IUCN/SSC Otter Specialist Group Bulletin
©IUCN/SCC Otter Specialist Group
Volume 41 Issue 5 (December 2024)
Abstracts
Forgotten but not Gone: Rediscovery of Eurasian Otter Lutra lutra in Lantau, Hong Kong
Pages 235 - 240 (Report)
Michael Ka Yiu Hui, Aiko K.Y. Leong, Huarong Zhang, Feng Yang, Ho Yuen Yeung, Yik Fui Philip Lo, And Jian-Huan Yang
Since its rediscovery in the 1980s in Hong Kong, the Eurasian Otter (Lutra lutra) has only been recorded sporadically and mostly confined to the Inner Deep Bay area in northwestern New Territories. Here, we present a spraint record collected from an islet of the Brothers Marine Park in northern Lantau waters in February 2024, which has been subsequently confirmed by molecular analysis. Our discovery represents the first verifiable evidence of otter presence in Lantau waters and largely extends its current known range in Hong Kong, bringing new hope for this locally critically endangered species. This finding highlights the urgent need for a more extensive search of suitable habitats in a broader area in order to assess the current distribution and status of the otters in Lantau and wider Hong Kong.
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Investigating the Dietary Composition of Smooth-Coated Otters (Lutrogale perspicillata) at Vaduvoor Bird Sanctuary in Thiruvarur District, Tamil Nadu, India<
Pages 241 - 248 (Report)
K. Chitrapriya, K. Viswanathan, R. Gowtham, A. Sankari, and M. Moorthi
Smooth-coated otters play a vital role in freshwater ecosystems. The freshwater Otters such as Lutrogale perspicillata are common across Asia. In this communication, we conducted the first study of the smooth-coated otter’s feeding patterns in response to variations in fish supply at the Vaduvoor Bird Sanctuary in Tamil Nadu, India. The bird sanctuary contained eleven fish species, while the otters ate eight different types of prey. The relative proportions of prey categories remained constant. The reserve is home to the Oreochromis mossambicus which formed a maximum 12±0.5% of the otter’s diet. Other species included Catla catla (11±0.4%), Anabas testudineus (7±0.3%), Cyprinus clupeoides (6±0.2%), Rastrelliger Kanaguria (11±0.4), Labeo rohita (6±0.3), and Clarias batrachus (1%). Finally, this study discusses the fish species that otter species primarily eat, as well as their preferences, types, and proposed diet compositions.
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Local Peoples’ Knowledge and Perceptions of, and Conservation Threats to, Eurasian Otters in the Kali Gandaki Watershed in Myagdi District, Nepal
Pages 249 - 261 (Report)
Pravin Giri and Purna Man Shrestha
While there are an increasing number of field surveys reporting on distribution and habitat factors of Eurasian otters (Lutra lutra) in Nepal, there is still a significant lack of research on human interactions with the species. This study documents the socioeconomic status of local people, their perceptions and knowledge about Eurasian otters, and the pervasive threats to otters around the Kali Gandaki watershed area in the Myagdi District. A semi-structured questionnaire survey, using a purposive sampling technique, was conducted in the study area to explore these factors. Seventy residents living in the watershed participated in the survey. Simple descriptive statistics were used to analyze the quantitative data and Fisher’s exact test was employed to evaluate the relationship between categorical variables. Our study findings show that local respondents have a positive attitude toward otters, likely attributed to the absence of commercial fishing activities. Around 62% of respondents reported that they believed otter populations have declined over the past 10 years. The majority of the respondents had little or no knowledge about the ecological value of otters in aquatic ecosystems. Nevertheless, a significant number of participants exhibited heightened enthusiasm and a keen interest in the conservation of otters in their locality. Hydropower dams and flash floods were ranked as the most prominent threats to the species' survival. Stringent enforcement of environmental laws related to riverine ecosystems coupled with community outreach programs are essential for the conservation of otters and their habitats.
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Diet of the Eurasian Otter (Lutra lutra) in Boujagh National Park, Guilan, Iran
Pages 262 - 279 (Article)
Niloofar Sojdeh, Saeid Naderi, Alireza Mirzajani, Shabnam Shadloo
In this study, the diet of the Eurasian otter (Lutra lutra) was investigated in Boujagh National Park for one year. During this investigation, 615 spraints were collected, and the contents of each were identified in the laboratory. To estimate the amount of food items consumption, several statistics, such as percentage of relative frequency of occurrence (RFO%), percentage of frequency of occurrence (PFO%), percentage of relative importance (RI%), and percentage of biomass (Bio%), were calculated. The results showed that fish were the most frequent food item in the species’ diet, and among the fishes, Gobiiformes, Mugiliformes, and Cypriniformes were the most abundant. RFO% were 14%, 12%, and 22% in the warm periods, and 26.94%, 20.23%, and 17.3% in the cold periods, respectively. Such fish species seem valuable because of their size, abundance, and behavioral characteristics. Other taxa, including insects, crustaceans, birds, reptiles, and amphibians were also observed in the otters’ diet. Among them, insects in both warm (RFO=13%) and cold (RFO=6.15%) periods, and reptiles in the warm (RFO=14%) seasons of the year, have had more nutritional importance in Boujagh National Park. The width of the ecological food niche and the diversity of the consumed prey have higher values in the warm seasons. Also, the otter’s food items overlap index indicates a medium value in both warm and cold periods of the year.
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