The fish of Lake Biwa were a product of nature, arising and evolving through a very long period before coming under the influence of various human activities. A stable interrelationship between human beings and fish built up over several thousand years, but the relationship has been breaking up recently. The condition of fish fauna in Lake Biwa has changed greatly due to the great and rapid expansion of human activities. The littoral zone of Lake Biwa is now overwhelmed by introduced fish, and the native fish have decreased markedly in number there. Some native fish in Lake Biwa are facing the crisis of extinction. People are ceasing to take interest in their everyday environment and in the local fish. However, we can still see native fish in the canals that feed and drain the paddy fields surrounding Lake Biwa. The conservation of Lake Biwa is not a problem only of water quality, but also of conserving the living beings that inhabit those waters. For the conservation of Lake Biwa, it is thus necessary for many people to redevelop an interest in their local environment and such formerly familiar organisms as the native fish.

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 In 1991 and 2000, many footprint fossils of proboscids and artiodactyls were discovered at the upper part of the Onma Formation (0.9-0.8Ma) exposed in the riverbed of the Saikawa River, Kanazawa, Ishikawa Prefecture, central Japan. Okuwa Fossil Footprint Research Group was formed to research these fossils, and the field investigation was performed in 2001.
 The field investigation discovered approximately 100 proboscid and 50 artiodactyl footprint fossils in the study area. Though this research, including geological studies, is still underway, we have reached several conclusions regarding these footprint fossils, and we herein provide an outline of our findings.
 Most proboscid footprint fossils are about 30cm in both length, and about10cm in depth. Two types of artiodactyl footprints were observed in this area. One is rare; the tip of the footprint is sharp and the main slot is of an elongate lanceolate form. The second type is abundant; the tip of the footprint is round and the main slot is of an elongate kidney form. The latter was compared with footprints and hooves of fifty-seven extant artiodactylids and was identified as footprints of a member of the genus Elaphurus by the shape and size.
 At the geological time in which the footprints were discovered, Elaphurus shikamai is known to have occurred, and it is therefore the most probable that these footprints are of this species.

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 The relationship between the height of tooth crown (CH) and total body length (TL) in the modern sandtiger shark, Carcharias taurus Rafinesque (Lamniformes: Odontaspididae) is examined using regression analyses. The results suggest: 1) that an increase in the CH of each tooth through replacement is proportional to the increase in the TL, 2) that the CH can be used to predict the TL, and 3) that distally located teeth develop faster through replacement compared to mesially located teeth. The quantitative dental data presented here can be used to infer the TL for modern Carcharias jaws without specimen data and for fossil odontaspidid individuals.

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