Although the 13 species of otters live globally, most of the species are facing an extinction crisis. The Eurasian otters (Lutra lutra) are widely distributed from the Eurasian continent to North Africa. However, this species is listed as NT (Near Threatened) on the IUCN Red List due to habitat destruction, pollution, and urbanization, making it an international conservation target species. In East Asia, China has reported a decline in the distribution of this species, and Taiwan has the last population inhabiting Kinmen Island. However, there have been signs of population recovery in South Korea since 2010, thanks to the country's public interest and conservation efforts. At last, the extinction of Japanese otters and the situation in the Tsushima Islands will be introduced. Hence, it seems that the habitat situation of Eurasian otters varies greatly depending on the country or region in East Asia, and the global network is essential for more effective conservation activities of this species.

Aquamarine Fukushima started keeping Eurasian otters in 2010 and succeeded in breeding them eight times. The exhibits was renovated in 2015 to recreate natural habitat of wild otters. Novel planting technique was employed for waterweeds and land plants to prevent the otters from damaginge them easily. In order to exhibit otters with fish, tests were conducted to determine which fish species shows a high survival rate. Consequently, we made the new enclosure’s environment as natural as possible for the otters. Furthermore, new breeding and nursing behaviors never seen before in captivity were observed, as described below. 1) In the old enclosure, the dam gave birth in a nest that she usually used. However, in the new enclosure, the dam used several nests prior to parturition and gave birth in a nest that she did not typically use. 2) In the old enclosure, the dam used only one nest during the nursing period. Meanwhile, the dam carried the pups and changed nest frequently in the new enclosure. Nest selections were also affected by the weather. 3) Wild Eurasian otters usually defecate in water during the nursing period. The dam defecated on land and in water in the old enclosure, but in the new enclosure, the mother defecated only in water. These new behaviors were also observed in wild otters in Europe. Therefore, it is probable that these natural behaviors were induced from the availability of multiple options for a nest and the diverse environment of the new enclosure.

Among infectious diseases found in captive penguins in zoos and aquariums in Japan, avian malaria has caused fatalities to the hosts and invited high interests for prevention and treatment. However, the prevalence of the avian Plasmodium, vector mosquito species have been unknown. Investigations on the birds and the mosquitoes in wild are usually restricted by weather, seasons and manpower. On the other hand, zoos and aquariums are an ideal field for epidemiological studies; individual information of captive animals such as age, sex, and health status is well known. Since 2004, we have been provided numerous samples from many zoos and aquariums, to elucidate the prevalence of avian malaria in penguins, and have detected many avian Plasmodium parasites. In addition, we found the same species of avian Plasmodium from mosquitoes as detected from penguins and clarified that these mosquitoes sucked the blood of various wild birds in the facilities including penguins. We also showed that the avian Plasmodium found in those captive penguins were transmitted from wild birds inhabiting around the facilities. We were also able to elucidate the transmission route of canine filarial worms in a zoo. All those results were achieved by taking advantage of zoos and aquariums with the full cooperation from the veterinarians and the keepers involved. We expect more effective and collaborative researches for ex situ conservation for rare species by studying the yearly prevalence, the pathogenicity and the treatment.

Physiology is the scientific study of functions and mechanisms in a living system, and it is necessary to obtain some kind of components of the body for carrying out studies in the field. Consequently, collaboration with aquaria is indispensable to study on giant aquatic animals like dolphins by physiological approaches. I have been carrying out collaborative works with aquaria on many kinds of subjects on dolphin physiology from a mix of basic- and applied-scientific standpoints. Here, my recent works began with (1) a question of whether secretion of thyroid hormones with an effect of metabolic activation is increased as surrounding temperature is decreased, (2) my curiosity about a perspective derived from blood metabolomic data, and (3) a request to find “circulating substances which support diving behaviors” from a big senior scientist, are briefly introduced with unsolved questions.

Infectious disease control is an extremely important issue in zoos and aquariums, where a wide variety of animals are reared. The variety of species kept in these facilities makes infectious disease control even more difficult. In this article, we discuss two topics from the field of bacteriological research: the prevalence of antimicrobial-resistant bacteria, which has become a problem in recent years, and the analysis of microbiota using next-generation sequencing. The first theme, the prevalence of antimicrobial-resistant Escherichia coli, was performed at an avian breeding facility. The results revealed that over 40% of the samples contain E. coli, and 60-70% of them showed resistance against some kind of antimicrobials. Furthermore, multidrug-resistant E. coli and β-lactamase-producing E. coli were detected. Rehabilitation of individuals and return program were performed in this facility; therefore, it requires more attention. The results of this study would probably help to control infectious diseases under captive management. The second theme, microbiota analysis, was performed on captive bottlenose dolphins (Tursiops truncatus) using their bronchoalveolar lavage aspirates. Results showed that the microbiota existed in their alveoli. In addition, we were able to detect many pathogenic bacteria using this method. These methods can be applied to individuals without symptoms and even to fungi that are difficult to culture, significantly contributing to health management as preventive medicine and countermeasures against infectious diseases in breeding.

Behavioral observation studies of captive animals are important not only for elucidating the ecology of animals that are difficult to observe in detail in the wild over a long period of time, but also for ensuring that animals in captivity are kept in a healthy state both physically and mentally. Even in the case of individual maintenance behavior, which is necessary for the maintenance of life and is universal for living organisms, the appropriate behavioral style differs depending on the animal species, individual, and living environment. Therefore, it is necessary to collect data on what behaviors, how long, and how they are expressed in captive environments by using indirect observation methods such as night vision camera equipment that can record and store images of behaviors without influence by the observer. In this paper, we introduce an example of research on sleeping behavior in captive Asian elephants (Elephans maximus)

One of the objectives of zoos and aquariums is "research and study". Recently, zoo staffs seem to regard “research” as a difficult task, perhaps because they have had more opportunities to learn about field research and professional research cases. The essence of "research" is "scientific verbalization" that combines novelty and reliability. If we are aware of this, "research" can be an extension of our daily routine work. For example, when introducing a new breeding hive, the effectiveness of the hive can be objectively evaluated by testing it with multiple pairs and multiple installation environments. Also, when you want to evaluate the effects of lighting on indoor nocturnal animals, you can conduct quantitative behavioral observations while changing only the lighting fixtures, and eliminate the effects of room temperature and spectator effects through statistical analysis. This kind of "scientific verbalization" elevates the daily work into “research results” that can be used to improve personal skills and share them with others. "Research" is a "tool" for fulfilling "objective" such as endanger species conservation and environmental education, and is an essential foundation for zoos and aquariums to fulfill their mission. If research activity such as having a scientific perspective, conducting analytical surveys, and publishing papers become part of our “daily lives,” Japanese zoos and aquariums may be able to compare with the world.

Research activities at zoos are do not necessarily have to be time-consuming and grand, and the trivial findings gained during daily work are often worth reporting. Case reports are easy for clinical veterinarians to write as an extension of their daily work. Writing a case report is not only useful for veterinarians, but also has great merits such as raising awareness of daily medical care. This paper introduces writing examples of case reports and their importance and attractiveness.

Although small toothed whales are sometimes exposed to novel captive environments, the factors that affect their habituation are still unknown. Sex, age, and other individuals are thought to influence their response to novel stimuli. We observed the habituation process of six species, including short-finned pilot whales (Globicephala macrorhynchus), melon-headed whales (Peponocephala electra), Risso’s dolphins (Grampus griseus), common bottlenose dolphins (Tursiops truncatus), rough-toothed dolphins (Steno bredanensis), and striped dolphins (Stenella coeruleoalba) to a novel captive space for 30 days and analyzed the factors affecting their habituation. The evaluated factors were observational days, sex, body length, number of individuals living together, number of feedings per day, and total forced feeding and hydration during the entire observational period. The results showed that all the species become habituated as the days passed. Additionally, the analysis by a cumulative linear model confirmed that the speed of habituation was sex-dependent in some species. The habituation in some species was positively related to the factors excluding observational days and sex, and habituation in the others was negatively related.

Medical training is an essential tool in the husbandry of marine mammals, as it is a method of having the animals maintain the medical positions for examination and treatment voluntarily without retaining. The purpose of the present study is to evaluate the effect of 2653 cases of medical training on pinnipeds medicine and husbandry in Toba Aquarium during 2006-2020. The case number of medical training has increased since 2015, and the largest number of cases were walrus examinations. The percentage of blood sampling and ultrasonography were 71.1% and 26.5%, respectively, and these were the majority of medical training. A high percentage of purposes was found in routine blood tests (48.4%) and reproductive examinations (40.0%). It was determined in this study that the period of embryonic diapause in the South American sea lion was 15 weeks and fetal growth rates of biparietal diameter in the South African fur seal were 0.85 cm/month. The medical training of pinnipeds was useful in reproductive technology, ophthalmology and anesthesia induction. Setting objectives and evaluation of medical training were necessary for advancing pinniped’s veterinary medicine, and clinicopathological data obtained by the medical training should be examined in detail to develop a training method that can contribute to the husbandry program and animal welfare of captive marine mammals.

Against a pandemic of emerged infectious disease, COVID-19, new generation vaccines based on nucleic acids or recombinant viruses, which had not been used as vaccines in humans, have been inoculated and shown to be successful. They are, however, heat-labile and need a cold-chain including deep-freezers for storage and transportation. Vaccinia virus (VAC) vector vaccine (VACV) is a pioneer of new generation of vaccines constructed by using molecular biological technology. VACV, which has contributed to eradication of smallpox, has excellent characteristics of vaccinia virus such as a high heat-stability and long-lasting immunological effects. It is possible to distinguish the immunological responses of vaccination from those of natural infections. We started our developmental researches 35 years ago, using attenuated VAC strains established in Japan. In this article, we first describe the early researches of VACVs; development of two VACVs for Bovine leukemia virus and Rinderpest morbillivirus antigens and their protective immunity in large mammals, sheep and cows. Second, application of VACV is described; Rabies-VACV, which has already been licensed, used in the field in Europe and USA, and resulted in a prominent decrease of rabies. Then, current status of VACV research is described; non-replicating VACVs in mammalian cells have been developed as new-generation and ultimately-safe vaccines. We discuss the possibility of future application of VACV for wildlife.

In this study, we collected ticks from wild boars and vegetation to survey a prevalence of Severe fever with thrombocytopenia syndrome virus (SFTSV) in tick population from Ito campus of Kyushu University (Fukuoka Prefecture, Japan) and its allied region. Ixodid ticks (Acari: Ixodidae) were collected from wild boar and vegetation at Ito campus, and were screened by reverse transcription PCR (RT-PCR) for detection of SFTSV. Five ixodid species were collected and identified in this survey. Haemaphysalis flava Neumann was the dominant species in this area. The RT-PCR results showed that all 152 pools of tick samples, included 12 pooled tick samples from two wild boars tested positive for antibodies to SFTSV, were negative for SFTSV.

We conducted husbandry training of a captive male American beaver (Castor canadensis) and collected blood from its tail vein by behavioral restraint for the first time. We adapted counterconditioning and systematic desensitization for stimulation of the blood collection site, and blood collection was achieved during the 31st session. Incorporating husbandry training made it possible to collect blood without capturing or anesthetizing the animal, and the use of positive reinforcement was considered desirable from the perspective of animal welfare.

Ancylostoma malayanum was collected from the small intestines of a Japanese black bear kept at a zoo in Kyushu, Japan. To date, the only reports of A. malayanum infections in Japan have been from a polar bear at a zoo and a wild brown bear in Hokkaido. This is the first report of an A. malayanum infection in a Japanese black bear. Past fecal examination results revealed hookworm infections in Japanese black bears, Himalayan black bears, brown bears, and American black bears kept at this zoo and bred at the facility, although the hookworm species was unknown. Numerous encapsulated Trichinella larvae were detected in the muscles throughout the entire body of the American black bear. This is also the first report of Trichinella in an American black bear at a zoo in Japan.

Two of six captive capybaras in a zoo had developed diarrhea and were given metronidazole to which they responded and the fecal appearance improved temporarily, however, both subsequently developed severe watery diarrhea and died. A large number of ciliates of the family Ophryoscolecidae, which parasitize the intestinal tract, were found in the fecal samples from three of the four surviving animals. These ciliates could not be detected in the two dead and one surviving capybara with a history of previous metronidazole administration. These results indicated that it might be necessary to consider the influence on the microflora including some key symbiotic ciliates and bacteria for digestion and absorption in the digestive system.

A lion (Panthera leo) with hematuria and anemia and suspected immune-mediated hemolytic anemia (IMHA) was treated with immunosuppressive therapy, but did not respond and died on the 93rd day. Histopathological examination revealed marked renal tubular necrosis, suggesting hemolysis. IMHA has not been reported in lions, and this is a valuable case for further investigation of highly effective immunosuppressive therapy.

A 29-year-old red-crowned crane at the Kanazawa Zoo developed drooping of the right wing. Right humerus revealed a closed fracture of the proximal 1/5th. Therefore, we performed reconstructive surgery using a tie-in technique that involved placement of intramedullary pins concomitant with external fixation. Commercially available epoxy putty was used for external fixation. This putty/fixator device was removed under anesthesia on the 35th day of hospitalization. We observed good ossification at the fracture site. This is the first report that describes the tie-in method using epoxy putty for treatment of humeral fractures in cranes.

A 12-year-old male American beaver (Castor canadensis) died after chronic regurgitation. Gross necropsy examination revealed thickening of the esophageal wall with stenosis. Histopathological examination showed that squamous tumor cells infiltrated all layers from the mucosal surface to the adventitia of the esophagus and were arranged in islands and cords with keratin pearls forming at the center. Based on these findings, we made the diagnosis of esophageal squamous cell carcinoma. This is the first report of esophageal squamous cell carcinoma in an American beaver.