This study is a report on stranded marine mammals from the coasts of the Sea of Japan during the period of 1. Jan. 1999 and 30. Apr. 2000, with some emphasis on results of pathological investigations. Materials studied are five cetacean and two pinniped species, totaling thirtynine individuals. The results include pulmonary edema and enphysema, severe systemic congection or acute circulatory failure, some ulcer of stomach and focal fibrosis of kidney caused by parasites, severe emaciation and enlargement of certain lymph nodes. Many allotrylic materials are found in the first and the second chambers of stomach in six out of eleven Stejneger's beaked whales. This investigation is carried out by the National Sience Museum, Tokyo.

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　We analyzed 325 cetacean live stranding cases recorded in the ICR Stranding Database 001201. In large species, killer whale Orcinus orca, short-finned pilot whale Globicephala macrorhynchus, false killer whale Pseudorca crassidens and Cuvier's beaked whale Ziphius cavirostris showed high ratio of live stranding. In small species, striped dolphin Stenella coeruleoalba, spotted dolphin Stenella attenuate, Risso's dolphin Grampus griseus, common dolphin Delphinus delphis and Kogia sp. also showed high ratio of live stranding. Most of these species were thought to be species which evolved social structure and/or subtropical pelagic species. On the other hand, Pacific white-sided dolphin Lagenorhynchus obliquidens and finless porpoise Neophocaena phocaenoides rarely live stranded in spite of large number of stranding records. Survival time of stranded cetaceans seemed to be within 48 hours (2days). Survival rate of stranded cetaceans rescued and cared in aquariums suggested that most of the live stranded animals released to the sea might die, in spite of rescue effort. Case study of a live stranding of a sperm whale Physeter macrocephalus in April 2000 suggested that 1) official conduct with support of whale scientists was important in the rescue of large species, 2) euthanasia of stranded whales should be considered for humane treatment.

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　Following histological analysis, a piece of bone jammed in the intake pipe of a jetfoil (rapid-transit hydrofoil) which had struck an unknown object, was identified as part of a rib of a marine mammal, probably a small-sized species of odontoceti. A young male Pacific white-sided dolphin stranded on the coast of Kashiwazaki, near Niigata, had a quiescent thyroid gland condition, although the histological architecture revealed considerable postmortem dissociation of glandular tissues. In addition, the seminiferous tubules of the specimen were occupied by numerous A-type spermatogonia and a few only B-type spermatogonia. No clearly-defined internal cavities were detected in the tubules. A young male harbor seal (with a signet ring cell carcinoma in the stomach and lymphoid adenocarcinoma) was stranded on the coast of Kurobe City, Toyama Bay. Its testis, containing both A- and B-type spermatogonia, in addition to a few primary spermatocytes, were immature, the oval seminiferous tubules having no well-defined internal cavities. Moreover, the interstitial (Leydig) cells were in an undifferentiated state.

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The Northwest Coast Indians living along the Pacific Coast from Southeastern Alaska, British Columbia to Washington,are hunters-gatherers who traditionally depended greatly upon marine resources for food. Indians of this area categorised killer whales (Orcinus Orca) into two types, resident killer whales and transient killer whales. Resident killer whales range in Discovery Passage during the summer, and eat fish there. Discovery Passages corresponds to the summer range of resident killer whales, “tribal” boundaries, as well as watershed and tree community boundaries. Transient killer whales, eating primarily marine mammals, are observed on the Pacific (west) west side of Vancourver Island. In this paper, I will compare observations of people on the east-side of Vancouver Island with those of people on the west-side of Vancouver Island. The Kwakwaka'wakw people live along Discovery passage, on the east-side of Vancouver Island and the main land. They observe resident killer whales every summer. Transient killer whales sometimes pass through Discovery Pass, and are considered as gods of longevity for Kwakwaka'wakw. The Nuu-chah-nulth People live along Pacific, or west-side of Vancouver Island. They observe transient killer whales throughout the year, and resident killer whales during the summer. They were a whaling people hunting grey whales in the Pacific. Transient killer whales catch small marine mammals in both Discovery Passage and the Pacific. But they catch whales only in the Pacific. Wolves, a special category among all animals for Nuu-chah-nulth people, are believed to be killer whales that emerged from the sea to live on the land. The impression held by peoples of the east and west coasts of Vancouver Island differ because: 1.The different types of killer whales (resident and transient) observed. 2.The Kwakwaka'waku are primarily salmon fishers with whom the killer whales compete, while the Nuu-chag-nulth are whalers. The Kwakwaka'waku are salmon fishers who depend largely upon the late summer to fall salmon run in the Discovery Passage. Resident killer whales also congregate in the Discovery passage at the same time to eat salmon. The Nuu-chag-nulth also are fishers but depend more on large whales. Thus, both humans, the most powerful land-based predators, and killer whales, the most powerful aquatic predators, both depend upon marine resources. In other words, both humans and killer whales take food from the ocean on the east and west sides of Vancouver Island.

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Many fossil cetaceans have been yielded from the Neogene marine sediments distributed in Yamagata Prefecture. More than one hundred fossil records were accumulated from the area so far. However most of those were partial bones and there were very few complete skeletons. Some fossils were important parts of skeleton for taxonomy. Some of features of the fossil records from the area were summarized as follows: The fossils dated back to approximately fifteen to two million years ago in the Neogene period. The number of fossil cetaceans in the area increased chronologically from the Late Miocene period through the Early Pliocene period and decreased suddenly in the Late Pliocene period. The most abundant fossil cetaceans were obtained from the Early Pliocene clastic rocks in the Shinjo Basin in the northern part of Yamagata Prefecture. Few fossils were found from the Ou Backbone Range area which runs along the eastern margin of Yamagata Prefecture from the north to the south. Some specimens were taxonomically examined and were identified as the following taxa: families of Physeteridae, Ziphiidae, Delphinidae, Balaenidae and Balaenopteridae, and genuses of Scaldicetus, Mesoplodon, Orcinus, Balaena, Balaenoptera and Megaptera.

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