It is important to understand the characteristics of fishing conditions for each fishing ground in the Seisyou region of Sagami Bay in order to explain the mechanism of catch fluctuation. Species compositions of the catch by six large-sized set-nets were analyzed by principal component analysis.
The Seisyou region of Sagami Bay was thus characterized by two principal components. The first principal component has positive correlations among all fishing grounds, and therefore seems to be a size factor. The second principal component has both positive and negative correlations among the Seisyou region, and therefore seems to be the degree of local polarization. The principal component tends to have a higher score for dominant species: black scraper, mackerel, sardine, horse mackerel, frigate mackerel.
