Eastern Tropical Pacific Dolphin Habitats: Interannual Variability, 1986-2000

摘要

We examined patterns of habitat use among schools of dolphins in the eastern tropical Pacific during the three-year period 1998, 1999, 2000, and compared those patterns to previously reported results from approximately a decade earlier (1986-1990). We used canonical correspondence analysis (CCA) to help define relationships between dolphin distributions and oceanographic conditions, compared CCA models, and the geographic distributions of preferred habitats between the two periods. When using a common set of six basic oceanographic variables the habitat models were essentially the same for the MOPS and STAR periods, and geographic distributions of patterns during 1998-2000 were within the same range of interannual variability observed during 1986-1990. After removing variation associated with the six basic oceanographic variables, remaining variance associated with inter-decadal differences was trivial. Improvements to the ordination were realized by including information on geographic locations, separating common dolphins into three stocks, and by including additional explanatory variables representing seabirds, fishes and cephalopods.