The meso- and benthopelagic faunas of Sagami Bay, Japan, were examined using 8 submersible dives over a one month period in May-June, 1997. An observational database containing 3041 records was created using a methodology which conservatively identified each animal observed to the most precise taxon possible. This database was used to elicit information on 75 discrete taxa. Thirteen species were new reports from Japanese waters, including 2 siphonophores, 6 medusae, 4 ctenophores, and 1 appendicularian. A review of relevant literature suggested more precise identification for some taxa. The utility of creating this kind of database was demonstrated through examples regarding trophic ecology, life history, and the effects of the type of submersible used to study pelagic species. Notes on the behavior of some specimens and a complete taxa list are presented.