The similarities appearing in species composition of set-net catch was examined to explicate the mechanism of catch fluctuation by using the cluster analysis on the six fishing grounds in the Seisyou region of Sagami Bay. The Seisyou region is located in the Western Sagami Bay.
As a result of similarities in species composition by cluster analysis, there is characterized for the tendency of dominant species catches, and then the similarities of set-net fishing grounds are classified by the five patterns. The yearly fluctuations of similarities varies in a short span of several years, influenced by species composition for each year. Further, the trend of Seisyou region is generally classified by Koyawata and Umezawa fishing grounds.
