MARKOV-CHAIN PROPERTIES RELATED TO TEMPORAL DOMINANCE CHANGES IN A PHILIPPINE PELAGIC FISHERY

Changes in the dominance order of pelagic fish assemblages exploited b y purse seine in the Philippines were studied based on a simple Markov chain model. Dominance order was classified using six assemblage grou ps (dominant families of fishes) at various sampling intervals. Result s of analyses indicated that transition probabilities from the various regular sampling intervals were reasonably similar. Limiting probabil ities for the various groups suggested ultimate replacement of the lar ger pelagic species with the family Clupeidae. Entropy values, calcula ted with respect to rows and columns of a transition probability matri x, were interpreted as providing predictions of short-term changes in dominance order. The model output was judged to be compatible with cur rent observational information on temporal changes in highly exploited multispecies fisheries.