Pathological Findings in Eurasian Otters (Lutra lutra) Found Dead between 2015−2020 in Schleswig-Holstein, Germany

In times of massive biodiversity loss and ongoing environmental crises, it is extremely important to ensure long-term conservation efforts of threatened species like Eurasian otters (Lutra lutra). To gain insights into the status of Northern Germany’s otter population, 92 otters found dead in Schleswig-Holstein between 2015−2020 were collected and underwent detailed dissection with the aim to establish a monitoring program for this population. Examinations followed a protocol especially designed for otters, including various biological data assessments and extended sampling. The finding sites showed a clear concentration in the Continental region. Seasonal concentration differed among the years, yet peaks were seen from fall to winter. Overall, more males than females were found, although this differed among the years. The majority of otters that could be aged were between 1–3 years. Placental scars and pregnancy were recorded in only few females. Nutritional status was good in most cases. Infectious diseases found included Vagococcus lutrae, Toxoplasma gondii, and Emmonsia spp. A major cause of death was roadkill. Known sample bias in studies focusing on roadkill was considered in the finding interpretation. Continuation of the population health investigations is mandatory to analyze potential trends and to establish an actual monitoring program for Eurasian otters in Schleswig-Holstein.

Current State of Natural Conditions and Ecosystems in Pamir-Alay

Research relevance in this article given analyzes the current state of the natural conditions of the Pamir-Alai ecosystem in Kyrgyzstan, where live over 2500 plant species, 20 mammal species and 288 bird species. Research objectives: Studying and preserving the general species diversity are the main conservation tasks. Research materials and methods: This article provides analysis of the current state of the natural conditions of the Pamir-Alai within Kyrgyzstan, where over 2500 species of plants, 20 species of mammals, 288 species of birds live. Research results: It is highlighted that the following species included in the Red Book of Kyrgyzstan are present in the Alai fauna: Eurasian otter (Lutra lutra), snow leopard (Uncia uncia), mountain sheep (Ovis ammon), stone marten (Martes foina). Conclusions: Considering the economic, scientific, natural value of flora and fauna, we must find an approach to the conservation, restoration and protection of wildlife.

Evolución de la población de nutria (Lutra lutra; Linnaeus, 1758) y depuración de agua en la Cuenca del Río Segura (España)

La nutria es una especie que sufrió una gran regresión en la cuenca del Segura en la segunda mitad del siglo XX, atravesando un periodo crítico en la década de 1980, sobre todo por la caza y el deterioro de la calidad del agua por el aumento de la población, actividades agrícolas e industriales, en un escenario con déficit de sistemas de depuración. Se analizan los tres muestreos de nutria realizados en 1984-1985, 1994-1995 y 2005-2006 en la Cuenca del Segura, que refleja una ampliación de su área de distribución, sobre todo en el último periodo, con la mejora de la calidad del agua por la progresiva implantación de depuradoras con el plan de saneamiento y depuración de aguas residuales en la Región de Murcia, pasando en treinta años de ser una especie rara a ocupar de forma estable gran parte de la cuenca.

A rare photographic record of Eurasian Otter Lutra lutra with a note on its habitat from the Bhagirathi Basin, western Himalaya, India

The Eurasian Otter Lutra lutra is an elusive, solitary animal that has one of the widest distributions of all palearctic mammals. Once widely distributed in Asia, the Eurasian Otter population is now vulnerable to urbanization, pollution, poaching, and dam construction. Eurasian Otter distribution in the Indian Himalayan rivers is little explored, and information from this high-altitude riverine ecosystem is sparse. This publication reports a rare photographic record of the Eurasian Otter which confirms its presence in the high-altitude temperate forest of the Upper Bhagirathi Basin, western Himalayan region. The otter was recorded during investigations of terrestrial and aquatic fauna in the Bhagirathi Basin (7,586 km2, 500–5,000 m) of Uttarakhand State, India from October 2015 to May 2019. Among aquatic fauna, Brown Trout were found to be abundant in high altitude river stretches, with a catch per unit effort of 1.02 kg h–1. Additionally, 26 families of freshwater macroinvertebrates underscored a rich diet available for the Brown Trout, which in turn is a potential food source for the otters. The riverine ecosystem is undergoing dramatic changes because of the increasing demand for hydropower plants in the Bhagirathi Basin. Although mitigation measures are currently in place for fish, the presence of otters further necessitates the need for targeted management for high-altitude Himalayan rivers. There is an imperative need for intensive otter surveys using methods such as camera traps in riparian habitats along the Bhagirathi River and its tributaries.

Genetic and viability assessment of a reintroduced Eurasian otter Lutra lutra population on the River Ticino, Italy

On the River Ticino in northern Italy, a small number of captive Eurasian otters Lutra lutra, belonging to the European breeding programme for self-sustaining captive populations, were reintroduced in 1997, after the species had been declared locally extinct in the 1980s. We surveyed for otter signs in 2008, 2010, 2016–2017 and 2018, confirming the presence of what is probably a small population. To assess the abundance and viability of the population, we genotyped fresh spraints collected during the last two surveys, using 11 microsatellite markers, and modelled the population trend using Vortex. A minimum of six individuals were identified from 25 faecal samples. The analysis of mitochondrial DNA determined that the reintroduced otters share a transversion that is characteristic of the Asiatic subspecies Lutra lutra barang, confirming the contribution of the Asiatic subspecies to the genetic pool of the captive-bred founder population. Population size was consistent with the release of three pairs of otters and all models implied that the number of founders was too small to ensure the long-term survival of the population. Stochastic factors are therefore likely to threaten the success of this reintroduction.

Contrasting gut microbiota in captive Eurasian otters (Lutra lutra) by age

Understanding the gut microbiota characteristics of endangered species such as the Eurasian otter (Lutra lutra), especially in their early stages of life, could be essential for improving their management and ex situ conservation strategies. Here, we analyzed the gut microbiota diversity, composition, and function of captive Eurasian otters at different ages using high-throughput 16S rRNA gene sequencing. We found that: (1) Clostridiaceae was abundant in all age stages; (2) Lactococcus in cubs is thought to predominate for digesting milk; (3) bacteria associated with amino acid metabolism increase with age, while bacteria associated with carbohydrate metabolism decrease with age, which is likely due to decrease in dietary carbohydrate content (e.g., milk) and increase in dietary protein contents (e.g., fishes) with age; and (4) fish-related bacteria were detected in feces of healthy adults and juveniles. Overall, the gut microbiota of captive Eurasian otters was taxonomically and functionally different by age, which is thought to be attributed to the difference in the diet in their life stages. This study provided baseline information regarding the gut microbiota of Eurasian otters for the first time and contributes to improvement in their management in captivity.