Otter Conservation Research Articles

New otter conservation network in Central America

New otter conservation network in Central America

Human disturbance and habitat structure drive eurasian otter habitat selection in heavily anthropized river basins

Assessing habitat selection is essential to protecting threatened species but also to understand what factors influence species that, although globally not currently in decline, act as flagships of their ecosystems and remain highly vulnerable to human impacts, such as the Eurasian otter. This paper examines otter habitat selection at the river reach scale in two heavily anthropized river basins. Both river basins encompass a wide spectrum of human pressures and biogeographic units, which offers an excellent opportunity to assess otter responses to anthropogenic activities in different scenarios. Through two modelling approaches (structure-agnostic way and a priori hypothesized habitat factors) we demonstrate that otters currently inhabiting these human-dominated landscapes show a trade-off between a preference for highly productive areas and for well-structured and safe areas. We suggest that habitat simplification and human disturbance, which were of minor relevance to the dramatic decline of otter populations in the 20th century, are emerging as potential threats in the context of worldwide increasing land use intensification. Furthermore, we found that otter habitat requirements were remarkably more stringent for breeding site selection than for occurrence, particularly concerning variables related to human disturbance. The results of this work provide tools for integrating ecological criteria oriented to effective otter conservation into river management in human-dominated landscapes, as well as serving as methodological support for lowland river restorations. Our results suggest that long-term otter conservation in anthropized rivers will depend on ensuring the availability of habitat patches that maintain sufficient structural complexity away from intensely outdoor recreational activities.

Multi-scale habitat influences sprainting and group size of a freshwater-obligate smooth-coated otter (Lutrogale perspicillata) in Tungabhadra Otter Conservation Reserve, India

BackgroundThe impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights into the habitat ecology of smooth-coated otters (Lutrogale perspicillata).MethodsWe sampled 180 stream segments (100–400 m) as spatial replicates of 60 1-km2 sites to record indirect evidence (i.e. spraints and mass latrine sites) and group sizes of smooth-coated otters along the Tungabhadra Otter Conservation Reserve (TOCR) during the dry season. To quantify habitat, we recorded stream characteristics, riparian vegetation, and anthropogenic disturbances at the local scale, and hydro-environmental characteristics and land uses at the landscape scale. Using Markovian-chain detection and occupancy models, we assessed the multi-scale habitat use of otters in their selection of suitable areas for scent-marking based on repeated presence-absence data on spraint/latrine locations along the TOCR. We further used linear regression techniques to explore relationships between the number of individuals in smooth-coated otter group and hydro-environmental characteristics, spraint/latrine encounter rate, anthropogenic pressure, land cover, topography, and vegetation.ResultsAt the local scale, the probability of spraint deposition and group size decreased with anthropogenic disturbance while the probability of spraint detections decreased with grass cover. At the landscape scale, the probability of otter site use for spraint deposition and group sizes increased in southeast flowing streams. Spraint deposition increased with the proportion of sugarcane fields, whereas in contrast, group size decreased with proportion of sugarcane fields.ConclusionsOur findings highlight the first empirical evidence on multi-scale habitat use of a southern Indian population of smooth-coated otters in an inland freshwater ecosystem surrounded by the scrub jungle–agriculture matrix. We suggest that habitat models built from analytical approaches that account for correlated detections can avoid biased predictions when estimating occupancy and detection probability of semi-aquatic or riparian mammal communities with linear distributions. Our findings indicate that human activity can impose constraints on the choice of sites used for spraint deposition and preliminary patterns in otter groups. The study provides some crucial evidence on the need to maintain areas with minimal human interference for sustainability of freshwater reserves.

Co-Occurrence Between Salmon Farming, Alien American Mink (Neogale vison), and Endangered Otters in Patagonia

The southern river otter (Lontra provocax) and the marine otter (Lontra felina) are endangered species that inhabit Chile. In southern Chile, both species cohabit with the American mink (Neogale vison), an invasive exotic species. The Chilean aquaculture industry has grown exponentially since the late 1980s, with salmon farming taking place from central Chile to the Patagonian fjords and channels. This study assessed co-occurrence between otters, mink, and aquaculture in Patagonia by (1) distributing a survey among workers, fisheries personnel, and aquaculture inspectors concerning observations of otters and mink inside or around aquaculture facilities and outcomes; and (2) a geographical assessment of distribution overlap between known otter territory and salmon farming-registered facilities. We recorded the first anecdotal evidence of interaction, described as co-occurrence, among native otters, American mink, and salmon aquaculture in Patagonia, which varied among seasons and seems to be increasing. We also recorded evidence of difficulty in recognition of the three mustelids among respondents. There is a geographically extended interaction between otters and salmon farms in Chile. The evidence of interaction among alien American mink, native endangered otters, and aquaculture is an early alarm for human–wildlife conflict, and further studies are recommended to ensure native otter conservation.

Examining the Biogeographic History and Evolution of Otters in the Americas to Identify Conservation Solutions

Anthropogenic impacts affect nearly every living species. The habitats and ranges of many taxa are now so modified that modern distribution information alone is insufficient to determine what conditions they can persist in. As climate change and other anthropogenic impacts increase, clear information on species’ needs and tolerances simultaneously becomes even more critical for conservation and harder to obtain. Historic records and paleontological data can provide key insights into organisms’ past requirements, resilience, and adaptive capacity, which can be used to identify specific areas of vulnerability and to inform conservation policies and strategies. Here we review the evolutionary history and paleobiogeography of North and South American river otters to investigate how geography and environmental change have driven river otter evolution in the Americas, and shaped the ecology, threats, and conservation status of each of the extant species in these clades. Members of the two extant American otter genera, Lontra and Pteronura, overlap in geographic and ecological niche space, and their shared history provides an opportunity for an evolutionarily-grounded examination of relative rarity, specialization, and level of conservation concern. Integrated paleobiological, historical, and modern ecological data indicates that American otters are less habitat-specific than previously thought. We found that changes in waterway connectivity impacts speciation and population connectivity, and likely plays a role in population health and persistence in times of stress. All American river otters exhibit sensitivity to anthropogenic habitat modifications but can coexist with humans in urbanized environments with proper support. This deeper-time perspective suggests that otter conservation in regard to both habitat alteration and climate change may strongly benefit from supporting riverine ecosystem productivity and connectivity in both wild and urban settings.

Effects of Sand Mining on Riverine Ecosystem and Otter Habitat in Kudli, Tungabhadra River

The Tungabhadra River in Karnataka has a significant amount of sand mining activity. With a growing demand for sand reflecting rapid urbanization and population growth, regulation has proven difficult leading to exploitation with serious environmental implications. Sand mining is a generic term referring to the process of extraction of sand from rivers, streams, lakes, and oceans. Illegal and unregulated sand mining would threaten the biodiversity of the river, and such alarming events were seen in almost all parts of the river Tungabhadra. The Tungabhadra River hosts India’s only otter conservation reserve, to conserve vulnerable species of smooth-coated otter. Furthermore, the TB River has significant habitat for a viable otter population along the entire length of the river. A study was conducted from June 2017 to January 2020 in 10 randomly selected stations with 31 sites. During the survey, we came across many threats to the otters, viz., pollution conflicts with fishermen, habitat deterioration by human activity, and so on. Among these factors, sand mining stands out to be the most disastrous to the survival of otter’s habitat. Among the 31 sampled sites, only 1 site was chosen called Kudli, which is examined, studied, and discussed in this paper.

Newly developed exit options for European otters from fish fykes

AbstractEntrapment and subsequent drowning in fish fykes poses an anthropogenic mortality hazard to Eurasian otters (Lutra lutra). Different concepts on how to solve this problem have been debated in the past. To proactively prevent future fatal interactions and increase acceptance among fishers, this study tested two exit mechanisms for otters to safely escape from fyke nets, while still retaining full trap functionality for inland fisheries. Both exit options, a tearable latex lacing around flexible metal wires (100% success rate, n = 6) and a steel hoop‐spring construction (90%, n = 10) were successfully tested in 16 otter escape trials and 30 additional tests for fish (pike, eel, and common bream) retention (100%). The results indicate that the modifications of the fish traps were effective for otter conservation and commercial fisheries. Thus, both options can be recommended as equally good otter protection measures for fyke‐net fisheries of the tested type and similar sizes. However, these data were yielded under controlled conditions and it is possible that field results could differ. Hence, the presented results should be additionally verified under field conditions.

Sea otters in a California estuary: Detecting temporal and spatial dynamics with volunteer monitoring

AbstractVolunteer monitoring can support conservation of imperiled wildlife, by providing higher resolution data in space and time than those available from professional scientists. However, concerns have been raised that data collected by amateurs are inaccurate or inconsistent and thus do not allow for robust detection of spatial or temporal trends. We evaluated the rigor and value of volunteer monitoring data for one iconic wildlife species, the southern sea otter (Enhydra lutris nereis), in Elkhorn Slough estuary in central California, USA, and explored whether volunteer monitoring could provide added value to complement limited professional surveys. First, we compiled and analyzed sea otter counts taken on daily ecotourist boat trips along the estuary, and then compared temporal patterns to data collected by professional scientists tasked with monitoring this federally listed species. Second, we analyzed data on sea otter abundance, habitat use, and behavior collected by a team of trained volunteers, the Elkhorn Slough Reserve Otter Monitoring Program. Overall, we demonstrated the ability to detect important ecological patterns relevant to sea otter conservation and wetland habitat management using volunteer‐derived datasets. Long‐term trends and inter‐annual variability were similar between professional agency monitoring data and volunteer datasets. Moreover, the much higher frequency of volunteer observations allowed for seasonal and tidal dynamics to be detected that could not be revealed by less frequent professional monitoring. We found higher sea otter abundance in the estuary in spring–summer, indicating seasonality in use of the estuary. We detected differences in habitat use of the estuary between higher and lower tides, and greater frequency of foraging at low tide and in certain areas. Volunteer observations revealed fine‐scale differences in habitat use: eelgrass beds were used much more heavily than adjacent areas only a few meters away. Volunteer data can thus provide critical information about coastal habitat use and behavior that can improve conservation strategies for threatened wildlife species.

Establishing an Evaluation Framework for Endangered Species Conservation Preferences for the Eurasian Otter

Wildlife conservation and management are critical issues that attract substantial attention. To develop a sustainable conservation project for the Kinmen Eurasian otter, the present study established a wildlife conservation framework and constructed a management program suitable for Kinmen Eurasian otter conservation based on the preferences of tourists and residents. The results of this study show that residents and tourists were not satisfied with the current status of Eurasian otter conservation in Kinmen and were willing to pay to change the status quo. Respondents preferred to maintain and artificially construct otter habitats, increase the otter population, limit traffic speed and establish underpasses, Kinmen Eurasian otter products, and educational parks. The findings of the market segmentation analysis divided respondents into two groups, passive conservationists and active conservationists. Both groups preferred protecting the Kinmen Eurasian otter to some extent. Passive conservationists, which included mostly residents and individuals with lower levels of education, lacked awareness of the Kinmen Eurasian otter and preferred to establish Kinmen Eurasian otter products and educational parks. Active conservationists were primarily tourists with higher levels of education who were familiar with the Kinmen Eurasian otter and had previously participated in Kinmen Eurasian otter conservation activities. These tourists preferred all conservation attributes and levels. Both groups of conservationists disliked the decline in the number of Eurasian otters in Kinmen. In addition to understanding respondents’ preferences for conservation strategies, these findings reveal the importance of promoting education about the Kinmen Eurasian otter.

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

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.

Is scat marking a reliable tool for otter census and surveys at the landscape scale?

Biological significance of scat marking by otters has been a controversial subject among scientists. Using multiyear (2014–2017) data of otter spraint counts in South Korea, this study aimed to test whether the observed pattern of spraint presence/absence is driven by detection error and if/how scat counts can be a proxy for otter abundance at the landscape scale. To test the first hypothesis, spraint presence/absence was analyzed through occupancy models, which relied on environmental variables related to otter detectability and presence. Spraint count models were used to test the second hypothesis against resource-related covariates in combination with landscape, anthropogenic, and climate variables through machine learning algorithms (MLAs). The detection probability has specifically decreased in areas characterized by high rainfall and human population densities, whereas the probability has increased near food-rich sites, characterized by high marking frequencies. The temporal trends of spraint count predictions were in line with changes in the diversity of fish communities in 2014–2017 instead of fish biomass, suggesting that the availability of feeding resources is higher where fish communities are more diverse. Because diverse fish communities can attract otters, fish diversity conservation is critical for preserving this mammal's populations. This fine scale four-year monitoring has contributed to the disentanglement of the role of spraint presence/absence and spraint counts in detectability and population trends. This will assist in identifying key resource areas and planning strategies to promote otter conservation and dispersal dynamics.

Health and Mortality Monitoring in Threatened Mammals: A First Post Mortem Study of Otters (Lutra lutra L.) in Italy.

Simple SummaryThe Eurasian otter (Lutra lutra) is a semiaquatic mammal listed as endangered in Italy. We conducted a first post mortem (PM) study of 28 otters, mostly collected between 2009 and 2017, in Italy. Vehicle collision was the most common cause of death and mainly involved young animals. The examined otters appeared to be smaller than individuals from northern Europe, and most of them were in good body condition. However, in some individuals, necropsy exams revealed different signs of disease, such as pleuropneumonia and peritonitis, gastritis, lymphoma, or bacterial infection from conspecific bites. Ticks and endoparasites were rarely detected. Data collected on scene of death helped to identify factors forcing otters to move over the road, suggesting road-kill mitigation measures. Comprehensive, standardized PM investigations through collaborative and coordinated research efforts are essential for otter conservation in Italy.Dead specimens provide valuable data for the conservation of threatened species, allowing investigations of mortality, health conditions, and demographic parameters. The Eurasian otter (Lutra lutra) is a semiaquatic carnivore listed as endangered in Italy. In 2009, we started the first post mortem (PM) study of otters in Italy, through collaborative research between mammal ecologists and veterinary pathologists, using standardized protocols. Twenty-eight otters, mostly collected between 2009 and 2017, were examined. Most otters were males (67%), between 1 and 3 years old (64%), and predominantly in good nutritional condition. Adult males were significantly larger than adult females (p < 0.02), as expected for the species, although both sexes appeared to be smaller than otters examined in Central–northern Europe. The youngest sexually mature female was 3 years old. Road traffic collisions were the major cause of death, especially in young individuals, and mainly occurred in autumn–winter, particularly for females. Investigations of the scene of death contributed to revealing factors forcing otters to travel out of the water and move over the road, suggesting appropriate measures to reduce vehicle collision risk. Other causes of death included blunt chest trauma of uncertain origin, dog and conspecific attacks, or diseases of infectious or non-infectious origin, such as ulcerative gastritis, pleuropneumonia and peritonitis. Other diagnosed diseases included lymphoma. Ecto- and endoparasites were rarely detected, although we report the first documentation of heartworm and Ixodes hexagonus infestation in Italian otters. It is important to continue comprehensive, standardized PM investigations of otters in Italy to define baseline health, biometric and demographic parameters, collect biological samples for comparative analyses, and to reduce road-kill mortality. The present study suggests that the timely collection of carcasses and collaborative and coordinated research efforts are essential for obtaining useful data for the conservation of otters.

Distribution of Smooth-coated Otters Lutrogale perspicillata (Mammalia: Carnivora: Mustelidae): in Ratnagiri, Maharashtra, India

This report describes the distribution of Smooth-coated Otters in Ratnagiri, Maharashtra, and investigates the utility of scat counts for quantifying otter occurrence. The study duration was from February to June 2020. Surveys were conducted along the Jog River in Anjarle and Aade River in Aadekond using camera traps. The results subjected to principal component analysis indicated that the occurrence of Smooth-coated Otters at Anjarle is 76% and at Aadekond 48%. We also mapped the distribution and threats associated with Smooth-coated Otters. This study serves as a baseline for efforts to support long-term otter research and conservation.

Population, distribution and diet composition of Smooth-coated Otter Lutrogale perspicillata Geoffroy, 1826 in Hosur and Dharmapuri Forest Divisions, India

Living in different aquatic ecosystems, otters play a vital role in maintaining aquatic species assemblages, particularly fish communities. Thus their wellbeing indicates the health of wetland ecosystems. Smooth-coated Otter Lutrogale perspicillata, a piscivorous mustelid, is widely distributed across Asia. Its population is declining due to habitat transformation, pollution and hunting. This study aimed to understand the ecological requirements of the species by assessing its distribution and its determinants, population and diet composition along the Cauvery River in Hosur and Dharmapuri Forest Divisions. Through monthly extensive surveys between December 2010 and February 2011, covering 62.5 km of Cauvery from the Karnataka border to Palar River junction, this study identified and mapped a 31 km stretch from Dubguli (Yellolapatti) to Biligundlu (Musulumaduvu) as an otter distribution area. Comparison of ecological parameters including bank type, water depth, river width, human disturbance, vegetation cover and water current with the distribution pattern of otters across 125 blocks revealed that water depth and vegetation cover influenced otter distribution positively, while human disturbance had negative influence (these three variables explained 54% of variation in otter distribution). Based on direct sightings, seven different groups consisting of 36 individuals were estimated as the minimum population. The mean group size was 3.8 ± 0.16 (range: 2–7) individuals. Twenty-one otter spraints were analyzed to determine diet composition, revealing that otters feed on insects, molluscs, crabs, fish, frogs, reptiles and birds. Fish constituted the bulk of otter diets. Conservation measures like reducing anthropogenic pressures (e.g., fishing, cattle pens, tourism), increasing awareness of sustainable fishing to stakeholders, and instituting long-term monitoring programs are suggested for the long-term conservation of otters in the study area.

Site-specific and seasonal variation in habitat use of Eurasian otters ( Lutralutra) in western China: implications for conservation.

As a top predator, the Eurasian otter (Lutra lutra) is an indicator of healthy freshwater ecosystems and a flagship species for conservation. Once widespread in China, the species is now distributed mainly in the upper reaches of the great rivers of western China. However, a lack of knowledge on local otter populations continues to hinder their conservation in China. Here, we conducted a detailed study on habitat use of Eurasian otters in Yushu City and Tangjiahe National Nature Reserve in western China using transect surveys. At both study sites, otters preferred to defecate on large rocks close to or protruding from the river and about 50 cm above the waterline. In Yushu, no spraints were found along the 5 km river bank section in the downtown area, with otters preferring sprainting sites with natural banks, riparian zones, and lower human population density. However, this pattern was not obvious at Tangjiahe, where river transformation and human disturbance are minor. Otter river use intensity was negatively correlated with elevation and human population density in Yushu in both seasons. In Tangjiahe, otter river use intensity was positively correlated with prey mass and flow rate and negatively correlated with human population in spring, but positively correlated with human population and negatively correlated with flow rate in autumn. These results reflect the flexible habitat use strategies of otters at different sites, underlining the necessity to study otters living in different regions and habitat types. We provide suggestions for river modification and call for more site-specific studies to promote otter conservation in China.

Next steps for ecosystem service models: integrating complex interactions and beneficiaries

Accounting for ecosystem services (ES)—the ways in which society and people directly benefit from ecological processes and functions—is crucial for developing sustainable landscape management approaches that consider the interrelationship between people and nature. Previous research has produced models that estimate the provision of potential ES by landscapes to help inform policy and stakeholder decision-making. However, most modelling efforts do not consider the delivery of ES to specific human populations or communities, making it difficult to evaluate any possible human welfare implications from alternative land use planning scenarios. In this paper, we first explore the recent state of science of ES modelling from the perspective of ES provision and delivery to the people that benefit from them. Second, we propose the addition of some essential aspects of complexity using the classic social–ecological system framework, crucial for developing models to inform pragmatic decision-making. Our propositions are illustrated using simplified examples inspired by sea otter conservation in the seascapes of British Columbia. Integrating these concepts in future ES models should serve as a baseline for future management approaches that more adequately capture the important implications of landscape scenarios on human well-being.

Volunteering for otter conservation in Nepal: communicating with local communities

Amongst three species of otters, the Asian Small-clawed Otter has not been recorded since Hodgson (1839). Since 1991, the Eurasian Otter has neither been photographed nor sighted in the country. Recently, the Smooth-coated Otter has been reported only from Bardia National Park and its west. In this chaotic situation, a volunteer project was initiated for otter conservation in Nepal three years ago. 1000 copies of an otter conservation awareness poster were printed in 2017 and a second set of posters in 2019. Posters were distributed to local communities while communicating with the local people along the way and during stays. Thus far, we have conducted awareness activities at selected sites in nine districts and four protected areas. Over three years, we have talked with more than 2000 local people about otters and disseminated more than 1300 posters. At all sites, local communities responded that they had not seen otters for 20 to 30 years or more and for the last 10 years, even in protected areas. However, there are hopes that the last scarce individuals or populations of otters remain at very few sites. Overfishing, river poisoning and pollution, hydropower dams and station construction, and sand and pebble extraction from rivers, are the major causes for depletion of otters in these areas. In the past, trapping by Tibetans for otter pelts and by nomads from the plains of Nepal and India were major causes for population declines. In conclusion, we convey a conservation message that humans must learn to co-exist with otters if the species are to survive.&#x0D;

Assessing the distribution pattern of otters in four rivers of the Indian Himalayan biodiversity hotspot

Abstract The Eurasian otter (Lutra lutra), smooth‐coated otter (Lutrogale perspicillata), and Asian small‐clawed otter (Aonyx cinereus) have all been reported previously from the Indian state of Uttarakhand. However, little information is available about their current distribution in a mountainous region that is subject to increasing human‐induced stressors (such as hydropower plants, pollution, sand and boulder mining, destructive fishing techniques, poaching). Owing to important roles played by these otters in structuring riverine food webs (particularly taking account of their roles as top carnivores), it is critical that they receive suitable protection in the face of projected temperature rise, change in precipitation patterns, and associated river flows in this Himalayan biodiversity hotspot. This study assesses otter distribution in four rivers of Uttarakhand as a basis for informing future conservation actions. Field surveys were conducted (October 2018–January 2019) in reaches of the Kosi, Ramganga, Khoh, and Song rivers, supported by semi‐structured interviews (N = 379) conducted with members of local communities to collect qualitative data on views and perceptions of otter species. In addition, community‐based otter awareness camps were organized for local youths (N = 105), adults (N = 115), and schoolchildren (N = 256 covering 10 schools). Habitat suitability maps were created using remote‐sensing data, survey findings, and a geographic information system to provide information about priority reaches of river to be targeted for future conservation efforts. This study provides critical interdisciplinary baseline information to guide decision‐makers towards developing a targeted, otter‐specific conservation programme for this important Himalayan biodiversity hotspot. The otter conservation education programmes conducted during this study resulted in a proposal to set up a community‐based conservation initiative to monitor and report otter sightings from the area, potentially representing a way forward for achieving simultaneous otter conservation and associated ecosystem benefits for local communities.

Sea Otter Hunting and Conservation in Southern California since the Gold Rush

The sea otter population along the Southern California coast was reduced by maritime hunting in the late nineteenth and early twentieth centuries but not entirely driven to extinction. Based on historical sources and archival newspaper accounts, the authors have devised a conservative estimate of otter hunting activity between 1855 and 1908 and determined where hunting was concentrated. Conservation efforts in the Progressive Era and the 1970s and a translocation program in the late twentieth century have resulted in a limited population resurgence.

Stakeholder preferences and consensus associated with managing an endangered aquatic predator: the Eurasian otter (Lutra lutra)

ABSTRACTUnderstanding public preferences is necessary for managing conservation conflicts. We used a face-to-face survey of 514 Greek residents to investigate preferences for managing damage to fish stocks by the endangered Eurasian otter. Similarities in acceptability and consensus were higher between the general public and recreational fishers, and lower between these groups and commercial fishers. Commercial fishers were proponents of management interventions, whereas the general public and recreational fishers were neutral. Compensation was preferred by all stakeholders, but fencing was favored only by commercial fishers. More invasive approaches were largely rejected, whereas increased factual knowledge about otter biology, taxonomy, and conservation increased the acceptability of noninvasive approaches. These findings could be used for informing the process of managing conflict between otter conservation and fisher interests aiming to achieve the long-term protection of otter populations and mitigating their potential impacts on fisheries and livelihoods.