcentage de fréquence relatif, les trois catégories de proies les plus communes identifiées dans les dejections des loutres à joues blanches étaient les crabes Potamonautes porlatus (Milne Edwards) (51%), les insectes (19%) et les poissons Tilapia sparrmanii (Smith) (18%). Chez les loutres à cou tacheté, les poissons (47%), les crabes (38%) et les grenouilles (8%) étaient les proies les plus communes tandis que chez les mangoustes aquatiques, on trouvait surtout des insectes (28%), des crabes (26%) et des mammifères (15%). Les mangoustes aquatiques et les loutres à cou tacheté mangeaient des crabes de taille semblable, significativement plus gros que ceux mangés par les loutres à joues blanches. Ces dernières mangeaient des crabes de taille très variable, y compris des spécimens bien plus gros que ceux consommés par les deux autres carnivores. Les loutres à joues blanches et les mangoustes aquatiques mangeaient des poissons de taille comparable, significativement plus petits que ceux mangés par les loutres à cou tacheté. Les résultats montrent que, même pendant une cohabitation forcée, dans un territoire relativement réduit, pendant une sécheresse, ces trois carnivores présentent des régimes alimentaires distincts.

Trophic overlap between three syntopic semi-aquatic carnivores: Cape clawless otter, spotted-necked otter and water mongoose

Trophic overlap between three syntopic semi-aquatic carnivores: Cape clawless otter, spotted-necked otter and water mongoose