DISTRIBUTION FIELDS FOR AQUATIC ECOSYSTEM COMPONENTS - METHOD OF IDENTIFICATION OF CORRELATION ZONES

1. Data from the two multidisciplinary surveys of Lake Kinneret (Israe l), including acoustic surveys of fish concentrations and concurrent s ampling of plankton at stations, were used to reconstruct fish and pla nkton distributions. No significant lake-wide correlations for the dis tribution fields were found. With respect to patchiness of the fish an d plankton distributions, we hypothesized that they might be correlate d in localized zones. 2. A method is suggested for the identification of areas where there are strong correlations of two distribution field s. The method is based on outlining zones where the gradients of the t wo fields of interest are in the same direction (or are opposite). Onl y areas larger than the autocorrelation circles (or ellipses) for the fields are considered. The correlation of the fields is calculated for each of the zones selected. 3. The method was used in analysing data from the multidisciplinary surveys. We were able to detect areas of th e lake where there were correlations for fish and plankton distributio ns. Analysis of specific conditions inside the correlation zones made it possible to construct hypotheses concerning the causes for the obse rved patterns of fish and plankton distributions.