Exploratory data analysis using four different techniques of classification and ordination was applied
to the catch data from a 15-month demersal trawl survey in Ragay Gulf, Philippines, in order to
characterize the area. The four techniques yield almost identical results and therefore lend confidence
to the three subareas identified: shallow, coralline and deep. Species characteristic of the subareas were
also identified. The observed pattern remained consistent during the study period, suggesting that
seasonal variability is not pronounced.
This study provides further empirical evidence of the zonation of fish communities by depth.
Preliminary comparison of the results of this study with those of studies of demersal fish community
assemblages in the Samar Sea shows that boundary depths defining zonation are different in the two
areas because of their different depth ranges and spatial scales. This comparison leads to the question
of whether the boundary depths as identified via classification and ordination methods could be a
function of the shape of the depth distribution of the samples. The use of a bootstrapping method to
investigate this question is suggested. The importance of applying exploratory data analysis to the catch
data from a demersal trawl survey done to assess fish stocks is also discussed.
Effects of Shoreline Urbanization on Littoral Fish Assemblages