The present paper overviews the organochlorine contamination in marine mammals with ecotoxicological concern. From a geographical point of view, the organochlorine contamination is still spreading on a global terms, and tropical zones represent a major emission source of these toxic pollutants. In this context, oceans play a role as a final sink for persistent organochlorines and thus marine mammals seem to be housing a garbage of toxic contaminants. Due to the specific physiological functions such as the presence of large lipid pool(blubber)for accumulating organochlorines, lactational transfer of these contaminants in large quantities over generations and small capacity to degrade them, marine mammals can amplify much greater amounts of toxic organochlorines in the body through food chain. Therefore, long-term accumulation and chronic toxic effects are of great concern in marine mammals. Additionally, it is unlikely to decline the residue levels of toxic organochlorines in marine mammals in near future, suggesting that the adverse effect of these contaminants are steadily being extended to these animals.

View full abstract

About 40 species of marine mammals have been reported from the seas around Japan. In order to obtain good understanding of these animals we have to make thorough examinations whenever they are available. There are more than 100 reports of marine mammal strandings that provide good opportunities to make investigations. Strandings, whether they are dead or alive, are fruitful sources of data and we have to be well prepared for the possible chances. Involvement of the veterinarians in stranding events are highly desirable for medical care of the live ones and pathological examinations of the dead ones.

View full abstract

Marine mammals in the world include 79 species of cetaceans, 34 speceis of pinnipeds, four species of sirenians, polar bear and sea otter. Of those, we can find 36 species of cetaceans, seven species of pinnipeds, dugong and sea otter in adjacent waters of Japan. The most dominant species are minke whale in baleen whales, finless porpoise and pacific white-sided dolphin in toothed whales. Recent sighting records of sea otter and dugong in coastal water are increasing. Present relationship between human and marine mammals can be divided into following five categories:1)stranding of marine mammals, 2)fishery activity which includes whaling, hunting and incidental take by fishing gear, 3)aquarium, 4)whale and dolphin watching, 5)field research and survey. In the view of wildlife medicine, the subjects we should pursuit are such as rescue of live stranded animals(which relates to 1 and 3 of those categories), management of wild marine mammal resource(2 and 5)and biological study of marine mammals(3, 4 and 5).

View full abstract

Significance of parasitology on marine mammal studies was summarized based on several aspects, i.e.faunal studies on parasites, utility of parasites as biological indicators and the pathobiology of parasitic diseases. Faunal studies on parasites are of an essential of marine mammal parasitology. Comparing the data with those from the different waters, not only distribution and host range of parasites will be understood, but also a useful biological indicator may possibly be found out. Many works have been accumulated from the world seas to date, however faunal studies have not yet been completed, especially in the waters around Japan. Extensive standing surveys will be needed to list parasites of marine mammals of Japan. Parasites have been used as biological indictors to mainly analyze stock structure, in several aquatic organisms including marine mammals. The life cycles of parasites are restricted by the biological characteristics of the hosts, which are often exhibited by parasites. However, the information on the life cycles of marine parasites is quite limited. The role of parasites as pathogens in the natural mortality and stranding of marine mammals is an unavoidable discussion. Many pathological changes derived from the parasite infestations have been reported and several parasites were pointed to be fatal pathogens. Digeneans of the genus Nasitrema, reside in the cranial sinus of small cetaceans, are of the examples that are thought to cause of death and stranding.

View full abstract

There have been few reports on the survey of pathological findings of cetaceans stranded on the coast of Japan. This is partly because of lack of the procedures and/or network of systemic sampling of fresh tissues for the pathological study of stranded marine mammals. In contrast, there is a number of reports on the cause of illness and death in wild, free-living cetaceans examined in other countries;the commonest cause of death was parasitic and bacterial pneumonia except for entanglement in fishing gear. Underlying mechanisms of catching these diseases common to terrestrial mammals are yet to be elucidated. Anthracosis, lung and hilar lymph nodes polluted by suspended particulate matter in the air, has been recently found in some cetaceans stranded on the coast of Japan. In addition to the data from the chemical analysis of tissues, scientific data obtained from pathological study of stranded marine mammals would be also one of the useful base for the assessment of global environment.

View full abstract

In piscivorous bats, Noctilio leporinus, the distribution and relative frequency of gastrointestinal endocrine cells immunoreactive for either serotonin, somatostatin, gastrin, motilin, secretin, gastric inhibitory polypeptide(GIP), neurotensin, enteroglucagon, bovine pancreatic polypeptide(BPP), avian pancreatic polypeptide(APP), polypeptide tyrosine tyrosine(PYY) or cholecystokinin(CCK) were examined. Four types of endocrine cells immunoreactive for serotonin, somatostatin, gastrin and enteroglucagon were found in the stomach. Moderate numbers of serotonin-immunoreative(IR) cells were found in the whole gastric mucosa, while numerous gastrin-IR cells and a few enteroglucagon-IR cells were restricted within the pyloric glands and the fundic glands, respectively. Somatostatin-IR cells were rare in the fundic glands and moderate numbers in the pyloric glands. In addition to these 4 types of endocrine cells, another 4 types of endocrine cells immunoreactive for motilin, secretin, GIP and neurotensin were also detected in the intestine. In the Brunner's glands, somatostatin- and gastrin-IR cells were found rarely, being not detected in every animal. No BPP-, APP-, PYY- and CCK-IR cells were detected.

View full abstract

Gross and morphometric studies were undertaken on 10 digestive tracts of the agouti(Dasyprocta leporina). The most prominent features included a long small intestine which had a mean length of 700.16±124 cm and formed 49.1±3.9 % of the total weight of the entire digestive tract. The large intestine had a large sacculated caecum which formed 16.8±4.11% of the total weight of the digestive tract. The colon and rectum had a mean length of 117.0±2.5 cm and formed 18.788±2.11 % of the total weight of the digestive tract. Large anal sac glands had openings into the anus. The histology of the different components of the digestive tract was done on a male agouti and the results suggested that the small intestine has a remarkable proliferation of villi;the epithelium is simple columnar. Numerous intestinal glands were located towards the base of the epithelium, and the glands had numerous globlet cells.

View full abstract

Some zoos in Japan killed many large animals providing against air raids during the Pacific War. Among the terrible history in zoo of Japan, the three Asian elephants in Ueno Zoo killed by Tokyo Metropolitan government office(Tokyo-to)have been symbolic in social respects of peace since the end of the War. We examined the records on the carcass of the elephants in detail and traced the existence of the specimens. And we applied the age determination methods to Asian elephant mandible stored in the University of Tokyo to distinguish the individual from the elephants killed in zoo. As a result, the specimens of these killed elephants have not been present in any university and museum, although the University of Tokyo and the National Science Museum were expected to store them. However, we could demonstrate how mammalian and veterinary researchers dealt these elephant carcasses.

View full abstract

Two newborn Small Asian mongooses on Okinawa had thin ash-white hair. Their eyes and ears were closed. Body weights of the male and the female at two days were 24 g and 27 g. The male opened its eyes on day 15, and the female on day 20. At two weeks, the outer hair, mottled with black and yellowish-white speckles, completely covered the juveniles. All milk teeth appeared by 28 days, and all permanent teeth had completely grown in by 126 days. The male weighed 958 g at 28 weeks, and the female 520 g. The mean daily body weight gain for each four-week period peaked at five to eight weeks. The daily body weight gain increased prior to eight weeks;however, the range of daily body weight gain and loss tended to widen after eight weeks. The daily body weight change was cyclical. The male body length continued to increase up to 28 weeks;the female continued growing up to around 24 weeks. At seven weeks, differences in the body shapes between the male and female were very much evident. The claws attained their adult form between six to eight weeks of age when sexual dimorphism begins to appear and feral mongooses are weaned. This stage is crucial for the mongoose, which morphologically and functionally undergoes a significant transformation from juvenile to adult.

View full abstract

Pulmonary mycosis of four domestic sika deer(Cervus nippon Temminck and Cervus elaphus)aged 1 to 2 weeks suffering from selenium deficiency(enzootic cardiomyopathy)were examined histopathologically, histochemically and by electron microscopy, From the morphological features of mycosis there were diagnosed aspergillosis in three cases and mucormycosis in one case. The pathologic reaction within lesions of aspergillus were dominated by granulomatous type with neutrophils, macrophages and giant cells, and mucor lesions were remarkable vasculitis with fungal thrombi. It is suggested that the atrophy of lymph follicules and decrease number of T lymphocytes in lymphatic organs is closely correlated with selenium deficiency and immunological disorders.

View full abstract

Some systematic pathological examinations of a dead domesticated crested ibis were carried out. Some characteristic pathological symptoms were found in liver and lung showing many tuberculosis-like features, being associated with liver cell degeneration, pneumon-congestion, pneumohemorrhagia, epithelium cells degeneration of tubuli tenales, interstitial hephritis, kidney hemorrhage and enteritis. Pathological examinations strongly indicated typical tuberculosis of Crested ibis. These pathological observations suggest some relationship between population size and survivability of captivated Crested ibis. The reason for these phenomena should be clarified in order to increase the number of this species in wild conditions.

View full abstract

Fifteen wild Japanese Black Bears, Ursus thibetanus japonicus, cought in cages for capture or wire traps, were immobilized intramuscularly with a combination of ketamine hydrochloride and xylazine hydrochloride in the bullet of blowgun or caputure rifle. Standard amount of the drug combination was assumed to be ketamine 10 mg/kg and xylazine 1.0 mg/kg in body weight 1 kg. The largest bear(a male)weighted 90 kg and the smallest bear(a female)weighted 26 kg. Actual drug dosages administered were ketamine 6.25 mg and xylazine 0.625 mg to ketamine 20.00 mg and xylazine 2.00 mg in body weight 1 kg. Immobilizing induction time were 3 to 11 minites. The total quantity of ketamine and xylazine solusion administered for each bears were 1.75(in a female weighted 26 kg) to 15 ml(in a male weighted 75 kg). Salivation and clonic spasm were slight in one bear, but the bear recovered without any treatment.

View full abstract

The morphology and size of Humboldt penguin spermatozoa have not been reported. This study the spermatozoa of Humboldt penguin were examined by scanning electron microscope and their dimensions were determined. The spermatozoa of Humboldt penguin were long, narrow, with gently curved head. As the result of measurement, the total length was 73.8±3.6 μm, head was 11.4±0.9 μm, acrosome was 1.1±0.2 μm, nucleus was 10.3±0.8 μm, midpiece was 2.8±0.2 μm and tail was 62.6±3.8 μm. respectively. The Humboldt penguin spermatozoa seemed to belong to the type of non-passerine birds. The spermatozoa size was slightly smaller than that of other species.

View full abstract

We did the pathological examination on two sea otters(11-year-old male and 7-year-old female)which were kept in an aquarium and died in association with prolonged anorexia and wastingness due to undetermined causes. One case showed focal myocardial degeneration, necrosis and fibrosis, and severe pulmonary edema due to congestion. Heart failure was considered to be responsible for the systemic congestive edema including lung. The other case showed marked fibrosis of the liver with degeneration and necrosis of hepatocytes;hepatic dysfunction was suspected to be the cause of death.

View full abstract

In Trinidad and Tobago, Wildlife is sold at higer prices than that of domestic animals. There could be some economic potential for the wildlife farmer. In 1990-91, 14 wildlife farms and 15 farmers were surveyed in Trinidad. Among those 8 were hobbyists, 2 were ordinary farmers, 3 were solely wildlife breeders and 2 were small bussiness farmers. The 11 farms were located in the rural parts of Trinidad. Four farms were located in sub-urban areas. Age structure of wildlife farmers were 3 in 21-30, 4 in 31-40, 5 in 41-50 and 3 in 51-60 years old. Most of the farms(13)reared agouti while two farms reared deer. The farmers sold the agouti meat for U.S.$7/kg in open season(October 1- March 31)and U.S.$10/kg in closed season(April 1-September 30). The vension(deer meat)was U.S.$10/kg in both seasons.

View full abstract