A fuzzy distinguishability on species composition similarities of pelagic fishes in different years in the southern Taiwan Strait

A fuzzy mathematical method is used to discriminate the similarities of pelagic fishes landed in the 9180 hauls by 10 light-seine information vessels in the southern Fujian waters from 1989 to 1998. The results indicate that the dominant species of the communities had an obvious alternation and the fuzzy adjacency of annual species composition varied between 0.659 and 0.923 with an average value of 0.791. The fuzzy clustering analysis indicates that the annual fuzzy adjacency in general remains good although the species composition of the pelagic fishes has changed to a certain degree since 1992. This paper concludes that the community structure of pelagic fishes in the southern Taiwan Strait remains relatively stable and the state of fish stocks shows a good potentiality for a larger utilization.