Otter research in Asia: Trends, biases and future directions

Basnet, Aarati; Ghimire, Prashant; Timilsina, Yajna Prasad; Bist, Bhuwan Singh

doi:10.1016/j.gecco.2020.e01391

Cited by 15 publications

(13 citation statements)

References 24 publications

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“…Our questionnaire survey of households revealed that local respondents older than 60 years who had sighted Smooth-coated Otters long ago have seen little presence of otters in the study area in the last decade. Similar results was found in the study conducted by Basnet et al (2020), an otter survey along the Budigandaki River and adjoining streams that lie in Bhimsen Rural Municipality and Sahid Lakhan Rural Municipality of Gorkha District.…”

Section: Population Trendsupporting

confidence: 88%

“…Otters spend 3-5 hours a day fishing and hunting for crab, frogs, and insects (Kafle et al 2008). Of 13 species of otters found in the world, three occur in Nepal: 1) The Eurasian Otter Lutra lutra, 2) The Smooth-coated Otter Lutrogale perscipillata, and 3) The Asian Small-clawed Otter Aonyx cinereus, (Acharya & Rajbhandari 2011;Basnet et al 2020). The Eurasian Otter is distributed along mountain streams, rivers, and lakes (Acharya 2006), and according to Shrestha (2003) the Smooth-coated Otter has been recorded from major river basins of Nepal: Koshi, Narayani, Karnali, and Mahakali.…”

Section: Introductionmentioning

confidence: 99%

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Distribution and threats to Smooth-Coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae) in Shuklaphanta National Park, Nepal

Joshi

Poudel

2021

J. Threat. Taxa

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This article aims to assess the distribution, threats and perceptions regarding otters in Shuklaphanta National Park (SNP). It also provides an overview of the conservation efforts of the Nepal government within and outside the protected areas. The study was carried out through preliminary survey of the wetlands using direct sighting techniques, plus indirect evidence including fur, spraints, dead remains, pugmarks, transect survey, key informant survey (n= 15), and questionnaire survey of households (n= 70) in buffer zone. This study found that otter signs were mostly concentrated in the moist soil near the wetlands area. Otter distribution was mostly recorded in Radhapur river, Kalikhich lake, Chaudhar river, Hattinala near hattisar area of pipraiya, Bahuni river, Shikari lake, and Salgaudi lake of Shuklaphanta National Park. Fire and extraction of construction materials from wetlands were identified as severe threats through social survey and key informant survey. For the maintenance of viable population of otters these threats should be minimized through effective biodiversity conservation techniques such as awareness programs and enforcement of laws inside the park. In recent decades, the populations have declined as a consequence of hunting and the overall loss of natural habitats. Overall, our study shows that information on the status, distribution and population trends of Smooth-coated Otters is limited. Therefore, we recommend that more studies should be carried out in this region to establish status, distribution and ecology to improve our understanding of otters in the face of increasing impacts on their habitats. In addition, it is mandatory for the implementation of conservation activities such as awareness to the locals and policy makers, appropriate habitat management and initiating scientific research to ensure a minimum viable population of the species in the country.

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Section: Population Trendsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Distribution and threats to Smooth-Coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae) in Shuklaphanta National Park, Nepal

Joshi

Poudel

2021

J. Threat. Taxa

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“…At present the IUCN Red List of Threatened Species reports that habitat protection has somewhat slowed Asian short-clawed otter population declines, but that sustained conservation efforts are nevertheless essential for the long-term survival of this ‘Vulnerable’ species [ 52 , 56 ]. We therefore suggest that Asian short-clawed otter reintroductions into protected areas with abundant natural prey may be a viable conservation strategy, as long as the reintroduced individuals have been appropriately prepared to overcome the challenges they will face in the wild.…”

Section: Discussionmentioning

confidence: 99%

“…Their highly dextrous short-clawed paws (relative to other otter species) enable them to manipulate and pry open the shells of their prey, while their rear-most upper teeth are larger than their other teeth so they can crunch through the exoskeletons of prey such as crabs [ 38 , 52 , 54 ]. Due to a reduction in their wild prey brought about by overfishing, pollution and habitat loss [ 52 , 55 , 56 ], Asian short-clawed otter populations are decreasing in the wild, and they are classified as ‘Vulnerable’ on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species [ 52 ]. Furthering our understanding of otter foraging behaviour may help inform conservation action in the future [ 57 ].…”

Section: Introductionmentioning

confidence: 99%

Captive Asian short-clawed otters ( Aonyx cinereus ) learn to exploit unfamiliar natural prey

et al. 2022

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Foraging plays a vital role in animal life histories, and learning whether unfamiliar food items are palatable is a key part of this process. Animals that engage in extractive foraging must also learn how to overcome the protective measures of their prey. While otters (subfamily Lutrinae) are a taxon known for their extractive foraging behaviour, how they learn about prey palatability and acquire extractive foraging techniques remains poorly understood. Here we investigated (i) how captive Asian short-clawed otters ( Aonyx cinereus ) learned to interact with, and extract meat from, unfamiliar natural prey and (ii) how their exploitation of such prey compared to their ability to overcome artificial foraging tasks containing familiar food rewards. Network-based diffusion analysis showed that otters learned to interact with unfamiliar natural prey by observing their group mates. However, once interacting with the prey, they learned to extract the meat mainly asocially. In addition, otters took longer to overcome the protective measures of unfamiliar natural prey than those of extractive food puzzles. Asian short-clawed otter populations are declining in the wild. Increasing our understanding of how they learn to overcome novel foraging challenges could help develop pre-release training procedures as part of reintroduction programmes for otter conservation.

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“…South‐East Asia, a global biodiversity hotspot, is home to four species of otters: smooth‐coated otter ( Lutrogale perspicillata ), Asian small‐clawed otter ( Aonyx cinereus ; Figure 1 ), hairy‐nosed otter ( Lutra sumatrana ), and Eurasian otter ( Lutra lutra ; Basnet et al, 2020 ). Among these four species, the smooth‐coated otter and the Asian small‐clawed otter are listed as Vulnerable, the hairy‐nosed otter as Endangered, and the Eurasian otter as Near‐Threatened in the IUCN's Red List assessment (Khoo et al, 2021 ; Roos et al, 2021 ; Sasaki et al, 2021 ; Wright et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Identification of three Asian otter species (Aonyx cinereus, Lutra sumatrana, and Lutrogale perspicillata) using a novel noninvasive PCR‐RFLP analysis

Sharma

Chee‐Yoong

Kannan

et al. 2022

Ecology and Evolution

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Four species of otters occur in tropical Asia, and all face multiple threats to their survival. Studies of distribution and population trends of these otter species in Asia, where they occur sympatrically, are complicated by their elusive nature and difficulties with reliable identification of species in field surveys. In Malaysia, only three species, the smooth‐coated otter, Asian small‐clawed otter, and hairy‐nosed otter have been reliably reported as residents. We designed a replicable and cost‐efficient PCR‐RFLP protocol to identify these three species. Using published reference sequences of mitochondrial regions, we designed and tested three PCR‐RFLP protocols on DNA extracted from reference samples and 33 spraints of wild otters collected along the North Central Selangor Coast of Malaysia. We amplified and sequenced two fragments (450 and 200 bp) of the mt D‐loop region and a 300‐bp fragment of the mt ND4 gene using primer sets TanaD, TanaD‐Mod, and OTR‐ND4, respectively. Amplification products were digested with restriction enzymes to generate species‐specific RFLP profiles. We analyzed the costs of all three protocols and compared these with the costs of sequencing for species identification. Amplification success was highest for the smallest PCR product, with the TanaD‐Mod primer amplifying DNA from all 33 spraints. TanaD and OTR‐ND4 primers amplified DNA from 60.6% and 63.6% spraints, respectively. PCR products of TanaD‐Mod provided the expected species‐specific RFLP profile for 32 (97%) of the spraints. PCR products of OTR‐ND4 provided the expected RFLP profile for all 21 samples that amplified, but TanaD produced spurious bands and inconsistent RFLP profiles. The OTR‐ND4 primer–enzyme protocol was the least expensive (437 USD) for processing 100 samples, followed by TanaD‐Mod (455 USD). We suggest the use of both OTR‐ND4 and TanaD‐Mod protocols that show potential for highly efficient and reliable species identification from noninvasive genetic sampling of three Asian otter species. We expect our novel noninvasive PCR‐RFLP analysis methods to facilitate population monitoring, ecological and behavioral studies on otters in tropical and subtropical Asia.

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Otter research in Asia: Trends, biases and future directions

Cited by 15 publications

References 24 publications

Distribution and threats to Smooth-Coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae) in Shuklaphanta National Park, Nepal

Distribution and threats to Smooth-Coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae) in Shuklaphanta National Park, Nepal

Captive Asian short-clawed otters ( Aonyx cinereus ) learn to exploit unfamiliar natural prey

Identification of three Asian otter species (Aonyx cinereus, Lutra sumatrana, and Lutrogale perspicillata) using a novel noninvasive PCR‐RFLP analysis

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